/* This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see . */ // // NMEA parser, adapted by Michael Smith from TinyGPS v9: // // TinyGPS - a small GPS library for Arduino providing basic NMEA parsing // Copyright (C) 2008-9 Mikal Hart // All rights reserved. // // /// @file AP_GPS_NMEA.h /// @brief NMEA protocol parser /// /// This is a lightweight NMEA parser, derived originally from the /// TinyGPS parser by Mikal Hart. It is frugal in its use of memory /// and tries to avoid unnecessary arithmetic. /// /// The parser handles GPGGA, GPRMC and GPVTG messages, and attempts to be /// robust in the face of occasional corruption in the input stream. It /// makes a basic effort to configure GPS' that are likely to be connected in /// NMEA mode (SiRF, MediaTek and ublox) to emit the correct message /// stream, but does not validate that the correct stream is being received. /// In particular, a unit emitting just GPRMC will show as having a fix /// even though no altitude data is being received. /// /// GPVTG data is parsed, but as the message may not contain the the /// qualifier field (this is common with e.g. older SiRF units) it is /// not considered a source of fix-valid information. /// #pragma once #include "AP_GPS.h" #include "GPS_Backend.h" #if AP_GPS_NMEA_ENABLED /// NMEA parser /// class AP_GPS_NMEA : public AP_GPS_Backend { friend class AP_GPS_NMEA_Test; public: using AP_GPS_Backend::AP_GPS_Backend; /// Checks the serial receive buffer for characters, /// attempts to parse NMEA data and updates internal state /// accordingly. bool read() override; static bool _detect(struct NMEA_detect_state &state, uint8_t data); const char *name() const override { return "NMEA"; } // driver specific health, returns true if the driver is healthy bool is_healthy(void) const override; // get lag in seconds bool get_lag(float &lag_sec) const override; void Write_AP_Logger_Log_Startup_messages() const override; private: /// Coding for the GPS sentences that the parser handles enum _sentence_types : uint16_t { //there are some more than 10 fields in some sentences , thus we have to increase these value. _GPS_SENTENCE_RMC = 32, _GPS_SENTENCE_GGA = 64, _GPS_SENTENCE_VTG = 96, _GPS_SENTENCE_HDT = 128, _GPS_SENTENCE_PHD = 138, // extension for AllyStar GPS modules _GPS_SENTENCE_THS = 160, // True heading with quality indicator, available on Trimble MB-Two _GPS_SENTENCE_KSXT = 170, // extension for Unicore, 21 fields _GPS_SENTENCE_AGRICA = 193, // extension for Unicore, 65 fields _GPS_SENTENCE_VERSIONA = 270, // extension for Unicore, version _GPS_SENTENCE_OTHER = 0 }; /// Update the decode state machine with a new character /// /// @param c The next character in the NMEA input stream /// @returns True if processing the character has resulted in /// an update to the GPS state /// bool _decode(char c); /// Parses the @p as a NMEA-style decimal number with /// up to 3 decimal digits. /// /// @returns The value expressed by the string in @p, /// multiplied by 100. /// static int32_t _parse_decimal_100(const char *p); /// Parses the current term as a NMEA-style degrees + minutes /// value with up to four decimal digits. /// /// This gives a theoretical resolution limit of around 1cm. /// /// @returns The value expressed by the string in _term, /// multiplied by 1e7. /// uint32_t _parse_degrees(); /// Processes the current term when it has been deemed to be /// complete. /// /// Each GPS message is broken up into terms separated by commas. /// Each term is then processed by this function as it is received. /// /// @returns True if completing the term has resulted in /// an update to the GPS state. bool _term_complete(); /// return true if we have a new set of NMEA messages bool _have_new_message(void); #if AP_GPS_NMEA_UNICORE_ENABLED /* parse an AGRICA field */ void parse_agrica_field(uint16_t term_number, const char *term); // parse VERSIONA field void