/** \file gps.h \brief GNSS core 'c' function library: GPS specific functions. \author Glenn D. MacGougan (GDM) \date 2005-08-14 \since 2005-07-31 \b "LICENSE INFORMATION" \n Copyright (c) 2007, refer to 'author' doxygen tags \n All rights reserved. \n Redistribution and use in source and binary forms, with or without modification, are permitted provided the following conditions are met: \n - Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. \n - 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. \n - The name(s) of the contributor(s) may not be used to endorse or promote products derived from this software without specific prior written permission. \n THIS SOFTWARE IS PROVIDED BY THE 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 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. */ #ifndef _C_GPS_H_ #define _C_GPS_H_ #ifdef __cplusplus extern "C" { #endif #include "basictypes.h" /// \brief A set of satellite orbit parameters that is used /// to calculate GPS satellite positions and velocities. In the ephemeris /// structure below, the parameters for computing satellite clock corrections /// are also included. /// /// \author Glenn D. MacGougan (GDM) /// \date 2005-08-14 /// \since 2005-08-14 /// /// \remarks /// (1) struct packaging: compatible with 4 and 8 byte packing \n /// /// \b REFERENCES \n /// [1] ICD-GPS-200C, p. 93-102 /// typedef struct { unsigned toe; //!< reference time ephemeris (0-604800) [s] unsigned toc; //!< reference time (clock) (0-604800) [s] unsigned short prn; //!< GPS PRN number unsigned short week; //!< 10 bit gps week 0-1023 (user must account for week rollover ) [week] unsigned short iodc; //!< 10 bit issue of data (clock) [] unsigned short reserved1; //!< reserved bytes unsigned char iode; //!< 8 bit issue of data (ephemeris) [] unsigned char health; //!< 6 bit health parameter, 0 if healthy, unhealth othersize [0=healthy] unsigned char alert_flag; //!< 1 = URA may be worse than indicated [0,1] unsigned char anti_spoof; //!< anti-spoof flag from 0=off, 1=on [0,1] unsigned char code_on_L2; //!< 0=reserved, 1=P code on L2, 2=C/A on L2 [0,1,2] unsigned char L2_P_data_flag; //!< flag indicating if P is on L2 1=true [0,1] unsigned char fit_interval_flag; //!< fit interval flag (four hour interval or longer) 0=4 fours, 1=greater [0,1] unsigned char ura; //!< User Range Accuracy lookup code, 0 is excellent, 15 is use at own risk [0-15], see p. 83 GPSICD200C unsigned short age_of_data_offset; //!< age of data offset [s] unsigned short tow_week; //!< The week corresponding to tow (0-1024+). Can be one week larger than week. [week] unsigned tow; //!< The time of week derived formt the Z-count in the Hand Over Word (HOW) [s] // clock parameters double tgd; //!< group delay [s] double af2; //!< polynomial clock correction coefficient (rate of clock drift) [s/s^2] double af1; //!< polynomial clock correction coefficient (clock drift) [s/s] Note: parameters from ephemeris preferred vs almanac (16 vs 11 bits) double af0; //!< polynomial clock correction coefficient (clock bias) [s] Note: parameters from ephemeris preferred vs almanac (22 vs 11 bits) // ephemeris parameters double m0; //!< mean anomaly at reference time [rad] double delta_n; //!< mean motion difference from computed value [rad/s] double ecc; //!< eccentricity [] double sqrta; //!< square root of the semi-major axis [m^(1/2)] double omega0; //!< longitude of ascending node of orbit plane at weekly epoch [rad] double i0; //!< inclination angle at reference time [rad] double w; //!< argument of perigee [rad] double omegadot; //!< rate of right ascension [rad/s] double idot; //!< rate of inclination angle [rad/s] double cuc; //!< amplitude of the cosine harmonic correction term to the argument of latitude [rad] double cus; //!