mirror of https://github.com/ArduPilot/ardupilot
Implement a completely new NMEA parser based on the TinyGPS parser by Mikal Hart.
Major new features: - No RAM buffer for the NMEA message being parsed; saves 120 bytes of RAM. - More robust parser, a little less likely to be confused by bad messages. - Added configuration strings for SiRF, ublox and MediaTek GPS in NMEA mode to select just the messages of interest. Note that the issue that TinyGPS has with co-ordinates with "different" numbers of decimal digits is addressed in this code. Size is comparable to the old parser. git-svn-id: https://arducopter.googlecode.com/svn/trunk@1468 f9c3cf11-9bcb-44bc-f272-b75c42450872
This commit is contained in:
DrZiplok@gmail.com
parent
3ac2193d48
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@ -1,244 +1,380 @@
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// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: t -*-
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/*
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GPS_NMEA.cpp - Generic NMEA GPS library for Arduino
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Code by Jordi Muñoz and Jose Julio. DIYDrones.com
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Edits by HappyKillmore
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This code works with boards based on ATMega168 / 328 and ATMega1280 (Serial port 1)
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This library is free software; you can redistribute it and / or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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//
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// NMEA parser, adapted by Michael Smith from TinyGPS v9:
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//
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// TinyGPS - a small GPS library for Arduino providing basic NMEA parsing
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// Copyright (C) 2008-9 Mikal Hart
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// All rights reserved.
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//
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// This library is free software; you can redistribute it and/or
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// modify it under the terms of the GNU Lesser General Public
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// License as published by the Free Software Foundation; either
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// version 2.1 of the License, or (at your option) any later version.
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//
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// This library 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 GNU
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// Lesser General Public License for more details.
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//
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GPS configuration : NMEA protocol
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Baud rate : 38400
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NMEA Sentences :
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$GPGGA : Global Positioning System fix Data
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$GPVTG : Ttack and Ground Speed
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Methods:
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init() : GPS Initialization
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read() : Call this funcion as often as you want to ensure you read the incomming gps data
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Properties:
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latitude : latitude * 10000000 (long value)
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longitude : longitude * 10000000 (long value)
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altitude : altitude * 1000 (milimeters) (long value)
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ground_speed : Speed (m / s) * 100 (long value)
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ground_course : Course (degrees) * 100 (long value)
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Type : 2 (This indicate that we are using the Generic NMEA library)
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new_data : 1 when a new data is received.
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You need to write a 0 to new_data when you read the data
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fix : > = 1: GPS FIX, 0: No fix (normal logic)
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quality : 0 = No fix
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1 = Bad (Num sats < 5)
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2 = Poor
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3 = Medium
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4 = Good
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/// @file AP_GPS_NMEA.cpp
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/// @brief NMEA protocol parser
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///
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/// This is a lightweight NMEA parser, derived originally from the
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/// TinyGPS parser by Mikal Hart.
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///
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#include <FastSerial.h>
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#include <AP_Common.h>
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#include <avr/pgmspace.h>
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#include <ctype.h>
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#include <stdint.h>
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NOTE : This code has been tested on a Locosys 20031 GPS receiver (MTK chipset)
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*/
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#include "AP_GPS_NMEA.h"
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// SiRF init messages //////////////////////////////////////////////////////////
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//
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// Note that we will only see a SiRF in NMEA mode if we are explicitly configured
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// for NMEA. GPS_AUTO will try to set any SiRF unit to binary mode as part of
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// the autodetection process.
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//
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const prog_char AP_GPS_NMEA::_SiRF_init_string[] PROGMEM =
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"$PSRF103,0,0,1,1*25\r\n" // GGA @ 1Hz
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"$PSRF103,1,0,0,1*25\r\n" // GLL off
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"$PSRF103,2,0,0,1*26\r\n" // GSA off
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"$PSRF103,3,0,0,1*27\r\n" // GSV off
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"$PSRF103,4,0,1,1*20\r\n" // RMC off
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"$PSRF103,5,0,1,1*20\r\n" // VTG @ 1Hz
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"$PSRF103,6,0,0,1*22\r\n" // MSS off
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"$PSRF103,8,0,0,1*2C\r\n" // ZDA off
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"$PSRF151,1*3F\r\n" // WAAS on (not always supported)
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"$PSRF106,21*0F\r\n" // datum = WGS84
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"";
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// MediaTek init messages //////////////////////////////////////////////////////
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//
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// Note that we may see a MediaTek in NMEA mode if we are connected to a non-DIYDrones
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// MediaTek-based GPS.
