/** ****************************************************************************** * @addtogroup OpenPilotModules OpenPilot Modules * @{ * @addtogroup GSPModule GPS Module * @brief Process GPS information * @{ * * @file GPS.c * @author The OpenPilot Team, http://www.openpilot.org Copyright (C) 2010. * @brief GPS module, handles GPS and NMEA stream * @see The GNU Public License (GPL) Version 3 * *****************************************************************************/ /* * 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, write to the Free Software Foundation, Inc., * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #include "openpilot.h" #include "GPS.h" #include #include "NMEA.h" #include "gpsposition.h" #include "homelocation.h" #include "gpstime.h" #include "WorldMagModel.h" #include "CoordinateConversions.h" // constants/macros/typdefs #define NMEA_BUFFERSIZE 128 #define GPS_TIMEOUT_MS 500 // Private functions static void gpsTask(void *parameters); static void setHomeLocation(GPSPositionData * gpsData); // Global variables // Private constants // Unfortunately need a good size stack for the WMM calculation #define STACK_SIZE configMINIMAL_STACK_SIZE + 1500 #define TASK_PRIORITY (tskIDLE_PRIORITY + 3) // Private types // Private variables static uint8_t gpsPort; static xTaskHandle gpsTaskHandle; static char gps_rx_buffer[NMEA_BUFFERSIZE]; static uint32_t timeOfLastUpdateMs; static uint32_t numUpdates; static uint32_t numChecksumErrors; static uint32_t numParsingErrors; /** * Initialise the gps module * \return -1 if initialisation failed * \return 0 on success */ int32_t GPSInitialize(void) { signed portBASE_TYPE xReturn; // TODO: Get gps settings object gpsPort = PIOS_COM_GPS; // Start gps task xReturn = xTaskCreate(gpsTask, (signed char *)"GPS", STACK_SIZE, NULL, TASK_PRIORITY, &gpsTaskHandle); return 0; } /** * gps task. Processes input buffer. It does not return. */ static void gpsTask(void *parameters) { int32_t gpsRxOverflow = 0; char c; portTickType xDelay = 100 / portTICK_RATE_MS; GPSPositionData GpsData; uint32_t timeNowMs; bool start_flag = false; bool found_cr = false; uint8_t rx_count = 0; //#define DISABLE_GPS_TRESHOLD //#define ENABLE_GPS_ONESENTENCE //#define ENABLE_DEFAULT_NMEA #ifdef DISABLE_GPS_TRESHOLD PIOS_COM_SendStringNonBlocking(gpsPort,"$PMTK397,0*23\r\n"); #endif #ifdef ENABLE_GPS_ONESENTENCE PIOS_COM_SendStringNonBlocking(gpsPort,"$PGCMD,21,2*6C\r\n"); #endif #ifdef ENABLE_DEFAULT_NMEA PIOS_COM_SendStringNonBlocking(gpsPort,"$PGCMD,21,3*6D\r\n"); #endif // Loop forever while (1) { /* This blocks the task until there is something on the buffer */ while (PIOS_COM_ReceiveBufferUsed(gpsPort) > 0) { c = PIOS_COM_ReceiveBuffer(gpsPort); /* detect start while acquiring stream */ if(!start_flag && (c == '$')) { start_flag = true; found_cr = false; rx_count = 0; } else if (!start_flag) continue; if(rx_count >= NMEA_BUFFERSIZE) { /* * The buffer is already full and we haven't found a valid NMEA sentence. * Flush the buffer and note the overflow event. */ gpsRxOverflow++; start_flag = false; found_cr = false; rx_count = 0; } else { gps_rx_buffer[rx_count] = c; rx_count++; } /* look for ending '\r\n' sequence */ if (!found_cr && (c == '\r') ) found_cr = true; else if (found_cr && (c != '\n') ) found_cr = false; // false end flag else if (found_cr && (c == '\n') ) { /* prepare to parse next sentence */ start_flag = false; found_cr = false; rx_count = 0; /* * Our rxBuffer must look like this now: * [0] = '$' * ... = zero or more bytes of sentence payload * [end_pos - 1] = '\r' * [end_pos] = '\n' * * Prepare to consume the sentence from the buffer */ /* Validate the checksum over the sentence */ if (!NMEA_checksum(&gps_rx_buffer[1])) { /* Invalid checksum. May indicate dropped characters on Rx. */ ++numChecksumErrors; } else { /* Valid checksum, use this packet to update the GPS position */ if (!NMEA_update_position(&gps_rx_buffer[1])) { ++numParsingErrors; } else { ++numUpdates; } timeOfLastUpdateMs = xTaskGetTickCount() * portTICK_RATE_MS; } } } // Check for GPS timeout timeNowMs = xTaskGetTickCount() * portTICK_RATE_MS; if ((timeNowMs - timeOfLastUpdateMs) > GPS_TIMEOUT_MS) { GPSPositionGet(&GpsData); GpsData.Status = GPSPOSITION_STATUS_NOGPS; GPSPositionSet(&GpsData); AlarmsSet(SYSTEMALARMS_ALARM_GPS, SYSTEMALARMS_ALARM_ERROR); } else { // Had an update HomeLocationData home; HomeLocationGet(&home); GPSPositionGet(&GpsData); if ((GpsData.Status == GPSPOSITION_STATUS_FIX3D) && (home.Set == HOMELOCATION_SET_FALSE)) { setHomeLocation(&GpsData); } //criteria for GPS-OK taken from this post... //http://forums.openpilot.org/topic/1523-professors-insgps-in-svn/page__view__findpost__p__5220 if ((GpsData.PDOP<3.5)&&(GpsData.Satellites>=7))AlarmsClear(SYSTEMALARMS_ALARM_GPS); else if (GpsData.Status == GPSPOSITION_STATUS_FIX3D) AlarmsSet(SYSTEMALARMS_ALARM_GPS, SYSTEMALARMS_ALARM_WARNING); else AlarmsSet(SYSTEMALARMS_ALARM_GPS, SYSTEMALARMS_ALARM_CRITICAL); } // Block task until next update vTaskDelay(xDelay); } } static void setHomeLocation(GPSPositionData * gpsData) { HomeLocationData home; HomeLocationGet(&home); GPSTimeData gps; GPSTimeGet(&gps); if (gps.Year >= 2000) { // Store LLA home.Latitude = gpsData->Latitude; home.Longitude = gpsData->Longitude; home.Altitude = gpsData->Altitude + gpsData->GeoidSeparation; // Compute home ECEF coordinates and the rotation matrix into NED double LLA[3] = { ((double)home.Latitude) / 10e6, ((double)home.Longitude) / 10e6, ((double)home.Altitude) }; double ECEF[3]; RneFromLLA(LLA, (float (*)[3])home.RNE); LLA2ECEF(LLA, ECEF); // TODO: Currently UAVTalk only supports float but these conversions use double // need to find out if they require that precision and if so extend UAVTAlk home.ECEF[0] = (int32_t) (ECEF[0] * 100); home.ECEF[1] = (int32_t) (ECEF[1] * 100); home.ECEF[2] = (int32_t) (ECEF[2] * 100); // Compute magnetic flux direction at home location WMM_GetMagVector(LLA[0], LLA[1], LLA[2], gps.Month, gps.Day, gps.Year, &home.Be[0]); home.Set = HOMELOCATION_SET_TRUE; HomeLocationSet(&home); } } /** * @} * @} */