< amplitude of the sine harmonic correction term to the argument of latitude [rad] double crc; //!< amplitude of the cosine harmonic correction term to the orbit radius [m] double crs; //!< amplitude of the sine harmonic correction term to the orbit radius [m] double cic; //!< amplitude of the cosine harmonic correction term to the angle of inclination [rad] double cis; //!< amplitude of the sine harmonic correction term to the angle of inclination [rad] } GPS_structEphemeris; /// \brief A limited set of satellite orbit parameters that is used to /// calculate rough GPS satellite positions and velocities. The parameters /// for computing rough satellite clock corrections are also included. /// /// \author Glenn D. MacGougan (GDM) /// \date 2005-08-18 /// \since 2005-08-18 /// /// \remarks /// (1) struct packaging: compatible with 4 and 8 byte packing /// /// \b REFERENCES \n /// [1] ICD-GPS-200C, p. 108 /// typedef struct { unsigned toa; //!< almanac time of applicability [s] unsigned reserved; //!< reserved [] double ecc; //!< eccentricity [] double i0; //!< inclination angle at reference time [rad] double omegadot; //!< rate of right ascension [rad/s] double sqrta; //!< square root of the semi-major axis [m^(1/2)] double omega0; //!< longitude of ascending node of orbit plane at weekly epoch [rad] double w; //!< argument of perigee [rad] double m0; //!< mean anomaly at reference time [rad] double af0; //!< polynomial clock correction coefficient (clock bias) [s] Note: parameters from ephemeris preferred vs almanac (22 vs 11 bits) double af1; //!< polynomial clock correction coefficient (clock drift) [s/s] Note: parameters from ephemeris preferred vs almanac (16 vs 11 bits) } GPS_structAlmanac; /// Computes the satellite clock and clock dirft corrections given the clock model and ephemeris /// information. /// /// \author Glenn D. MacGougan (GDM) /// \date 2005-08-12 /// \since 2005-08-12 /// /// \remarks /// (1) The clock correction parameter is sensitive to the polynomial coefficient source which is /// either ephemeris related from subframe 1 or from the gps almanac (subframes 4,5). The /// ephemeris parameters have higher precision 22 & 16 vs 11 & 11 bits. \n /// (2) User must compensate for the GPS week rollover \n /// /// \b REFERENCES \n /// [1] ICD-GPS-200C, p. 88-101 \n /// [2] Teunissen, P. J. G. & A. Kleusberg (editors) (1998). GPS for Geodesy, 2nd Edition. pp. 43-107 /// [3] Hofmann-Wellenhof, B. & J. Collins (1994). GPS Theory and Practice, 3rd Edition. \n /// Springer-Verlag Wien New York, pp. 43-74 \n /// [4] Wong, R.V.C & K.P. Schwarz (1985). Dynamic Positioning with an Integrated GPS-INS. Formulae and /// Baseline Tests. University of Calgary. UCSE Report #30003. pp. 22 \n /// void GPS_ComputeSatelliteClockCorrectionAndDrift( const unsigned short transmission_gpsweek, //!< GPS week when signal was transmit (0-1024+) [weeks] const double transmission_gpstow, //!< GPS time of week when signal was transmit [s] const unsigned short ephem_week, //!< ephemeris: GPS week (0-1024+) [weeks] const unsigned toe, //!< ephemeris: time of week [s] const unsigned toc, //!< ephemeris: clock reference time of week [s] const double af0, //!< ephemeris: polynomial clock correction coefficient [s], Note: parameters from ephemeris preferred vs almanac (22 vs 11 bits) const double af1, //!< ephemeris: polynomial clock correction coefficient [s/s], Note: parameters from ephemeris preferred vs almanac (16 vs 11 bits) const double af2, //!< ephemeris: polynomial clock correction coefficient [s/s^2] const double ecc, //!< ephemeris: eccentricity of satellite orbit [] const double sqrta, //!< ephemeris: square root of the semi-major axis of orbit [m^(1/2)] const double delta_n, //!