/*!
 * \file rtklib_rtcm3.cc
 * \brief RTCM functions for v3
 * \authors <ul>
 *          <li> 2007-2013, T. Takasu
 *          <li> 2017, Javier Arribas
 *          <li> 2017, Carles Fernandez
 *          </ul>
 *
 * This is a derived work from RTKLIB http://www.rtklib.com/
 * The original source code at https://github.com/tomojitakasu/RTKLIB is
 * released under the BSD 2-clause license with an additional exclusive clause
 * that does not apply here. This additional clause is reproduced below:
 *
 * " The software package includes some companion executive binaries or shared
 * libraries necessary to execute APs on Windows. These licenses succeed to the
 * original ones of these software. "
 *
 * Neither the executive binaries nor the shared libraries are required by, used
 * or included in GNSS-SDR.
 *
 * -------------------------------------------------------------------------
 * Copyright (C) 2007-2013, T. Takasu
 * Copyright (C) 2017, Javier Arribas
 * Copyright (C) 2017, Carles Fernandez
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 *
 *----------------------------------------------------------------------------*/


#include "rtklib_rtcm3.h"
#include "rtklib_rtkcmn.h"




/* get sign-magnitude bits ---------------------------------------------------*/
double getbitg(const unsigned char *buff, int pos, int len)
{
    double value = getbitu(buff, pos+1, len-1);
    return getbitu(buff, pos, 1) ? -value : value;
}


/* adjust weekly rollover of gps time ----------------------------------------*/
void adjweek(rtcm_t *rtcm, double tow)
{
    double tow_p;
    int week;

    /* if no time, get cpu time */
    if (rtcm->time.time == 0) rtcm->time = utc2gpst(timeget());
    tow_p = time2gpst(rtcm->time, &week);
    if      (tow < tow_p-302400.0) tow += 604800.0;
    else if (tow > tow_p+302400.0) tow -= 604800.0;
    rtcm->time = gpst2time(week, tow);
}


/* adjust weekly rollover of bdt time ----------------------------------------*/
int adjbdtweek(int week)
{
    int w;
    (void)time2bdt(gpst2bdt(utc2gpst(timeget())), &w);
    if (w < 1) w = 1; /* use 2006/1/1 if time is earlier than 2006/1/1 */
    return week+(w-week+512)/1024*1024;
}


/* adjust daily rollover of glonass time -------------------------------------*/
void adjday_glot(rtcm_t *rtcm, double tod)
{
    gtime_t time;
    double tow, tod_p;
    int week;

    if (rtcm->time.time == 0) rtcm->time = utc2gpst(timeget());
    time = timeadd(gpst2utc(rtcm->time), 10800.0); /* glonass time */
    tow = time2gpst(time, &week);
    tod_p = fmod(tow, 86400.0); tow -= tod_p;
    if      (tod < tod_p-43200.0) tod += 86400.0;
    else if (tod > tod_p+43200.0) tod -= 86400.0;
    time = gpst2time(week, tow+tod);
    rtcm->time = utc2gpst(timeadd(time, -10800.0));
}


/* adjust carrier-phase rollover ---------------------------------------------*/
double adjcp(rtcm_t *rtcm, int sat, int freq, double cp)
{
    if (rtcm->cp[sat-1][freq] == 0.0) ;
    else if (cp < rtcm->cp[sat-1][freq]-750.0) cp += 1500.0;
    else if (cp > rtcm->cp[sat-1][freq]+750.0) cp -= 1500.0;
    rtcm->cp[sat-1][freq] = cp;
    return cp;
}


/* loss-of-lock indicator ----------------------------------------------------*/
int lossoflock(rtcm_t *rtcm, int sat, int freq, int lock)
{
    int lli = (!lock && !rtcm->lock[sat-1][freq]) || lock < rtcm->lock[sat-1][freq];
    rtcm->lock[sat-1][freq] = (unsigned short)lock;
    return lli;
}


/* s/n ratio -----------------------------------------------------------------*/
unsigned char snratio(double snr)
{
    return (unsigned char)(snr <= 0.0 || 255.5 <= snr ? 0.0:snr*4.0+0.5);
}


/* get observation data index ------------------------------------------------*/
int obsindex(obs_t *obs, gtime_t time, int sat)
{
    int i, j;

    for (i = 0; i < obs->n; i++)
        {
            if (obs->data[i].sat == sat) return i; /* field already exists */
        }
    if (i >= MAXOBS) return -1; /* overflow */

    /* add new field */
    obs->data[i].time = time;
    obs->data[i].sat = sat;
    for (j = 0; j < NFREQ+NEXOBS; j++)
        {
            obs->data[i].L[j] = obs->data[i].P[j] = 0.0;
            obs->data[i].D[j] = 0.0;
            obs->data[i].SNR[j] = obs->data[i].LLI[j] = obs->data[i].code[j] = 0;
        }
    obs->n++;
    return i;
}


/* test station id consistency -----------------------------------------------*/
int test_staid(rtcm_t *rtcm, int staid)
{
    char *p;
    int type, id;

    /* test station id option */
    if ((p = strstr(rtcm->opt, "-STA=")) && sscanf(p, "-STA=%d", &id) == 1)
        {
            if (staid != id) return 0;
        }
    /* save station id */
    if (rtcm->staid == 0 || rtcm->obsflag)
        {
            rtcm->staid = staid;
        }
    else if (staid != rtcm->staid)
        {
            type = getbitu(rtcm->buff, 24, 12);
            trace(2, "rtcm3 %d staid invalid id=%d %d\n", type, staid, rtcm->staid);

            /* reset station id if station id error */
            rtcm->staid = 0;
            return 0;
        }
    return 1;
}


/* decode type 1001-1004 message header --------------------------------------*/
int decode_head1001(rtcm_t *rtcm, int *sync)
{
    double tow;
    char *msg;
    int i = 24, staid, nsat, type;

    type = getbitu(rtcm->buff, i, 12); i += 12;

    if (i+52 <= rtcm->len*8)
        {
            staid = getbitu(rtcm->buff, i, 12);       i += 12;
            tow   = getbitu(rtcm->buff, i, 30)*0.001; i += 30;
            *sync = getbitu(rtcm->buff, i, 1);        i +=  1;
            nsat  = getbitu(rtcm->buff, i, 5);
        }
    else
        {
            trace(2, "rtcm3 %d length error: len=%d\n", type, rtcm->len);
            return -1;
        }
    /* test station id */
    if (!test_staid(rtcm, staid)) return -1;

    adjweek(rtcm, tow);

    trace(4, "decode_head1001: time=%s nsat=%d sync=%d\n", time_str(rtcm->time, 2),
            nsat, *sync);

    if (rtcm->outtype)
        {
            msg = rtcm->msgtype+strlen(rtcm->msgtype);
            sprintf(msg, " staid=%4d %s nsat=%2d sync=%d", staid,
                    time_str(rtcm->time, 2), nsat, *sync);
        }
    return nsat;
}


/* decode type 1001: L1-only gps rtk observation -----------------------------*/
int decode_type1001(rtcm_t *rtcm)
{
    int sync;
    if (decode_head1001(rtcm, &sync) < 0) return -1;
    rtcm->obsflag=!sync;
    return sync ? 0:1;
}


/* decode type 1002: extended L1-only gps rtk observables --------------------*/
int decode_type1002(rtcm_t *rtcm)
{
    double pr1, cnr1, tt, cp1;
    int i = 24+64, j, index, nsat, sync, prn, code, sat, ppr1, lock1, amb, sys;

    if ((nsat = decode_head1001(rtcm, &sync)) < 0) return -1;

    for (j = 0; j < nsat && rtcm->obs.n < MAXOBS && i+74 <= rtcm->len*8; j++)
        {
            prn   = getbitu(rtcm->buff, i, 6);  i +=  6;
            code  = getbitu(rtcm->buff, i, 1);  i +=  1;
            pr1   = getbitu(rtcm->buff, i, 24); i += 24;
            ppr1  = getbits(rtcm->buff, i, 20); i += 20;
            lock1 = getbitu(rtcm->buff, i, 7);  i +=  7;
            amb   = getbitu(rtcm->buff, i, 8);  i +=  8;
            cnr1  = getbitu(rtcm->buff, i, 8);  i +=  8;
            if (prn < 40)
                {
                    sys = SYS_GPS;
                }
            else
                {
                    sys = SYS_SBS; prn += 80;
                }
            if (!(sat = satno(sys, prn)))
                {
                    trace(2, "rtcm3 1002 satellite number error: prn=%d\n", prn);
                    continue;
                }
            tt = timediff(rtcm->obs.data[0].time, rtcm->time);
            if (rtcm->obsflag || fabs(tt)>1E-9)
                {
                    rtcm->obs.n = rtcm->obsflag = 0;
                }
            if ((index = obsindex(&rtcm->obs, rtcm->time, sat)) < 0) continue;
            pr1 = pr1*0.02+amb*PRUNIT_GPS;
            if (ppr1 != (int)0xFFF80000)
                {
                    rtcm->obs.data[index].P[0] = pr1;
                    cp1 = adjcp(rtcm, sat, 0, ppr1*0.0005/lam_carr[0]);
                    rtcm->obs.data[index].L[0] = pr1/lam_carr[0]+cp1;
                }
            rtcm->obs.data[index].LLI[0] = lossoflock(rtcm, sat, 0, lock1);
            rtcm->obs.data[index].SNR[0] = snratio(cnr1*0.25);
            rtcm->obs.data[index].code[0] = code ? CODE_L1P:CODE_L1C;
        }
    return sync ? 0:1;
}


/* decode type 1003: L1&L2 gps rtk observables -------------------------------*/
int decode_type1003(rtcm_t *rtcm)
{
    int sync;
    if (decode_head1001(rtcm, &sync) < 0) return -1;
    rtcm->obsflag = !sync;
    return sync ? 0:1;
}


/* decode type 1004: extended L1&L2 gps rtk observables ----------------------*/
int decode_type1004(rtcm_t *rtcm)
{
    const int L2codes[] = {CODE_L2X, CODE_L2P, CODE_L2D, CODE_L2W};
    double pr1, cnr1, cnr2, tt, cp1, cp2;
    int i = 24+64, j, index, nsat, sync, prn, sat, code1, code2, pr21, ppr1, ppr2;
    int lock1, lock2, amb, sys;

    if ((nsat = decode_head1001(rtcm, &sync)) < 0) return -1;

    for (j = 0; j < nsat && rtcm->obs.n < MAXOBS && i+125 <= rtcm->len*8; j++)
        {
            prn   = getbitu(rtcm->buff, i, 6);  i +=  6;
            code1 = getbitu(rtcm->buff, i, 1);  i +=  1;
            pr1   = getbitu(rtcm->buff, i, 24); i += 24;
            ppr1  = getbits(rtcm->buff, i, 20); i += 20;
            lock1 = getbitu(rtcm->buff, i, 7);  i +=  7;
            amb   = getbitu(rtcm->buff, i, 8);  i +=  8;
            cnr1  = getbitu(rtcm->buff, i, 8);  i +=  8;
            code2 = getbitu(rtcm->buff, i, 2);  i +=  2;
            pr21  = getbits(rtcm->buff, i, 14); i += 14;
            ppr2  = getbits(rtcm->buff, i, 20); i += 20;
            lock2 = getbitu(rtcm->buff, i, 7);  i +=  7;
            cnr2  = getbitu(rtcm->buff, i, 8);  i +=  8;
            if (prn < 40)
                {
                    sys = SYS_GPS;
                }
            else
                {
                    sys = SYS_SBS; prn += 80;
                }
            if (!(sat = satno(sys, prn)))
                {
                    trace(2, "rtcm3 1004 satellite number error: sys=%d prn=%d\n", sys, prn);
                    continue;
                }
            tt = timediff(rtcm->obs.data[0].time, rtcm->time);
            if (rtcm->obsflag || fabs(tt)>1E-9)
                {
                    rtcm->obs.n = rtcm->obsflag = 0;
                }
            if ((index = obsindex(&rtcm->obs, rtcm->time, sat)) < 0) continue;
            pr1 = pr1*0.02+amb*PRUNIT_GPS;
            if (ppr1 != (int)0xFFF80000)
                {
                    rtcm->obs.data[index].P[0] = pr1;
                    cp1 = adjcp(rtcm, sat, 0, ppr1*0.0005/lam_carr[0]);
                    rtcm->obs.data[index].L[0] = pr1/lam_carr[0]+cp1;
                }
            rtcm->obs.data[index].LLI[0] = lossoflock(rtcm, sat, 0, lock1);
            rtcm->obs.data[index].SNR[0] = snratio(cnr1*0.25);
            rtcm->obs.data[index].code[0] = code1 ? CODE_L1P:CODE_L1C;

            if (pr21 != (int)0xFFFFE000)
                {
                    rtcm->obs.data[index].P[1] = pr1+pr21*0.02;
                }
            if (ppr2 != (int)0xFFF80000)
                {
                    cp2 = adjcp(rtcm, sat, 1, ppr2*0.0005/lam_carr[1]);
                    rtcm->obs.data[index].L[1] = pr1/lam_carr[1]+cp2;
                }
            rtcm->obs.data[index].LLI[1] = lossoflock(rtcm, sat, 1, lock2);
            rtcm->obs.data[index].SNR[1] = snratio(cnr2*0.25);
            rtcm->obs.data[index].code[1] = L2codes[code2];
        }
    rtcm->obsflag = !sync;
    return sync ? 0:1;
}


/* get signed 38bit field ----------------------------------------------------*/
double getbits_38(const unsigned char *buff, int pos)
{
    return (double)getbits(buff, pos, 32)*64.0+getbitu(buff, pos+32, 6);
}


/* decode type 1005: stationary rtk reference station arp --------------------*/
int decode_type1005(rtcm_t *rtcm)
{
    double rr[3], re[3], pos[3];
    char *msg;
    int i = 24+12, j, staid, itrf;

    if (i+140 == rtcm->len*8)
        {
            staid = getbitu(rtcm->buff, i, 12); i += 12;
            itrf  = getbitu(rtcm->buff, i, 6); i +=  6+4;
            rr[0] = getbits_38(rtcm->buff, i); i += 38+2;
            rr[1] = getbits_38(rtcm->buff, i); i += 38+2;
            rr[2] = getbits_38(rtcm->buff, i);
        }
    else
        {
            trace(2, "rtcm3 1005 length error: len=%d\n", rtcm->len);
            return -1;
        }
    if (rtcm->outtype)
        {
            msg = rtcm->msgtype+strlen(rtcm->msgtype);
            for (j = 0; j < 3; j++) re[j] = rr[j]*0.0001;
            ecef2pos(re, pos);
            sprintf(msg, " staid=%4d pos=%.8f %.8f %.3f", staid, pos[0]*R2D, pos[1]*R2D,
                    pos[2]);
        }
    /* test station id */
    if (!test_staid(rtcm, staid)) return -1;

    rtcm->sta.deltype = 0; /* xyz */
    for (j = 0; j < 3; j++)
        {
            rtcm->sta.pos[j] = rr[j]*0.0001;
            rtcm->sta.del[j] = 0.0;
        }
    rtcm->sta.hgt = 0.0;
    rtcm->sta.itrf = itrf;
    return 5;
}


