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| #include <inttypes.h> |
| #include "ubx.h" |
| |
| // ubx protocol parser state machine |
| #define UBXSTATE_IDLE 0 |
| #define UBXSTATE_SYNC1 1 |
| #define UBXSTATE_SYNC2 2 |
| #define UBXSTATE_CLASS 3 |
| #define UBXSTATE_LEN1 4 |
| #define UBXSTATE_LEN2 5 |
| #define UBXSTATE_DATA 6 |
| #define UBXSTATE_CKA 7 |
| #define UBXSTATE_CKB 8 |
| |
| // ublox protocoll identifier |
| #define UBX_CLASS_NAV 0x01 |
| #define UBX_ID_POSLLH 0x02 |
| #define UBX_ID_POSUTM 0x08 |
| #define UBX_ID_STATUS 0x03 |
| #define UBX_ID_VELNED 0x12 |
| #define UBX_SYNC1_CHAR 0xB5 |
| #define UBX_SYNC2_CHAR 0x62 |
| |
| |
| typedef struct { |
| uint32_t ITOW; // ms GPS Millisecond Time of Week |
| uint8_t GPSfix; // GPSfix Type, range 0..6 |
| uint8_t Flags; // Navigation Status Flags |
| uint8_t DiffS; // Differential Status |
| uint8_t res; // reserved |
| uint32_t TTFF; // Time to first fix (millisecond time tag) |
| uint32_t MSSS; // Milliseconds since Startup / Reset |
| uint8_t packetStatus; |
| } GPS_STATUS_t; |
| |
| typedef struct { |
| uint32_t ITOW; // ms GPS Millisecond Time of Week |
| int32_t LON; // 1e-07 deg Longitude |
| int32_t LAT; // 1e-07 deg Latitude |
| int32_t HEIGHT; // mm Height above Ellipsoid |
| int32_t HMSL; // mm Height above mean sea level |
| uint32_t Hacc; // mm Horizontal Accuracy Estimate |
| uint32_t Vacc; // mm Vertical Accuracy Estimate |
| uint8_t packetStatus; |
| } GPS_POSLLH_t; |
| |
| typedef struct { |
| uint32_t ITOW; // ms GPS Millisecond Time of Week |
| int32_t EAST; // cm UTM Easting |
| int32_t NORTH; // cm UTM Nording |
| int32_t ALT; // cm altitude |
| uint8_t ZONE; // UTM zone number |
| uint8_t HEM; // Hemisphere Indicator (0=North, 1=South) |
| uint8_t packetStatus; |
| } GPS_POSUTM_t; |
| |
| typedef struct { |
| uint32_t ITOW; // ms GPS Millisecond Time of Week |
| int32_t VEL_N; // cm/s NED north velocity |
| int32_t VEL_E; // cm/s NED east velocity |
| int32_t VEL_D; // cm/s NED down velocity |
| uint32_t Speed; // cm/s Speed (3-D) |
| uint32_t GSpeed; // cm/s Ground Speed (2-D) |
| int32_t Heading; // 1e-05 deg Heading 2-D |
| uint32_t SAcc; // cm/s Speed Accuracy Estimate |
| uint32_t CAcc; // deg Course / Heading Accuracy Estimate |
| uint8_t packetStatus; |
| } GPS_VELNED_t; |
| |
| |
| GPS_STATUS_t GpsStatus; |
| GPS_POSLLH_t GpsPosLlh; |
| GPS_POSUTM_t GpsPosUtm; |
| GPS_VELNED_t GpsVelNed; |
| |
| GPS_INFO_t actualPos; |
| |
| void UpdateGPSInfo (void) |
| { |
| if (GpsStatus.packetStatus == VALID) // valid packet |
| { |
| actualPos.satfix = GpsStatus.GPSfix; |
| GpsStatus.packetStatus = PROCESSED; // never update old data |
| } |
| if (GpsPosLlh.packetStatus == VALID) // valid packet |
| { |
| actualPos.longitude = GpsPosLlh.LON; |
| actualPos.latitude = GpsPosLlh.LAT; |
| actualPos.altitude = GpsPosLlh.HEIGHT; |
| GpsPosLlh.packetStatus = PROCESSED; // never update old data |
| } |
| if (GpsPosUtm.packetStatus == VALID) // valid packet |
| { |
| actualPos.utmeast = GpsPosUtm.EAST; |
| actualPos.utmnorth = GpsPosUtm.NORTH; |
| actualPos.utmalt = GpsPosUtm.ALT; |
| GpsPosUtm.packetStatus = PROCESSED; // never update old data |
| } |
| if (GpsVelNed.packetStatus == VALID) // valid packet |
| { |
| actualPos.veleast = GpsVelNed.VEL_E; |
| actualPos.velnorth = GpsVelNed.VEL_N; |
| actualPos.veltop = -GpsVelNed.VEL_D; |
| GpsPosUtm.packetStatus = PROCESSED; // never update old data |
| } |
| } |
| |
