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glonass bug fix: Adds more reliable GPST 2 UTC conversion

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Adds logic to check for exact epoch when performing leap second
correction and also fixes unit test in code for GLONASS
This commit is contained in:
Damian Miralles 2017-12-26 10:29:09 -07:00
parent ad07c8940b
commit aa2464cc28
7 changed files with 51 additions and 35 deletions
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28
src/algorithms/PVT/libs/rinex_printer.cc
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@ -7398,18 +7398,8 @@ boost::posix_time::ptime Rinex_Printer::compute_UTC_time(const Glonass_Gnav_Ephe
double obs_time_utc = 0.0, obs_time_glot = 0.0;
int i = 0;
// GLONASST already includes leap second addition or deletion
for (i = 0; GLONASS_LEAP_SECONDS[i][0]>0; i++)
{
if (eph.d_yr >= GLONASS_LEAP_SECONDS[i][0])
{
// We substract the leap second when going from gpst to utc
obs_time_utc = obs_time - fabs(GLONASS_LEAP_SECONDS[i][6]);
break;
}
}
// Get observation time in GLONASS time
obs_time_glot = obs_time_utc + glot2utc;
// Get observation time in nearly GLONASS time. Correction for leap seconds done at the end
obs_time_glot = obs_time + glot2utc;
// Get seconds of day in glonass time
tod = fmod (obs_time_glot, 86400);
@ -7424,6 +7414,20 @@ boost::posix_time::ptime Rinex_Printer::compute_UTC_time(const Glonass_Gnav_Ephe
boost::posix_time::time_duration t2(0, 0, glot2utc);
boost::posix_time::ptime utc_time = glo_time - t2;
// Adjust for leap second correction
for (i = 0; GLONASS_LEAP_SECONDS[i][0]>0; i++)
{
boost::posix_time::time_duration t3(GLONASS_LEAP_SECONDS[i][3], GLONASS_LEAP_SECONDS[i][4], GLONASS_LEAP_SECONDS[i][5]);
boost::gregorian::date d3(GLONASS_LEAP_SECONDS[i][0], GLONASS_LEAP_SECONDS[i][1], GLONASS_LEAP_SECONDS[i][2]);
boost::posix_time::ptime ls_time(d3, t3);
if (utc_time >= ls_time)
{
// We subtract the leap second when going from gpst to utc
utc_time = utc_time - boost::posix_time::time_duration(0,0,fabs(GLONASS_LEAP_SECONDS[i][6]));
break;
}
}
return utc_time;
}

2
src/algorithms/PVT/libs/rinex_printer.h
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@ -156,7 +156,7 @@ public:
/*!
* \brief Generates the GLONASS GNAV Observation data header. Example: bands("1C"), bands("1C 2C"), bands("2C"), ... Default: "1C".
*/
void rinex_obs_header(std::fstream & out, const Glonass_Gnav_Ephemeris & eph, const double d_TOW_first_observation, const std::string bands = "1C");
void rinex_obs_header(std::fstream & out, const Glonass_Gnav_Ephemeris & eph, const double d_TOW_first_observation, const std::string bands = "1G");
/*!
* \brief Generates the Mixed (GPS L1 C/A /GLONASS) Observation data header. Example: galileo_bands("1C"), galileo_bands("1B 5X"), galileo_bands("5X"), ... Default: "1B".

12
src/core/system_parameters/GLONASS_L1_CA.h
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@ -89,8 +89,12 @@ const double GLONASS_L1_CA_CHIP_PERIOD = 1.9569e-06; //!< GLONASS L1 C/
const double GLONASS_L1_CA_SYMBOL_RATE_BPS = 1000;
const int GLONASS_L1_CA_NBR_SATS = 24; // STRING DATA WITHOUT PREAMBLE
//FIXME Probably should use leap seconds definitions of rtklib
const double GLONASS_LEAP_SECONDS[21][7] = { /* leap seconds (y,m,d,h,m,s,utc-gpst) */
/*!
* \brief Record of leap seconds definition for GLOT to GPST conversion and vice versa
* \details Each entry is defined by an array of 7 elements consisting of yr,month,day,hr,min,sec,utc-gpst
* \note Ideally should use leap seconds definitions of rtklib
*/
const double GLONASS_LEAP_SECONDS[19][7] = {
{2017, 1, 1, 0, 0, 0, -18},
{2015, 7, 1, 0, 0, 0, -17},
{2012, 7, 1, 0, 0, 0, -16},
@ -112,7 +116,7 @@ const double GLONASS_LEAP_SECONDS[21][7] = { /* leap seconds (y,m,d,h,m,s,utc-gp
{}
};
// GLONASS SV's orbital slots PRN = (orbital_slot - 1)
//!< GLONASS SV's orbital slots PRN = (orbital_slot - 1)
const std::map<unsigned int, int> GLONASS_PRN =
{{ 0, 8,}, //For test
{ 1, 1,}, //Plane 1
@ -134,7 +138,7 @@ const std::map<unsigned int, int> GLONASS_PRN =
{17, 4,}, //Plane 3
{18,-3,}, //Plane 3
{19, 3,}, //Plane 3
{20, -5,}, //Plane 3
{20,-5,}, //Plane 3
{21, 4,}, //Plane 3
{22,-3,}, //Plane 3
{23, 3,}, //Plane 3