/* decode type 1006: stationary rtk reference station arp with height --------*/
int decode_type1006(rtcm_t *rtcm)
{
    double rr[3], re[3], pos[3], anth;
    char *msg;
    int i = 24+12, j, staid, itrf;

    if (i+156 <= rtcm->len*8)
        {
            staid = getbitu(rtcm->buff, i, 12); i += 12;
            itrf  = getbitu(rtcm->buff, i, 6); i +=  6+4;
            rr[0] = getbits_38(rtcm->buff, i); i += 38+2;
            rr[1] = getbits_38(rtcm->buff, i); i += 38+2;
            rr[2] = getbits_38(rtcm->buff, i); i += 38;
            anth  = getbitu(rtcm->buff, i, 16);
        }
    else
        {
            trace(2, "rtcm3 1006 length error: len=%d\n", rtcm->len);
            return -1;
        }
    if (rtcm->outtype)
        {
            msg = rtcm->msgtype+strlen(rtcm->msgtype);
            for (j = 0; j < 3; j++) re[j] = rr[j]*0.0001;
            ecef2pos(re, pos);
            sprintf(msg, " staid=%4d pos=%.8f %.8f %.3f anth=%.3f", staid, pos[0]*R2D,
                    pos[1]*R2D, pos[2], anth);
        }
    /* test station id */
    if (!test_staid(rtcm, staid)) return -1;

    rtcm->sta.deltype = 1; /* xyz */
    for (j = 0; j < 3; j++)
        {
            rtcm->sta.pos[j] = rr[j]*0.0001;
            rtcm->sta.del[j] = 0.0;
        }
    rtcm->sta.hgt = anth*0.0001;
    rtcm->sta.itrf = itrf;
    return 5;
}


/* decode type 1007: antenna descriptor --------------------------------------*/
int decode_type1007(rtcm_t *rtcm)
{
    char des[32] = "";
    char *msg;
    int i = 24+12, j, staid, n, setup;

    n = getbitu(rtcm->buff, i+12, 8);

    if (i+28+8*n <= rtcm->len*8)
        {
            staid = getbitu(rtcm->buff, i, 12); i += 12+8;
            for (j = 0; j < n && j < 31; j++)
                {
                    des[j] = (char)getbitu(rtcm->buff, i, 8); i += 8;
                }
            setup = getbitu(rtcm->buff, i, 8);
        }
    else
        {
            trace(2, "rtcm3 1007 length error: len=%d\n", rtcm->len);
            return -1;
        }
    if (rtcm->outtype)
        {
            msg = rtcm->msgtype+strlen(rtcm->msgtype);
            sprintf(msg, " staid=%4d", staid);
        }
    /* test station id */
    if (!test_staid(rtcm, staid)) return -1;

    strncpy(rtcm->sta.antdes, des, n); rtcm->sta.antdes[n] = '\0';
    rtcm->sta.antsetup = setup;
    rtcm->sta.antsno[0] = '\0';
    return 5;
}


/* decode type 1008: antenna descriptor & serial number ----------------------*/
int decode_type1008(rtcm_t *rtcm)
{
    char des[32] = "", sno[32] = "";
    char *msg;
    int i = 24+12, j, staid, n, m, setup;

    n = getbitu(rtcm->buff, i+12, 8);
    m = getbitu(rtcm->buff, i+28+8*n, 8);

    if (i+36+8*(n+m) <= rtcm->len*8)
        {
            staid = getbitu(rtcm->buff, i, 12); i += 12+8;
            for (j = 0; j < n && j < 31; j++)
                {
                    des[j] = (char)getbitu(rtcm->buff, i, 8); i += 8;
                }
            setup = getbitu(rtcm->buff, i, 8); i += 8+8;
            for (j = 0; j < m && j < 31; j++)
                {
                    sno[j] = (char)getbitu(rtcm->buff, i, 8); i += 8;
                }
        }
    else
        {
            trace(2, "rtcm3 1008 length error: len=%d\n", rtcm->len);
            return -1;
        }
    if (rtcm->outtype)
        {
            msg = rtcm->msgtype+strlen(rtcm->msgtype);
            sprintf(msg, " staid=%4d", staid);
        }
    /* test station id */
    if (!test_staid(rtcm, staid)) return -1;

    strncpy(rtcm->sta.antdes, des, n); rtcm->sta.antdes[n] = '\0';
    rtcm->sta.antsetup = setup;
    strncpy(rtcm->sta.antsno, sno, m); rtcm->sta.antsno[m] = '\0';
    return 5;
}


/* decode type 1009-1012 message header --------------------------------------*/
int decode_head1009(rtcm_t *rtcm, int *sync)
{
    double tod;
    char *msg;
    int i = 24, staid, nsat, type;

    type = getbitu(rtcm->buff, i, 12); i += 12;

    if (i+49 <= rtcm->len*8)
        {
            staid = getbitu(rtcm->buff, i, 12);       i += 12;
            tod   = getbitu(rtcm->buff, i, 27)*0.001; i += 27; /* sec in a day */
            *sync = getbitu(rtcm->buff, i, 1);       i +=  1;
            nsat  = getbitu(rtcm->buff, i, 5);
        }
    else
        {
            trace(2, "rtcm3 %d length error: len=%d\n", type, rtcm->len);
            return -1;
        }
    /* test station id */
    if (!test_staid(rtcm, staid)) return -1;

    adjday_glot(rtcm, tod);

    trace(4, "decode_head1009: time=%s nsat=%d sync=%d\n", time_str(rtcm->time, 2),
            nsat, *sync);

    if (rtcm->outtype)
        {
            msg = rtcm->msgtype+strlen(rtcm->msgtype);
            sprintf(msg, " staid=%4d %s nsat=%2d sync=%d", staid,
                    time_str(rtcm->time, 2), nsat, *sync);
        }
    return nsat;
}


/* decode type 1009: L1-only glonass rtk observables -------------------------*/
int decode_type1009(rtcm_t *rtcm)
{
    int sync;
    if (decode_head1009(rtcm, &sync) < 0) return -1;
    rtcm->obsflag = !sync;
    return sync ? 0:1;
}


/* decode type 1010: extended L1-only glonass rtk observables ----------------*/
int decode_type1010(rtcm_t *rtcm)
{
    double pr1, cnr1, tt, cp1, lam1;
    int i = 24+61, j, index, nsat, sync, prn, sat, code, freq, ppr1, lock1, amb, sys = SYS_GLO;

    if ((nsat = decode_head1009(rtcm, &sync)) < 0) return -1;

    for (j = 0; j < nsat && rtcm->obs.n < MAXOBS && i+79 <= rtcm->len*8; j++)
        {
            prn   = getbitu(rtcm->buff, i, 6); i +=  6;
            code  = getbitu(rtcm->buff, i, 1); i +=  1;
            freq  = getbitu(rtcm->buff, i, 5); i +=  5;
            pr1   = getbitu(rtcm->buff, i, 25); i += 25;
            ppr1  = getbits(rtcm->buff, i, 20); i += 20;
            lock1 = getbitu(rtcm->buff, i, 7); i +=  7;
            amb   = getbitu(rtcm->buff, i, 7); i +=  7;
            cnr1  = getbitu(rtcm->buff, i, 8); i +=  8;
            if (!(sat = satno(sys, prn)))
                {
                    trace(2, "rtcm3 1010 satellite number error: prn=%d\n", prn);
                    continue;
                }
            tt = timediff(rtcm->obs.data[0].time, rtcm->time);
            if (rtcm->obsflag || fabs(tt)>1E-9)
                {
                    rtcm->obs.n = rtcm->obsflag = 0;
                }
            if ((index = obsindex(&rtcm->obs, rtcm->time, sat)) < 0) continue;
            pr1 = pr1*0.02+amb*PRUNIT_GLO;
            if (ppr1 != (int)0xFFF80000)
                {
                    rtcm->obs.data[index].P[0] = pr1;
                    lam1 = SPEED_OF_LIGHT/(FREQ1_GLO+DFRQ1_GLO*(freq-7));
                    cp1 = adjcp(rtcm, sat, 0, ppr1*0.0005/lam1);
                    rtcm->obs.data[index].L[0] = pr1/lam1+cp1;
                }
            rtcm->obs.data[index].LLI[0] = lossoflock(rtcm, sat, 0, lock1);
            rtcm->obs.data[index].SNR[0] = snratio(cnr1*0.25);
            rtcm->obs.data[index].code[0] = code ? CODE_L1P:CODE_L1C;
        }
    return sync ? 0:1;
}


/* decode type 1011: L1&L2 glonass rtk observables ---------------------------*/
int decode_type1011(rtcm_t *rtcm)
{
    int sync;
    if (decode_head1009(rtcm, &sync) < 0) return -1;
    rtcm->obsflag = !sync;
    return sync ? 0:1;
}


/* decode type 1012: extended L1&L2 glonass rtk observables ------------------*/
int decode_type1012(rtcm_t *rtcm)
{
    double pr1, cnr1, cnr2, tt, cp1, cp2, lam1, lam2;
    int i = 24+61, j, index, nsat, sync, prn, sat, freq, code1, code2, pr21, ppr1, ppr2;
    int lock1, lock2, amb, sys = SYS_GLO;

    if ((nsat = decode_head1009(rtcm, &sync)) < 0) return -1;

    for (j = 0; j < nsat && rtcm->obs.n < MAXOBS && i+130 <= rtcm->len*8; j++)
        {
            prn   = getbitu(rtcm->buff, i, 6); i +=  6;
            code1 = getbitu(rtcm->buff, i, 1); i +=  1;
            freq  = getbitu(rtcm->buff, i, 5); i +=  5;
            pr1   = getbitu(rtcm->buff, i, 25); i += 25;
            ppr1  = getbits(rtcm->buff, i, 20); i += 20;
            lock1 = getbitu(rtcm->buff, i, 7); i +=  7;
            amb   = getbitu(rtcm->buff, i, 7); i +=  7;
            cnr1  = getbitu(rtcm->buff, i, 8); i +=  8;
            code2 = getbitu(rtcm->buff, i, 2); i +=  2;
            pr21  = getbits(rtcm->buff, i, 14); i += 14;
            ppr2  = getbits(rtcm->buff, i, 20); i += 20;
            lock2 = getbitu(rtcm->buff, i, 7); i +=  7;
            cnr2  = getbitu(rtcm->buff, i, 8); i +=  8;
            if (!(sat = satno(sys, prn)))
                {
                    trace(2, "rtcm3 1012 satellite number error: sys=%d prn=%d\n", sys, prn);
                    continue;
                }
            tt = timediff(rtcm->obs.data[0].time, rtcm->time);
            if (rtcm->obsflag || fabs(tt)>1E-9)
                {
                    rtcm->obs.n = rtcm->obsflag = 0;
                }
            if ((index = obsindex(&rtcm->obs, rtcm->time, sat)) < 0) continue;
            pr1 = pr1*0.02+amb*PRUNIT_GLO;
            if (ppr1 != (int)0xFFF80000)
                {
                    lam1 = SPEED_OF_LIGHT/(FREQ1_GLO+DFRQ1_GLO*(freq-7));
                    rtcm->obs.data[index].P[0] = pr1;
                    cp1 = adjcp(rtcm, sat, 0, ppr1*0.0005/lam1);
                    rtcm->obs.data[index].L[0] = pr1/lam1+cp1;
                }
            rtcm->obs.data[index].LLI[0] = lossoflock(rtcm, sat, 0, lock1);
            rtcm->obs.data[index].SNR[0] = snratio(cnr1*0.25);
            rtcm->obs.data[index].code[0] = code1 ? CODE_L1P:CODE_L1C;

            if (pr21 != (int)0xFFFFE000)
                {
                    rtcm->obs.data[index].P[1] = pr1+pr21*0.02;
                }
            if (ppr2 != (int)0xFFF80000)
                {
                    lam2 = SPEED_OF_LIGHT/(FREQ2_GLO+DFRQ2_GLO*(freq-7));
                    cp2 = adjcp(rtcm, sat, 1, ppr2*0.0005/lam2);
                    rtcm->obs.data[index].L[1] = pr1/lam2+cp2;
                }
            rtcm->obs.data[index].LLI[1] = lossoflock(rtcm, sat, 1, lock2);
            rtcm->obs.data[index].SNR[1] = snratio(cnr2*0.25);
            rtcm->obs.data[index].code[1] = code2 ? CODE_L2P:CODE_L2C;
        }
    rtcm->obsflag = !sync;
    return sync ? 0:1;
}


/* decode type 1013: system parameters ---------------------------------------*/
int decode_type1013(rtcm_t *rtcm)
{
    return 0;
}


/* decode type 1019: gps ephemerides -----------------------------------------*/
int decode_type1019(rtcm_t *rtcm)
{
    eph_t eph = {0};
    double toc, sqrtA;
    char *msg;
    int i = 24+12, prn, sat, week, sys = SYS_GPS;

    if (i+476 <= rtcm->len*8)
        {
            prn        = getbitu(rtcm->buff, i, 6);              i +=  6;
            week       = getbitu(rtcm->buff, i, 10);             i += 10;
            eph.sva    = getbitu(rtcm->buff, i, 4);              i +=  4;
            eph.code   = getbitu(rtcm->buff, i, 2);              i +=  2;
            eph.idot   = getbits(rtcm->buff, i, 14)*TWO_N43*SC2RAD; i += 14;
            eph.iode   = getbitu(rtcm->buff, i, 8);              i +=  8;
            toc        = getbitu(rtcm->buff, i, 16)*16.0;        i += 16;
            eph.f2     = getbits(rtcm->buff, i, 8)*TWO_N55;      i +=  8;
            eph.f1     = getbits(rtcm->buff, i, 16)*TWO_N43;     i += 16;
            eph.f0     = getbits(rtcm->buff, i, 22)*TWO_N31;     i += 22;
            eph.iodc   = getbitu(rtcm->buff, i, 10);             i += 10;
            eph.crs    = getbits(rtcm->buff, i, 16)*TWO_N5;      i += 16;
            eph.deln   = getbits(rtcm->buff, i, 16)*TWO_N43*SC2RAD; i += 16;
            eph.M0     = getbits(rtcm->buff, i, 32)*TWO_N31*SC2RAD; i += 32;
            eph.cuc    = getbits(rtcm->buff, i, 16)*TWO_N29;     i += 16;
            eph.e      = getbitu(rtcm->buff, i, 32)*TWO_N33;     i += 32;
            eph.cus    = getbits(rtcm->buff, i, 16)*TWO_N29;     i += 16;
            sqrtA      = getbitu(rtcm->buff, i, 32)*TWO_N19;     i += 32;
            eph.toes   = getbitu(rtcm->buff, i, 16)*16.0;        i += 16;
            eph.cic    = getbits(rtcm->buff, i, 16)*TWO_N29;        i += 16;
            eph.OMG0   = getbits(rtcm->buff, i, 32)*TWO_N31*SC2RAD; i += 32;
            eph.cis    = getbits(rtcm->buff, i, 16)*TWO_N29;        i += 16;
            eph.i0     = getbits(rtcm->buff, i, 32)*TWO_N31*SC2RAD; i += 32;
            eph.crc    = getbits(rtcm->buff, i, 16)*TWO_N5;         i += 16;
            eph.omg    = getbits(rtcm->buff, i, 32)*TWO_N31*SC2RAD; i += 32;
            eph.OMGd   = getbits(rtcm->buff, i, 24)*TWO_N43*SC2RAD; i += 24;
            eph.tgd[0] = getbits(rtcm->buff, i, 8)*TWO_N31;      i +=  8;
            eph.svh    = getbitu(rtcm->buff, i, 6);              i +=  6;
            eph.flag   = getbitu(rtcm->buff, i, 1);              i +=  1;
            eph.fit    = getbitu(rtcm->buff, i, 1) ? 0.0:4.0; /* 0:4hr, 1:>4hr */
        }
    else
        {
            trace(2, "rtcm3 1019 length error: len=%d\n", rtcm->len);
            return -1;
        }
    if (prn >= 40)
        {
            sys = SYS_SBS; prn += 80;
        }
    trace(4, "decode_type1019: prn=%d iode=%d toe=%.0f\n", prn, eph.iode, eph.toes);

    if (rtcm->outtype)
        {
            msg = rtcm->msgtype+strlen(rtcm->msgtype);
            sprintf(msg, " prn=%2d iode=%3d iodc=%3d week=%d toe=%6.0f toc=%6.0f svh=%02X",
                    prn, eph.iode, eph.iodc, week, eph.toes, toc, eph.svh);
        }
    if (!(sat = satno(sys, prn)))
        {
            trace(2, "rtcm3 1019 satellite number error: prn=%d\n", prn);
            return -1;
        }
    eph.sat = sat;
    eph.week = adjgpsweek(week);
    eph.toe = gpst2time(eph.week, eph.toes);
    eph.toc = gpst2time(eph.week, toc);
    eph.ttr = rtcm->time;
    eph.A = sqrtA*sqrtA;
    if (!strstr(rtcm->opt, "-EPHALL"))
        {
            if (eph.iode == rtcm->nav.eph[sat-1].iode) return 0; /* unchanged */
        }
    rtcm->nav.eph[sat-1] = eph;
    rtcm->ephsat = sat;
    return 2;
}


