/** Assemble an NMEA GPRMC message and send it out NMEA USARTs.
* NMEA RMC contains minimum GPS data
*
* \param nav_meas Pointer to navigation_measurement struct.
* \param soln Pointer to gnss_solution struct
* \param gps_t Pointer to the current GPS Time
*/
void nmea_gprmc(const navigation_measurement_t *nav_meas,
const gnss_solution *soln, const gps_time_t *gps_t)
{
/* NMEA Parameters
* Ex.
* $GPRMC,220516,A,5133.82,N,00042.24,W,173.8,231.8,130694,004.2,W*70
* | | | | | | | | | | | | |
* Command | | Lat N/S | | | | Date Stamp | W/E |
* Time (UTC) | Long W/E | True Course | Cksum
* Validity (A-OK) Speed Variation
* Variation is ignored as we have no way to maintain that information
* currently
*/
time_t unix_t;
struct tm t;
unix_t = gps2time(*gps_t);
gmtime_r(&unix_t, &t);
double frac_s = fmod(gps_t->tow, 1.0);
s16 lat_deg = R2D * (soln->pos_llh[0]);
double lat_min = MINUTES(soln->pos_llh[0]);
s16 lon_deg = R2D * (soln->pos_llh[1]);
double lon_min = MINUTES(soln->pos_llh[1]);
lat_deg = abs(lat_deg);
lon_deg = abs(lon_deg);
char lat_dir = soln->pos_llh[0] < 0 ? 'S' : 'N';
char lon_dir = soln->pos_llh[1] < 0 ? 'W' : 'E';
float velocity;
float x,y,z;
x = soln->vel_ned[0];
y = soln->vel_ned[1];
z = soln->vel_ned[2];
float course = atan2(y,x);
/* Conversion to magnitue knots */
velocity = MS2KNOTTS(x,y,z);
double az, el;
wgsecef2azel(nav_meas[0].sat_pos, soln->pos_ecef, &az, &el);
char buf[100];
u8 n = sprintf(buf,
"$GPRMC,%02d%02d%06.3f,A," /* Command, Time (UTC), Valid */
"%02d%010.7f,%c,%03d%010.7f,%c," /* Lat/Lon */
"%06.2f,%05.1f," /* Speed, Course */
"%02d%02d%02d," /* Date Stamp */
",", /* Variation */
t.tm_hour, t.tm_min, t.tm_sec + frac_s,
lat_deg, lat_min, lat_dir, lon_deg, lon_min, lon_dir,
velocity, course * R2D,
t.tm_mday, t.tm_mon, t.tm_year-100);
u8 sum = nmea_checksum(buf);
sprintf(buf + n, "*%02X\r\n", sum);
nmea_output(buf);
}
/** Assemble a NMEA GPGSV message and send it out NMEA USARTs.
* NMEA GPGSV message contains GPS satellites in view.
*
* \param n_used Number of satellites currently being tracked.
* \param nav_meas Pointer to navigation_measurement struct.
* \param soln Pointer to gnss_solution struct.
*/
void nmea_gpgsv(u8 n_used, navigation_measurement_t *nav_meas,
gnss_solution *soln)
{
if (n_used == 0)
return;
u8 n_mess = (n_used + 3) / 4;
char buf[80];
char *buf0 = buf + sprintf(buf, "$GPGSV,%d,", n_mess);
char *bufp = buf0;
u8 n = 0;
double az, el;
for (u8 i = 0; i < n_mess; i++) {
bufp = buf0;
bufp += sprintf(bufp, "%d,%d", i + 1, n_used);
for (u8 j = 0; j < 4; j++) {
if (n < n_used) {
wgsecef2azel(nav_meas[n].sat_pos, soln->pos_ecef, &az, &el);
bufp += sprintf(
bufp, ",%02d,%02d,%03d,%02d",
nav_meas[n].prn + 1,
(u8)round(el * 180.0 / M_PI),
(u16)round(az * 180.0 / M_PI),
(u8)(10.0 * nav_meas[n].snr)
);
} else {
bufp += sprintf(bufp, ",,,,");
}
n++;
}
sprintf(bufp, "*%02X\r\n", nmea_checksum(buf));
nmea_output(buf);
}
}
/** Assemble an NMEA GPVTG message and send it out NMEA USARTs.
