Break up decodeExtendedSquiiter, it was getting pretty large.
This commit is contained in:
Oliver Jowett
parent
a1fdc07db2
commit
f9419f13d5
284
mode_s.c
284
mode_s.c
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@ -181,7 +181,7 @@ static int decodeAC12Field(int AC12Field, altitude_unit_t *unit) {
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//
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// Decode the 7 bit ground movement field PWL exponential style scale
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//
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static int decodeMovementField(int movement) {
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static unsigned decodeMovementField(unsigned movement) {
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int gspeed;
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// Note : movement codes 0,125,126,127 are all invalid, but they are
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@ -762,59 +762,15 @@ static void decodeBDS20(struct modesMessage *mm)
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mm->callsign[8] = '\0';
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}
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static void decodeExtendedSquitter(struct modesMessage *mm)
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static void decodeESIdentAndCategory(struct modesMessage *mm)
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{
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unsigned char *me = mm->ME;
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int metype = mm->metype = getbits(me, 1, 5);
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int mesub = mm->mesub = (metype == 29 ? getbits(me, 6, 7) : getbits(me, 6, 8)); // Extended squitter message subtype
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int check_imf = 0;
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// Check CF on DF18 to work out the format of the ES and whether we need to look for an IMF bit
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if (mm->msgtype == 18) {
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switch (mm->CF) {
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case 0: // ADS-B ES/NT devices that report the ICAO 24-bit address in the AA field
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break;
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case 1: // Reserved for ADS-B for ES/NT devices that use other addressing techniques in the AA field
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mm->addr |= MODES_NON_ICAO_ADDRESS;
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break;
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case 2: // Fine TIS-B message (formats are close enough to DF17 for our purposes)
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mm->source = SOURCE_TISB;
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check_imf = 1;
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break;
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case 3: // Coarse TIS-B airborne position and velocity.
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// TODO: decode me.
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// For now we only look at the IMF bit.
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mm->source = SOURCE_TISB;
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if (getbit(me, 1))
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mm->addr |= MODES_NON_ICAO_ADDRESS;
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return;
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case 5: // TIS-B messages that relay ADS-B Messages using anonymous 24-bit addresses (format not explicitly defined, but it seems to follow DF17)
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mm->source = SOURCE_TISB;
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mm->addr |= MODES_NON_ICAO_ADDRESS;
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break;
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case 6: // ADS-B rebroadcast using the same type codes and message formats as defined for DF = 17 ADS-B messages
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check_imf = 1;
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break;
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default: // All others, we don't know the format.
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mm->addr |= MODES_NON_ICAO_ADDRESS; // assume non-ICAO
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return;
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}
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}
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switch (metype) {
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case 1: case 2: case 3: case 4: {
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// Aircraft Identification and Category
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uint32_t chars1, chars2;
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unsigned char *me = mm->ME;
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chars1 = getbits(me, 9, 32);
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chars2 = getbits(me, 33, 56);
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mm->mesub = getbits(me, 6, 8);
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unsigned chars1 = getbits(me, 9, 32);
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unsigned chars2 = getbits(me, 33, 56);
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// A common failure mode seems to be to intermittently send
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// all zeros. Catch that here.
