OpenModem/hardware/GPS.c
2019-04-05 13:26:53 +02:00

287 lines
7.6 KiB
C

#include "GPS.h"
Serial *serial;
bool gps_installed = false;
bool gps_power = true;
uint8_t nmea_read_length = 0;
char nmea_input_buf[NMEA_MAX_LENGTH];
char nmea_parse_buf[NMEA_MAX_LENGTH];
bool gps_detect(void) {
GPS_DDR &= ~_BV(GPS_EN_PIN);
return (GPS_INPUT & _BV(GPS_EN_PIN));
}
void gps_powerup(void) {
GPS_PORT |= _BV(GPS_EN_PIN);
}
void gps_powerdown(void) {
GPS_PORT &= ~_BV(GPS_EN_PIN);
}
bool gps_enabled(void) {
return gps_power;
}
void gps_init(Serial *ser) {
serial = ser;
memset(nmea_input_buf, 0, sizeof(nmea_input_buf));
memset(nmea_parse_buf, 0, sizeof(nmea_parse_buf));
gps_speed_knots = 0;
gps_speed_kmh = 0;
gps_bearing = 0;
if (gps_detect()) {
gps_installed = true;
serial_setbaudrate_9600(1);
gps_send_command(PMTK_SET_BAUD_57600);
serial_setbaudrate_57600(1);
gps_send_command(PMTK_API_SET_FIX_CTL_1HZ);
gps_send_command(PMTK_SET_NMEA_OUTPUT_RMCGGA);
GPS_DDR |= _BV(GPS_EN_PIN);
if (gps_enabled()) { gps_powerup(); } else { gps_powerdown(); }
} else {
gps_installed = false;
gps_power = false;
}
}
void gps_update_rtc(void) {
// TODO: implement this
}
void gps_jobs(void) {
if (gps_enabled()) { gps_powerup(); } else { gps_powerdown(); }
}
void gps_send_command(const char *cmd) {
fprintf_P(&serial->uart1, cmd);
}
void gps_nmea_parse(uint8_t sentence_length) {
if (sentence_length > 4) {
if (nmea_parse_buf[sentence_length-4] == '*') {
uint16_t checksum = gps_nmea_parse_hex(nmea_parse_buf[sentence_length-3]);
checksum *= 16;
checksum += gps_nmea_parse_hex(nmea_parse_buf[sentence_length-2]);
for (uint8_t i=1; i < sentence_length-4; i++) {
checksum ^= nmea_parse_buf[i];
}
if (checksum != 0) {
return;
} else {
// Parse GGA sentence
if (strstr(nmea_parse_buf, "$GPGGA")) {
char *pointer = nmea_parse_buf;
// Parse UTC time
pointer = strchr(pointer, ',')+1;
uint32_t nmea_time = (float)atof(pointer);
// Parse latitude
pointer = strchr(pointer, ',')+1;
char nmea_lat_deg_str[3];
nmea_lat_deg_str[0] = pointer[0];
nmea_lat_deg_str[1] = pointer[1];
nmea_lat_deg_str[2] = '\0';
char nmea_lat_min_str[3];
nmea_lat_min_str[0] = pointer[2];
nmea_lat_min_str[1] = pointer[3];
nmea_lat_min_str[2] = '\0';
char nmea_lat_dec_str[5];
nmea_lat_dec_str[0] = pointer[5];
nmea_lat_dec_str[1] = pointer[6];
nmea_lat_dec_str[2] = pointer[7];
nmea_lat_dec_str[3] = pointer[8];
nmea_lat_dec_str[4] = '\0';
// Parse latitude sign
pointer = strchr(pointer, ',')+1;
char nmea_lat_sign = pointer[0];
// Parse longtitude
pointer = strchr(pointer, ',')+1;
char nmea_lon_deg_str[4];
nmea_lon_deg_str[0] = pointer[0];
nmea_lon_deg_str[1] = pointer[1];
nmea_lon_deg_str[2] = pointer[2];
nmea_lon_deg_str[3] = '\0';
char nmea_lon_min_str[3];
nmea_lon_min_str[0] = pointer[3];
nmea_lon_min_str[1] = pointer[4];
nmea_lon_min_str[2] = '\0';
char nmea_lon_dec_str[5];
nmea_lon_dec_str[0] = pointer[6];
nmea_lon_dec_str[1] = pointer[7];
nmea_lon_dec_str[2] = pointer[8];
nmea_lon_dec_str[3] = pointer[9];
nmea_lon_dec_str[4] = '\0';
// Parse longtitude sign
pointer = strchr(pointer, ',')+1;
char nmea_lon_sign = pointer[0];
// Get fix quality
pointer = strchr(pointer, ',')+1;
uint8_t nmea_fix = atoi(pointer);
if (nmea_fix == 1) {
gps_fix = true;
} else {
gps_fix = false;
}
if (gps_fix) {
// Set times
gps_t_hour = nmea_time / 10000;
gps_t_minute = (nmea_time % 10000) / 100;
gps_t_second = (nmea_time % 100);