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//
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const prog_char AP_GPS_NMEA::_MTK_init_string[] PROGMEM =
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"$PMTK314,0,0,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0*28\r\n" // GGA & VTG once every fix
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"$PMTK330,0*2E" // datum = WGS84
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"$PMTK313,1*2E\r\n" // SBAS on
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"$PMTK301,2*2E\r\n" // use SBAS data for DGPS
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"";
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// ublox init messages /////////////////////////////////////////////////////////
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//
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// Note that we will only see a ublox in NMEA mode if we are explicitly configured
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// for NMEA. GPS_AUTO will try to set any ublox unit to binary mode as part of
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// the autodetection process.
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//
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// We don't attempt to send $PUBX,41 as the unit must already be talking NMEA
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// and we don't know the baudrate.
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//
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const prog_char AP_GPS_NMEA::_ublox_init_string[] PROGMEM =
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"$PUBX,40,gga,0,1,0,0,0,0*7B\r\n" // GGA on at one per fix
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"$PUBX,40,vtg,0,1,0,0,0,0*7F\r\n" // VTG on at one per fix
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"$PUBX,40,rmc,0,0,0,0,0,0*67\r\n" // RMC off (XXX suppress other message types?)
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"";
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// NMEA message identifiers ////////////////////////////////////////////////////
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//
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const char AP_GPS_NMEA::_gprmc_string[] PROGMEM = "GPRMC";
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const char AP_GPS_NMEA::_gpgga_string[] PROGMEM = "GPGGA";
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const char AP_GPS_NMEA::_gpvtg_string[] PROGMEM = "GPVTG";
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// Convenience macros //////////////////////////////////////////////////////////
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//
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#define DIGIT_TO_VAL(_x) (_x - '0')
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// Constructors ////////////////////////////////////////////////////////////////
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AP_GPS_NMEA::AP_GPS_NMEA(Stream *s) : GPS(s)
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AP_GPS_NMEA::AP_GPS_NMEA(Stream *s) :
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GPS(s)
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{
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FastSerial *fs = (FastSerial *)_port;
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// Re-open the port with enough receive buffering for the messages we expect
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// and very little tx buffering, since we don't care about sending.
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// Leave the port speed alone as we don't actually know at what rate we're running...
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//
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fs->begin(0, 200, 16);
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}
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// Public Methods //////////////////////////////////////////////////////////////
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void
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AP_GPS_NMEA::init(void)
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void AP_GPS_NMEA::init(void)
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{
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//Type = 2;
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// initialize serial port for binary protocol use
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_port->print(NMEA_OUTPUT_SENTENCES);
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_port->print(NMEA_OUTPUT_4HZ);
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_port->print(SBAS_ON);
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_port->print(DGPS_SBAS);
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_port->print(DATUM_GOOGLE);
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BetterStream *bs = (BetterStream *)_port;
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// send the SiRF init strings
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bs->print_P(_SiRF_init_string);
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// send the MediaTek init strings
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bs->print_P(_MTK_init_string);
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// send the ublox init strings
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bs->print_P(_ublox_init_string);
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}
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// This code don´t wait for data, only proccess the data available on serial port
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// We can call this function on the main loop (50Hz loop)
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// If we get a complete packet this function call parse_nmea_gps() to parse and update the GPS info.
