mirror of https://github.com/gnss-sdr/gnss-sdr
218 lines
12 KiB
C++
218 lines
12 KiB
C++
/*!
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* \file gps_navigation_message.h
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* \brief Interface of a GPS NAV Data message decoder
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* \author Javier Arribas, 2011. jarribas(at)cttc.es
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*
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* -------------------------------------------------------------------------
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*
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* Copyright (C) 2010-2018 (see AUTHORS file for a list of contributors)
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*
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* GNSS-SDR is a software defined Global Navigation
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* Satellite Systems receiver
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*
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* This file is part of GNSS-SDR.
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*
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* GNSS-SDR is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* GNSS-SDR is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with GNSS-SDR. If not, see <https://www.gnu.org/licenses/>.
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*
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* -------------------------------------------------------------------------
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*/
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#ifndef GNSS_SDR_GPS_NAVIGATION_MESSAGE_H_
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#define GNSS_SDR_GPS_NAVIGATION_MESSAGE_H_
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#include "GPS_L1_CA.h"
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#include "gps_ephemeris.h"
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#include "gps_iono.h"
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#include "gps_utc_model.h"
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#include <bitset>
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#include <cstdint>
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#include <map>
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#include <string>
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#include <utility> // for pair
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#include <vector>
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/*!
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* \brief This class decodes a GPS NAV Data message as described in IS-GPS-200E
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*
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* See http://www.gps.gov/technical/icwg/IS-GPS-200E.pdf Appendix II
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*/
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class Gps_Navigation_Message
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{
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public:
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/*!
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* Default constructor
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*/
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Gps_Navigation_Message();
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bool b_valid_ephemeris_set_flag; // flag indicating that this ephemeris set have passed the validation check
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// broadcast orbit 1
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int32_t d_TOW; //!< Time of GPS Week of the ephemeris set (taken from subframes TOW) [s]
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int32_t d_TOW_SF1; //!< Time of GPS Week from HOW word of Subframe 1 [s]
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int32_t d_TOW_SF2; //!< Time of GPS Week from HOW word of Subframe 2 [s]
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int32_t d_TOW_SF3; //!< Time of GPS Week from HOW word of Subframe 3 [s]
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int32_t d_TOW_SF4; //!< Time of GPS Week from HOW word of Subframe 4 [s]
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int32_t d_TOW_SF5; //!< Time of GPS Week from HOW word of Subframe 5 [s]
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int32_t d_IODE_SF2;
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int32_t d_IODE_SF3;
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double d_Crs; //!< Amplitude of the Sine Harmonic Correction Term to the Orbit Radius [m]
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double d_Delta_n; //!< Mean Motion Difference From Computed Value [semi-circles/s]
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double d_M_0; //!< Mean Anomaly at Reference Time [semi-circles]
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// broadcast orbit 2
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double d_Cuc; //!< Amplitude of the Cosine Harmonic Correction Term to the Argument of Latitude [rad]
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double d_e_eccentricity; //!< Eccentricity [dimensionless]
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double d_Cus; //!< Amplitude of the Sine Harmonic Correction Term to the Argument of Latitude [rad]
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double d_sqrt_A; //!< Square Root of the Semi-Major Axis [sqrt(m)]
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// broadcast orbit 3
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int32_t d_Toe; //!< Ephemeris data reference time of week (Ref. 20.3.3.4.3 IS-GPS-200E) [s]
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int32_t d_Toc; //!< clock data reference time (Ref. 20.3.3.3.3.1 IS-GPS-200E) [s]
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double d_Cic; //!< Amplitude of the Cosine Harmonic Correction Term to the Angle of Inclination [rad]
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double d_OMEGA0; //!< Longitude of Ascending Node of Orbit Plane at Weekly Epoch [semi-circles]
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double d_Cis; //!< Amplitude of the Sine Harmonic Correction Term to the Angle of Inclination [rad]
