OpenModem/hardware/GPS.c
2020-10-23 13:53:34 +02:00

325 lines
7.8 KiB
C

#include "GPS.h"
#include "util/Config.h"
#include "protocol/KISS.h"
#include <time.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;
gps_fix = false;
gps_time_set = false;
if (gps_detect()) {
gps_installed = true;
GPS_DDR |= _BV(GPS_EN_PIN);
if (config_gps_mode == CONFIG_GPS_AUTODETECT || config_gps_mode == CONFIG_GPS_REQUIRED) {
gps_powerup();
serial_setbaudrate_9600(1);
delay_ms(100);
gps_send_command(PMTK_SET_BAUD_57600);
delay_ms(100);
serial_setbaudrate_57600(1);
delay_ms(100);
gps_send_command(PMTK_API_SET_FIX_CTL_1HZ);
gps_send_command(PMTK_SET_NMEA_OUTPUT_RMCGGA);
gps_power = true;
} else {
gps_power = false;
gps_powerdown();
}
} else {
gps_installed = false;
gps_power = false;
}
}
void gps_update_rtc(void) {
struct tm now;
now.tm_year = (gps_t_year+2000) - 1900;
now.tm_mon = gps_t_month-1;
now.tm_mday = gps_t_day;
now.tm_hour = gps_t_hour;
now.tm_min = gps_t_minute;
now.tm_sec = gps_t_second;
now.tm_isdst = -1;
time_t timestamp = mktime(&now);
rtc_set_seconds(timestamp);
gps_time_set = true;
}
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 (config_gps_nmea_output == CONFIG_GPS_NMEA_RAW) {
printf("%s\n\r", nmea_parse_buf);
}
if (config_gps_nmea_output == CONFIG_GPS_NMEA_ENCAP) {
kiss_output_nmea(nmea_parse_buf, 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;
// Ignore UTC time
pointer = strchr(pointer, ',')+1;
// 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 > 0 && nmea_fix < 7) {
gps_fix = true;
} else {
gps_fix = false;
}
if (gps_fix) {
// 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);
}
}
// Parse RMC sentence
if (strstr(nmea_parse_buf, "$GPRMC")) {
if (gps_fix) {
char *pointer = nmea_parse_buf;
uint32_t nmea_date = 0;
uint32_t nmea_time = 0;
// Get UTC time
pointer = strchr(pointer, ',')+1;
if (!gps_time_set) nmea_time = (float)atof(pointer);
// 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);
// Get date
pointer = strchr(pointer, ',')+1;
if (!gps_time_set) nmea_date = (float)atof(pointer);
// Set times
if (!gps_time_set) {
gps_t_hour = nmea_time / 10000;
gps_t_minute = (nmea_time % 10000) / 100;
gps_t_second = (nmea_time % 100);
gps_t_day = nmea_date / 10000;
gps_t_month = (nmea_date % 10000) / 100;
gps_t_year = (nmea_date % 100);
gps_update_rtc();
}
} 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);
memset(nmea_parse_buf, 0, sizeof(nmea_parse_buf));
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;
}