< ephemeris: mean motion difference from computed value [rad] const double m0, //!< ephemeris: mean anomaly at reference time [rad] const double tgd, //!< ephemeris: group delay differential between L1 and L2 [s] const unsigned char mode, //!< 0=L1 only, 1=L2 only (see p. 90, ICD-GPS-200C) double* clock_correction, //!< satellite clock correction [m] double* clock_drift //!< satellite clock drift correction [m/s] ); /// Computes the satellite position and velocity in WGS84 based on the supplied ephemeris/almanac /// parameters. /// /// \author Glenn D. MacGougan (GDM) /// \date 2005-07-31 /// \since 2005-07-31 /// /// \b REFERENCES \n /// [1] ICD-GPS-200C, p. 94-101 \n /// [2] Teunissen, P. J. G. & A. Kleusberg (editors) (1998). GPS for Geodesy, 2nd Edition. pp. 43-107 \n /// [3] Hofmann-Wellenhof, B. & J. Collins (1994). GPS Theory and Practice, 3rd Edition. /// Springer-Verlag Wien New York, pp. 43-74 \n /// [4] Wong, R.V.C & K.P. Schwarz (1985). Dynamic Positioning with an Integrated GPS-INS. Formulae and /// Baseline Tests. University of Calgary. UCSE Report #30003. pp. 22 \n /// void GPS_ComputeSatellitePositionAndVelocity( const unsigned short transmission_gpsweek, //!< GPS week when signal was transmit (0-1024+) [weeks] const double transmission_gpstow, //!< GPS time of week when signal was transmit [s] const unsigned short ephem_week, //!< ephemeris: GPS week (0-1024+) [weeks] const unsigned toe, //!< ephemeris: time of week [s] const double m0, //!< ephemeris: mean anomaly at reference time [rad] const double delta_n, //!< ephemeris: mean motion difference from computed value [rad] const double ecc, //!< ephemeris: eccentricity [] const double sqrta, //!< ephemeris: square root of the semi-major axis [m^(1/2)] const double omega0, //!< ephemeris: longitude of ascending node of orbit plane at weekly epoch [rad] const double i0, //!< ephemeris: inclination angle at reference time [rad] const double w, //!< ephemeris: argument of perigee [rad] const double omegadot, //!< ephemeris: rate of right ascension [rad/s] const double idot, //!< ephemeris: rate of inclination angle [rad/s] const double cuc, //!< ephemeris: amplitude of the cosine harmonic correction term to the argument of latitude [rad] const double cus, //!< ephemeris: amplitude of the sine harmonic correction term to the argument of latitude [rad] const double crc, //!< ephemeris: amplitude of the cosine harmonic correction term to the orbit radius [m] const double crs, //!< ephemeris: amplitude of the sine harmonic correction term to the orbit radius [m] const double cic, //!< ephemeris: amplitude of the cosine harmonic correction term to the angle of inclination [rad] const double cis, //!< ephemeris: amplitude of the sine harmonic correction term to the angle of inclination [rad] const double estimateOfTrueRange, //!< best estimate of the signal propagation time (in m) for Sagnac effect compensation [m] const double estimteOfRangeRate, //!< best estimate of the true signal Doppler (in m/s) for Sagnac effect compensation [m/s] double* x, //!< satellite x [m] double* y, //!< satellite y [m] double* z, //!< satellite z [m] double* vx, //!< satellite velocity x [m/s] double* vy, //!< satellite velocity y [m/s] double* vz //!< satellite velocity z [m/s] ); /// Computes the user to satellite range given the user and /// satellite position. /// /// \author Glenn D. MacGougan (GDM) /// \date 2006-11-23 /// \since 2006-11-23 /// void GPS_ComputeUserToSatelliteRange( const double userX, //!< user X position WGS84 ECEF [m] const double userY, //!< user Y position WGS84 ECEF [m] const double userZ, //!< user Z position WGS84 ECEF [m] const double satX, //!< satellite X position WGS84 ECEF [m] const double satY, //!< satellite Y positoin WGS84 ECEF [m] const double satZ, //!