* NMEA VTG contains course and speed
*
* \param nav_meas Pointer to navigation_measurement struct.
* \param soln Pointer to gnss_solution struct
*/
void nmea_gpvtg(const navigation_measurement_t *nav_meas,
const gnss_solution *soln)
{
/* NMEA Parameters for GPVTG
* Ex.
* $GPVTG,054.7,T,034.4,M,005.5,N,010.2,K
* | | | | | | | | |
* Command | 'T' | 'M' | 'N' | 'K'
* True Course | Speed (K) |
* Mag. course Speed (km/hr)
*/
double az, el;
wgsecef2azel(nav_meas[0].sat_pos, soln->pos_ecef, &az, &el);
float vknots, vkmhr;
float x,y,z;
x = soln->vel_ned[0];
y = soln->vel_ned[1];
z = soln->vel_ned[2];
float course = atan2(y,x);
/* Conversion to magnitue knots */
vknots = MS2KNOTTS(x,y,z);
/* Conversion to magnitue km/hr */
vkmhr = MS2KMHR(x,y,z);
char buf[80];
u8 n = sprintf(buf,
"$GPVTG,%05.1f,T," /* Command, course, */
",M," /* Magnetic Course (omitted) */
"%06.2f,N,%06.2f,K", /* Speed (knots, km/hr) */
course* R2D,
vknots, vkmhr);
u8 sum = nmea_checksum(buf);
sprintf(buf + n, "*%02X\r\n", sum);
nmea_output(buf);
}
/** Assemble a NMEA GPGGA message and send it out NMEA USARTs.
* NMEA GPGGA message contains Global Positioning System Fix Data.
*
* \param soln Pointer to gnss_solution struct.
* \param dops Pointer to dops_t struct.
*/
void nmea_gpgga(gnss_solution *soln, dops_t *dops)
{
time_t unix_t;
struct tm t;
unix_t = gps2time(soln->time);
gmtime_r(&unix_t, &t);
double frac_s = fmod(soln->time.tow, 1.0);
s8 lat_deg = (s8)((180.0 / M_PI) * soln->pos_llh[0]);
double lat_min = fabs(60 * ((180.0 / M_PI) * soln->pos_llh[0] - lat_deg));
s8 lon_deg = (s8)((180.0 / M_PI) * soln->pos_llh[1]);
double lon_min = fabs(60 * ((180.0 / M_PI) * soln->pos_llh[1] - lon_deg));
lat_deg = abs(lat_deg);
lon_deg = abs(lon_deg);
char lat_dir = soln->pos_llh[0] < 0 ? 'S' : 'N';
char lon_dir = soln->pos_llh[1] < 0 ? 'W' : 'E';
u8 fix_type = 1;
char buf[80];
u8 n = sprintf(buf,
"$GPGGA,%02d%02d%06.3f,"
"%02d%010.7f,%c,%03d%010.7f,%c,"
"%01d,%02d,%.1f,%1.f,M,,M,,",
t.tm_hour, t.tm_min, t.tm_sec + frac_s,
lat_deg, lat_min, lat_dir, lon_deg, lon_min, lon_dir,
fix_type, soln->n_used, dops->hdop, soln->pos_llh[2]
);
u8 sum = nmea_checksum(buf);
sprintf(buf + n, "*%02X\r\n", sum);
nmea_output(buf);
}
/** Assemble a NMEA GPGSA message and send it out NMEA USARTs.
* NMEA GPGSA message contains DOP and active satellites.
*
* \param chans Pointer to tracking_channel_t struct.
* \param dops Pointer to dops_t struct.