34
src/core/system_parameters/glonass_gnav_ephemeris.cc
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@ -124,28 +124,32 @@ void Glonass_Gnav_Ephemeris::glot_to_gpst(double tod_offset, double glot2utc_cor
boost::posix_time::time_duration t(0, 0, tod);
boost::gregorian::date d1(d_yr, 1, 1);
boost::gregorian::days d2(d_N_T-1);
boost::posix_time::ptime glonass_time(d1+d2, t);
boost::gregorian::date utc_date = glonass_time.date();
boost::posix_time::ptime utc_time(d1+d2, t);
boost::gregorian::date utc_date = utc_time.date();
boost::posix_time::ptime gps_time;
// Adjust for leap second correction
for (i = 0; GLONASS_LEAP_SECONDS[i][0]>0; i++)
{
boost::posix_time::time_duration t3(GLONASS_LEAP_SECONDS[i][3], GLONASS_LEAP_SECONDS[i][4], GLONASS_LEAP_SECONDS[i][5]);
boost::gregorian::date d3(GLONASS_LEAP_SECONDS[i][0], GLONASS_LEAP_SECONDS[i][1], GLONASS_LEAP_SECONDS[i][2]);
boost::posix_time::ptime ls_time(d3, t3);
if (utc_time >= ls_time)
{
// We add the leap second when going from utc to gpst
gps_time = utc_time + boost::posix_time::time_duration(0,0,fabs(GLONASS_LEAP_SECONDS[i][6]));
break;
}
}
// Total number of days
std::string fdat = boost::posix_time::to_simple_string(glonass_time);
std::string fdat = boost::posix_time::to_simple_string(gps_time);
days = static_cast<double>((utc_date - gps_epoch).days());
// Total number of seconds
sec_of_day = static_cast<double>((glonass_time.time_of_day()).total_seconds());
sec_of_day = static_cast<double>((gps_time.time_of_day()).total_seconds());
total_sec = days*86400 + sec_of_day;
// GLONASST already includes leap second addition or deletion
for (i = 0; GLONASS_LEAP_SECONDS[i][0]>0; i++)
{
if (d_yr >= GLONASS_LEAP_SECONDS[i][0])
{
// We add the leap second when going from utc to gpst
total_sec += fabs(GLONASS_LEAP_SECONDS[i][6]);
break;
}
}
// Compute Week number
*wn = floor(total_sec/604800);

5
src/tests/unit-tests/signal-processing-blocks/pvt/rinex_printer_test.cc
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@ -95,8 +95,9 @@ TEST(RinexPrinterTest, GlonassObsHeader)
const Glonass_Gnav_Ephemeris eph = Glonass_Gnav_Ephemeris();
std::shared_ptr<Rinex_Printer> rp1;
rp1 = std::make_shared<Rinex_Printer>();
rp1->rinex_obs_header(rp1->obsFile, eph, 0.0);
rp1 = std::make_shared<Rinex_Printer>(3);
const std::string bands = "1G";
rp1->rinex_obs_header(rp1->obsFile, eph, 0.0, bands);
rp1->obsFile.seekp(0);
while(!rp1->obsFile.eof())

2
src/tests/unit-tests/system-parameters/glonass_gnav_ephemeris_test.cc
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@ -130,7 +130,7 @@ TEST(GlonassGnavEphemerisTest, ConvertGlonassT2GpsT3)
double tow = 0.0;
double true_leap_sec = 17;
double true_week = 1886;
double true_tow = 259200+true_leap_sec;
double true_tow = 259200+true_leap_sec+tod;
gnav_eph.glot_to_gpst(tod + glo2utc, 0.0, 0.0, &week, &tow);

3
src/tests/unit-tests/system-parameters/glonass_gnav_nav_message_test.cc
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@ -172,6 +172,7 @@ TEST(GlonassGnavNavigationMessageTest, String3Decoder)
gnav_ephemeris.d_Zn = 19929.2377929688;
// Call target test method
gnav_nav_message.flag_ephemeris_str_2 = true;
gnav_nav_message.string_decoder(str3);
// Perform assertions of decoded fields
@ -209,6 +210,7 @@ TEST(GlonassGnavNavigationMessageTest, String4Decoder)
gnav_ephemeris.d_M = 1;
// Call target test method
gnav_nav_message.flag_ephemeris_str_3 = true;
gnav_nav_message.string_decoder(str4);
// Perform assertions of decoded fields
@ -243,6 +245,7 @@ TEST(GlonassGnavNavigationMessageTest, String5Decoder)
gnav_utc_model.d_tau_gps = 9.313225746154785e-08;
// Call target test method
gnav_nav_message.flag_ephemeris_str_4 = true;
gnav_nav_message.string_decoder(str5);
// Perform assertions of decoded fields