< satellite Z position WGS84 ECEF [m] double* range //!< user to satellite range [m] ); /// Computes the user to satellite range and range rate given the user and satellite /// position and velocities. /// /// \author Glenn D. MacGougan (GDM) /// \date 2005-08-15 /// \since 2005-08-15 /// void GPS_ComputeUserToSatelliteRangeAndRangeRate( const double userX, //!< user X position WGS84 ECEF [m] const double userY, //!< user Y position WGS84 ECEF [m] const double userZ, //!< user Z position WGS84 ECEF [m] const double userVx, //!< user X velocity WGS84 ECEF [m/s] const double userVy, //!< user Y velocity WGS84 ECEF [m/s] const double userVz, //!< user Z velocity WGS84 ECEF [m/s] const double satX, //!< satellite X position WGS84 ECEF [m] const double satY, //!< satellite Y positoin WGS84 ECEF [m] const double satZ, //!< satellite Z position WGS84 ECEF [m] const double satVx, //!< satellite X velocity WGS84 ECEF [m/s] const double satVy, //!< satellite Y velocity WGS84 ECEF [m/s] const double satVz, //!< satellite Z velocity WGS84 ECEF [m/s] double* range, //!< user to satellite range [m] double* range_rate //!< user to satellite range rate [m/s] ); /// Computes the satellite position and velocity in WGS84 based on almanac data. /// /// \author Glenn D. MacGougan (GDM) /// \date 2005-08-15 /// \since 2005-08-15 /// /// \remarks /// (1) Assumes L1 for the clock correction mode \n /// (2) This calculation solves for the satellite position at the true GPS time of week specified. /// It includes compensation for the satellite clock correction and the Saganc effect, which /// is a function of the user position. \n /// /// \b REFERENCES \n /// [1] ICD-GPS-200C /// void GPS_ComputeSatellitePositionVelocityAzimuthElevationDoppler_BasedOnAlmanacData( const double userX, //!< user X position WGS84 ECEF [m] const double userY, //!< user Y position WGS84 ECEF [m] const double userZ, //!< user Z position WGS84 ECEF [m] const unsigned short gpsweek, //!< user gps week (0-1024+) [week] const double gpstow, //!< user time of week [s] const double toa, //!< time of applicability [s] const unsigned short almanac_week, //!< gps week of almanac (0-1024+) [week] const unsigned short prn, //!< GPS prn number [] const double ecc, //!< eccentricity [] const double i0, //!< orbital inclination at reference time [rad] const double omegadot, //!< rate of right ascension [rad/s] const double sqrta, //!< square root of the semi-major axis [m^(1/2)] const double omega0, //!< longitude of ascending node of orbit plane at weekly epoch [rad] const double w, //!< argument of perigee [rad] const double m0, //!< mean anomaly at reference time [rad] const double af0, //!< polynomial clock correction coefficient (clock bias) [s], Note: parameters from ephemeris preferred vs almanac (22 vs 11 bits) const double af1, //!< polynomial clock correction coefficient (clock drift) [s/s], Note: parameters from ephemeris preferred vs almanac (16 vs 11 bits) double* clock_correction, //!< clock correction for this satellite for this epoch [m] double* clock_drift, //!< clock drift correction for this satellite for this epoch [m/s] double* satX, //!< satellite X position WGS84 ECEF [m] double* satY, //!< satellite Y position WGS84 ECEF [m] double* satZ, //!< satellite Z position WGS84 ECEF [m] double* satVx, //!< satellite X velocity WGS84 ECEF [m/s] double* satVy, //!< satellite Y velocity WGS84 ECEF [m/s] double* satVz, //!< satellite Z velocity WGS84 ECEF [m/s] double* azimuth, //!< satelilte azimuth [rad] double* elevation, //!< satelilte elevation [rad] double* doppler //!