/* decode type 1020: glonass ephemerides -------------------------------------*/
int decode_type1020(rtcm_t *rtcm)
{
    geph_t geph = {0};
    double tk_h, tk_m, tk_s, toe, tow, tod, tof;
    char *msg;
    int i = 24+12, prn, sat, week, tb, bn, sys = SYS_GLO;

    if (i+348 <= rtcm->len*8)
        {
            prn         = getbitu(rtcm->buff, i, 6);             i +=  6;
            geph.frq    = getbitu(rtcm->buff, i, 5)-7;           i +=  5+2+2;
            tk_h        = getbitu(rtcm->buff, i, 5);             i +=  5;
            tk_m        = getbitu(rtcm->buff, i, 6);             i +=  6;
            tk_s        = getbitu(rtcm->buff, i, 1)*30.0;        i +=  1;
            bn          = getbitu(rtcm->buff, i, 1);             i +=  1+1;
            tb          = getbitu(rtcm->buff, i, 7);             i +=  7;
            geph.vel[0] = getbitg(rtcm->buff, i, 24)*TWO_N20*1E3; i += 24;
            geph.pos[0] = getbitg(rtcm->buff, i, 27)*TWO_N11*1E3; i += 27;
            geph.acc[0] = getbitg(rtcm->buff, i, 5)*TWO_N30*1E3; i +=  5;
            geph.vel[1] = getbitg(rtcm->buff, i, 24)*TWO_N20*1E3; i += 24;
            geph.pos[1] = getbitg(rtcm->buff, i, 27)*TWO_N11*1E3; i += 27;
            geph.acc[1] = getbitg(rtcm->buff, i, 5)*TWO_N30*1E3; i +=  5;
            geph.vel[2] = getbitg(rtcm->buff, i, 24)*TWO_N20*1E3; i += 24;
            geph.pos[2] = getbitg(rtcm->buff, i, 27)*TWO_N11*1E3; i += 27;
            geph.acc[2] = getbitg(rtcm->buff, i, 5)*TWO_N30*1E3; i +=  5+1;
            geph.gamn   = getbitg(rtcm->buff, i, 11)*TWO_N40;     i += 11+3;
            geph.taun   = getbitg(rtcm->buff, i, 22)*TWO_N30;
        }
    else
        {
            trace(2, "rtcm3 1020 length error: len=%d\n", rtcm->len);
            return -1;
        }
    if (!(sat = satno(sys, prn)))
        {
            trace(2, "rtcm3 1020 satellite number error: prn=%d\n", prn);
            return -1;
        }
    trace(4, "decode_type1020: prn=%d tk=%02.0f:%02.0f:%02.0f\n", prn, tk_h, tk_m, tk_s);

    if (rtcm->outtype)
        {
            msg = rtcm->msgtype+strlen(rtcm->msgtype);
            sprintf(msg, " prn=%2d tk=%02.0f:%02.0f:%02.0f frq=%2d bn=%d tb=%d",
                    prn, tk_h, tk_m, tk_s, geph.frq, bn, tb);
        }
    geph.sat = sat;
    geph.svh = bn;
    geph.iode = tb&0x7F;
    if (rtcm->time.time == 0) rtcm->time = utc2gpst(timeget());
    tow = time2gpst(gpst2utc(rtcm->time), &week);
    tod = fmod(tow, 86400.0); tow -= tod;
    tof = tk_h*3600.0+tk_m*60.0+tk_s-10800.0; /* lt->utc */
    if      (tof < tod-43200.0) tof += 86400.0;
    else if (tof>tod+43200.0) tof -= 86400.0;
    geph.tof = utc2gpst(gpst2time(week, tow+tof));
    toe = tb*900.0-10800.0; /* lt->utc */
    if      (toe < tod-43200.0) toe += 86400.0;
    else if (toe>tod+43200.0) toe -= 86400.0;
    geph.toe = utc2gpst(gpst2time(week, tow+toe)); /* utc->gpst */

    if (!strstr(rtcm->opt, "-EPHALL"))
        {
            if (fabs(timediff(geph.toe, rtcm->nav.geph[prn-1].toe)) < 1.0 &&
                    geph.svh == rtcm->nav.geph[prn-1].svh) return 0; /* unchanged */
        }
    rtcm->nav.geph[prn-1] = geph;
    rtcm->ephsat = sat;
    return 2;
}


/* decode type 1021: helmert/abridged molodenski -----------------------------*/
int decode_type1021(rtcm_t *rtcm)
{
    trace(2, "rtcm3 1021: not supported message\n");
    return 0;
}


/* decode type 1022: moledenski-badekas transfromation -----------------------*/
int decode_type1022(rtcm_t *rtcm)
{
    trace(2, "rtcm3 1022: not supported message\n");
    return 0;
}


/* decode type 1023: residual, ellipoidal grid representation ----------------*/
int decode_type1023(rtcm_t *rtcm)
{
    trace(2, "rtcm3 1023: not supported message\n");
    return 0;
}


/* decode type 1024: residual, plane grid representation ---------------------*/
int decode_type1024(rtcm_t *rtcm)
{
    trace(2, "rtcm3 1024: not supported message\n");
    return 0;
}


/* decode type 1025: projection (types except LCC2SP, OM) ---------------------*/
int decode_type1025(rtcm_t *rtcm)
{
    trace(2, "rtcm3 1025: not supported message\n");
    return 0;
}


/* decode type 1026: projection (LCC2SP - lambert conic conformal (2sp)) -----*/
int decode_type1026(rtcm_t *rtcm)
{
    trace(2, "rtcm3 1026: not supported message\n");
    return 0;
}


/* decode type 1027: projection (type OM - oblique mercator) -----------------*/
int decode_type1027(rtcm_t *rtcm)
{
    trace(2, "rtcm3 1027: not supported message\n");
    return 0;
}


/* decode type 1029: unicode text string -------------------------------------*/
int decode_type1029(rtcm_t *rtcm)
{
    char *msg;
    int i = 24+12, j, staid, mjd, tod, nchar, cunit;

    if (i+60 <= rtcm->len*8)
        {
            staid = getbitu(rtcm->buff, i, 12); i += 12;
            mjd   = getbitu(rtcm->buff, i, 16); i += 16;
            tod   = getbitu(rtcm->buff, i, 17); i += 17;
            nchar = getbitu(rtcm->buff, i, 7); i +=  7;
            cunit = getbitu(rtcm->buff, i, 8); i +=  8;
        }
    else
        {
            trace(2, "rtcm3 1029 length error: len=%d\n", rtcm->len);
            return -1;
        }
    if (i+nchar*8>rtcm->len*8)
        {
            trace(2, "rtcm3 1029 length error: len=%d nchar=%d\n", rtcm->len, nchar);
            return -1;
        }
    for (j = 0; j < nchar && j < 126; j++)
        {
            rtcm->msg[j] = getbitu(rtcm->buff, i, 8); i += 8;
        }
    rtcm->msg[j] = '\0';

    if (rtcm->outtype)
        {
            msg = rtcm->msgtype+strlen(rtcm->msgtype);
            sprintf(msg, " staid=%4d text=%s", staid, rtcm->msg);
        }
    return 0;
}


/* decode type 1030: network rtk residual ------------------------------------*/
int decode_type1030(rtcm_t *rtcm)
{
    trace(2, "rtcm3 1030: not supported message\n");
    return 0;
}


/* decode type 1031: glonass network rtk residual ----------------------------*/
int decode_type1031(rtcm_t *rtcm)
{
    trace(2, "rtcm3 1031: not supported message\n");
    return 0;
}


/* decode type 1032: physical reference station position information ---------*/
int decode_type1032(rtcm_t *rtcm)
{
    trace(2, "rtcm3 1032: not supported message\n");
    return 0;
}


/* decode type 1033: receiver and antenna descriptor -------------------------*/
int decode_type1033(rtcm_t *rtcm)
{
    char des[32] = "", sno[32] = "", rec[32] = "", ver[32] = "", rsn[32] = "";
    char *msg;
    int i = 24+12, j, staid, n, m, n1, n2, n3, setup;

    n  = getbitu(rtcm->buff, i+12, 8);
    m  = getbitu(rtcm->buff, i+28+8*n, 8);
    n1 = getbitu(rtcm->buff, i+36+8*(n+m), 8);
    n2 = getbitu(rtcm->buff, i+44+8*(n+m+n1), 8);
    n3 = getbitu(rtcm->buff, i+52+8*(n+m+n1+n2), 8);

    if (i+60+8*(n+m+n1+n2+n3) <= rtcm->len*8)
        {
            staid =  getbitu(rtcm->buff, i, 12); i += 12+8;
            for (j = 0; j < n && j < 31; j++)
                {
                    des[j] = (char)getbitu(rtcm->buff, i, 8); i += 8;
                }
            setup =  getbitu(rtcm->buff, i, 8); i += 8+8;
            for (j = 0; j < m && j < 31; j++)
                {
                    sno[j] = (char)getbitu(rtcm->buff, i, 8); i += 8;
                }
            i += 8;
            for (j = 0; j < n1 && j < 31; j++)
                {
                    rec[j] = (char)getbitu(rtcm->buff, i, 8); i += 8;
                }
            i += 8;
            for (j = 0; j < n2 && j < 31; j++)
                {
                    ver[j] = (char)getbitu(rtcm->buff, i, 8); i += 8;
                }
            i += 8;
            for (j = 0; j < n3 && j < 31; j++)
                {
                    rsn[j] = (char)getbitu(rtcm->buff, i, 8); i += 8;
                }
        }
    else
        {
            trace(2, "rtcm3 1033 length error: len=%d\n", rtcm->len);
            return -1;
        }
    if (rtcm->outtype)
        {
            msg = rtcm->msgtype+strlen(rtcm->msgtype);
            sprintf(msg, " staid=%4d", staid);
        }
    /* test station id */
    if (!test_staid(rtcm, staid)) return -1;

    strncpy(rtcm->sta.antdes, des, n ); rtcm->sta.antdes [n]  = '\0';
    rtcm->sta.antsetup = setup;
    strncpy(rtcm->sta.antsno, sno, m ); rtcm->sta.antsno [m]  = '\0';
    strncpy(rtcm->sta.rectype, rec, n1); rtcm->sta.rectype[n1] = '\0';
    strncpy(rtcm->sta.recver, ver, n2); rtcm->sta.recver [n2] = '\0';
    strncpy(rtcm->sta.recsno, rsn, n3); rtcm->sta.recsno [n3] = '\0';

    trace(3, "rtcm3 1033: ant=%s:%s rec=%s:%s:%s\n", des, sno, rec, ver, rsn);
    return 5;
}


/* decode type 1034: gps network fkp gradient --------------------------------*/
int decode_type1034(rtcm_t *rtcm)
{
    trace(2, "rtcm3 1034: not supported message\n");
    return 0;
}


/* decode type 1035: glonass network fkp gradient ----------------------------*/
int decode_type1035(rtcm_t *rtcm)
{
    trace(2, "rtcm3 1035: not supported message\n");
    return 0;
}


/* decode type 1037: glonass network rtk ionospheric correction difference ---*/
int decode_type1037(rtcm_t *rtcm)
{
    trace(2, "rtcm3 1037: not supported message\n");
    return 0;
}


/* decode type 1038: glonass network rtk geometic correction difference ------*/
int decode_type1038(rtcm_t *rtcm)
{
    trace(2, "rtcm3 1038: not supported message\n");
    return 0;
}


/* decode type 1039: glonass network rtk combined correction difference ------*/
int decode_type1039(rtcm_t *rtcm)
{
    trace(2, "rtcm3 1039: not supported message\n");
    return 0;
}


/* decode type 1044: qzss ephemerides (ref [15]) -----------------------------*/
int decode_type1044(rtcm_t *rtcm)
{
    eph_t eph = {0};
    double toc, sqrtA;
    char *msg;
    int i = 24+12, prn, sat, week, sys = SYS_QZS;

    if (i+473 <= rtcm->len*8)
        {
            prn       = getbitu(rtcm->buff, i, 4)+192;          i +=  4;
            toc       = getbitu(rtcm->buff, i, 16)*16.0;         i += 16;
            eph.f2     = getbits(rtcm->buff, i, 8)*TWO_N55;        i +=  8;
            eph.f1     = getbits(rtcm->buff, i, 16)*TWO_N43;        i += 16;
            eph.f0     = getbits(rtcm->buff, i, 22)*TWO_N31;        i += 22;
            eph.iode  = getbitu(rtcm->buff, i, 8);              i +=  8;
            eph.crs    = getbits(rtcm->buff, i, 16)*TWO_N5;         i += 16;
            eph.deln   = getbits(rtcm->buff, i, 16)*TWO_N43*SC2RAD; i += 16;
            eph.M0     = getbits(rtcm->buff, i, 32)*TWO_N31*SC2RAD; i += 32;
            eph.cuc    = getbits(rtcm->buff, i, 16)*TWO_N29;        i += 16;
            eph.e     = getbitu(rtcm->buff, i, 32)*TWO_N33;        i += 32;
            eph.cus    = getbits(rtcm->buff, i, 16)*TWO_N29;        i += 16;
            sqrtA     = getbitu(rtcm->buff, i, 32)*TWO_N19;        i += 32;
            eph.toes  = getbitu(rtcm->buff, i, 16)*16.0;         i += 16;
            eph.cic    = getbits(rtcm->buff, i, 16)*TWO_N29;        i += 16;
            eph.OMG0   = getbits(rtcm->buff, i, 32)*TWO_N31*SC2RAD; i += 32;
            eph.cis    = getbits(rtcm->buff, i, 16)*TWO_N29;        i += 16;
            eph.i0     = getbits(rtcm->buff, i, 32)*TWO_N31*SC2RAD; i += 32;
            eph.crc    = getbits(rtcm->buff, i, 16)*TWO_N5;         i += 16;
            eph.omg    = getbits(rtcm->buff, i, 32)*TWO_N31*SC2RAD; i += 32;
            eph.OMGd   = getbits(rtcm->buff, i, 24)*TWO_N43*SC2RAD; i += 24;
            eph.idot   = getbits(rtcm->buff, i, 14)*TWO_N43*SC2RAD; i += 14;
            eph.code  = getbitu(rtcm->buff, i, 2);              i +=  2;
            week      = getbitu(rtcm->buff, i, 10);              i += 10;
            eph.sva   = getbitu(rtcm->buff, i, 4);              i +=  4;
            eph.svh   = getbitu(rtcm->buff, i, 6);              i +=  6;
            eph.tgd[0] = getbits(rtcm->buff, i, 8)*TWO_N31;        i +=  8;
            eph.iodc  = getbitu(rtcm->buff, i, 10);              i += 10;
            eph.fit   = getbitu(rtcm->buff, i, 1) ? 0.0:2.0; /* 0:2hr, 1:>2hr */
        }
    else
        {
            trace(2, "rtcm3 1044 length error: len=%d\n", rtcm->len);
            return -1;
        }
    trace(4, "decode_type1044: prn=%d iode=%d toe=%.0f\n", prn, eph.iode, eph.toes);

    if (rtcm->outtype)
        {
            msg = rtcm->msgtype+strlen(rtcm->msgtype);
            sprintf(msg, " prn=%3d iode=%3d iodc=%3d week=%d toe=%6.0f toc=%6.0f svh=%02X",
                    prn, eph.iode, eph.iodc, week, eph.toes, toc, eph.svh);
        }
    if (!(sat = satno(sys, prn)))
        {
            trace(2, "rtcm3 1044 satellite number error: prn=%d\n", prn);
            return -1;
        }
    eph.sat = sat;
    eph.week = adjgpsweek(week);
    eph.toe = gpst2time(eph.week, eph.toes);
    eph.toc = gpst2time(eph.week, toc);
    eph.ttr = rtcm->time;
    eph.A = sqrtA*sqrtA;
    if (!strstr(rtcm->opt, "-EPHALL"))
        {
            if (eph.iode == rtcm->nav.eph[sat-1].iode &&
                    eph.iodc == rtcm->nav.eph[sat-1].iodc) return 0; /* unchanged */
        }
    rtcm->nav.eph[sat-1] = eph;
    rtcm->ephsat = sat;
    return 2;
}