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bool
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AP_GPS_NMEA::read(void)
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bool AP_GPS_NMEA::read(void)
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{
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char c;
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char data;
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int numc;
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int i;
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bool parsed = false;
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numc = _port->available();
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if (numc > 0){
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for (i = 0; i < numc; i++){
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c = _port->read();
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if (c == '$'){ // NMEA Start
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bufferidx = 0;
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buffer[bufferidx++] = c;
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GPS_checksum = 0;
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GPS_checksum_calc = true;
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continue;
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}
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if (c == '\r'){ // NMEA End
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buffer[bufferidx++] = 0;
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parsed = parse_nmea_gps();
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} else {
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if (bufferidx < (GPS_BUFFERSIZE - 1)){
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if (c == '*')
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GPS_checksum_calc = false; // Checksum calculation end
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buffer[bufferidx++] = c;
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if (GPS_checksum_calc){
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GPS_checksum ^= c; // XOR
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}
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} else {
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bufferidx = 0; // Buffer overflow : restart
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}
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}
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while (numc--) {
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if (_decode(_port->read())) {
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parsed = true;
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}
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}
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return parsed;
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}
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/****************************************************************
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*
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* * ** * ** * ** * ** * ** * ** * ** * ** * ** * ** * ** * ** * ** * ** * ** * ** * ** * ** * ** * ** * **/
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// Private Methods //////////////////////////////////////////////////////////////
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bool
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AP_GPS_NMEA::parse_nmea_gps(void)
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bool AP_GPS_NMEA::_decode(char c)
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{
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uint8_t NMEA_check;
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long aux_deg;
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long aux_min;
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char *parseptr;
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bool valid_sentence = false;
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if (strncmp(buffer,"$GPGGA",6)==0){ // Check if sentence begins with $GPGGA
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if (buffer[bufferidx-4]=='*'){ // Check for the "*" character
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NMEA_check = parseHex(buffer[bufferidx - 3]) * 16 + parseHex(buffer[bufferidx - 2]); // Read the checksums characters
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if (GPS_checksum == NMEA_check){ // Checksum validation
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//Serial.println("buffer");
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parseptr = strchr(buffer, ',')+1;
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//parseptr = strchr(parseptr, ',')+1;
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time = parsenumber(parseptr, 2); // GPS UTC time hhmmss.ss
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parseptr = strchr(parseptr, ',')+1;
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aux_deg = parsedecimal(parseptr, 2); // degrees
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aux_min = parsenumber(parseptr + 2, 4); // minutes (sexagesimal) => Convert to decimal
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latitude = aux_deg * 10000000 + (aux_min * 50) / 3; // degrees + minutes / 0.6 ( * 10000000) (0.6 = 3 / 5)
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parseptr = strchr(parseptr, ',')+1;
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if ( * parseptr == 'S')
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latitude = -1 * latitude; // South latitudes are negative
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parseptr = strchr(parseptr, ',')+1;
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// W longitudes are Negative
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aux_deg = parsedecimal(parseptr, 3); // degrees
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aux_min = parsenumber(parseptr + 3, 4); // minutes (sexagesimal)
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longitude = aux_deg * 10000000 + (aux_min * 50) / 3; // degrees + minutes / 0.6 ( * 10000000)
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//longitude = -1*longitude; // This Assumes that we are in W longitudes...
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parseptr = strchr(parseptr, ',')+1;
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if ( * parseptr == 'W')
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longitude = -1 * longitude; // West longitudes are negative
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parseptr = strchr(parseptr, ',')+1;
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fix = parsedecimal(parseptr, 1);
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parseptr = strchr(parseptr, ',')+1;
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num_sats = parsedecimal(parseptr, 2);
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parseptr = strchr(parseptr, ',')+1;
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hdop = parsenumber(parseptr, 1); // HDOP * 10
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parseptr = strchr(parseptr, ',')+1;
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altitude = parsenumber(parseptr, 1) * 100; // altitude in decimeters * 100 = milimeters
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if (fix < 1)
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quality = 0; // No FIX
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else if(num_sats < 5)
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quality = 1; // Bad (Num sats < 5)
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else if(hdop > 30)
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quality = 2; // Poor (HDOP > 30)
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else if(hdop > 25)
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quality = 3; // Medium (HDOP > 25)
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else
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quality = 4; // Good (HDOP < 25)
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} else {
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_error("GPSERR: Checksum error!!\n");
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return false;
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}
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switch (c) {
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case ',': // term terminators
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_parity ^= c;
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case '\r':
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case '\n':
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case '*':
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if (_term_offset < sizeof(_term)) {
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_term[_term_offset] = 0;
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valid_sentence = _term_complete();
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}
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} else if (strncmp(buffer,"$GPVTG",6)==0){ // Check if sentence begins with $GPVTG
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//Serial.println(buffer);
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if (buffer[bufferidx-4]=='*'){ // Check for the "*" character
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NMEA_check = parseHex(buffer[bufferidx - 3]) * 16 + parseHex(buffer[bufferidx - 2]); // Read the checksums characters
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if (GPS_checksum == NMEA_check){ // Checksum validation