< satellite doppler with respect to the user position [m/s], Note: User must convert to Hz ); /// Computes the satellite position and velocity in WGS84 based on ephemeris data. /// /// \author Glenn D. MacGougan (GDM) /// \date 2005-08-15 /// \since 2005-08-15 /// /// \remarks /// (1) Assumes L1 for the clock correction mode \n /// (2) This calculation solves for the satellite position at the true GPS time of week specified. /// It includes compensation for the satellite clock correction and the Saganc effect, which /// is a function of the user position. \n /// (3) This function can be called with almanac data by inputting the almanac information and /// zero for the terms not available. toe and toc are the toa in that case. \n /// /// \b REFERENCES \n /// [1] ICD-GPS-200C /// void GPS_ComputeSatellitePositionVelocityAzimuthElevationDoppler_BasedOnEphmerisData( const double userX, //!< user X position WGS84 ECEF [m] const double userY, //!< user Y position WGS84 ECEF [m] const double userZ, //!< user Z position WGS84 ECEF [m] const unsigned short gpsweek, //!< gps week of signal transmission (0-1024+) [week] const double gpstow, //!< time of week of signal transmission (gpstow-psr/c) [s] const unsigned short ephem_week, //!< ephemeris: GPS week (0-1024+) [weeks] const unsigned toe, //!< ephemeris: time of week [s] const unsigned toc, //!< ephemeris: clock reference time of week [s] const double af0, //!< ephemeris: polynomial clock correction coefficient [s], Note: parameters from ephemeris preferred vs almanac (22 vs 11 bits) const double af1, //!< ephemeris: polynomial clock correction coefficient [s/s], Note: parameters from ephemeris preferred vs almanac (16 vs 11 bits) const double af2, //!< ephemeris: polynomial clock correction coefficient [s/s^2] const double tgd, //!< ephemeris: group delay differential between L1 and L2 [s] const double m0, //!< ephemeris: mean anomaly at reference time [rad] const double delta_n, //!< ephemeris: mean motion difference from computed value [rad/s] const double ecc, //!< ephemeris: eccentricity [] const double sqrta, //!< ephemeris: square root of the semi-major axis [m^(1/2)] const double omega0, //!< ephemeris: longitude of ascending node of orbit plane at weekly epoch [rad] const double i0, //!< ephemeris: inclination angle at reference time [rad] const double w, //!< ephemeris: argument of perigee [rad] const double omegadot, //!< ephemeris: rate of right ascension [rad/s] const double idot, //!< ephemeris: rate of inclination angle [rad/s] const double cuc, //!< ephemeris: amplitude of the cosine harmonic correction term to the argument of latitude [rad] const double cus, //!< ephemeris: amplitude of the sine harmonic correction term to the argument of latitude [rad] const double crc, //!< ephemeris: amplitude of the cosine harmonic correction term to the orbit radius [m] const double crs, //!< ephemeris: amplitude of the sine harmonic correction term to the orbit radius [m] const double cic, //!< ephemeris: amplitude of the cosine harmonic correction term to the angle of inclination [rad] const double cis, //!< ephemeris: amplitude of the sine harmonic correction term to the angle of inclination [rad] double* clock_correction, //!< clock correction for this satellite for this epoch [m] double* clock_drift, //!< clock drift correction for this satellite for this epoch [m/s] double* satX, //!< satellite X position WGS84 ECEF [m] double* satY, //!< satellite Y position WGS84 ECEF [m] double* satZ, //!< satellite Z position WGS84 ECEF [m] double* satVx, //!< satellite X velocity WGS84 ECEF [m/s] double* satVy, //!< satellite Y velocity WGS84 ECEF [m/s] double* satVz, //!< satellite Z velocity WGS84 ECEF [m/s] double* azimuth, //!< satelilte azimuth [rad] double* elevation, //!< satelilte elevation [rad] double* doppler //!