/* decode type 1045: galileo satellite ephemerides (ref [15]) ----------------*/
int decode_type1045(rtcm_t *rtcm)
{
    eph_t eph = {0};
    double toc, sqrtA;
    char *msg;
    int i = 24+12, prn, sat, week, e5a_hs, e5a_dvs, rsv, sys = SYS_GAL;

    if (i+484 <= rtcm->len*8)
        {
            prn        = getbitu(rtcm->buff, i, 6);              i +=  6;
            week       = getbitu(rtcm->buff, i, 12);              i += 12; /* gst-week */
            eph.iode   = getbitu(rtcm->buff, i, 10);              i += 10;
            eph.sva    = getbitu(rtcm->buff, i, 8);              i +=  8;
            eph.idot   = getbits(rtcm->buff, i, 14)*TWO_N43*SC2RAD; i += 14;
            toc        = getbitu(rtcm->buff, i, 14)*60.0;         i += 14;
            eph.f2     = getbits(rtcm->buff, i, 6)*TWO_N59;        i +=  6;
            eph.f1     = getbits(rtcm->buff, i, 21)*TWO_N46;        i += 21;
            eph.f0     = getbits(rtcm->buff, i, 31)*TWO_N34;        i += 31;
            eph.crs    = getbits(rtcm->buff, i, 16)*TWO_N5;         i += 16;
            eph.deln   = getbits(rtcm->buff, i, 16)*TWO_N43*SC2RAD; i += 16;
            eph.M0     = getbits(rtcm->buff, i, 32)*TWO_N31*SC2RAD; i += 32;
            eph.cuc    = getbits(rtcm->buff, i, 16)*TWO_N29;        i += 16;
            eph.e      = getbitu(rtcm->buff, i, 32)*TWO_N33;        i += 32;
            eph.cus    = getbits(rtcm->buff, i, 16)*TWO_N29;        i += 16;
            sqrtA      = getbitu(rtcm->buff, i, 32)*TWO_N19;        i += 32;
            eph.toes   = getbitu(rtcm->buff, i, 14)*60.0;         i += 14;
            eph.cic    = getbits(rtcm->buff, i, 16)*TWO_N29;        i += 16;
            eph.OMG0   = getbits(rtcm->buff, i, 32)*TWO_N31*SC2RAD; i += 32;
            eph.cis    = getbits(rtcm->buff, i, 16)*TWO_N29;        i += 16;
            eph.i0     = getbits(rtcm->buff, i, 32)*TWO_N31*SC2RAD; i += 32;
            eph.crc    = getbits(rtcm->buff, i, 16)*TWO_N5;         i += 16;
            eph.omg    = getbits(rtcm->buff, i, 32)*TWO_N31*SC2RAD; i += 32;
            eph.OMGd   = getbits(rtcm->buff, i, 24)*TWO_N43*SC2RAD; i += 24;
            eph.tgd[0] = getbits(rtcm->buff, i, 10)*TWO_N32;        i += 10; /* E5a/E1 */
            e5a_hs     = getbitu(rtcm->buff, i, 2);              i +=  2; /* OSHS */
            e5a_dvs    = getbitu(rtcm->buff, i, 1);              i +=  1; /* OSDVS */
            rsv        = getbitu(rtcm->buff, i, 7);
        }
    else
        {
            trace(2, "rtcm3 1045 length error: len=%d\n", rtcm->len);
            return -1;
        }
    trace(4, "decode_type1045: prn=%d iode=%d toe=%.0f\n", prn, eph.iode, eph.toes);

    if (rtcm->outtype)
        {
            msg = rtcm->msgtype+strlen(rtcm->msgtype);
            sprintf(msg, " prn=%2d iode=%3d week=%d toe=%6.0f toc=%6.0f hs=%d dvs=%d",
                    prn, eph.iode, week, eph.toes, toc, e5a_hs, e5a_dvs);
        }
    if (!(sat = satno(sys, prn)))
        {
            trace(2, "rtcm3 1045 satellite number error: prn=%d\n", prn);
            return -1;
        }
    eph.sat = sat;
    eph.week = week+1024; /* gal-week = gst-week + 1024 */
    eph.toe = gpst2time(eph.week, eph.toes);
    eph.toc = gpst2time(eph.week, toc);
    eph.ttr = rtcm->time;
    eph.A = sqrtA*sqrtA;
    eph.svh = (e5a_hs<<4)+(e5a_dvs<<3);
    eph.code = 2; /* data source = f/nav e5a */
    if (!strstr(rtcm->opt, "-EPHALL"))
        {
            if (eph.iode == rtcm->nav.eph[sat-1].iode) return 0; /* unchanged */
        }
    rtcm->nav.eph[sat-1] = eph;
    rtcm->ephsat = sat;
    return 2;
}


/* decode type 1046: galileo satellite ephemerides (extension for IGS MGEX) --*/
int decode_type1046(rtcm_t *rtcm)
{
    eph_t eph = {0};
    double toc, sqrtA;
    char *msg;
    int i = 24+12, prn, sat, week, e5a_hs, e5a_dvs, rsv, sys = SYS_GAL;

    if (i+484 <= rtcm->len*8)
        {
            prn        = getbitu(rtcm->buff, i, 6);              i +=  6;
            week       = getbitu(rtcm->buff, i, 12);              i += 12; /* gst-week */
            eph.iode   = getbitu(rtcm->buff, i, 10);              i += 10;
            eph.sva    = getbitu(rtcm->buff, i, 8);              i +=  8;
            eph.idot   = getbits(rtcm->buff, i, 14)*TWO_N43*SC2RAD; i += 14;
            toc        = getbitu(rtcm->buff, i, 14)*60.0;         i += 14;
            eph.f2     = getbits(rtcm->buff, i, 6)*TWO_N59;        i +=  6;
            eph.f1     = getbits(rtcm->buff, i, 21)*TWO_N46;        i += 21;
            eph.f0     = getbits(rtcm->buff, i, 31)*TWO_N34;        i += 31;
            eph.crs    = getbits(rtcm->buff, i, 16)*TWO_N5;         i += 16;
            eph.deln   = getbits(rtcm->buff, i, 16)*TWO_N43*SC2RAD; i += 16;
            eph.M0     = getbits(rtcm->buff, i, 32)*TWO_N31*SC2RAD; i += 32;
            eph.cuc    = getbits(rtcm->buff, i, 16)*TWO_N29;        i += 16;
            eph.e      = getbitu(rtcm->buff, i, 32)*TWO_N33;        i += 32;
            eph.cus    = getbits(rtcm->buff, i, 16)*TWO_N29;        i += 16;
            sqrtA      = getbitu(rtcm->buff, i, 32)*TWO_N19;        i += 32;
            eph.toes   = getbitu(rtcm->buff, i, 14)*60.0;         i += 14;
            eph.cic    = getbits(rtcm->buff, i, 16)*TWO_N29;        i += 16;
            eph.OMG0   = getbits(rtcm->buff, i, 32)*TWO_N31*SC2RAD; i += 32;
            eph.cis    = getbits(rtcm->buff, i, 16)*TWO_N29;        i += 16;
            eph.i0     = getbits(rtcm->buff, i, 32)*TWO_N31*SC2RAD; i += 32;
            eph.crc    = getbits(rtcm->buff, i, 16)*TWO_N5;         i += 16;
            eph.omg    = getbits(rtcm->buff, i, 32)*TWO_N31*SC2RAD; i += 32;
            eph.OMGd   = getbits(rtcm->buff, i, 24)*TWO_N43*SC2RAD; i += 24;
            eph.tgd[0] = getbits(rtcm->buff, i, 10)*TWO_N32;        i += 10; /* E5a/E1 */
            e5a_hs     = getbitu(rtcm->buff, i, 2);              i +=  2; /* OSHS */
            e5a_dvs    = getbitu(rtcm->buff, i, 1);              i +=  1; /* OSDVS */
            rsv        = getbitu(rtcm->buff, i, 7);
        }
    else
        {
            trace(2, "rtcm3 1046 length error: len=%d\n", rtcm->len);
            return -1;
        }
    trace(4, "decode_type1046: prn=%d iode=%d toe=%.0f\n", prn, eph.iode, eph.toes);

    if (rtcm->outtype)
        {
            msg = rtcm->msgtype+strlen(rtcm->msgtype);
            sprintf(msg, " prn=%2d iode=%3d week=%d toe=%6.0f toc=%6.0f hs=%d dvs=%d",
                    prn, eph.iode, week, eph.toes, toc, e5a_hs, e5a_dvs);
        }
    if (!(sat = satno(sys, prn)))
        {
            trace(2, "rtcm3 1046 satellite number error: prn=%d\n", prn);
            return -1;
        }
    eph.sat = sat;
    eph.week = week+1024; /* gal-week = gst-week + 1024 */
    eph.toe = gpst2time(eph.week, eph.toes);
    eph.toc = gpst2time(eph.week, toc);
    eph.ttr = rtcm->time;
    eph.A = sqrtA*sqrtA;
    eph.svh = (e5a_hs<<4)+(e5a_dvs<<3);
    eph.code = 2; /* data source = f/nav e5a */
    if (!strstr(rtcm->opt, "-EPHALL"))
        {
            if (eph.iode == rtcm->nav.eph[sat-1].iode) return 0; /* unchanged */
        }
    rtcm->nav.eph[sat-1] = eph;
    rtcm->ephsat = sat;
    return 2;
}


/* decode type 1047: beidou ephemerides (tentative mt and format) ------------*/
int decode_type1047(rtcm_t *rtcm)
{
    eph_t eph = {0};
    double toc, sqrtA;
    char *msg;
    int i = 24+12, prn, sat, week, sys = SYS_BDS;

    if (i+476 <= rtcm->len*8)
        {
            prn        = getbitu(rtcm->buff, i, 6);              i +=  6;
            week       = getbitu(rtcm->buff, i, 10);              i += 10;
            eph.sva    = getbitu(rtcm->buff, i, 4);              i +=  4;
            eph.code   = getbitu(rtcm->buff, i, 2);              i +=  2;
            eph.idot   = getbits(rtcm->buff, i, 14)*TWO_N43*SC2RAD; i += 14;
            eph.iode   = getbitu(rtcm->buff, i, 8);              i +=  8;
            toc        = getbitu(rtcm->buff, i, 16)*16.0;         i += 16;
            eph.f2     = getbits(rtcm->buff, i, 8)*TWO_N55;        i +=  8;
            eph.f1     = getbits(rtcm->buff, i, 16)*TWO_N43;        i += 16;
            eph.f0     = getbits(rtcm->buff, i, 22)*TWO_N31;        i += 22;
            eph.iodc   = getbitu(rtcm->buff, i, 10);              i += 10;
            eph.crs    = getbits(rtcm->buff, i, 16)*TWO_N5;         i += 16;
            eph.deln   = getbits(rtcm->buff, i, 16)*TWO_N43*SC2RAD; i += 16;
            eph.M0     = getbits(rtcm->buff, i, 32)*TWO_N31*SC2RAD; i += 32;
            eph.cuc    = getbits(rtcm->buff, i, 16)*TWO_N29;        i += 16;
            eph.e      = getbitu(rtcm->buff, i, 32)*TWO_N33;        i += 32;
            eph.cus    = getbits(rtcm->buff, i, 16)*TWO_N29;        i += 16;
            sqrtA      = getbitu(rtcm->buff, i, 32)*TWO_N19;        i += 32;
            eph.toes   = getbitu(rtcm->buff, i, 16)*16.0;         i += 16;
            eph.cic    = getbits(rtcm->buff, i, 16)*TWO_N29;        i += 16;
            eph.OMG0   = getbits(rtcm->buff, i, 32)*TWO_N31*SC2RAD; i += 32;
            eph.cis    = getbits(rtcm->buff, i, 16)*TWO_N29;        i += 16;
            eph.i0     = getbits(rtcm->buff, i, 32)*TWO_N31*SC2RAD; i += 32;
            eph.crc    = getbits(rtcm->buff, i, 16)*TWO_N5;         i += 16;
            eph.omg    = getbits(rtcm->buff, i, 32)*TWO_N31*SC2RAD; i += 32;
            eph.OMGd   = getbits(rtcm->buff, i, 24)*TWO_N43*SC2RAD; i += 24;
            eph.tgd[0] = getbits(rtcm->buff, i, 8)*TWO_N31;        i +=  8;
            eph.svh    = getbitu(rtcm->buff, i, 6);              i +=  6;
            eph.flag   = getbitu(rtcm->buff, i, 1);              i +=  1;
            eph.fit    = getbitu(rtcm->buff, i, 1) ? 0.0:4.0; /* 0:4hr, 1:>4hr */
        }
    else
        {
            trace(2, "rtcm3 1047 length error: len=%d\n", rtcm->len);
            return -1;
        }
    trace(4, "decode_type1047: prn=%d iode=%d toe=%.0f\n", prn, eph.iode, eph.toes);

    if (rtcm->outtype)
        {
            msg = rtcm->msgtype+strlen(rtcm->msgtype);
            sprintf(msg, " prn=%2d iode=%3d iodc=%3d week=%d toe=%6.0f toc=%6.0f svh=%02X",
                    prn, eph.iode, eph.iodc, week, eph.toes, toc, eph.svh);
        }
    if (!(sat = satno(sys, prn)))
        {
            trace(2, "rtcm3 1047 satellite number error: prn=%d\n", prn);
            return -1;
        }
    eph.sat = sat;
    eph.week = adjbdtweek(week);
    eph.toe = bdt2gpst(bdt2time(eph.week, eph.toes)); /* bdt -> gpst */
    eph.toc = bdt2gpst(bdt2time(eph.week, toc));      /* bdt -> gpst */
    eph.ttr = rtcm->time;
    eph.A = sqrtA*sqrtA;
    if (!strstr(rtcm->opt, "-EPHALL"))

        {
            if (timediff(eph.toe, rtcm->nav.eph[sat-1].toe) == 0.0 &&
                    eph.iode == rtcm->nav.eph[sat-1].iode &&
                    eph.iodc == rtcm->nav.eph[sat-1].iodc) return 0; /* unchanged */
        }
    rtcm->nav.eph[sat-1] = eph;
    rtcm->ephsat = sat;
    return 2;
}


