/*! * \file rtklib_tides.cc * \brief Tidal displacement corrections * \authors * * 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) 2007-2008, T. Takasu * Copyright (C) 2017, Javier Arribas * Copyright (C) 2017, Carles Fernandez * All rights reserved. * * SPDX-License-Identifier: BSD-2-Clause * *----------------------------------------------------------------------------*/ #include "rtklib_tides.h" #include "rtklib_rtkcmn.h" /* solar/lunar tides (ref [2] 7) ---------------------------------------------*/ // #ifndef IERS_MODEL void tide_pl(const double *eu, const double *rp, double GMp, const double *pos, double *dr) { const double H3 = 0.292; const double L3 = 0.015; double r; double ep[3]; double latp; double lonp; double p; double K2; double K3; double a; double H2; double L2; double dp; double du; double cosp; double sinl; double cosl; int i; trace(4, "tide_pl : pos=%.3f %.3f\n", pos[0] * R2D, pos[1] * R2D); if ((r = norm_rtk(rp, 3)) <= 0.0) { return; } for (i = 0; i < 3; i++) { ep[i] = rp[i] / r; } K2 = GMp / GME * std::pow(RE_WGS84, 2.04) * std::pow(RE_WGS84, 2.0) / (r * r * r); K3 = K2 * RE_WGS84 / r; latp = asin(ep[2]); lonp = atan2(ep[1], ep[0]); cosp = cos(latp); sinl = sin(pos[0]); cosl = cos(pos[0]); /* step1 in phase (degree 2) */ p = (3.0 * sinl * sinl - 1.0) / 2.0; H2 = 0.6078 - 0.0006 * p; L2 = 0.0847 + 0.0002 * p; a = dot(ep, eu, 3); dp = K2 * 3.0 * L2 * a; du = K2 * (H2 * (1.5 * a * a - 0.5) - 3.0 * L2 * a * a); /* step1 in phase (degree 3) */ dp += K3 * L3 * (7.5 * a * a - 1.5); du += K3 * (H3 * (2.5 * a * a * a - 1.5 * a) - L3 * (7.5 * a * a - 1.5) * a); /* step1 out-of-phase (only radial) */ du += 3.0 / 4.0 * 0.0025 * K2 * sin(2.0 * latp) * sin(2.0 * pos[0]) * sin(pos[1] - lonp); du += 3.0 / 4.0 * 0.0022 * K2 * cosp * cosp * cosl * cosl * sin(2.0 * (pos[1] - lonp)); dr[0] = dp * ep[0] + du * eu[0]; dr[1] = dp * ep[1] + du * eu[1]; dr[2] = dp * ep[2] + du * eu[2]; trace(5, "tide_pl : dr=%.3f %.3f %.3f\n", dr[0], dr[1], dr[2]); } /* displacement by solid earth tide (ref [2] 7) ------------------------------*/ void tide_solid(const double *rsun, const double *rmoon, const double *pos, const double *E, double gmst, int opt, double *dr) { double dr1[3] = {0.0, 0.0, 0.0}; double dr2[3] = {0.0, 0.0, 0.0}; double eu[3]; double du; double dn; double sinl; double sin2l; trace(3, "tide_solid: pos=%.3f %.3f opt=%d\n", pos[0] * R2D, pos[1] * R2D, opt); /* step1: time domain */ eu[0] = E[2]; eu[1] = E[5]; eu[2] = E[8]; tide_pl(eu, rsun, GMS, pos, dr1); tide_pl(eu, rmoon, GMM, pos, dr2); /* step2: frequency domain, only K1 radial */ sin2l = sin(2.0 * pos[0]); du = -0.012 * sin2l * sin(gmst + pos[1]); dr[0] = dr1[0] + dr2[0] + du * E[2]; dr[1] = dr1[1] + dr2[1] + du * E[5]; dr[2] = dr1[2] + dr2[2] + du * E[8]; /* eliminate permanent deformation */ if (opt & 8) { sinl = sin(pos[0]); du = 0.1196 * (1.5 * sinl * sinl - 0.5); dn = 0.0247 * sin2l; dr[0] += du * E[2] + dn * E[1]; dr[1] += du * E[5] + dn * E[4]; dr[2] += du * E[8] + dn * E[7]; } trace(5, "tide_solid: dr=%.3f %.3f %.3f\n", dr[0], dr[1], dr[2]); } // #endif /* !IERS_MODEL */ /* displacement by ocean tide loading (ref [2] 7) ----------------------------*/ void tide_oload(gtime_t tut, const double *odisp, double *denu) { const double args[][5] = { {1.40519E-4, 2.0, -2.0, 0.0, 0.00}, /* M2 */ {1.45444E-4, 0.0, 0.0, 0.0, 0.00}, /* S2 */ {1.37880E-4, 2.0, -3.0, 1.0, 0.00}, /* N2 */ {1.45842E-4, 2.0, 0.0, 0.0, 0.00}, /* K2 */ {0.72921E-4, 1.0, 0.0, 0.0, 0.25}, /* K1 */ {0.67598E-4, 1.0, -2.0, 0.0, -0.25}, /* O1 */ {0.72523E-4, -1.0, 0.0, 0.0, -0.25}, /* P1 */ {0.64959E-4, 1.0, -3.0, 1.0, -0.25}, /* Q1 */ {0.53234E-5, 0.0, 2.0, 0.0, 0.00}, /* Mf */ {0.26392E-5, 0.0, 1.0, -1.0, 0.00}, /* Mm */ {0.03982E-5, 2.0, 0.0, 0.0, 0.00} /* Ssa */ }; const double ep1975[] = {1975, 1, 1, 0, 0, 0}; double ep[6]; double fday; double days; double t; double t2; double t3; double a[5]; double ang; double dp[3] = {0}; int i; int j; trace(3, "tide_oload:\n"); /* angular argument: see subroutine arg.f for reference [1] */ time2epoch(tut, ep); fday = ep[3] * 3600.0 + ep[4] * 60.0 + ep[5]; ep[3] = ep[4] = ep[5] = 0.0; days = timediff(epoch2time(ep), epoch2time(ep1975)) / 86400.0 + 1.0; t = (27392.500528 + 1.000000035 * days) / 36525.0; t2 = t * t; t3 = t2 * t; a[0] = fday; a[1] = (279.69668 + 36000.768930485 * t + 3.03E-4 * t2) * D2R; /* H0 */ a[2] = (270.434358 + 481267.88314137 * t - 0.001133 * t2 + 1.9E-6 * t3) * D2R; /* S0 */ a[3] = (334.329653 + 4069.0340329577 * t - 0.010325 * t2 - 1.2E-5 * t3) * D2R; /* P0 */ a[4] = 2.0 * PI; /* displacements by 11 constituents */ for (i = 0; i < 11; i++) { ang = 0.0; for (j = 0; j < 5; j++) { ang += a[j] * args[i][j]; } for (j = 0; j < 3; j++) { dp[j] += odisp[j + i * 6] * cos(ang - odisp[j + 3 + i * 6] * D2R); } } denu[0] = -dp[1]; denu[1] = -dp[2]; denu[2] = dp[0]; trace(5, "tide_oload: denu=%.3f %.3f %.3f\n", denu[0], denu[1], denu[2]); } /* iers mean pole (ref [7] eq.7.25) ------------------------------------------*/ void iers_mean_pole(gtime_t tut, double *xp_bar, double *yp_bar) { const double ep2000[] = {2000, 1, 1, 0, 0, 0}; double y; double y2; double y3; y = timediff(tut, epoch2time(ep2000)) / 86400.0 / 365.25; if (y < 3653.0 / 365.25) { /* until 2010.0 */ y2 = y * y; y3 = y2 * y; *xp_bar = 55.974 + 1.8243 * y + 0.18413 * y2 + 0.007024 * y3; /* (mas) */ *yp_bar = 346.346 + 1.7896 * y - 0.10729 * y2 - 0.000908 * y3; } else { /* after 2010.0 */ *xp_bar = 23.513 + 7.6141 * y; /* (mas) */ *yp_bar = 358.891 - 0.6287 * y; } } /* displacement by pole tide (ref [7] eq.7.26) --------------------------------*/ void tide_pole(gtime_t tut, const double *pos, const double *erpv, double *denu) { double xp_bar; double yp_bar; double m1; double m2; double cosl; double sinl; trace(3, "tide_pole: pos=%.3f %.3f\n", pos[0] * R2D, pos[1] * R2D); /* iers mean pole (mas) */ iers_mean_pole(tut, &xp_bar, &yp_bar); /* ref [7] eq.7.24 */ m1 = erpv[0] / AS2R - xp_bar * 1E-3; /* (as) */ m2 = -erpv[1] / AS2R + yp_bar * 1E-3; /* sin(2*theta) = sin(2*phi), cos(2*theta)=-cos(2*phi) */ cosl = cos(pos[1]); sinl = sin(pos[1]); denu[0] = 9E-3 * sin(pos[0]) * (m1 * sinl - m2 * cosl); /* de= Slambda (m) */ denu[1] = -9E-3 * cos(2.0 * pos[0]) * (m1 * cosl + m2 * sinl); /* dn=-Stheta (m) */ denu[2] = -33E-3 * sin(2.0 * pos[0]) * (m1 * cosl + m2 * sinl); /* du= Sr (m) */ trace(5, "tide_pole : denu=%.3f %.3f %.3f\n", denu[0], denu[1], denu[2]); } /* tidal displacement ---------------------------------------------------------- * displacements by earth tides * args : gtime_t tutc I time in utc * double *rr I site position (ecef) (m) * int opt I options (one of the following) * 1: solid earth tide * 2: ocean tide loading * 4: pole tide * 8: elimate permanent deformation * double *erp I earth rotation parameters (NULL: not used) * double *odisp I ocean loading parameters (NULL: not used) * odisp[0+i*6]: consituent i amplitude radial(m) * odisp[1+i*6]: consituent i amplitude west (m) * odisp[2+i*6]: consituent i amplitude south (m) * odisp[3+i*6]: consituent i phase radial (deg) * odisp[4+i*6]: consituent i phase west (deg) * odisp[5+i*6]: consituent i phase south (deg) * (i=0:M2,1:S2,2:N2,3:K2,4:K1,5:O1,6:P1,7:Q1, * 8:Mf,9:Mm,10:Ssa) * double *dr O displacement by earth tides (ecef) (m) * return : none * notes : see ref [1], [2] chap 7 * see ref [4] 5.2.1, 5.2.2, 5.2.3 * ver.2.4.0 does not use ocean loading and pole tide corrections *-----------------------------------------------------------------------------*/ void tidedisp(gtime_t tutc, const double *rr, int opt, const erp_t *erp, const double *odisp, double *dr) { gtime_t tut; double pos[2]; double E[9]; double drt[3]; double denu[3]; double rs[3]; double rm[3]; double gmst; double erpv[5] = {0}; int i; #ifdef IERS_MODEL double ep[6], fhr; int year, mon, day; #endif trace(3, "tidedisp: tutc=%s\n", time_str(tutc, 0)); if (erp) { geterp(erp, tutc, erpv); } tut = timeadd(tutc, erpv[2]); dr[0] = dr[1] = dr[2] = 0.0; if (norm_rtk(rr, 3) <= 0.0) { return; } pos[0] = asin(rr[2] / norm_rtk(rr, 3)); pos[1] = atan2(rr[1], rr[0]); xyz2enu(pos, E); if (opt & 1) { /* solid earth tides */ /* sun and moon position in ecef */ sunmoonpos(tutc, erpv, rs, rm, &gmst); #ifdef IERS_MODEL time2epoch(tutc, ep); year = static_cast(ep[0]); mon = static_cast(ep[1]); day = static_cast(ep[2]); fhr = ep[3] + ep[4] / 60.0 + ep[5] / 3600.0; /* call DEHANTTIDEINEL */ // dehanttideinel_((double *)rr,&year,&mon,&day,&fhr,rs,rm,drt); #else tide_solid(rs, rm, pos, E, gmst, opt, drt); #endif for (i = 0; i < 3; i++) { dr[i] += drt[i]; } } if ((opt & 2) && odisp) { /* ocean tide loading */ tide_oload(tut, odisp, denu); matmul("TN", 3, 1, 3, 1.0, E, denu, 0.0, drt); for (i = 0; i < 3; i++) { dr[i] += drt[i]; } } if ((opt & 4) && erp) { /* pole tide */ tide_pole(tut, pos, erpv, denu); matmul("TN", 3, 1, 3, 1.0, E, denu, 0.0, drt); for (i = 0; i < 3; i++) { dr[i] += drt[i]; } } trace(5, "tidedisp: dr=%.3f %.3f %.3f\n", dr[0], dr[1], dr[2]); }