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parseptr = strchr(buffer, ',')+1;
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ground_course = parsenumber(parseptr, 1) * 10; // Ground course in degrees * 100
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parseptr = strchr(parseptr, ',')+1;
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parseptr = strchr(parseptr, ',')+1;
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parseptr = strchr(parseptr, ',')+1;
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parseptr = strchr(parseptr, ',')+1;
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parseptr = strchr(parseptr, ',')+1;
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parseptr = strchr(parseptr, ',')+1;
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ground_speed = parsenumber(parseptr, 1) * 100 / 36; // Convert Km / h to m / s ( * 100)
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//GPS_line = true;
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} else {
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_error("GPSERR: Checksum error!!\n");
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return false;
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}
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++_term_number;
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_term_offset = 0;
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_is_checksum_term = c == '*';
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return valid_sentence;
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case '$': // sentence begin
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_term_number = _term_offset = 0;
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_parity = 0;
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_sentence_type = _GPS_SENTENCE_OTHER;
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_is_checksum_term = false;
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_gps_data_good = false;
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return valid_sentence;
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}
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// ordinary characters
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if (_term_offset < sizeof(_term) - 1)
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_term[_term_offset++] = c;
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if (!_is_checksum_term)
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_parity ^= c;
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return valid_sentence;
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}
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//
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// internal utilities
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//
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int AP_GPS_NMEA::_from_hex(char a)
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{
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if (a >= 'A' && a <= 'F')
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return a - 'A' + 10;
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else if (a >= 'a' && a <= 'f')
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return a - 'a' + 10;
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else
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return a - '0';
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}
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unsigned long AP_GPS_NMEA::_parse_decimal()
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{
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char *p = _term;
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unsigned long ret = 100UL * atol(p);
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while (isdigit(*p))
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++p;
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if (*p == '.') {
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if (isdigit(p[1])) {
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ret += 10 * (p[1] - '0');
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if (isdigit(p[2]))
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ret += p[2] - '0';
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}
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} else {
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bufferidx = 0;
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_error("GPSERR: Bad sentence!!\n");
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}
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return ret;
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}
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unsigned long AP_GPS_NMEA::_parse_degrees()
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{
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char *p, *q;
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uint8_t deg = 0, min = 0;
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unsigned int frac_min = 0;
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unsigned long result;
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// scan for decimal point or end of field
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for (p = _term; isdigit(*p); p++)
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;
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q = _term;
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// convert degrees
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while ((p - q) > 2) {
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if (deg)
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deg *= 10;
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deg += DIGIT_TO_VAL(*q++);
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}
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// convert minutes
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while (p > q) {
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if (min)
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min *= 10;
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min += DIGIT_TO_VAL(*q++);
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}
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// convert fractional minutes
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// expect up to four digits, result is in
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// ten-thousandths of a minute
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if (*p == '.') {
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q = p + 1;
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for (int i = 0; i < 4; i++) {
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frac_min *= 10;
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if (isdigit(*q))
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frac_min += *q++ - '0';
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}
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}
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return deg * 100000UL + (min * 10000UL + frac_min) / 6;
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}
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// Processes a just-completed term
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// Returns true if new sentence has just passed checksum test and is validated
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bool AP_GPS_NMEA::_term_complete()
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{
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// handle the last term in a message
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if (_is_checksum_term) {
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uint8_t checksum = 16 * _from_hex(_term[0]) + _from_hex(_term[1]);
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if (checksum == _parity) {
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if (_gps_data_good) {
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switch (_sentence_type) {
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case _GPS_SENTENCE_GPRMC:
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time = _new_time;
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date = _new_date;
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latitude = _new_latitude * 100; // degrees*10e5 -> 10e7
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longitude = _new_longitude * 100; // degrees*10e5 -> 10e7
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ground_speed = _new_speed;
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ground_course = _new_course;
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num_sats = _new_satellite_count;
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hdop = _new_hdop;
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fix = true;
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break;
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case _GPS_SENTENCE_GPGGA:
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altitude = _new_altitude;
|
||||
time = _new_time;
|
||||
latitude = _new_latitude * 100; // degrees*10e5 -> 10e7
|
||||
longitude = _new_longitude * 100; // degrees*10e5 -> 10e7
|
||||
fix = true;
|
||||
break;
|
||||
case _GPS_SENTENCE_VTG:
|
||||
ground_speed = _new_speed;
|
||||
ground_course = _new_course;
|
||||
// VTG has no fix indicator, can't change fix status
|
||||
break;
|
||||
}
|
||||
} else {
|
||||
switch (_sentence_type) {
|
||||
case _GPS_SENTENCE_GPRMC:
|
||||
case _GPS_SENTENCE_GPGGA:
|
||||
// Only these sentences give us information about
|
||||
// fix status.