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@ -834,36 +790,40 @@ static void decodeExtendedSquitter(struct modesMessage *mm)
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mm->callsign[8] = '\0';
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}
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mm->category = ((0x0E - metype) << 4) | mesub;
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mm->category = ((0x0E - mm->metype) << 4) | mm->mesub;
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mm->category_valid = 1;
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break;
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}
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}
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static void decodeESAirborneVelocity(struct modesMessage *mm, int check_imf)
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{
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// Airborne Velocity Message
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unsigned char *me = mm->ME;
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mm->mesub = getbits(me, 6, 8);
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case 19: { // Airborne Velocity Message
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if (check_imf && getbit(me, 9))
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mm->addr |= MODES_NON_ICAO_ADDRESS;
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if ( (mesub >= 1) && (mesub <= 4) ) {
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int vert_rate = getbits(me, 38, 46);
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if (mm->mesub < 1 || mm->mesub > 4)
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return;
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unsigned vert_rate = getbits(me, 38, 46);
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if (vert_rate) {
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--vert_rate;
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if (getbit(me, 37)) {
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vert_rate = 0 - vert_rate;
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}
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mm->vert_rate = vert_rate * 64;
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mm->vert_rate = (vert_rate - 1) * (getbit(me, 37) ? -64 : 64);
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mm->vert_rate_valid = 1;
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}
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mm->vert_rate_source = (getbit(me, 36) ? ALTITUDE_GNSS : ALTITUDE_BARO);
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}
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if ((mesub == 1) || (mesub == 2)) {
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switch (mm->mesub) {
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case 1: case 2:
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{
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unsigned ew_raw = getbits(me, 15, 24);
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unsigned ns_raw = getbits(me, 26, 35);
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if (ew_raw && ns_raw) {
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int ew_vel = (ew_raw - 1) * (getbit(me, 14) ? -1 : 1) * ((mesub == 2) ? 4 : 1);
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int ns_vel = (ns_raw - 1) * (getbit(me, 25) ? -1 : 1) * ((mesub == 2) ? 4 : 1);
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int ew_vel = (ew_raw - 1) * (getbit(me, 14) ? -1 : 1) * ((mm->mesub == 2) ? 4 : 1);
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int ns_vel = (ns_raw - 1) * (getbit(me, 25) ? -1 : 1) * ((mm->mesub == 2) ? 4 : 1);
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// Compute velocity and angle from the two speed components
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mm->speed = (unsigned) sqrt((ns_vel * ns_vel) + (ew_vel * ew_vel) + 0.5);
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@ -881,14 +841,14 @@ static void decodeExtendedSquitter(struct modesMessage *mm)
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mm->speed_source = SPEED_GROUNDSPEED;
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}
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} else if (mesub == 3 || mesub == 4) {
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break;
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}
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case 3: case 4:
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{
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unsigned airspeed = getbits(me, 26, 35);
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if (airspeed) {
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--airspeed;
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if (mesub == 4) { // If (supersonic) unit is 4 kts
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airspeed *= 4;
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}
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mm->speed = airspeed;
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mm->speed = (airspeed - 1) * (mm->mesub == 4 ? 4 : 1);
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mm->speed_source = getbit(me, 25) ? SPEED_TAS : SPEED_IAS;
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mm->speed_valid = 1;
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}
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@ -898,6 +858,8 @@ static void decodeExtendedSquitter(struct modesMessage *mm)
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mm->heading_source = HEADING_MAGNETIC;
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mm->heading_valid = 1;
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}
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break;
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}
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}
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unsigned raw_delta = getbits(me, 50, 56);
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@ -905,13 +867,12 @@ static void decodeExtendedSquitter(struct modesMessage *mm)
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mm->gnss_delta_valid = 1;
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mm->gnss_delta = (raw_delta - 1) * (getbit(me, 49) ? -25 : 25);
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}
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}
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break;
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}
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case 5: case 6: case 7: case 8: {
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// Ground position
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int movement;
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static void decodeESSurfacePosition(struct modesMessage *mm, int check_imf)
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{
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// Surface position and movement
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unsigned char *me = mm->ME;
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if (check_imf && getbit(me, 21))
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mm->addr |= MODES_NON_ICAO_ADDRESS;
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@ -920,11 +881,11 @@ static void decodeExtendedSquitter(struct modesMessage *mm)
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mm->cpr_lat = getbits(me, 23, 39);
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mm->cpr_lon = getbits(me, 40, 56);
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mm->cpr_odd = getbit(me, 22);
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mm->cpr_nucp = (14 - metype);
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mm->cpr_nucp = (14 - mm->metype);
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mm->cpr_valid = 1;
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movement = getbits(me, 6, 12);