/* decode type 63: beidou ephemerides (rtcm draft) ---------------------------*/
int decode_type63(rtcm_t *rtcm)
{
    eph_t eph = {0};
    double toc, sqrtA;
    char *msg;
    int i = 24+12, prn, sat, week, sys = SYS_BDS;

    if (i+499 <= rtcm->len*8)
        {
            prn        = getbitu(rtcm->buff, i, 6);              i +=  6;
            week       = getbitu(rtcm->buff, i, 13);              i += 13;
            eph.sva    = getbitu(rtcm->buff, i, 4);              i +=  4;
            eph.idot   = getbits(rtcm->buff, i, 14)*TWO_N43*SC2RAD; i += 14;
            eph.iode   = getbitu(rtcm->buff, i, 5);              i +=  5; /* AODE */
            toc        = getbitu(rtcm->buff, i, 17)*8.0;          i += 17;
            eph.f2     = getbits(rtcm->buff, i, 11)*TWO_N55;        i += 11;
            eph.f1     = getbits(rtcm->buff, i, 22)*TWO_N50;        i += 22;
            eph.f0     = getbits(rtcm->buff, i, 24)*TWO_N33;        i += 24;
            eph.iodc   = getbitu(rtcm->buff, i, 5);              i +=  5; /* AODC */
            eph.crs    = getbits(rtcm->buff, i, 18)*TWO_N6;         i += 18;
            eph.deln   = getbits(rtcm->buff, i, 16)*TWO_N43*SC2RAD; i += 16;
            eph.M0     = getbits(rtcm->buff, i, 32)*TWO_N31*SC2RAD; i += 32;
            eph.cuc    = getbits(rtcm->buff, i, 18)*TWO_N31;        i += 18;
            eph.e      = getbitu(rtcm->buff, i, 32)*TWO_N33;        i += 32;
            eph.cus    = getbits(rtcm->buff, i, 18)*TWO_N31;        i += 18;
            sqrtA      = getbitu(rtcm->buff, i, 32)*TWO_N19;        i += 32;
            eph.toes   = getbitu(rtcm->buff, i, 17)*8.0;          i += 17;
            eph.cic    = getbits(rtcm->buff, i, 18)*TWO_N31;        i += 18;
            eph.OMG0   = getbits(rtcm->buff, i, 32)*TWO_N31*SC2RAD; i += 32;
            eph.cis    = getbits(rtcm->buff, i, 18)*TWO_N31;        i += 18;
            eph.i0     = getbits(rtcm->buff, i, 32)*TWO_N31*SC2RAD; i += 32;
            eph.crc    = getbits(rtcm->buff, i, 18)*TWO_N6;         i += 18;
            eph.omg    = getbits(rtcm->buff, i, 32)*TWO_N31*SC2RAD; i += 32;
            eph.OMGd   = getbits(rtcm->buff, i, 24)*TWO_N43*SC2RAD; i += 24;
            eph.tgd[0] = getbits(rtcm->buff, i, 10)*1E-10;        i += 10;
            eph.tgd[1] = getbits(rtcm->buff, i, 10)*1E-10;        i += 10;
            eph.svh    = getbitu(rtcm->buff, i, 1);              i +=  1;
        }
    else
        {
            trace(2, "rtcm3 63 length error: len=%d\n", rtcm->len);
            return -1;
        }
    trace(4, "decode_type63: prn=%d iode=%d toe=%.0f\n", prn, eph.iode, eph.toes);

    if (rtcm->outtype)
        {
            msg = rtcm->msgtype+strlen(rtcm->msgtype);
            sprintf(msg, " prn=%2d iode=%3d iodc=%3d week=%d toe=%6.0f toc=%6.0f svh=%02X",
                    prn, eph.iode, eph.iodc, week, eph.toes, toc, eph.svh);
        }
    if (!(sat = satno(sys, prn)))
        {
            trace(2, "rtcm3 63 satellite number error: prn=%d\n", prn);
            return -1;
        }
    eph.sat = sat;
    eph.week = adjbdtweek(week);
    eph.toe = bdt2gpst(bdt2time(eph.week, eph.toes)); /* bdt -> gpst */
    eph.toc = bdt2gpst(bdt2time(eph.week, toc));      /* bdt -> gpst */
    eph.ttr = rtcm->time;
    eph.A = sqrtA*sqrtA;
    if (!strstr(rtcm->opt, "-EPHALL"))
        {
            if (timediff(eph.toe, rtcm->nav.eph[sat-1].toe) == 0.0 &&
                    eph.iode == rtcm->nav.eph[sat-1].iode &&
                    eph.iodc == rtcm->nav.eph[sat-1].iodc) return 0; /* unchanged */
        }
    rtcm->nav.eph[sat-1] = eph;
    rtcm->ephsat = sat;
    return 2;
}


/* decode ssr 1, 4 message header ---------------------------------------------*/
int decode_ssr1_head(rtcm_t *rtcm, int sys, int *sync, int *iod,
        double *udint, int *refd, int *hsize)
{
    double tod, tow;
    char *msg;
    int i = 24+12, nsat, udi, provid = 0, solid = 0, ns = 6;

#ifndef SSR_QZSS_DRAFT_V05
    ns = sys == SYS_QZS ? 4:6;
#endif
    if (i+(sys == SYS_GLO ? 53:50+ns)>rtcm->len*8) return -1;

    if (sys == SYS_GLO)
        {
            tod = getbitu(rtcm->buff, i, 17); i += 17;
            adjday_glot(rtcm, tod);
        }
    else
        {
            tow = getbitu(rtcm->buff, i, 20); i += 20;
            adjweek(rtcm, tow);
        }
    udi    = getbitu(rtcm->buff, i, 4);  i +=  4;
    *sync  = getbitu(rtcm->buff, i, 1);  i +=  1;
    *refd  = getbitu(rtcm->buff, i, 1);  i +=  1; /* satellite ref datum */
    *iod   = getbitu(rtcm->buff, i, 4);  i +=  4; /* iod */
    provid = getbitu(rtcm->buff, i, 16); i += 16; /* provider id */
    solid  = getbitu(rtcm->buff, i, 4);  i +=  4; /* solution id */
    nsat   = getbitu(rtcm->buff, i, ns); i += ns;
    *udint = ssrudint[udi];

    trace(4, "decode_ssr1_head: time=%s sys=%d nsat=%d sync=%d iod=%d provid=%d solid=%d\n",
            time_str(rtcm->time, 2), sys, nsat, *sync, *iod, provid, solid);

    if (rtcm->outtype)
        {
            msg = rtcm->msgtype+strlen(rtcm->msgtype);
            sprintf(msg, " %s nsat=%2d iod=%2d udi=%2d sync=%d",
                    time_str(rtcm->time, 2), nsat, *iod, udi, *sync);
        }
    *hsize = i;
    return nsat;
}


/* decode ssr 2, 3, 5, 6 message header -----------------------------------------*/
int decode_ssr2_head(rtcm_t *rtcm, int sys, int *sync, int *iod,
        double *udint, int *hsize)
{
    double tod, tow;
    char *msg;
    int i = 24+12, nsat, udi, provid = 0, solid = 0, ns = 6;

#ifndef SSR_QZSS_DRAFT_V05
    ns = sys == SYS_QZS ? 4:6;
#endif
    if (i+(sys == SYS_GLO ? 52:49+ns)>rtcm->len*8) return -1;

    if (sys == SYS_GLO)
        {
            tod = getbitu(rtcm->buff, i, 17); i += 17;
            adjday_glot(rtcm, tod);
        }
    else
        {
            tow = getbitu(rtcm->buff, i, 20); i += 20;
            adjweek(rtcm, tow);
        }
    udi    = getbitu(rtcm->buff, i, 4);  i +=  4;
    *sync  = getbitu(rtcm->buff, i, 1);  i +=  1;
    *iod   = getbitu(rtcm->buff, i, 4);  i +=  4;
    provid = getbitu(rtcm->buff, i, 16); i += 16; /* provider id */
    solid  = getbitu(rtcm->buff, i, 4);  i +=  4; /* solution id */
    nsat   = getbitu(rtcm->buff, i, ns); i += ns;
    *udint = ssrudint[udi];

    trace(4, "decode_ssr2_head: time=%s sys=%d nsat=%d sync=%d iod=%d provid=%d solid=%d\n",
            time_str(rtcm->time, 2), sys, nsat, *sync, *iod, provid, solid);

    if (rtcm->outtype)
        {
            msg = rtcm->msgtype+strlen(rtcm->msgtype);
            sprintf(msg, " %s nsat=%2d iod=%2d udi=%2d sync=%d",
                    time_str(rtcm->time, 2), nsat, *iod, udi, *sync);
        }
    *hsize = i;
    return nsat;
}


/* decode ssr 7 message header -----------------------------------------------*/
int decode_ssr7_head(rtcm_t *rtcm, int sys, int *sync, int *iod,
        double *udint, int *dispe, int *mw, int *hsize)
{
    double tod, tow;
    char *msg;
    int i = 24+12, nsat, udi, provid = 0, solid = 0, ns = 6;

#ifndef SSR_QZSS_DRAFT_V05
    ns = sys == SYS_QZS ? 4:6;
#endif
    if (i+(sys == SYS_GLO ? 54:51+ns)>rtcm->len*8) return -1;

    if (sys == SYS_GLO)
        {
            tod = getbitu(rtcm->buff, i, 17); i += 17;
            adjday_glot(rtcm, tod);
        }
    else
        {
            tow = getbitu(rtcm->buff, i, 20); i += 20;
            adjweek(rtcm, tow);
        }
    udi    = getbitu(rtcm->buff, i, 4);  i +=  4;
    *sync  = getbitu(rtcm->buff, i, 1);  i +=  1;
    *iod   = getbitu(rtcm->buff, i, 4);  i +=  4;
    provid = getbitu(rtcm->buff, i, 16); i += 16; /* provider id */
    solid  = getbitu(rtcm->buff, i, 4);  i +=  4; /* solution id */
    *dispe = getbitu(rtcm->buff, i, 1);  i +=  1; /* dispersive bias consistency ind */
    *mw    = getbitu(rtcm->buff, i, 1);  i +=  1; /* MW consistency indicator */
    nsat   = getbitu(rtcm->buff, i, ns); i += ns;
    *udint = ssrudint[udi];

    trace(4, "decode_ssr7_head: time=%s sys=%d nsat=%d sync=%d iod=%d provid=%d solid=%d\n",
            time_str(rtcm->time, 2), sys, nsat, *sync, *iod, provid, solid);

    if (rtcm->outtype)
        {
            msg = rtcm->msgtype+strlen(rtcm->msgtype);
            sprintf(msg, " %s nsat=%2d iod=%2d udi=%2d sync=%d",
                    time_str(rtcm->time, 2), nsat, *iod, udi, *sync);
        }
    *hsize = i;
    return nsat;
}




/* decode ssr 1: orbit corrections -------------------------------------------*/
int decode_ssr1(rtcm_t *rtcm, int sys)
{
    double udint, deph[3], ddeph[3];
    int i, j, k, type, sync, iod, nsat, prn, sat, iode, iodcrc, refd = 0, np, ni, nj, offp;

    type = getbitu(rtcm->buff, 24, 12);

    if ((nsat = decode_ssr1_head(rtcm, sys, &sync, &iod, &udint, &refd, &i)) < 0)
        {
            trace(2, "rtcm3 %d length error: len=%d\n", type, rtcm->len);
            return -1;
        }
    switch (sys)
    {
    case SYS_GPS: np = 6; ni =  8; nj =  0; offp =   0; break;
    case SYS_GLO: np = 5; ni =  8; nj =  0; offp =   0; break;
    case SYS_GAL: np = 6; ni = 10; nj =  0; offp =   0; break;
    case SYS_QZS: np = 4; ni =  8; nj =  0; offp = 192; break;
    case SYS_BDS: np = 6; ni = 10; nj = 24; offp =   1; break;
    case SYS_SBS: np = 6; ni =  9; nj = 24; offp = 120; break;
    default: return sync ? 0:10;
    }
    for (j = 0; j < nsat && i+121+np+ni+nj <= rtcm->len*8; j++)
        {
            prn      = getbitu(rtcm->buff, i, np)+offp; i += np;
            iode     = getbitu(rtcm->buff, i, ni);      i += ni;
            iodcrc   = getbitu(rtcm->buff, i, nj);      i += nj;
            deph [0] = getbits(rtcm->buff, i, 22)*1E-4; i += 22;
            deph [1] = getbits(rtcm->buff, i, 20)*4E-4; i += 20;
            deph [2] = getbits(rtcm->buff, i, 20)*4E-4; i += 20;
            ddeph[0] = getbits(rtcm->buff, i, 21)*1E-6; i += 21;
            ddeph[1] = getbits(rtcm->buff, i, 19)*4E-6; i += 19;
            ddeph[2] = getbits(rtcm->buff, i, 19)*4E-6; i += 19;

            if (!(sat = satno(sys, prn)))
                {
                    trace(2, "rtcm3 %d satellite number error: prn=%d\n", type, prn);
                    continue;
                }
            rtcm->ssr[sat-1].t0 [0] = rtcm->time;
            rtcm->ssr[sat-1].udi[0] = udint;
            rtcm->ssr[sat-1].iod[0] = iod;
            rtcm->ssr[sat-1].iode = iode;     /* sbas/bds: toe/t0 modulo */
            rtcm->ssr[sat-1].iodcrc = iodcrc; /* sbas/bds: iod crc */
            rtcm->ssr[sat-1].refd = refd;

            for (k = 0;k < 3;k++)
                {
                    rtcm->ssr[sat-1].deph [k] = deph [k];
                    rtcm->ssr[sat-1].ddeph[k] = ddeph[k];
                }
            rtcm->ssr[sat-1].update = 1;
        }
    return sync ? 0:10;
}


/* decode ssr 2: clock corrections -------------------------------------------*/
int decode_ssr2(rtcm_t *rtcm, int sys)
{
    double udint, dclk[3];
    int i, j, k, type, sync, iod, nsat, prn, sat, np, offp;

    type = getbitu(rtcm->buff, 24, 12);

    if ((nsat = decode_ssr2_head(rtcm, sys, &sync, &iod, &udint, &i)) < 0)
        {
            trace(2, "rtcm3 %d length error: len=%d\n", type, rtcm->len);
            return -1;
        }
    switch (sys)
    {
    case SYS_GPS: np = 6; offp =   0; break;
    case SYS_GLO: np = 5; offp =   0; break;
    case SYS_GAL: np = 6; offp =   0; break;
    case SYS_QZS: np = 4; offp = 192; break;
    case SYS_BDS: np = 6; offp =   1; break;
    case SYS_SBS: np = 6; offp = 120; break;
    default: return sync ? 0:10;
    }
    for (j = 0; j < nsat && i+70+np <= rtcm->len*8; j++)
        {
            prn     = getbitu(rtcm->buff, i, np)+offp; i += np;
            dclk[0] = getbits(rtcm->buff, i, 22)*1E-4; i += 22;
            dclk[1] = getbits(rtcm->buff, i, 21)*1E-6; i += 21;
            dclk[2] = getbits(rtcm->buff, i, 27)*2E-8; i += 27;

            if (!(sat = satno(sys, prn)))
                {
                    trace(2, "rtcm3 %d satellite number error: prn=%d\n", type, prn);
                    continue;
                }
            rtcm->ssr[sat-1].t0 [1] = rtcm->time;
            rtcm->ssr[sat-1].udi[1] = udint;
            rtcm->ssr[sat-1].iod[1] = iod;

            for (k = 0;k < 3;k++)
                {
                    rtcm->ssr[sat-1].dclk[k] = dclk[k];
                }
            rtcm->ssr[sat-1].update = 1;
        }
    return sync ? 0:10;
}


