NMEA mode don't work with multi-system modules (eg. mt3333)

Issue details

because in AP_GPS_NMEA.cpp data compared with GPVTG GPRMC etc so ARDUPILOT want to listen NMEA v2. But new multi-system modules emits NMEA v4 where messages has prefix GA for Galileo, GN for Glonass and GL for unified data.

Version

all versions

Platform

[ * ] All [ ] AntennaTracker [ ] Copter [ ] Plane [ ] Rover

Here is small patch to correct this. ----- cut here --- --- AP_GPS_NMEA.cpp.orig 2016-06-01 17:28:22.351546727 +0500 +++ AP_GPS_NMEA.cpp 2016-06-01 17:31:56.599765010 +0500 @@ -93,9 +93,9 @@ . // NMEA message identifiers //////////////////////////////////////////////////// // -const char AP_GPS_NMEA::_gprmc_string[] = "GPRMC"; -const char AP_GPS_NMEA::_gpgga_string[] = "GPGGA"; -const char AP_GPS_NMEA::_gpvtg_string[] = "GPVTG"; +const char AP_GPS_NMEA::_gprmc_string[] = "RMC"; +const char AP_GPS_NMEA::_gpgga_string[] = "GGA"; +const char AP_GPS_NMEA::_gpvtg_string[] = "VTG"; . // Convenience macros ////////////////////////////////////////////////////////// // @@ -339,12 +339,12 @@ } . // the first term determines the sentence type

if (_term_number == 0) {
if (!strcmp(_term, _gprmc_string)) {
if (_term_number == 0 && _term[0]=='G') { // check is it really the first character "G"?
if ( !strcmp(_term+2, _gprmc_string)) { // ignore gp gn gl prefixes detect rmc gga or vtg string _sentence_type = _GPS_SENTENCE_GPRMC;
} else if (!strcmp(_term, _gpgga_string)) {
} else if (!strcmp(_term+2, _gpgga_string)) { _sentence_type = _GPS_SENTENCE_GPGGA;
} else if (!strcmp(_term, _gpvtg_string)) {
} else if (!strcmp(_term+2, _gpvtg_string)) { _sentence_type = _GPS_SENTENCE_GPVTG; // VTG may not contain a data qualifier, presume the solution is good // unless it tells us otherwise. ----- up to here ---

ArduPilot / ardupilot