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// broadcast orbit 4
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double d_i_0; //!< Inclination Angle at Reference Time [semi-circles]
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double d_Crc; //!< Amplitude of the Cosine Harmonic Correction Term to the Orbit Radius [m]
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double d_OMEGA; //!< Argument of Perigee [semi-cicles]
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double d_OMEGA_DOT; //!< Rate of Right Ascension [semi-circles/s]
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// broadcast orbit 5
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double d_IDOT; //!< Rate of Inclination Angle [semi-circles/s]
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int32_t i_code_on_L2; //!< If 1, P code ON in L2; if 2, C/A code ON in L2;
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int32_t i_GPS_week; //!< GPS week number, aka WN [week]
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bool b_L2_P_data_flag; //!< When true, indicates that the NAV data stream was commanded OFF on the P-code of the L2 channel
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// broadcast orbit 6
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int32_t i_SV_accuracy; //!< User Range Accuracy (URA) index of the SV (reference paragraph 6.2.1) for the standard positioning service user (Ref 20.3.3.3.1.3 IS-GPS-200E)
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int32_t i_SV_health;
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double d_TGD; //!< Estimated Group Delay Differential: L1-L2 correction term only for the benefit of "L1 P(Y)" or "L2 P(Y)" s users [s]
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int32_t d_IODC; //!< Issue of Data, Clock
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// broadcast orbit 7
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int32_t i_AODO; //!< Age of Data Offset (AODO) term for the navigation message correction table (NMCT) contained in subframe 4 (reference paragraph 20.3.3.5.1.9) [s]
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bool b_fit_interval_flag; //!< indicates the curve-fit interval used by the CS (Block II/IIA/IIR/IIR-M/IIF) and SS (Block IIIA) in determining the ephemeris parameters, as follows: 0 = 4 hours, 1 = greater than 4 hours.
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double d_spare1;
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double d_spare2;
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double d_A_f0; //!< Coefficient 0 of code phase offset model [s]
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double d_A_f1; //!< Coefficient 1 of code phase offset model [s/s]
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double d_A_f2; //!< Coefficient 2 of code phase offset model [s/s^2]
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// Almanac
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int32_t i_Toa; //!< Almanac reference time [s]
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int32_t i_WN_A; //!< Modulo 256 of the GPS week number to which the almanac reference time (i_Toa) is referenced
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std::map<int32_t, int32_t> almanacHealth; //!< Map that stores the health information stored in the almanac
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std::map<int32_t, std::string> satelliteBlock; //!< Map that stores to which block the PRN belongs http://www.navcen.uscg.gov/?Do=constellationStatus
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// Flags
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/*! \brief If true, enhanced level of integrity assurance.
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*
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* If false, indicates that the conveying signal is provided with the legacy level of integrity assurance.
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* That is, the probability that the instantaneous URE of the conveying signal exceeds 4.42 times the upper bound
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* value of the current broadcast URA index, for more than 5.2 seconds, without an accompanying alert, is less
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* than 1E-5 per hour. If true, indicates that the conveying signal is provided with an enhanced level of
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* integrity assurance. That is, the probability that the instantaneous URE of the conveying signal exceeds 5.73
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* times the upper bound value of the current broadcast URA index, for more than 5.2 seconds, without an
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* accompanying alert, is less than 1E-8 per hour.
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*/
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bool b_integrity_status_flag;
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bool b_alert_flag; //!< If true, indicates that the SV URA may be worse than indicated in d_SV_accuracy, use that SV at our own risk.
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bool b_antispoofing_flag; //!< If true, the AntiSpoofing mode is ON in that SV
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// clock terms
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//double d_master_clock; // GPS transmission time
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double d_satClkCorr; // GPS clock error
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double d_dtr; // relativistic clock correction term
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double d_satClkDrift;
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// satellite positions
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double d_satpos_X; //!< Earth-fixed coordinate x of the satellite [m]. Intersection of the IERS Reference Meridian (IRM) and the plane passing through the origin and normal to the Z-axis.
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double d_satpos_Y; //!< Earth-fixed coordinate y of the satellite [m]. Completes a right-handed, Earth-Centered, Earth-Fixed orthogonal coordinate system.
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double d_satpos_Z; //!< Earth-fixed coordinate z of the satellite [m]. The direction of the IERS (International Earth Rotation and Reference Systems Service) Reference Pole (IRP).