/* decode ssr 3: satellite code biases ---------------------------------------*/
int decode_ssr3(rtcm_t *rtcm, int sys)
{
    const int *codes;
    double udint, bias, cbias[MAXCODE];
    int i, j, k, type, mode, sync, iod, nsat, prn, sat, nbias, np, offp, ncode;

    type = getbitu(rtcm->buff, 24, 12);

    if ((nsat = decode_ssr2_head(rtcm, sys, &sync, &iod, &udint, &i)) < 0)
        {
            trace(2, "rtcm3 %d length error: len=%d\n", type, rtcm->len);
            return -1;
        }
    switch (sys)
    {
    case SYS_GPS: np = 6; offp =   0; codes = codes_gps; ncode = 17; break;
    case SYS_GLO: np = 5; offp =   0; codes = codes_glo; ncode =  4; break;
    case SYS_GAL: np = 6; offp =   0; codes = codes_gal; ncode = 19; break;
    case SYS_QZS: np = 4; offp = 192; codes = codes_qzs; ncode = 13; break;
    case SYS_BDS: np = 6; offp =   1; codes = codes_bds; ncode =  9; break;
    case SYS_SBS: np = 6; offp = 120; codes = codes_sbs; ncode =  4; break;
    default: return sync ? 0:10;
    }
    for (j = 0; j < nsat && i+5+np <= rtcm->len*8; j++)
        {
            prn   = getbitu(rtcm->buff, i, np)+offp; i += np;
            nbias = getbitu(rtcm->buff, i, 5);      i +=  5;

            for (k = 0;k < MAXCODE;k++) cbias[k] = 0.0;
            for (k = 0;k < nbias && i+19 <= rtcm->len*8;k++)
                {
                    mode = getbitu(rtcm->buff, i, 5);      i +=  5;
                    bias = getbits(rtcm->buff, i, 14)*0.01; i += 14;
                    if (mode <= ncode)
                        {
                            cbias[codes[mode]-1] = (float)bias;
                        }
                    else
                        {
                            trace(2, "rtcm3 %d not supported mode: mode=%d\n", type, mode);
                        }
                }
            if (!(sat = satno(sys, prn)))
                {
                    trace(2, "rtcm3 %d satellite number error: prn=%d\n", type, prn);
                    continue;
                }
            rtcm->ssr[sat-1].t0 [4] = rtcm->time;
            rtcm->ssr[sat-1].udi[4] = udint;
            rtcm->ssr[sat-1].iod[4] = iod;

            for (k = 0;k < MAXCODE;k++)
                {
                    rtcm->ssr[sat-1].cbias[k] = (float)cbias[k];
                }
            rtcm->ssr[sat-1].update = 1;
        }
    return sync ? 0:10;
}


/* decode ssr 4: combined orbit and clock corrections ------------------------*/
int decode_ssr4(rtcm_t *rtcm, int sys)
{
    double udint, deph[3], ddeph[3], dclk[3];
    int i, j, k, type, nsat, sync, iod, prn, sat, iode, iodcrc, refd = 0, np, ni, nj, offp;

    type = getbitu(rtcm->buff, 24, 12);

    if ((nsat = decode_ssr1_head(rtcm, sys, &sync, &iod, &udint, &refd, &i)) < 0)
        {
            trace(2, "rtcm3 %d length error: len=%d\n", type, rtcm->len);
            return -1;
        }
    switch (sys)
    {
    case SYS_GPS: np = 6; ni =  8; nj =  0; offp =   0; break;
    case SYS_GLO: np = 5; ni =  8; nj =  0; offp =   0; break;
    case SYS_GAL: np = 6; ni = 10; nj =  0; offp =   0; break;
    case SYS_QZS: np = 4; ni =  8; nj =  0; offp = 192; break;
    case SYS_BDS: np = 6; ni = 10; nj = 24; offp =   1; break;
    case SYS_SBS: np = 6; ni =  9; nj = 24; offp = 120; break;
    default: return sync ? 0:10;
    }
    for (j = 0; j < nsat && i+191+np+ni+nj <= rtcm->len*8; j++)
        {
            prn      = getbitu(rtcm->buff, i, np)+offp; i += np;
            iode     = getbitu(rtcm->buff, i, ni);      i += ni;
            iodcrc   = getbitu(rtcm->buff, i, nj);      i += nj;
            deph [0] = getbits(rtcm->buff, i, 22)*1E-4; i += 22;
            deph [1] = getbits(rtcm->buff, i, 20)*4E-4; i += 20;
            deph [2] = getbits(rtcm->buff, i, 20)*4E-4; i += 20;
            ddeph[0] = getbits(rtcm->buff, i, 21)*1E-6; i += 21;
            ddeph[1] = getbits(rtcm->buff, i, 19)*4E-6; i += 19;
            ddeph[2] = getbits(rtcm->buff, i, 19)*4E-6; i += 19;

            dclk [0] = getbits(rtcm->buff, i, 22)*1E-4; i += 22;
            dclk [1] = getbits(rtcm->buff, i, 21)*1E-6; i += 21;
            dclk [2] = getbits(rtcm->buff, i, 27)*2E-8; i += 27;

            if (!(sat = satno(sys, prn)))
                {
                    trace(2, "rtcm3 %d satellite number error: prn=%d\n", type, prn);
                    continue;
                }
            rtcm->ssr[sat-1].t0 [0] = rtcm->ssr[sat-1].t0 [1] = rtcm->time;
            rtcm->ssr[sat-1].udi[0] = rtcm->ssr[sat-1].udi[1] = udint;
            rtcm->ssr[sat-1].iod[0] = rtcm->ssr[sat-1].iod[1] = iod;
            rtcm->ssr[sat-1].iode = iode;
            rtcm->ssr[sat-1].iodcrc = iodcrc;
            rtcm->ssr[sat-1].refd = refd;

            for (k = 0;k < 3;k++)
                {
                    rtcm->ssr[sat-1].deph [k] = deph [k];
                    rtcm->ssr[sat-1].ddeph[k] = ddeph[k];
                    rtcm->ssr[sat-1].dclk [k] = dclk [k];
                }
            rtcm->ssr[sat-1].update = 1;
        }
    return sync ? 0:10;
}


/* decode ssr 5: ura ---------------------------------------------------------*/
int decode_ssr5(rtcm_t *rtcm, int sys)
{
    double udint;
    int i, j, type, nsat, sync, iod, prn, sat, ura, np, offp;

    type = getbitu(rtcm->buff, 24, 12);

    if ((nsat = decode_ssr2_head(rtcm, sys, &sync, &iod, &udint, &i)) < 0)
        {
            trace(2, "rtcm3 %d length error: len=%d\n", type, rtcm->len);
            return -1;
        }
    switch (sys)
    {
    case SYS_GPS: np = 6; offp =   0; break;
    case SYS_GLO: np = 5; offp =   0; break;
    case SYS_GAL: np = 6; offp =   0; break;
    case SYS_QZS: np = 4; offp = 192; break;
    case SYS_BDS: np = 6; offp =   1; break;
    case SYS_SBS: np = 6; offp = 120; break;
    default: return sync ? 0:10;
    }
    for (j = 0; j < nsat && i+6+np <= rtcm->len*8; j++)
        {
            prn = getbitu(rtcm->buff, i, np)+offp; i += np;
            ura = getbitu(rtcm->buff, i, 6);      i +=  6;

            if (!(sat = satno(sys, prn)))
                {
                    trace(2, "rtcm3 %d satellite number error: prn=%d\n", type, prn);
                    continue;
                }
            rtcm->ssr[sat-1].t0 [3] = rtcm->time;
            rtcm->ssr[sat-1].udi[3] = udint;
            rtcm->ssr[sat-1].iod[3] = iod;
            rtcm->ssr[sat-1].ura = ura;
            rtcm->ssr[sat-1].update = 1;
        }
    return sync ? 0:10;
}


/* decode ssr 6: high rate clock correction ----------------------------------*/
int decode_ssr6(rtcm_t *rtcm, int sys)
{
    double udint, hrclk;
    int i, j, type, nsat, sync, iod, prn, sat, np, offp;

    type = getbitu(rtcm->buff, 24, 12);

    if ((nsat = decode_ssr2_head(rtcm, sys, &sync, &iod, &udint, &i)) < 0)
        {
            trace(2, "rtcm3 %d length error: len=%d\n", type, rtcm->len);
            return -1;
        }
    switch (sys)
    {
    case SYS_GPS: np = 6; offp =   0; break;
    case SYS_GLO: np = 5; offp =   0; break;
    case SYS_GAL: np = 6; offp =   0; break;
    case SYS_QZS: np = 4; offp = 192; break;
    case SYS_BDS: np = 6; offp =   1; break;
    case SYS_SBS: np = 6; offp = 120; break;
    default: return sync ? 0:10;
    }
    for (j = 0; j < nsat && i+22+np <= rtcm->len*8; j++)
        {
            prn   = getbitu(rtcm->buff, i, np)+offp; i += np;
            hrclk = getbits(rtcm->buff, i, 22)*1E-4; i += 22;

            if (!(sat = satno(sys, prn)))
                {
                    trace(2, "rtcm3 %d satellite number error: prn=%d\n", type, prn);
                    continue;
                }
            rtcm->ssr[sat-1].t0 [2] = rtcm->time;
            rtcm->ssr[sat-1].udi[2] = udint;
            rtcm->ssr[sat-1].iod[2] = iod;
            rtcm->ssr[sat-1].hrclk = hrclk;
            rtcm->ssr[sat-1].update = 1;
        }
    return sync ? 0:10;
}


/* decode ssr 7: phase bias --------------------------------------------------*/
int decode_ssr7(rtcm_t *rtcm, int sys)
{
    const int *codes;
    double udint, bias, std, pbias[MAXCODE], stdpb[MAXCODE];
    int i, j, k, type, mode, sync, iod, nsat, prn, sat, nbias, ncode, np, mw, offp, sii, swl;
    int dispe, sdc, yaw_ang, yaw_rate;

    type = getbitu(rtcm->buff, 24, 12);

    if ((nsat = decode_ssr7_head(rtcm, sys, &sync, &iod, &udint, &dispe, &mw, &i)) < 0)
        {
            trace(2, "rtcm3 %d length error: len=%d\n", type, rtcm->len);
            return -1;
        }
    switch (sys)
    {
    case SYS_GPS: np = 6; offp =   0; codes = codes_gps; ncode = 17; break;
    case SYS_GLO: np = 5; offp =   0; codes = codes_glo; ncode =  4; break;
    case SYS_GAL: np = 6; offp =   0; codes = codes_gal; ncode = 19; break;
    case SYS_QZS: np = 4; offp = 192; codes = codes_qzs; ncode = 13; break;
    case SYS_BDS: np = 6; offp =   1; codes = codes_bds; ncode =  9; break;
    default: return sync ? 0:10;
    }
    for (j = 0; j < nsat && i+5+17+np <= rtcm->len*8; j++)
        {
            prn      = getbitu(rtcm->buff, i, np)+offp; i += np;
            nbias    = getbitu(rtcm->buff, i, 5);      i +=  5;
            yaw_ang  = getbitu(rtcm->buff, i, 9);      i +=  9;
            yaw_rate = getbits(rtcm->buff, i, 8);      i +=  8;

            for (k = 0;k < MAXCODE;k++) pbias[k] = stdpb[k] = 0.0;
            for (k = 0;k < nbias && i+49 <= rtcm->len*8;k++)
                {
                    mode = getbitu(rtcm->buff, i, 5); i +=  5;
                    sii  = getbitu(rtcm->buff, i, 1); i +=  1; /* integer-indicator */
                    swl  = getbitu(rtcm->buff, i, 2); i +=  2; /* WL integer-indicator */
                    sdc  = getbitu(rtcm->buff, i, 4); i +=  4; /* discontinuity counter */
                    bias = getbits(rtcm->buff, i, 20); i += 20; /* phase bias (m) */
                    std  = getbitu(rtcm->buff, i, 17); i += 17; /* phase bias std-dev (m) */
                    if (mode <= ncode)
                        {
                            pbias[codes[mode]-1] = bias*0.0001; /* (m) */
                            stdpb[codes[mode]-1] = std *0.0001; /* (m) */
                        }
                    else
                        {
                            trace(2, "rtcm3 %d not supported mode: mode=%d\n", type, mode);
                        }
                }
            if (!(sat = satno(sys, prn)))
                {
                    trace(2, "rtcm3 %d satellite number error: prn=%d\n", type, prn);
                    continue;
                }
            rtcm->ssr[sat-1].t0 [5] = rtcm->time;
            rtcm->ssr[sat-1].udi[5] = udint;
            rtcm->ssr[sat-1].iod[5] = iod;
            rtcm->ssr[sat-1].yaw_ang  = yaw_ang / 256.0*180.0; /* (deg) */
            rtcm->ssr[sat-1].yaw_rate = yaw_rate / 8192.0*180.0; /* (deg/s) */

            for (k = 0;k < MAXCODE;k++)
                {
                    rtcm->ssr[sat-1].pbias[k] = pbias[k];
                    rtcm->ssr[sat-1].stdpb[k] = (float)stdpb[k];
                }
        }
    return 20;
}


/* get signal index ----------------------------------------------------------*/
void sigindex(int sys, const unsigned char *code, const int *freq, int n,
        const char *opt, int *ind)
{
    int i, nex, pri, pri_h[8] = {0}, index[8] = {0}, ex[32] = {0};

    /* test code priority */
    for (i = 0; i < n; i++)
        {
            if (!code[i]) continue;

            if (freq[i]>NFREQ)
                { /* save as extended signal if freq > NFREQ */
                    ex[i] = 1;
                    continue;
                }
            /* code priority */
            pri = getcodepri(sys, code[i], opt);

            /* select highest priority signal */
            if (pri>pri_h[freq[i]-1])
                {
                    if (index[freq[i]-1]) ex[index[freq[i]-1]-1] = 1;
                    pri_h[freq[i]-1] = pri;
                    index[freq[i]-1] = i+1;
                }
            else ex[i] = 1;
        }
    /* signal index in obs data */
    for (i = nex = 0; i < n; i++)
        {
            if (ex[i] == 0) ind[i] = freq[i]-1;
            else if (nex < NEXOBS) ind[i] = NFREQ+nex++;
            else
                { /* no space in obs data */
                    trace(2, "rtcm msm: no space in obs data sys=%d code=%d\n", sys, code[i]);
                    ind[i] = -1;
                }
#if 0
            trace(2, "sig pos: sys=%d code=%d ex=%d ind=%d\n", sys, code[i], ex[i], ind[i]);
#endif
        }
}