< satellite doppler with respect to the user position [m/s], Note: User must convert to Hz ); /// Decodes the raw gps ephemeris (note, with the parity bits removed). /// /// \author Glenn D. MacGougan (GDM) /// \date 2005-08-15 /// \since 2005-08-15 /// /// \returns TRUE(1) if successful, FALSE(0) otherwise /// /// \remarks /// (1) Parity bits must be removed from the input subframe data \n /// (2) Returns TRUE(1) if data is successfully decoded \n /// (3) Returns FALSE(0) if the subframe id's are incorrect, i.e. must be subframe1, subframe2, subframe3 in that order \n /// (4) Returns FALSE(0) if the iode's are not consistent for all subframes, note 8 LSB bits of the iodc should equal /// subframe2 and subframe3 iode \n /// (5) Uses IBM PC format byte alignment \n /// /// \b REFERENCES \n /// [1] ICD-GPS-200C /// BOOL GPS_DecodeRawGPSEphemeris( const unsigned char subframe1[30], //!< subframe 1 data, 30 bytes * 8bits/byte = 240 bits, thus parity bits have been removed const unsigned char subframe2[30], //!< subframe 2 data, 30 bytes * 8bits/byte = 240 bits, thus parity bits have been removed const unsigned char subframe3[30], //!< subframe 3 data, 30 bytes * 8bits/byte = 240 bits, thus parity bits have been removed unsigned short prn, //!< GPS PRN number (helps with debugging) unsigned* tow, //!< time of week in subframe1, the time of the leading bit edge of subframe 2 [s] unsigned short* iodc, //!< 10 bit issue of data (clock), 8 LSB bits will match the iode [] unsigned char* iode, //!< 8 bit issue of data (ephemeris) [] unsigned* toe, //!< reference time ephemeris (0-604800) [s] unsigned* toc, //!< reference time (clock) (0-604800) [s] unsigned short* week, //!< 10 bit gps week 0-1023 (user must account for week rollover ) [week] unsigned char* health, //!< 6 bit health parameter, 0 if healthy, unhealth othersize [0=healthy] unsigned char* alert_flag, //!< 1 = URA may be worse than indicated [0,1] unsigned char* anti_spoof, //!< anti-spoof flag from 0=off, 1=on [0,1] unsigned char* code_on_L2, //!< 0=reserved, 1=P code on L2, 2=C/A on L2 [0,1,2] unsigned char* ura, //!< User Range Accuracy lookup code, 0 is excellent, 15 is use at own risk [0-15], see p. 83 GPSICD200C unsigned char* L2_P_data_flag, //!< flag indicating if P is on L2 1=true [0,1] unsigned char* fit_interval_flag, //!< fit interval flag (four hour interval or longer) 0=4 fours, 1=greater [0,1] unsigned short* age_of_data_offset, //!< age of data offset [s] double* tgd, //!< group delay [s] double* af2, //!< polynomial clock correction coefficient (rate of clock drift) [s/s^2] double* af1, //!< polynomial clock correction coefficient (clock drift) [s/s] double* af0, //!< polynomial clock correction coefficient (clock bias) [s] double* m0, //!< mean anomaly at reference time [rad] double* delta_n, //!< mean motion difference from computed value [rad/s] double* ecc, //!< eccentricity [] double* sqrta, //!< square root of the semi-major axis [m^(1/2)] double* omega0, //!< longitude of ascending node of orbit plane at weekly epoch [rad] double* i0, //!< inclination angle at reference time [rad] double* w, //!< argument of perigee [rad] double* omegadot, //!< rate of right ascension [rad/s] double* idot, //!< rate of inclination angle [rad/s] double* cuc, //!< amplitude of the cosine harmonic correction term to the argument of latitude [rad] double* cus, //!< amplitude of the sine harmonic correction term to the argument of latitude [rad] double* crc, //!< amplitude of the cosine harmonic correction term to the orbit radius [m] double* crs, //!< amplitude of the sine harmonic correction term to the orbit radius [m] double* cic, //!< amplitude of the cosine harmonic correction term to the angle of inclination [rad] double* cis //!< amplitude of the sine harmonic correction term to the angle of inclination [rad] ); #ifdef __cplusplus } #endif #endif // _C_GPS_H_