|
||||
fix = false;
|
||||
}
|
||||
}
|
||||
// we got a good message
|
||||
return true;
|
||||
}
|
||||
// we got a bad message, ignore it
|
||||
return false;
|
||||
}
|
||||
return true;
|
||||
}
|
||||
|
||||
|
||||
// Parse hexadecimal numbers
|
||||
uint8_t
|
||||
AP_GPS_NMEA::parseHex(char c) {
|
||||
if (c < '0')
|
||||
return (0);
|
||||
if (c <= '9')
|
||||
return (c - '0');
|
||||
if (c < 'A')
|
||||
return (0);
|
||||
if (c <= 'F')
|
||||
return ((c - 'A')+10);
|
||||
}
|
||||
|
||||
// Decimal number parser
|
||||
long
|
||||
AP_GPS_NMEA::parsedecimal(char *str, uint8_t num_car) {
|
||||
long d = 0;
|
||||
uint8_t i;
|
||||
|
||||
i = num_car;
|
||||
while ((str[0] != 0) && (i > 0)) {
|
||||
if ((str[0] > '9') || (str[0] < '0'))
|
||||
return d;
|
||||
d *= 10;
|
||||
d += str[0] - '0';
|
||||
str++;
|
||||
i--;
|
||||
}
|
||||
return d;
|
||||
}
|
||||
|
||||
// Function to parse fixed point numbers (numdec=number of decimals)
|
||||
long
|
||||
AP_GPS_NMEA::parsenumber(char *str, uint8_t numdec) {
|
||||
long d = 0;
|
||||
uint8_t ndec = 0;
|
||||
|
||||
while (str[0] != 0) {
|
||||
if (str[0] == '.'){
|
||||
ndec = 1;
|
||||
// the first term determines the sentence type
|
||||
if (_term_number == 0) {
|
||||
if (!strcmp_P(_term, _gprmc_string)) {
|
||||
_sentence_type = _GPS_SENTENCE_GPRMC;
|
||||
} else if (!strcmp_P(_term, _gpgga_string)) {
|
||||
_sentence_type = _GPS_SENTENCE_GPGGA;
|
||||
} else if (!strcmp_P(_term, _gpvtg_string)) {
|
||||
_sentence_type = _GPS_SENTENCE_VTG;
|
||||
// VTG may not contain a data qualifier, presume the solution is good
|
||||
// unless it tells us otherwise.
|
||||
_gps_data_good = true;
|
||||
} else {
|
||||
if ((str[0] > '9') || (str[0] < '0'))
|
||||
return d;
|
||||
d *= 10;
|
||||
d += str[0] - '0';
|
||||
if (ndec > 0)
|
||||
ndec++;
|
||||
if (ndec > numdec) // we reach the number of decimals...
|
||||
return d;
|
||||
_sentence_type = _GPS_SENTENCE_OTHER;
|
||||
}
|
||||
str++;
|
||||
return false;
|
||||
}
|
||||
return d;
|
||||
|
||||
// 10 = RMC, 20 = GGA, 30 = VTG
|
||||
if (_sentence_type != _GPS_SENTENCE_OTHER && _term[0]) {
|
||||
switch (_sentence_type + _term_number) {
|
||||
// operational status
|
||||
//
|
||||
case 12: // validity (RMC)
|
||||
_gps_data_good = _term[0] == 'A';
|
||||
break;
|
||||
case 26: // Fix data (GGA)
|
||||
_gps_data_good = _term[0] > '0';
|
||||
break;
|
||||
case 39: // validity (VTG) (we may not see this field)
|
||||
_gps_data_good = _term[0] != 'N';
|
||||
break;
|
||||
case 27: // satellite count (GGA)
|
||||
_new_satellite_count = atol(_term);
|
||||
break;
|
||||
case 28: // HDOP (GGA)
|
||||
_new_hdop = _parse_decimal();
|
||||
break;
|
||||
|
||||
// time and date
|
||||
//
|
||||
case 11: // Time (RMC)
|
||||
case 21: // Time (GGA)
|
||||
_new_time = _parse_decimal();
|
||||
break;
|
||||
case 19: // Date (GPRMC)
|
||||
_new_date = atol(_term);
|
||||
break;
|
||||
|
||||
// location
|
||||
//
|
||||
case 13: // Latitude
|
||||
case 22:
|
||||
_new_latitude = _parse_degrees();
|
||||
break;
|
||||
case 14: // N/S
|
||||
case 23:
|
||||
if (_term[0] == 'S')
|
||||
_new_latitude = -_new_latitude;
|
||||
break;
|
||||
case 15: // Longitude