/* save obs data in msm message ----------------------------------------------*/
void save_msm_obs(rtcm_t *rtcm, int sys, msm_h_t *h, const double *r,
        const double *pr, const double *cp, const double *rr,
        const double *rrf, const double *cnr, const int *lock,
        const int *ex, const int *half)
{
    const char *sig[32];
    double tt, wl;
    unsigned char code[32];
    char *msm_type = (char*)"", *q = NULL;
    int i, j, k, type, prn, sat, fn, index = 0, freq[32], ind[32];

    type = getbitu(rtcm->buff, 24, 12);

    switch (sys)
    {
    case SYS_GPS: msm_type = q = rtcm->msmtype[0]; break;
    case SYS_GLO: msm_type = q = rtcm->msmtype[1]; break;
    case SYS_GAL: msm_type = q = rtcm->msmtype[2]; break;
    case SYS_QZS: msm_type = q = rtcm->msmtype[3]; break;
    case SYS_SBS: msm_type = q = rtcm->msmtype[4]; break;
    case SYS_BDS: msm_type = q = rtcm->msmtype[5]; break;
    }
    /* id to signal */
    for (i = 0; i < h->nsig; i++)
        {
            switch (sys)
            {
            case SYS_GPS: sig[i] = msm_sig_gps[h->sigs[i]-1]; break;
            case SYS_GLO: sig[i] = msm_sig_glo[h->sigs[i]-1]; break;
            case SYS_GAL: sig[i] = msm_sig_gal[h->sigs[i]-1]; break;
            case SYS_QZS: sig[i] = msm_sig_qzs[h->sigs[i]-1]; break;
            case SYS_SBS: sig[i] = msm_sig_sbs[h->sigs[i]-1]; break;
            case SYS_BDS: sig[i] = msm_sig_cmp[h->sigs[i]-1]; break;
            default: sig[i] = ""; break;
            }
            /* signal to rinex obs type */
            code[i] = obs2code(sig[i], freq+i);

            /* freqency index for beidou */
            if (sys == SYS_BDS)
                {
                    if      (freq[i] == 5) freq[i] = 2; /* B2 */
                    else if (freq[i] == 4) freq[i] = 3; /* B3 */
                }
            if (code[i] != CODE_NONE)
                {
                    if (q) q += sprintf(q, "L%s%s", sig[i], i < h->nsig-1 ? ", ":"");
                }
            else
                {
                    if (q) q += sprintf(q, "(%d)%s", h->sigs[i], i < h->nsig-1 ? ", ":"");

                    trace(2, "rtcm3 %d: unknown signal id=%2d\n", type, h->sigs[i]);
                }
        }
    trace(3, "rtcm3 %d: signals=%s\n", type, msm_type);

    /* get signal index */
    sigindex(sys, code, freq, h->nsig, rtcm->opt, ind);

    for (i = j = 0; i < h->nsat; i++)
        {
            prn = h->sats[i];
            if      (sys == SYS_QZS) prn += MINPRNQZS-1;
            else if (sys == SYS_SBS) prn += MINPRNSBS-1;

            if ((sat = satno(sys, prn)))
                {
                    tt = timediff(rtcm->obs.data[0].time, rtcm->time);
                    if (rtcm->obsflag || fabs(tt)>1E-9)
                        {
                            rtcm->obs.n = rtcm->obsflag = 0;
                        }
                    index = obsindex(&rtcm->obs, rtcm->time, sat);
                }
            else
                {
                    trace(2, "rtcm3 %d satellite error: prn=%d\n", type, prn);
                }
            for (k = 0;k < h->nsig;k++)
                {
                    if (!h->cellmask[k+i*h->nsig]) continue;

                    if (sat && index >= 0 && ind[k] >= 0)
                        {
                            /* satellite carrier wave length */
                            wl = satwavelen(sat, freq[k]-1, &rtcm->nav);

                            /* glonass wave length by extended info */
                            if (sys == SYS_GLO && ex && ex[i] <= 13)
                                {
                                    fn = ex[i]-7;
                                    wl = SPEED_OF_LIGHT/((freq[k] == 2 ? FREQ2_GLO : FREQ1_GLO)+
                                            (freq[k] == 2 ? DFRQ2_GLO:DFRQ1_GLO)*fn);
                                }
                            /* pseudorange (m) */
                            if (r[i] != 0.0 && pr[j]>-1E12)
                                {
                                    rtcm->obs.data[index].P[ind[k]] = r[i]+pr[j];
                                }
                            /* carrier-phase (cycle) */
                            if (r[i] != 0.0 && cp[j]>-1E12 && wl>0.0)
                                {
                                    rtcm->obs.data[index].L[ind[k]] = (r[i]+cp[j])/wl;
                                }
                            /* doppler (hz) */
                            if (rr  &&  rrf  &&  rrf[j]>-1E12 && wl>0.0)
                                {
                                    rtcm->obs.data[index].D[ind[k]] = (float)(-(rr[i]+rrf[j])/wl);
                                }
                            rtcm->obs.data[index].LLI[ind[k]] =
                                    lossoflock(rtcm, sat, ind[k], lock[j])+(half[j] ? 3 : 0);
                            rtcm->obs.data[index].SNR [ind[k]] = (unsigned char)(cnr[j]*4.0);
                            rtcm->obs.data[index].code[ind[k]] = code[k];
                        }
                    j++;
                }
        }
}



/* decode type msm message header --------------------------------------------*/
int decode_msm_head(rtcm_t *rtcm, int sys, int *sync, int *iod,
        msm_h_t *h, int *hsize)
{
    msm_h_t h0 = {0};
    double tow, tod;
    char *msg;
    int i = 24, j, dow, mask, staid, type, ncell = 0;

    type = getbitu(rtcm->buff, i, 12); i += 12;

    *h = h0;
    if (i+157 <= rtcm->len*8)
        {
            staid      = getbitu(rtcm->buff, i, 12);       i += 12;

            if (sys == SYS_GLO)
                {
                    dow    = getbitu(rtcm->buff, i, 3);       i +=  3;
                    tod    = getbitu(rtcm->buff, i, 27)*0.001; i += 27;
                    adjday_glot(rtcm, tod);
                }
            else if (sys == SYS_BDS)
                {
                    tow    = getbitu(rtcm->buff, i, 30)*0.001; i += 30;
                    tow += 14.0; /* BDT -> GPST */
                    adjweek(rtcm, tow);
                }
            else
                {
                    tow    = getbitu(rtcm->buff, i, 30)*0.001; i += 30;
                    adjweek(rtcm, tow);
                }
            *sync      = getbitu(rtcm->buff, i, 1);       i += 1;
            *iod       = getbitu(rtcm->buff, i, 3);       i += 3;
            h->time_s  = getbitu(rtcm->buff, i, 7);       i += 7;
            h->clk_str = getbitu(rtcm->buff, i, 2);       i += 2;
            h->clk_ext = getbitu(rtcm->buff, i, 2);       i += 2;
            h->smooth  = getbitu(rtcm->buff, i, 1);       i += 1;
            h->tint_s  = getbitu(rtcm->buff, i, 3);       i += 3;
            for (j = 1; j <= 64; j++)
                {
                    mask = getbitu(rtcm->buff, i, 1); i += 1;
                    if (mask) h->sats[h->nsat++] = j;
                }
            for (j = 1; j <= 32; j++)
                {
                    mask = getbitu(rtcm->buff, i, 1); i += 1;
                    if (mask) h->sigs[h->nsig++] = j;
                }
        }
    else
        {
            trace(2, "rtcm3 %d length error: len=%d\n", type, rtcm->len);
            return -1;
        }
    /* test station id */
    if (!test_staid(rtcm, staid)) return -1;

    if (h->nsat*h->nsig>64)
        {
            trace(2, "rtcm3 %d number of sats and sigs error: nsat=%d nsig=%d\n",
                    type, h->nsat, h->nsig);
            return -1;
        }
    if (i+h->nsat*h->nsig>rtcm->len*8)
        {
            trace(2, "rtcm3 %d length error: len=%d nsat=%d nsig=%d\n", type,
                    rtcm->len, h->nsat, h->nsig);
            return -1;
        }
    for (j = 0; j < h->nsat*h->nsig; j++)
        {
            h->cellmask[j] = getbitu(rtcm->buff, i, 1); i += 1;
            if (h->cellmask[j]) ncell++;
        }
    *hsize = i;

    trace(4, "decode_head_msm: time=%s sys=%d staid=%d nsat=%d nsig=%d sync=%d iod=%d ncell=%d\n",
            time_str(rtcm->time, 2), sys, staid, h->nsat, h->nsig, *sync, *iod, ncell);

    if (rtcm->outtype)
        {
            msg = rtcm->msgtype+strlen(rtcm->msgtype);
            sprintf(msg, " staid=%4d %s nsat=%2d nsig=%2d iod=%2d ncell=%2d sync=%d",
                    staid, time_str(rtcm->time, 2), h->nsat, h->nsig, *iod, ncell, *sync);
        }
    return ncell;
}


/* decode unsupported msm message --------------------------------------------*/
int decode_msm0(rtcm_t *rtcm, int sys)
{
    msm_h_t h = {0};
    int i, sync, iod;
    if (decode_msm_head(rtcm, sys, &sync, &iod, &h, &i) < 0) return -1;
    rtcm->obsflag = !sync;
    return sync ? 0:1;
}


/* decode msm 4: full pseudorange and phaserange plus cnr --------------------*/
int decode_msm4(rtcm_t *rtcm, int sys)
{
    msm_h_t h = {0};
    double r[64], pr[64], cp[64], cnr[64];
    int i, j, type, sync, iod, ncell, rng, rng_m, prv, cpv, lock[64], half[64];

    type = getbitu(rtcm->buff, 24, 12);

    /* decode msm header */
    if ((ncell = decode_msm_head(rtcm, sys, &sync, &iod, &h, &i)) < 0) return -1;

    if (i+h.nsat*18+ncell*48>rtcm->len*8)
        {
            trace(2, "rtcm3 %d length error: nsat=%d ncell=%d len=%d\n", type, h.nsat,
                    ncell, rtcm->len);
            return -1;
        }
    for (j = 0; j < h.nsat; j++) r[j] = 0.0;
    for (j = 0; j < ncell; j++) pr[j] = cp[j] = -1E16;

    /* decode satellite data */
    for (j = 0; j < h.nsat; j++)
        { /* range */
            rng   = getbitu(rtcm->buff, i, 8); i +=  8;
            if (rng != 255) r[j] = rng*RANGE_MS;
        }
    for (j = 0; j < h.nsat; j++)
        {
            rng_m = getbitu(rtcm->buff, i, 10); i += 10;
            if (r[j] != 0.0) r[j] += rng_m*TWO_N10*RANGE_MS;
        }
    /* decode signal data */
    for (j = 0; j < ncell; j++)
        { /* pseudorange */
            prv = getbits(rtcm->buff, i, 15); i += 15;
            if (prv != -16384) pr[j] = prv*TWO_N24*RANGE_MS;
        }
    for (j = 0; j < ncell; j++)
        { /* phaserange */
            cpv = getbits(rtcm->buff, i, 22); i += 22;
            if (cpv != -2097152) cp[j] = cpv*TWO_N29*RANGE_MS;
        }
    for (j = 0; j < ncell; j++)
        { /* lock time */
            lock[j] = getbitu(rtcm->buff, i, 4); i += 4;
        }
    for (j = 0; j < ncell; j++)
        { /* half-cycle ambiguity */
            half[j] = getbitu(rtcm->buff, i, 1); i += 1;
        }
    for (j = 0; j < ncell; j++)
        { /* cnr */
            cnr[j] = getbitu(rtcm->buff, i, 6)*1.0; i += 6;
        }
    /* save obs data in msm message */
    save_msm_obs(rtcm, sys, &h, r, pr, cp, NULL, NULL, cnr, lock, NULL, half);

    rtcm->obsflag = !sync;
    return sync ? 0:1;
}


/* decode msm 5: full pseudorange, phaserange, phaserangerate and cnr --------*/
int decode_msm5(rtcm_t *rtcm, int sys)
{
    msm_h_t h = {0};
    double r[64], rr[64], pr[64], cp[64], rrf[64], cnr[64];
    int i, j, type, sync, iod, ncell, rng, rng_m, rate, prv, cpv, rrv, lock[64];
    int ex[64], half[64];

    type = getbitu(rtcm->buff, 24, 12);

    /* decode msm header */
    if ((ncell = decode_msm_head(rtcm, sys, &sync, &iod, &h, &i)) < 0) return -1;

    if (i+h.nsat*36+ncell*63>rtcm->len*8)
        {
            trace(2, "rtcm3 %d length error: nsat=%d ncell=%d len=%d\n", type, h.nsat,
                    ncell, rtcm->len);
            return -1;
        }
    for (j = 0; j < h.nsat; j++)
        {
            r[j] = rr[j] = 0.0; ex[j] = 15;
        }
    for (j = 0; j < ncell; j++) pr[j] = cp[j] = rrf[j] = -1E16;

    /* decode satellite data */
    for (j = 0; j < h.nsat; j++)
        { /* range */
            rng   = getbitu(rtcm->buff, i, 8); i +=  8;
            if (rng != 255) r[j] = rng*RANGE_MS;
        }
    for (j = 0; j < h.nsat; j++)
        { /* extended info */
            ex[j] = getbitu(rtcm->buff, i, 4); i +=  4;
        }
    for (j = 0; j < h.nsat; j++)
        {
            rng_m = getbitu(rtcm->buff, i, 10); i += 10;
            if (r[j] != 0.0) r[j] += rng_m*TWO_N10*RANGE_MS;
        }
    for (j = 0; j < h.nsat; j++)
        { /* phaserangerate */
            rate  = getbits(rtcm->buff, i, 14); i += 14;
            if (rate != -8192) rr[j] = rate*1.0;
        }
    /* decode signal data */
    for (j = 0; j < ncell; j++)
        { /* pseudorange */
            prv = getbits(rtcm->buff, i, 15); i += 15;
            if (prv != -16384) pr[j] = prv*TWO_N24*RANGE_MS;
        }
    for (j = 0; j < ncell; j++)
        { /* phaserange */
            cpv = getbits(rtcm->buff, i, 22); i += 22;
            if (cpv != -2097152) cp[j] = cpv*TWO_N29*RANGE_MS;
        }
    for (j = 0; j < ncell; j++)
        { /* lock time */
            lock[j] = getbitu(rtcm->buff, i, 4); i += 4;
        }
    for (j = 0; j < ncell; j++)
        { /* half-cycle ambiguity */
            half[j] = getbitu(rtcm->buff, i, 1); i += 1;
        }
    for (j = 0; j < ncell; j++)
        { /* cnr */
            cnr[j] = getbitu(rtcm->buff, i, 6)*1.0; i += 6;
        }
    for (j = 0; j < ncell; j++)
        { /* phaserangerate */
            rrv = getbits(rtcm->buff, i, 15); i += 15;
            if (rrv != -16384) rrf[j] = rrv*0.0001;
        }
    /* save obs data in msm message */
    save_msm_obs(rtcm, sys, &h, r, pr, cp, rr, rrf, cnr, lock, ex, half);

    rtcm->obsflag = !sync;
    return sync ? 0:1;
}


/* decode msm 6: full pseudorange and phaserange plus cnr (high-res) ---------*/
int decode_msm6(rtcm_t *rtcm, int sys)
{
    msm_h_t h = {0};
    double r[64], pr[64], cp[64], cnr[64];
    int i, j, type, sync, iod, ncell, rng, rng_m, prv, cpv, lock[64], half[64];

    type = getbitu(rtcm->buff, 24, 12);

    /* decode msm header */
    if ((ncell = decode_msm_head(rtcm, sys, &sync, &iod, &h, &i)) < 0) return -1;

    if (i+h.nsat*18+ncell*65>rtcm->len*8)
        {
            trace(2, "rtcm3 %d length error: nsat=%d ncell=%d len=%d\n", type, h.nsat,
                    ncell, rtcm->len);
            return -1;
        }
    for (j = 0; j < h.nsat; j++) r[j] = 0.0;
    for (j = 0; j < ncell; j++) pr[j] = cp[j] = -1E16;

