#endif
#include <ao_aprs.h>
+#include <math.h>
// Public methods, constants, and data structures for each class.
/// AX.25 compliant packet header that contains destination, station call sign, and path.
/// 0x76 for SSID-11, 0x78 for SSID-12
static uint8_t TNC_AX25_HEADER[] = {
- 'A' << 1, 'P' << 1, 'A' << 1, 'M' << 1, ' ' << 1, ' ' << 1, 0x60, \
- 'N' << 1, '0' << 1, 'C' << 1, 'A' << 1, 'L' << 1, 'L' << 1, 0x78, \
- 'W' << 1, 'I' << 1, 'D' << 1, 'E' << 1, '2' << 1, ' ' << 1, 0x65, \
+ 'A' << 1, 'P' << 1, 'A' << 1, 'M' << 1, ' ' << 1, ' ' << 1, 0x60,
+ 'N' << 1, '0' << 1, 'C' << 1, 'A' << 1, 'L' << 1, 'L' << 1, 0x78,
+ 'W' << 1, 'I' << 1, 'D' << 1, 'E' << 1, '2' << 1, ' ' << 1, 0x65,
0x03, 0xf0 };
#define TNC_CALLSIGN_OFF 7
} // END switch
}
+static void tncCompressInt(uint8_t *dest, int32_t value, int len) {
+ int i;
+ for (i = len - 1; i >= 0; i--) {
+ dest[i] = value % 91 + 33;
+ value /= 91;
+ }
+}
+
+static int ao_num_sats(void)
+{
+ int i;
+ int n = 0;
+
+ for (i = 0; i < ao_gps_tracking_data.channels; i++) {
+ if (ao_gps_tracking_data.sats[i].svid)
+ n++;
+ }
+ return n;
+}
+
+static char ao_gps_locked(void)
+{
+ if (ao_gps_data.flags & AO_GPS_VALID)
+ return 'L';
+ else
+ return 'U';
+}
+
+static int tncComment(uint8_t *buf)
+{
+#if HAS_ADC
+ struct ao_data packet;
+
+ ao_arch_critical(ao_data_get(&packet););
+
+ int16_t battery = ao_battery_decivolt(packet.adc.v_batt);
+#ifdef AO_SENSE_DROGUE
+ int16_t apogee = ao_ignite_decivolt(AO_SENSE_DROGUE(&packet));
+#endif
+#ifdef AO_SENSE_MAIN
+ int16_t main = ao_ignite_decivolt(AO_SENSE_MAIN(&packet));
+#endif
+
+ return sprintf((char *) buf,
+ "%c%d B%d.%d"
+#ifdef AO_SENSE_DROGUE
+ " A%d.%d"
+#endif
+#ifdef AO_SENSE_MAIN
+ " M%d.%d"
+#endif
+ , ao_gps_locked(),
+ ao_num_sats(),
+ battery/10,
+ battery % 10
+#ifdef AO_SENSE_DROGUE
+ , apogee/10,
+ apogee%10
+#endif
+#ifdef AO_SENSE_MAIN
+ , main/10,
+ main%10
+#endif
+ );
+#else
+ return sprintf((char *) buf,
+ "%c%d",
+ ao_gps_locked(),
+ ao_num_sats());
+#endif
+}
+
/**
* Generate the plain text position packet.
*/
static int tncPositionPacket(void)
{
- int32_t latitude = ao_gps_data.latitude;
- int32_t longitude = ao_gps_data.longitude;
- int32_t altitude = ao_gps_data.altitude;
-
- uint16_t lat_deg;
- uint16_t lon_deg;
- uint16_t lat_min;
- uint16_t lat_frac;
- uint16_t lon_min;
- uint16_t lon_frac;
-
- char lat_sign = 'N', lon_sign = 'E';
-
- if (latitude < 0) {
- lat_sign = 'S';
- latitude = -latitude;
+ static int32_t latitude;
+ static int32_t longitude;
+ static int32_t altitude;
+ int32_t lat, lon, alt;
+ uint8_t *buf;
+
+ if (ao_gps_data.flags & AO_GPS_VALID) {
+ latitude = ao_gps_data.latitude;
+ longitude = ao_gps_data.longitude;
+ altitude = ao_gps_data.altitude;
+ if (altitude < 0)
+ altitude = 0;
}
- if (longitude < 0) {
- lon_sign = 'W';
- longitude = -longitude;
- }
+ buf = tncBuffer;
+ *buf++ = '!';
- /* Round latitude and longitude by 0.005 minutes */
- latitude = latitude + 833;
- if (latitude > 900000000)
- latitude = 900000000;
- longitude = longitude + 833;
- if (longitude > 1800000000)
- longitude = 1800000000;
-
- lat_deg = latitude / 10000000;
- latitude -= lat_deg * 10000000;
- latitude *= 60;
- lat_min = latitude / 10000000;
- latitude -= lat_min * 10000000;
- lat_frac = latitude / 100000;
-
- lon_deg = longitude / 10000000;
- longitude -= lon_deg * 10000000;
- longitude *= 60;
- lon_min = longitude / 10000000;
- longitude -= lon_min * 10000000;
- lon_frac = longitude / 100000;
-
- if (altitude < 0)
- altitude = 0;
-
- altitude = (altitude * (int32_t) 10000 + (3048/2)) / (int32_t) 3048;
-
- return sprintf ((char *) tncBuffer, "=%02u%02u.%02u%c\\%03u%02u.%02u%cO /A=%06u\015",
- lat_deg, lat_min, lat_frac, lat_sign,
- lon_deg, lon_min, lon_frac, lon_sign,
- altitude);
+ /* Symbol table ID */
+ *buf++ = '/';
+
+ lat = ((uint64_t) 380926 * (900000000 - latitude)) / 10000000;
+ lon = ((uint64_t) 190463 * (1800000000 + longitude)) / 10000000;
+
+#define ALTITUDE_LOG_BASE 0.001998002662673f /* log(1.002) */
+
+ alt = (altitude * (int32_t) 10000 + (3048/2)) / (int32_t) 3048;
+ alt = logf((float) altitude) * (1/ALTITUDE_LOG_BASE);
+
+ tncCompressInt(buf, lat, 4);
+ buf += 4;
+ tncCompressInt(buf, lon, 4);
+ buf += 4;
+
+ /* Symbol code */
+ *buf++ = '\'';
+
+ tncCompressInt(buf, alt, 2);
+ buf += 2;
+
+ *buf++ = 33 + ((1 << 5) | (2 << 3));
+
+ buf += tncComment(buf);
+
+ return buf - tncBuffer;
}
static int16_t