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if ((movement) && (movement < 125)) {
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unsigned movement = getbits(me, 6, 12);
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if (movement > 0 && movement < 125) {
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mm->speed_valid = 1;
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mm->speed = decodeMovementField(movement);
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mm->speed_source = SPEED_GROUNDSPEED;
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@ -935,19 +896,19 @@ static void decodeExtendedSquitter(struct modesMessage *mm)
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mm->heading_source = HEADING_TRUE;
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mm->heading = getbits(me, 14, 20) * 360 / 128;
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}
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}
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break;
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}
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case 0: // Airborne position, baro altitude only
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case 9: case 10: case 11: case 12: case 13: case 14: case 15: case 16: case 17: case 18: // Airborne position, baro
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case 20: case 21: case 22: { // Airborne position, GNSS altitude (HAE or MSL)
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int AC12Field = getbits(me, 9, 20);
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static void decodeESAirbornePosition(struct modesMessage *mm, int check_imf)
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{
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// Airborne position and altitude
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unsigned char *me = mm->ME;
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if (check_imf && getbit(me, 8))
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mm->addr |= MODES_NON_ICAO_ADDRESS;
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if (metype == 0) {
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unsigned AC12Field = getbits(me, 9, 20);
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if (mm->metype == 0) {
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mm->cpr_nucp = 0;
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} else {
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// Catch some common failure modes and don't mark them as valid
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@ -969,12 +930,12 @@ static void decodeExtendedSquitter(struct modesMessage *mm)
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mm->cpr_valid = 1;
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mm->cpr_odd = getbit(me, 22);
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if (metype == 18 || metype == 22)
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if (mm->metype == 18 || mm->metype == 22)
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mm->cpr_nucp = 0;
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else if (metype < 18)
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mm->cpr_nucp = (18 - metype);
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else if (mm->metype < 18)
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mm->cpr_nucp = (18 - mm->metype);
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else
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mm->cpr_nucp = (29 - metype);
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mm->cpr_nucp = (29 - mm->metype);
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}
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}
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@ -984,28 +945,33 @@ static void decodeExtendedSquitter(struct modesMessage *mm)
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mm->altitude_valid = 1;
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}
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mm->altitude_source = (metype == 20 || metype == 21 || metype == 22) ? ALTITUDE_GNSS : ALTITUDE_BARO;
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mm->altitude_source = (mm->metype == 20 || mm->metype == 21 || mm->metype == 22) ? ALTITUDE_GNSS : ALTITUDE_BARO;
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}
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}
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break;
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}
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static void decodeESTestMessage(struct modesMessage *mm)
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{
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unsigned char *me = mm->ME;
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case 23: { // Test message
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if (mesub == 7) { // (see 1090-WP-15-20)
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mm->mesub = getbits(me, 6, 8);
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if (mm->mesub == 7) { // (see 1090-WP-15-20)
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int ID13Field = getbits(me, 9, 21);
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if (ID13Field) {
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mm->squawk_valid = 1;
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mm->squawk = decodeID13Field(ID13Field);
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}
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}
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break;
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}
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}
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case 24: // Reserved for Surface System Status
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break;
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static void decodeESAircraftStatus(struct modesMessage *mm, int check_imf)
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{
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// Extended Squitter Aircraft Status
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unsigned char *me = mm->ME;
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case 28: { // Extended Squitter Aircraft Status
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if (mesub == 1) { // Emergency status squawk field
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mm->mesub = getbits(me, 6, 8);
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if (mm->mesub == 1) { // Emergency status squawk field
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int ID13Field = getbits(me, 12, 24);
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if (ID13Field) {
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mm->squawk_valid = 1;
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@ -1015,16 +981,20 @@ static void decodeExtendedSquitter(struct modesMessage *mm)
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if (check_imf && getbit(me, 56))
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mm->addr |= MODES_NON_ICAO_ADDRESS;
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}
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break;
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}
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}
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static void decodeESTargetStatus(struct modesMessage *mm, int check_imf)
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{
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unsigned char *me = mm->ME;
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mm->mesub = getbits(me, 6, 7); // an unusual message: only 2 bits of subtype
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case 29: // Aircraft Trajectory Intent
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if (check_imf && getbit(me, 51))
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mm->addr |= MODES_NON_ICAO_ADDRESS;
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if (mesub == 0) { // Target state and status, V1