*/
void nmea_gpgsa(tracking_channel_t *chans, dops_t *dops)
{
char buf[80] = "$GPGSA,A,3,";
char *bufp = buf + strlen(buf);
for (u8 i = 0; i < 12; i++) {
if (i < nap_track_n_channels && chans[i].state == TRACKING_RUNNING)
bufp += sprintf(bufp, "%02d,", chans[i].prn + 1);
else
*bufp++ = ',';
}
if (dops)
bufp += sprintf(bufp, "%.1f,%.1f,%.1f", dops->pdop, dops->hdop, dops->vdop);
else
bufp += sprintf(bufp, ",,");
u8 sum = nmea_checksum(buf);
sprintf(bufp, "*%02X\r\n", sum);
nmea_output(buf);
}
/** Assemble an NMEA GPGLL message and send it out NMEA USARTs.
* NMEA GLL contains course and speed
*
* \param soln Pointer to gnss_solution struct
* \param gpt_t Pointer to the current GPS Time
*/
void nmea_gpgll(const gnss_solution *soln, const gps_time_t *gps_t)
{
/* NMEA Parameters for GPGLL
* Ex.
* $GPGLL,5133.81,N,00042.25,W,225444,A*75
* | | | | | | |
* Command | N/S Lon E/W | Valid
* LAT UTC
*/
time_t unix_t;
struct tm t;
unix_t = gps2time(*gps_t);
gmtime_r(&unix_t, &t);
double frac_s = fmod(gps_t->tow, 1.0);
s16 lat_deg = R2D * (soln->pos_llh[0]);
double lat_min = MINUTES(soln->pos_llh[0]);
s16 lon_deg = R2D * (soln->pos_llh[1]);
double lon_min = MINUTES(soln->pos_llh[1]);
lat_deg = abs(lat_deg);
lon_deg = abs(lon_deg);
char lat_dir = soln->pos_llh[0] < 0 ? 'S' : 'N';
char lon_dir = soln->pos_llh[1] < 0 ? 'W' : 'E';
char buf[80];
u8 n = sprintf(buf,
"$GPGLL,"
"%02d%010.7f,%c,%03d%010.7f,%c," /* Lat/Lon */
"%02d%02d%06.3f,A", /* Time (UTC), Valid */
lat_deg, lat_min, lat_dir, lon_deg, lon_min, lon_dir,
t.tm_hour, t.tm_min, t.tm_sec + frac_s);
u8 sum = nmea_checksum(buf);
sprintf(buf + n, "*%02X\r\n", sum);
nmea_output(buf);
}
/** Assemble a NMEA GPGGA message and send it out NMEA USARTs.
* NMEA GPGGA message contains Global Positioning System Fix Data.
*
* \param soln Pointer to gnss_solution struct.
* \param dops Pointer to dops_t struct.
*/
void nmea_gpgga(const double pos_llh[3], const gps_time_t *gps_t, u8 n_used,
u8 fix_type, double hdop)
{
time_t unix_t;
struct tm t;
unix_t = gps2time(*gps_t);
gmtime_r(&unix_t, &t);
double frac_s = fmod(gps_t->tow, 1.0);
s16 lat_deg = R2D * (pos_llh[0]);
double lat_min = MINUTES(pos_llh[0]);
s16 lon_deg = R2D * (pos_llh[1]);
double lon_min = MINUTES(pos_llh[1]);
lat_deg = abs(lat_deg);
lon_deg = abs(lon_deg);
char lat_dir = pos_llh[0] < 0 ? 'S' : 'N';
char lon_dir = pos_llh[1] < 0 ? 'W' : 'E';
char buf[80];
u8 n = sprintf(buf,
"$GPGGA,%02d%02d%06.3f,"
"%02d%010.7f,%c,%03d%010.7f,%c,"
"%01d,%02d,%.1f,%.2f,M,,M,,",
t.tm_hour, t.tm_min, t.tm_sec + frac_s,
lat_deg, lat_min, lat_dir, lon_deg, lon_min, lon_dir,
fix_type, n_used, hdop, pos_llh[2]
);
u8 sum = nmea_checksum(buf);
sprintf(buf + n, "*%02X\r\n", sum);
nmea_output(buf);
}