gps_update_rtc();
// Set latitude and longtitude
gps_lat_degrees = atoi(nmea_lat_deg_str);
gps_lat_minutes = atoi(nmea_lat_min_str);
gps_lat_seconds = (atoi(nmea_lat_dec_str)/10000.0)*60.0;
gps_lon_degrees = atoi(nmea_lon_deg_str);
gps_lon_minutes = atoi(nmea_lon_min_str);
gps_lon_seconds = (atoi(nmea_lon_dec_str)/10000.0)*60.0;
gps_lat = gps_lat_degrees + (gps_lat_minutes/60.0) + (gps_lat_seconds/3600.0);
gps_lon = gps_lon_degrees + (gps_lon_minutes/60.0) + (gps_lon_seconds/3600.0);
// Get satellites
pointer = strchr(pointer, ',')+1;
gps_sats = atoi(pointer);
// Get horizontal dilution of position
pointer = strchr(pointer, ',')+1;
gps_hdop = atof(pointer);
// Get altitude
pointer = strchr(pointer, ',')+1;
gps_altitude = atof(pointer);
// Ignore altitude unit reference
pointer = strchr(pointer, ',')+1;
// Get geoid height
pointer = strchr(pointer, ',')+1;
gps_geoid_height = atof(pointer);
// TODO: Check this calculation
gps_height_above_msl = gps_geoid_height + gps_altitude;
// Ignore geoid height unit reference
pointer = strchr(pointer, ',')+1;
gps_lat_sign = nmea_lat_sign;
gps_lon_sign = nmea_lon_sign;
gps_lat *= (gps_lat_sign == 'N' ? 1 : -1);
gps_lon *= (gps_lon_sign == 'E' ? 1 : -1);
// TODO: Remove this
// printf("GPS fix: %d\r\n", nmea_fix);
// printf("GPS satellites: %d\r\n", gps_sats);
// printf("GPS latitude: %d\" %d' %.2fs %c\r\n", gps_lat_degrees, gps_lat_minutes, gps_lat_seconds, gps_lat_sign);
// printf("GPS longtitude: %d\" %d' %.2fs %c\r\n", gps_lon_degrees, gps_lon_minutes, gps_lon_seconds, gps_lon_sign);
// printf("GPS coords: %.6f,%.6f\r\n", gps_lat, gps_lon);
// printf("GPS speed %.2f Km/h\r\n", gps_speed_kmh);
// printf("GPS speed %.2f knots\r\n", gps_speed_knots);
// printf("GPS bearing %.2f\r\n", gps_bearing);
// printf("GPS height above MSL: %.2f\r\n", gps_height_above_msl);
// printf("GPS altitude: %.2f\r\n", gps_altitude);
// printf("GPS geoid height: %.2f\r\n", gps_geoid_height);
// printf("GPS HDOP: %.2f\r\n", gps_hdop);
// printf("GPS time %d:%d:%d UTC\r\n", gps_t_hour, gps_t_minute, gps_t_second);
}
}
// Parse RMC sentence
if (strstr(nmea_parse_buf, "$GPRMC")) {
if (gps_fix) {
char *pointer = nmea_parse_buf;
// Ignore UTC time
pointer = strchr(pointer, ',')+1;
// Ignore navigation receiver warning
pointer = strchr(pointer, ',')+1;
// Ignore latitude
pointer = strchr(pointer, ',')+1;
// Ignore latitude sign
pointer = strchr(pointer, ',')+1;
// Ignore longtitude
pointer = strchr(pointer, ',')+1;
// Ignore longtitude sign
pointer = strchr(pointer, ',')+1;
// Get ground speed
pointer = strchr(pointer, ',')+1;
gps_speed_knots = atof(pointer);
gps_speed_kmh = gps_speed_knots * 1.852;
// Get bearing
pointer = strchr(pointer, ',')+1;
gps_bearing = atof(pointer);
} else {
gps_speed_knots = 0;
gps_speed_kmh = 0;
}
}
}
}
}
}
void gps_serial_callback(char byte) {
if (byte == '\n') {
for (uint8_t i = 0; i < NMEA_MAX_LENGTH; i++)
nmea_parse_buf[i] = nmea_input_buf[i];
memset(nmea_input_buf, 0, sizeof(nmea_input_buf));
gps_nmea_parse(nmea_read_length);
nmea_read_length = 0;
} else {
if (nmea_read_length < NMEA_MAX_LENGTH) {
nmea_input_buf[nmea_read_length++] = byte;
}
}
}
void gps_poll(void) {
while (!fifo_isempty_locked(&uart1FIFO)) {
char sbyte = fifo_pop_locked(&uart1FIFO);
gps_serial_callback(sbyte);
}
}
uint8_t gps_nmea_parse_hex(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;
return 0;
}