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if (mm->mesub == 0) { // Target state and status, V1
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// TODO: need RTCA/DO-260A
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} else if (mesub == 1) { // Target state and status, V2
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} else if (mm->mesub == 1) { // Target state and status, V2
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mm->tss.valid = 1;
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mm->tss.sil_type = getbit(me, 8) ? SIL_PER_SAMPLE : SIL_PER_HOUR;
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mm->tss.altitude_type = getbit(me, 9) ? TSS_ALTITUDE_FMS : TSS_ALTITUDE_MCP;
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@ -1065,12 +1035,15 @@ static void decodeExtendedSquitter(struct modesMessage *mm)
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mm->tss.acas_operational = getbit(me, 53);
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}
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break;
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}
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case 30: // Aircraft Operational Coordination
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break;
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static void decodeESOperationalStatus(struct modesMessage *mm, int check_imf)
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{
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unsigned char *me = mm->ME;
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case 31: // Aircraft Operational Status
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mm->mesub = getbits(me, 6, 8);
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// Aircraft Operational Status
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if (check_imf && getbit(me, 56))
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mm->addr |= MODES_NON_ICAO_ADDRESS;
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@ -1161,6 +1134,91 @@ static void decodeExtendedSquitter(struct modesMessage *mm)
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break;
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}
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}
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}
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static void decodeExtendedSquitter(struct modesMessage *mm)
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{
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unsigned char *me = mm->ME;
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unsigned metype = mm->metype = getbits(me, 1, 5);
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unsigned check_imf = 0;
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// Check CF on DF18 to work out the format of the ES and whether we need to look for an IMF bit
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if (mm->msgtype == 18) {
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switch (mm->CF) {
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case 0: // ADS-B ES/NT devices that report the ICAO 24-bit address in the AA field
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break;
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case 1: // Reserved for ADS-B for ES/NT devices that use other addressing techniques in the AA field
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mm->addr |= MODES_NON_ICAO_ADDRESS;
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break;
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case 2: // Fine TIS-B message (formats are close enough to DF17 for our purposes)
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mm->source = SOURCE_TISB;
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check_imf = 1;
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break;
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case 3: // Coarse TIS-B airborne position and velocity.
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// TODO: decode me.
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// For now we only look at the IMF bit.
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mm->source = SOURCE_TISB;
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if (getbit(me, 1))
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mm->addr |= MODES_NON_ICAO_ADDRESS;
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return;
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case 5: // TIS-B messages that relay ADS-B Messages using anonymous 24-bit addresses (format not explicitly defined, but it seems to follow DF17)
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mm->source = SOURCE_TISB;
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mm->addr |= MODES_NON_ICAO_ADDRESS;
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break;
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case 6: // ADS-B rebroadcast using the same type codes and message formats as defined for DF = 17 ADS-B messages
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check_imf = 1;
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break;
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default: // All others, we don't know the format.
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mm->addr |= MODES_NON_ICAO_ADDRESS; // assume non-ICAO
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return;
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}
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}
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switch (metype) {
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case 1: case 2: case 3: case 4:
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decodeESIdentAndCategory(mm);
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break;
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case 19:
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decodeESAirborneVelocity(mm, check_imf);
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break;
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case 5: case 6: case 7: case 8:
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decodeESSurfacePosition(mm, check_imf);
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break;
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case 0: // Airborne position, baro altitude only
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case 9: case 10: case 11: case 12: case 13: case 14: case 15: case 16: case 17: case 18: // Airborne position, baro
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case 20: case 21: case 22: // Airborne position, GNSS altitude (HAE or MSL)
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decodeESAirbornePosition(mm, check_imf);
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break;
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case 23:
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decodeESTestMessage(mm);
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break;
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case 24: // Reserved for Surface System Status
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break;
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case 28:
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decodeESAircraftStatus(mm, check_imf);
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break;
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case 29:
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decodeESTargetStatus(mm, check_imf);
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break;
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case 30: // Aircraft Operational Coordination
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break;
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case 31:
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decodeESOperationalStatus(mm, check_imf);
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break;
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default:
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