| // this function should be called within the UART RX ISR |
| void ubx_parser(uint8_t c) |
| { |
| static uint8_t ubxstate = UBXSTATE_IDLE; |
| static uint8_t cka, ckb; |
| static uint16_t msglen; |
| static int8_t *ubxP, *ubxEp, *ubxSp; // pointers to data currently transfered |
| |
| switch(ubxstate) |
| { |
| case UBXSTATE_IDLE: // check 1st sync byte |
| if (c == UBX_SYNC1_CHAR) ubxstate = UBXSTATE_SYNC1; |
| else ubxstate = UBXSTATE_IDLE; // out of synchronization |
| break; |
| |
| case UBXSTATE_SYNC1: // check 2nd sync byte |
| if (c == UBX_SYNC2_CHAR) ubxstate = UBXSTATE_SYNC2; |
| else ubxstate = UBXSTATE_IDLE; // out of synchronization |
| break; |
| |
| case UBXSTATE_SYNC2: // check msg class to be NAV |
| if (c == UBX_CLASS_NAV) ubxstate = UBXSTATE_CLASS; |
| else ubxstate = UBXSTATE_IDLE; // unsupported message class |
| break; |
| |
| case UBXSTATE_CLASS: // check message identifier |
| switch(c) |
| { |
| case UBX_ID_POSUTM: // utm position |
| ubxP = (int8_t *)&GpsPosUtm; // data start pointer |
| ubxEp = (int8_t *)(&GpsPosUtm + sizeof(GPS_POSUTM_t)); // data end pointer |
| ubxSp = (int8_t *)&GpsPosUtm.packetStatus; // status pointer |
| |
| break; |
| |
| case UBX_ID_POSLLH: // geodetic position |
| ubxP = (int8_t *)&GpsStatus; // data start pointer |
| ubxEp = (int8_t *)(&GpsStatus + sizeof(GPS_STATUS_t)); // data end pointer |
| ubxSp = (int8_t *)&GpsStatus.packetStatus; // status pointer |
| break; |
| |
| case UBX_ID_STATUS: // receiver status |
| ubxP = (int8_t *)&GpsStatus; // data start pointer |
| ubxEp = (int8_t *)(&GpsStatus + sizeof(GPS_STATUS_t)); // data end pointer |
| ubxSp = (int8_t *)&GpsStatus.packetStatus; // status pointer |
| break; |
| |
| case UBX_ID_VELNED: // velocity vector in tangent plane |
| ubxP = (int8_t *)&GpsVelNed; // data start pointer |
| ubxEp = (int8_t *)(&GpsVelNed + sizeof(GPS_VELNED_t)); // data end pointer |
| ubxSp = (int8_t *)&GpsVelNed.packetStatus; // status pointer |
| break; |
| |
| default: // unsupported identifier |
| ubxstate = UBXSTATE_IDLE; |
| break; |
| } |
| if (ubxstate != UBXSTATE_IDLE) |
| { |
| ubxstate = UBXSTATE_LEN1; |
| cka = UBX_CLASS_NAV + c; |
| ckb = UBX_CLASS_NAV + cka; |
| } |
| break; |
| |
| case UBXSTATE_LEN1: // 1st message length byte |
| msglen = c; |
| cka += c; |
| ckb += cka; |
| ubxstate = UBXSTATE_LEN2; |
| break; |
| |
| case UBXSTATE_LEN2: // 2nd message length byte |
| msglen += ((uint16_t)c)<<8; |
| cka += c; |
| ckb += cka; |
| // if the old data are not processed so far then break parsing now |
| // to avoid writing new data in ISR during reading by another function |
| if ( *ubxSp == VALID ) ubxstate = UBXSTATE_IDLE; |
| else // data invalid or allready processd |
| { |
| *ubxSp = INVALID; |
| ubxstate = UBXSTATE_DATA; |
| } |
| break; |
| |
| case UBXSTATE_DATA: |
| if (ubxP < ubxEp) *ubxP++ = c; // copy curent data byte if any space is left |
| cka += c; |
| ckb += cka; |
| if (--msglen == 0) ubxstate = UBXSTATE_CKA; // switch to next state if all data was read |
| break; |
| |
| case UBXSTATE_CKA: |
| if (c == cka) ubxstate = UBXSTATE_CKB; |
| else ubxstate = UBXSTATE_IDLE; |
| break; |
| |
| case UBXSTATE_CKB: |
| if (c == ckb) |
| { |
| *ubxSp = VALID; // new data are availabe |
| UpdateGPSInfo(); //update GPS info respectively |
| } |
| ubxstate = UBXSTATE_IDLE; // ready to parse new data |
| break; |
| |
| default: // unknown ubx state |
| ubxstate = UBXSTATE_IDLE; |
| break; |
| } |
| |
| } |
| |