|
||||
case 24:
|
||||
_new_longitude = _parse_degrees();
|
||||
break;
|
||||
case 16: // E/W
|
||||
case 25:
|
||||
if (_term[0] == 'W')
|
||||
_new_longitude = -_new_longitude;
|
||||
break;
|
||||
case 29: // Altitude (GPGGA)
|
||||
_new_altitude = _parse_decimal();
|
||||
break;
|
||||
|
||||
// course and speed
|
||||
//
|
||||
case 17: // Speed (GPRMC)
|
||||
_new_speed = (_parse_decimal() * 514) / 100; // knots-> m/sec, approximiates * 0.514
|
||||
break;
|
||||
case 37: // Speed (VTG)
|
||||
_new_speed = _parse_decimal();
|
||||
break;
|
||||
case 18: // Course (GPRMC)
|
||||
case 31: // Course (VTG)
|
||||
_new_course = _parse_decimal();
|
||||
break;
|
||||
}
|
||||
}
|
||||
|
||||
return false;
|
||||
}
|
||||
|
|
|
|||
|
|
@ -1,59 +1,160 @@
|
|||
// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: t -*-
|
||||
|
||||
//
|
||||
// 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.
|
||||
//
|
||||
// This library is free software; you can redistribute it and/or
|
||||
// modify it under the terms of the GNU Lesser General Public
|
||||
// License as published by the Free Software Foundation; either
|
||||
// version 2.1 of the License, or (at your option) any later version.
|
||||
//
|
||||
// This library 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
|
||||
// Lesser General Public License for more details.
|
||||
//
|
||||
|
||||
/// @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.
|
||||
///
|
||||
|
||||
|
||||
#ifndef AP_GPS_NMEA_h
|
||||
#define AP_GPS_NMEA_h
|
||||
|
||||
#include <GPS.h>
|
||||
#define GPS_BUFFERSIZE 120
|
||||
#include <avr/pgmspace.h>
|
||||
|
||||
#define NMEA_OUTPUT_SENTENCES "$PMTK314,0,0,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0*28\r\n" //Set GPGGA and GPVTG
|
||||
|
||||
#define NMEA_BAUD_RATE_4800 "$PSRF100,1,4800,8,1,0*0E\r\n"
|
||||
#define NMEA_BAUD_RATE_9600 "$PSRF100,1,9600,8,1,0*0D\r\n"
|
||||
#define NMEA_BAUD_RATE_19200 "$PSRF100,1,19200,8,1,0*38\r\n"
|
||||
#define NMEA_BAUD_RATE_38400 "$PSRF100,1,38400,8,1,0*3D\r\n"
|
||||
#define NMEA_BAUD_RATE_57600 "$PSRF100,1,57600,8,1,0*36\r\n"
|
||||
|
||||
#define NMEA_OUTPUT_1HZ "$PMTK220,1000*1F\r\n"
|
||||
#define NMEA_OUTPUT_2HZ "$PMTK220,500*2B\r\n"
|
||||
#define NMEA_OUTPUT_4HZ "$PMTK220,250*29\r\n"
|
||||
#define NMEA_OTUPUT_5HZ "$PMTK220,200*2C\r\n"
|
||||
#define NMEA_OUTPUT_10HZ "$PMTK220,100*2F\r\n"
|
||||
|
||||
#define SBAS_ON "$PMTK313,1*2E\r\n"
|
||||
#define SBAS_OFF "$PMTK313,0*2F\r\n"
|
||||
|
||||
#define WAAS_ON "$PSRF151,1*3F\r\n"
|
||||
#define WAAS_OFF "$PSRF151,0*3E\r\n"
|
||||
|
||||
#define DGPS_OFF "$PMTK301,0*2C\r\n"
|
||||
#define DGPS_RTCM "$PMTK301,1*2D\r\n"
|
||||
#define DGPS_SBAS "$PMTK301,2*2E\r\n"
|
||||
|
||||
#define DATUM_GOOGLE "$PMTK330,0*2E\r\n"
|
||||
|
||||
/// NMEA parser
|
||||
///
|
||||
class AP_GPS_NMEA : public GPS
|
||||
{
|
||||
public:
|
||||
// Methods
|
||||
public:
|
||||
/// Constructor
|
||||
///
|
||||
AP_GPS_NMEA(Stream *s);
|
||||
virtual void init();
|
||||
virtual bool read();
|
||||
|
||||
// Properties
|
||||
uint8_t quality; // GPS Signal quality
|
||||
/// Perform a (re)initialisation of the GPS; sends the
|
||||
/// protocol configuration messages.