    /* decode satellite data */
    for (j = 0; j < h.nsat; j++)
        { /* range */
            rng   = getbitu(rtcm->buff, i, 8); i +=  8;
            if (rng != 255) r[j] = rng*RANGE_MS;
        }
    for (j = 0; j < h.nsat; j++)
        {
            rng_m = getbitu(rtcm->buff, i, 10); i += 10;
            if (r[j] != 0.0) r[j] += rng_m*TWO_N10*RANGE_MS;
        }
    /* decode signal data */
    for (j = 0; j < ncell; j++)
        { /* pseudorange */
            prv = getbits(rtcm->buff, i, 20); i += 20;
            if (prv != -524288) pr[j] = prv*TWO_N29*RANGE_MS;
        }
    for (j = 0; j < ncell; j++)
        { /* phaserange */
            cpv = getbits(rtcm->buff, i, 24); i += 24;
            if (cpv != -8388608) cp[j] = cpv*TWO_N31*RANGE_MS;
        }
    for (j = 0; j < ncell; j++)
        { /* lock time */
            lock[j] = getbitu(rtcm->buff, i, 10); i += 10;
        }
    for (j = 0; j < ncell; j++)
        { /* half-cycle ambiguity */
            half[j] = getbitu(rtcm->buff, i, 1); i += 1;
        }
    for (j = 0; j < ncell; j++)
        { /* cnr */
            cnr[j] = getbitu(rtcm->buff, i, 10)*0.0625; i += 10;
        }
    /* save obs data in msm message */
    save_msm_obs(rtcm, sys, &h, r, pr, cp, NULL, NULL, cnr, lock, NULL, half);

    rtcm->obsflag = !sync;
    return sync ? 0:1;
}


/* decode msm 7: full pseudorange, phaserange, phaserangerate and cnr (h-res) */
int decode_msm7(rtcm_t *rtcm, int sys)
{
    msm_h_t h = {0};
    double r[64], rr[64], pr[64], cp[64], rrf[64], cnr[64];
    int i, j, type, sync, iod, ncell, rng, rng_m, rate, prv, cpv, rrv, lock[64];
    int ex[64], half[64];

    type = getbitu(rtcm->buff, 24, 12);

    /* decode msm header */
    if ((ncell = decode_msm_head(rtcm, sys, &sync, &iod, &h, &i)) < 0) return -1;

    if (i+h.nsat*36+ncell*80 > rtcm->len*8)
        {
            trace(2, "rtcm3 %d length error: nsat=%d ncell=%d len=%d\n", type, h.nsat,
                    ncell, rtcm->len);
            return -1;
        }
    for (j = 0; j < h.nsat; j++)
        {
            r[j] = rr[j] = 0.0; ex[j] = 15;
        }
    for (j = 0; j < ncell; j++) pr[j] = cp[j] = rrf[j] = -1E16;

    /* decode satellite data */
    for (j = 0; j < h.nsat; j++)
        { /* range */
            rng   = getbitu(rtcm->buff, i, 8); i +=  8;
            if (rng != 255) r[j] = rng*RANGE_MS;
        }
    for (j = 0; j < h.nsat; j++)
        { /* extended info */
            ex[j] = getbitu(rtcm->buff, i, 4); i +=  4;
        }
    for (j = 0; j < h.nsat; j++)
        {
            rng_m = getbitu(rtcm->buff, i, 10); i += 10;
            if (r[j] != 0.0) r[j] += rng_m*TWO_N10*RANGE_MS;
        }
    for (j = 0; j < h.nsat; j++)
        { /* phaserangerate */
            rate  = getbits(rtcm->buff, i, 14); i += 14;
            if (rate != -8192) rr[j] = rate*1.0;
        }
    /* decode signal data */
    for (j = 0; j < ncell; j++)
        { /* pseudorange */
            prv = getbits(rtcm->buff, i, 20); i += 20;
            if (prv != -524288) pr[j] = prv*TWO_N29*RANGE_MS;
        }
    for (j = 0; j < ncell; j++)
        { /* phaserange */
            cpv = getbits(rtcm->buff, i, 24); i += 24;
            if (cpv != -8388608) cp[j] = cpv*TWO_N31*RANGE_MS;
        }
    for (j = 0; j < ncell; j++)
        { /* lock time */
            lock[j] = getbitu(rtcm->buff, i, 10); i += 10;
        }
    for (j = 0; j < ncell; j++)
        { /* half-cycle amiguity */
            half[j] = getbitu(rtcm->buff, i, 1); i += 1;
        }
    for (j = 0; j < ncell; j++)
        { /* cnr */
            cnr[j] = getbitu(rtcm->buff, i, 10)*0.0625; i += 10;
        }
    for (j = 0; j < ncell; j++)
        { /* phaserangerate */
            rrv = getbits(rtcm->buff, i, 15); i += 15;
            if (rrv != -16384) rrf[j] = rrv*0.0001;
        }
    /* save obs data in msm message */
    save_msm_obs(rtcm, sys, &h, r, pr, cp, rr, rrf, cnr, lock, ex, half);

    rtcm->obsflag = !sync;
    return sync ? 0:1;
}


/* decode type 1230: glonass L1 and L2 code-phase biases ---------------------*/
int decode_type1230(rtcm_t *rtcm)
{
    trace(2, "rtcm3 1230: not supported message\n");
    return 0;
}


/* decode rtcm ver.3 message -------------------------------------------------*/
int decode_rtcm3(rtcm_t *rtcm)
{
    double tow;
    int ret = 0, type = getbitu(rtcm->buff, 24, 12), week;

    trace(3, "decode_rtcm3: len=%3d type=%d\n", rtcm->len, type);

    if (rtcm->outtype)
        {
            sprintf(rtcm->msgtype, "RTCM %4d (%4d):", type, rtcm->len);
        }
    /* real-time input option */
    if (strstr(rtcm->opt, "-RT_INP"))
        {
            tow = time2gpst(utc2gpst(timeget()), &week);
            rtcm->time = gpst2time(week, floor(tow));
        }
    switch (type)
    {
    case 1001: ret = decode_type1001(rtcm); break; /* not supported */
    case 1002: ret = decode_type1002(rtcm); break;
    case 1003: ret = decode_type1003(rtcm); break; /* not supported */
    case 1004: ret = decode_type1004(rtcm); break;
    case 1005: ret = decode_type1005(rtcm); break;
    case 1006: ret = decode_type1006(rtcm); break;
    case 1007: ret = decode_type1007(rtcm); break;
    case 1008: ret = decode_type1008(rtcm); break;
    case 1009: ret = decode_type1009(rtcm); break; /* not supported */
    case 1010: ret = decode_type1010(rtcm); break;
    case 1011: ret = decode_type1011(rtcm); break; /* not supported */
    case 1012: ret = decode_type1012(rtcm); break;
    case 1013: ret = decode_type1013(rtcm); break; /* not supported */
    case 1019: ret = decode_type1019(rtcm); break;
    case 1020: ret = decode_type1020(rtcm); break;
    case 1021: ret = decode_type1021(rtcm); break; /* not supported */
    case 1022: ret = decode_type1022(rtcm); break; /* not supported */
    case 1023: ret = decode_type1023(rtcm); break; /* not supported */
    case 1024: ret = decode_type1024(rtcm); break; /* not supported */
    case 1025: ret = decode_type1025(rtcm); break; /* not supported */
    case 1026: ret = decode_type1026(rtcm); break; /* not supported */
    case 1027: ret = decode_type1027(rtcm); break; /* not supported */
    case 1029: ret = decode_type1029(rtcm); break;
    case 1030: ret = decode_type1030(rtcm); break; /* not supported */
    case 1031: ret = decode_type1031(rtcm); break; /* not supported */
    case 1032: ret = decode_type1032(rtcm); break; /* not supported */
    case 1033: ret = decode_type1033(rtcm); break;
    case 1034: ret = decode_type1034(rtcm); break; /* not supported */
    case 1035: ret = decode_type1035(rtcm); break; /* not supported */
    case 1037: ret = decode_type1037(rtcm); break; /* not supported */
    case 1038: ret = decode_type1038(rtcm); break; /* not supported */
    case 1039: ret = decode_type1039(rtcm); break; /* not supported */
    case 1044: ret = decode_type1044(rtcm); break;
    case 1045: ret = decode_type1045(rtcm); break;
    case 1046: ret = decode_type1046(rtcm); break; /* extension for IGS MGEX */
    case 1047: ret = decode_type1047(rtcm); break; /* beidou ephemeris (tentative mt) */
    case   63: ret = decode_type63  (rtcm); break; /* beidou ephemeris (rtcm draft) */
    case 1057: ret = decode_ssr1(rtcm, SYS_GPS); break;
    case 1058: ret = decode_ssr2(rtcm, SYS_GPS); break;
    case 1059: ret = decode_ssr3(rtcm, SYS_GPS); break;
    case 1060: ret = decode_ssr4(rtcm, SYS_GPS); break;
    case 1061: ret = decode_ssr5(rtcm, SYS_GPS); break;
    case 1062: ret = decode_ssr6(rtcm, SYS_GPS); break;
    case 1063: ret = decode_ssr1(rtcm, SYS_GLO); break;
    case 1064: ret = decode_ssr2(rtcm, SYS_GLO); break;
    case 1065: ret = decode_ssr3(rtcm, SYS_GLO); break;
    case 1066: ret = decode_ssr4(rtcm, SYS_GLO); break;
    case 1067: ret = decode_ssr5(rtcm, SYS_GLO); break;
    case 1068: ret = decode_ssr6(rtcm, SYS_GLO); break;
    case 1071: ret = decode_msm0(rtcm, SYS_GPS); break; /* not supported */
    case 1072: ret = decode_msm0(rtcm, SYS_GPS); break; /* not supported */
    case 1073: ret = decode_msm0(rtcm, SYS_GPS); break; /* not supported */
    case 1074: ret = decode_msm4(rtcm, SYS_GPS); break;
    case 1075: ret = decode_msm5(rtcm, SYS_GPS); break;
    case 1076: ret = decode_msm6(rtcm, SYS_GPS); break;
    case 1077: ret = decode_msm7(rtcm, SYS_GPS); break;
    case 1081: ret = decode_msm0(rtcm, SYS_GLO); break; /* not supported */
    case 1082: ret = decode_msm0(rtcm, SYS_GLO); break; /* not supported */
    case 1083: ret = decode_msm0(rtcm, SYS_GLO); break; /* not supported */
    case 1084: ret = decode_msm4(rtcm, SYS_GLO); break;
    case 1085: ret = decode_msm5(rtcm, SYS_GLO); break;
    case 1086: ret = decode_msm6(rtcm, SYS_GLO); break;
    case 1087: ret = decode_msm7(rtcm, SYS_GLO); break;
    case 1091: ret = decode_msm0(rtcm, SYS_GAL); break; /* not supported */
    case 1092: ret = decode_msm0(rtcm, SYS_GAL); break; /* not supported */
    case 1093: ret = decode_msm0(rtcm, SYS_GAL); break; /* not supported */
    case 1094: ret = decode_msm4(rtcm, SYS_GAL); break;
    case 1095: ret = decode_msm5(rtcm, SYS_GAL); break;
    case 1096: ret = decode_msm6(rtcm, SYS_GAL); break;
    case 1097: ret = decode_msm7(rtcm, SYS_GAL); break;
    case 1101: ret = decode_msm0(rtcm, SYS_SBS); break; /* not supported */
    case 1102: ret = decode_msm0(rtcm, SYS_SBS); break; /* not supported */
    case 1103: ret = decode_msm0(rtcm, SYS_SBS); break; /* not supported */
    case 1104: ret = decode_msm4(rtcm, SYS_SBS); break;
    case 1105: ret = decode_msm5(rtcm, SYS_SBS); break;
    case 1106: ret = decode_msm6(rtcm, SYS_SBS); break;
    case 1107: ret = decode_msm7(rtcm, SYS_SBS); break;
    case 1111: ret = decode_msm0(rtcm, SYS_QZS); break; /* not supported */
    case 1112: ret = decode_msm0(rtcm, SYS_QZS); break; /* not supported */
    case 1113: ret = decode_msm0(rtcm, SYS_QZS); break; /* not supported */
    case 1114: ret = decode_msm4(rtcm, SYS_QZS); break;
    case 1115: ret = decode_msm5(rtcm, SYS_QZS); break;
    case 1116: ret = decode_msm6(rtcm, SYS_QZS); break;
    case 1117: ret = decode_msm7(rtcm, SYS_QZS); break;
    case 1121: ret = decode_msm0(rtcm, SYS_BDS); break; /* not supported */
    case 1122: ret = decode_msm0(rtcm, SYS_BDS); break; /* not supported */
    case 1123: ret = decode_msm0(rtcm, SYS_BDS); break; /* not supported */
    case 1124: ret = decode_msm4(rtcm, SYS_BDS); break;
    case 1125: ret = decode_msm5(rtcm, SYS_BDS); break;
    case 1126: ret = decode_msm6(rtcm, SYS_BDS); break;
    case 1127: ret = decode_msm7(rtcm, SYS_BDS); break;
    case 1230: ret = decode_type1230(rtcm);     break; /* not supported */
    case 1240: ret = decode_ssr1(rtcm, SYS_GAL); break;
    case 1241: ret = decode_ssr2(rtcm, SYS_GAL); break;
    case 1242: ret = decode_ssr3(rtcm, SYS_GAL); break;
    case 1243: ret = decode_ssr4(rtcm, SYS_GAL); break;
    case 1244: ret = decode_ssr5(rtcm, SYS_GAL); break;
    case 1245: ret = decode_ssr6(rtcm, SYS_GAL); break;
    case 1246: ret = decode_ssr1(rtcm, SYS_QZS); break;
    case 1247: ret = decode_ssr2(rtcm, SYS_QZS); break;
    case 1248: ret = decode_ssr3(rtcm, SYS_QZS); break;
    case 1249: ret = decode_ssr4(rtcm, SYS_QZS); break;
    case 1250: ret = decode_ssr5(rtcm, SYS_QZS); break;
    case 1251: ret = decode_ssr6(rtcm, SYS_QZS); break;
    case 1252: ret = decode_ssr1(rtcm, SYS_SBS); break;
    case 1253: ret = decode_ssr2(rtcm, SYS_SBS); break;
    case 1254: ret = decode_ssr3(rtcm, SYS_SBS); break;
    case 1255: ret = decode_ssr4(rtcm, SYS_SBS); break;
    case 1256: ret = decode_ssr5(rtcm, SYS_SBS); break;
    case 1257: ret = decode_ssr6(rtcm, SYS_SBS); break;
    case 1258: ret = decode_ssr1(rtcm, SYS_BDS); break;
    case 1259: ret = decode_ssr2(rtcm, SYS_BDS); break;
    case 1260: ret = decode_ssr3(rtcm, SYS_BDS); break;
    case 1261: ret = decode_ssr4(rtcm, SYS_BDS); break;
    case 1262: ret = decode_ssr5(rtcm, SYS_BDS); break;
    case 1263: ret = decode_ssr6(rtcm, SYS_BDS); break;
    case 2065: ret = decode_ssr7(rtcm, SYS_GPS); break; /* tentative */
    case 2066: ret = decode_ssr7(rtcm, SYS_GLO); break; /* tentative */
    case 2067: ret = decode_ssr7(rtcm, SYS_GAL); break; /* tentative */
    case 2068: ret = decode_ssr7(rtcm, SYS_QZS); break; /* tentative */
    case 2070: ret = decode_ssr7(rtcm, SYS_BDS); break; /* tentative */
    }
    if (ret >= 0)
        {
            type -= 1000;
            if      (   1 <= type && type <=  299) rtcm->nmsg3[type    ]++; /* 1001-1299 */
            else if (1000 <= type && type <= 1099) rtcm->nmsg3[type-700]++; /* 2000-2099 */
            else rtcm->nmsg3[0]++;
        }
    return ret;
}