parse_versiona_field(uint16_t term_number, const char *term); #endif uint8_t _parity; ///< NMEA message checksum accumulator uint32_t _crc32; ///< CRC for unicore messages bool _is_checksum_term; ///< current term is the checksum char _term[30]; ///< buffer for the current term within the current sentence uint16_t _sentence_type; ///< the sentence type currently being processed bool _is_unicore; ///< true if in a unicore '#' sentence uint16_t _term_number; ///< term index within the current sentence uint8_t _term_offset; ///< character offset with the term being received uint16_t _sentence_length; bool _sentence_done; ///< set when a sentence has been fully decoded // The result of parsing terms within a message is stored temporarily until // the message is completely processed and the checksum validated. // This avoids the need to buffer the entire message. int32_t _new_time; ///< time parsed from a term int32_t _new_date; ///< date parsed from a term int32_t _new_latitude; ///< latitude parsed from a term int32_t _new_longitude; ///< longitude parsed from a term int32_t _new_altitude; ///< altitude parsed from a term int32_t _new_speed; ///< speed parsed from a term int32_t _new_course; ///< course parsed from a term float _new_gps_yaw; ///< yaw parsed from a term uint16_t _new_hdop; ///< HDOP parsed from a term uint8_t _new_satellite_count; ///< satellite count parsed from a term uint8_t _new_quality_indicator; ///< GPS quality indicator parsed from a term uint32_t _last_RMC_ms; uint32_t _last_GGA_ms; uint32_t _last_VTG_ms; uint32_t _last_yaw_ms; uint32_t _last_vvelocity_ms; uint32_t _last_vaccuracy_ms; uint32_t _last_3D_velocity_ms; uint32_t _last_KSXT_pos_ms; uint32_t _last_AGRICA_ms; uint32_t _last_fix_ms; /// @name Init strings /// In ::init, an attempt is made to configure the GPS /// unit to send just the messages that we are interested /// in using these strings //@{ static const char _SiRF_init_string[]; ///< init string for SiRF units static const char _ublox_init_string[]; ///< init string for ublox units //@} static const char _initialisation_blob[]; /* the $PHD message is an extension from AllyStar that gives vertical velocity and more accuracy estimates. It is designed as a mapping from ublox UBX protocol messages to NMEA. So class 1, message 12 is a mapping to NMEA of the NAV-VELNED UBX message and contains the same fields. Class 1 message 26 is called "NAV-PVERR", but does not correspond to a UBX message example: $PHD,01,12,TIIITTITT,,245808000,0,0,0,0,0,10260304,0,0*27 $PHD,01,26,TTTTTTT,,245808000,877,864,1451,11,11,17*17 */ struct { uint8_t msg_class; uint8_t msg_id; uint32_t itow; int32_t fields[8]; } _phd; /* The KSXT message is an extension from Unicore that gives 3D velocity and yaw example: $KSXT,20211016083433.00,116.31296102,39.95817066,49.4911,223.57,-11.32,330.19,0.024,,1,3,28,27,,,,-0.012,0.021,0.020,,*2D */ struct { double fields[21]; } _ksxt; #if AP_GPS_NMEA_UNICORE_ENABLED /* unicore AGRICA message parsing */ struct { uint32_t start_byte; uint8_t rtk_status; uint8_t heading_status; Vector3f vel_NED; Vector3f vel_stddev; double lat, lng; float alt; uint32_t itow; float undulation; double slave_lat, slave_lng; float slave_alt; Vector3f pos_stddev; } _agrica; struct { char type[10]; char version[20]; char build_date[13]; } _versiona; bool _have_unicore_versiona; #endif // AP_GPS_NMEA_UNICORE_ENABLED bool _expect_agrica; // last time we sent type specific config strings uint32_t last_config_ms; // send type specific config strings void send_config(void); }; #if AP_GPS_NMEA_UNICORE_ENABLED && !defined(NMEA_UNICORE_SETUP) // we don't know what port the GPS may be using, so configure all 3. We need to get it sending // one message to allow the NMEA detector to run #define NMEA_UNICORE_SETUP "CONFIG COM1 230400 8 n 1\r\nCONFIG COM2 230400 8 n 1\r\nCONFIG COM3 230400 8 n 1\r\nGPGGA 0.2\r\n" #endif #endif // AP_GPS_NMEA_ENABLED