|
||||
///
|
||||
virtual void init();
|
||||
|
||||
private:
|
||||
// Internal variables
|
||||
uint8_t GPS_checksum;
|
||||
uint8_t GPS_checksum_calc;
|
||||
char buffer[GPS_BUFFERSIZE];
|
||||
int bufferidx;
|
||||
/// Checks the serial receive buffer for characters,
|
||||
/// attempts to parse NMEA data and updates internal state
|
||||
/// accordingly.
|
||||
///
|
||||
virtual bool read();
|
||||
|
||||
bool parse_nmea_gps(void);
|
||||
uint8_t parseHex(char c);
|
||||
long parsedecimal(char *str,uint8_t num_car);
|
||||
long parsenumber(char *str,uint8_t numdec);
|
||||
private:
|
||||
/// Coding for the GPS sentences that the parser handles
|
||||
enum _sentence_types {
|
||||
_GPS_SENTENCE_GPRMC = 10,
|
||||
_GPS_SENTENCE_GPGGA = 20,
|
||||
_GPS_SENTENCE_VTG = 30,
|
||||
_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);
|
||||
|
||||
/// Return the numeric value of an ascii hex character
|
||||
///
|
||||
/// @param a The character to be converted
|
||||
/// @returns The value of the character as a hex digit
|
||||
///
|
||||
int _from_hex(char a);
|
||||
|
||||
/// Parses the current term as a NMEA-style decimal number with
|
||||
/// up to two decimal digits.
|
||||
///
|
||||
/// @returns The value expressed by the string in _term,
|
||||
/// multiplied by 100.
|
||||
///
|
||||
unsigned long _parse_decimal();
|
||||
|
||||
/// 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 18cm.
|
||||
///
|
||||
/// @returns The value expressed by the string in _term,
|
||||
/// multiplied by 10000.
|
||||
///
|
||||
unsigned long _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();
|
||||
|
||||
uint8_t _parity; ///< NMEA message checksum accumulator
|
||||
bool _is_checksum_term; ///< current term is the checksum
|
||||
char _term[15]; ///< buffer for the current term within the current sentence
|
||||
uint8_t _sentence_type; ///< the sentence type currently being processed
|
||||
uint8_t _term_number; ///< term index within the current sentence
|
||||
uint8_t _term_offset; ///< character offset with the term being received
|
||||
bool _gps_data_good; ///< set when the sentence indicates data is good
|
||||
|
||||
// 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.
|
||||
long _new_time; ///< time parsed from a term
|
||||
long _new_date; ///< date parsed from a term
|
||||
long _new_latitude; ///< latitude parsed from a term
|
||||
long _new_longitude; ///< longitude parsed from a term
|
||||
long _new_altitude; ///< altitude parsed from a term
|
||||
long _new_speed; ///< speed parsed from a term
|
||||
long _new_course; ///< course parsed from a term
|
||||
int _new_hdop; ///< HDOP parsed from a term
|
||||
uint8_t _new_satellite_count; ///< satellite count parsed from a term
|
||||
|
||||
/// @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 prog_char _SiRF_init_string[]; ///< init string for SiRF units
|
||||
static const prog_char _MTK_init_string[]; ///< init string for MediaTek units
|
||||
static const prog_char _ublox_init_string[]; ///< init string for ublox units
|
||||
//@}
|
||||
|
||||
/// @name GPS message identifier strings
|
||||
//@{
|
||||
static const prog_char _gprmc_string[];
|
||||
static const prog_char _gpgga_string[];
|
||||
static const prog_char _gpvtg_string[];
|
||||
//@}
|
||||
};
|
||||
|
||||
#endif
|
||||
|
|
|
|||
Loading…
Reference in New Issue