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// satellite identification info
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int32_t i_channel_ID;
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uint32_t i_satellite_PRN;
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// time synchro
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double d_subframe_timestamp_ms; // [ms]
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// Ionospheric parameters
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bool flag_iono_valid; //!< If set, it indicates that the ionospheric parameters are filled (page 18 has arrived and decoded)
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double d_alpha0; //!< Coefficient 0 of a cubic equation representing the amplitude of the vertical delay [s]
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double d_alpha1; //!< Coefficient 1 of a cubic equation representing the amplitude of the vertical delay [s/semi-circle]
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double d_alpha2; //!< Coefficient 2 of a cubic equation representing the amplitude of the vertical delay [s(semi-circle)^2]
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double d_alpha3; //!< Coefficient 3 of a cubic equation representing the amplitude of the vertical delay [s(semi-circle)^3]
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double d_beta0; //!< Coefficient 0 of a cubic equation representing the period of the model [s]
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double d_beta1; //!< Coefficient 1 of a cubic equation representing the period of the model [s/semi-circle]
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double d_beta2; //!< Coefficient 2 of a cubic equation representing the period of the model [s(semi-circle)^2]
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double d_beta3; //!< Coefficient 3 of a cubic equation representing the period of the model [s(semi-circle)^3]
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// UTC parameters
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bool flag_utc_model_valid; //!< If set, it indicates that the UTC model parameters are filled
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double d_A0; //!< Constant of a model that relates GPS and UTC time (ref. 20.3.3.5.2.4 IS-GPS-200E) [s]
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double d_A1; //!< 1st order term of a model that relates GPS and UTC time (ref. 20.3.3.5.2.4 IS-GPS-200E) [s/s]
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double d_A2; //!< 2nd order term of a model that relates GPS and UTC time (ref. 20.3.3.5.2.4 IS-GPS-200E) [s/s]
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int32_t d_t_OT; //!< Reference time for UTC data (reference 20.3.4.5 and 20.3.3.5.2.4 IS-GPS-200E) [s]
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int32_t i_WN_T; //!< UTC reference week number [weeks]
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int32_t d_DeltaT_LS; //!< delta time due to leap seconds [s]. Number of leap seconds since 6-Jan-1980 as transmitted by the GPS almanac.
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int32_t i_WN_LSF; //!< Week number at the end of which the leap second becomes effective [weeks]
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int32_t i_DN; //!< Day number (DN) at the end of which the leap second becomes effective [days]
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int32_t d_DeltaT_LSF; //!< Scheduled future or recent past (relative to NAV message upload) value of the delta time due to leap seconds [s]
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// Satellite velocity
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double d_satvel_X; //!< Earth-fixed velocity coordinate x of the satellite [m]
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double d_satvel_Y; //!< Earth-fixed velocity coordinate y of the satellite [m]
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double d_satvel_Z; //!< Earth-fixed velocity coordinate z of the satellite [m]
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// public functions
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void reset();
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/*!
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* \brief Obtain a GPS SV Ephemeris class filled with current SV data
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*/
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Gps_Ephemeris get_ephemeris();
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/*!
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* \brief Obtain a GPS ionospheric correction parameters class filled with current SV data
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*/
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Gps_Iono get_iono();
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/*!
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* \brief Obtain a GPS UTC model parameters class filled with current SV data
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*/
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Gps_Utc_Model get_utc_model();
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/*!
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* \brief Decodes the GPS NAV message
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*/
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int32_t subframe_decoder(char* subframe);
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/*!
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* \brief Computes the Coordinated Universal Time (UTC) and
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* returns it in [s] (IS-GPS-200E, 20.3.3.5.2.4)
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*/
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double utc_time(const double gpstime_corrected) const;
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bool satellite_validation();
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private:
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uint64_t read_navigation_unsigned(std::bitset<GPS_SUBFRAME_BITS> bits, const std::vector<std::pair<int32_t, int32_t>>& parameter);
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int64_t read_navigation_signed(std::bitset<GPS_SUBFRAME_BITS> bits, const std::vector<std::pair<int32_t, int32_t>>& parameter);
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bool read_navigation_bool(std::bitset<GPS_SUBFRAME_BITS> bits, const std::vector<std::pair<int32_t, int32_t>>& parameter);
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void print_gps_word_bytes(uint32_t GPS_word);
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};
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#endif
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