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Track HAE altitude separately to baro altitude where possible.

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This commit is contained in:
Oliver Jowett 2016-01-01 13:42:30 +00:00
parent c4a2a5c9fb
commit efd6b94310
4 changed files with 64 additions and 6 deletions
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4
dump1090.h
View file

@ -163,6 +163,8 @@ typedef struct rtlsdr_dev rtlsdr_dev_t;
#define MODES_ACFLAGS_REL_CPR_USED (1<<16) // Lat/lon derived from relative CPR
#define MODES_ACFLAGS_CATEGORY_VALID (1<<17) // Aircraft category is known
#define MODES_ACFLAGS_FROM_MLAT (1<<18) // Data was derived from multilateration
#define MODES_ACFLAGS_ALTITUDE_HAE_VALID (1<<19) // altitude_hae is valid
#define MODES_ACFLAGS_HAE_DELTA_VALID (1<<20) // hae_delta is valid
#define MODES_ACFLAGS_LLEITHER_VALID (MODES_ACFLAGS_LLEVEN_VALID | MODES_ACFLAGS_LLODD_VALID)
#define MODES_ACFLAGS_LLBOTH_VALID (MODES_ACFLAGS_LLEVEN_VALID | MODES_ACFLAGS_LLODD_VALID)
@ -389,6 +391,8 @@ struct modesMessage {
int vert_rate; // Vertical rate.
int velocity; // Reported by aircraft, or computed from from EW and NS velocity
unsigned category; // A0 - D7 encoded as a single hex byte
int altitude_hae; // altitude reported as GNSS HAE
int hae_delta; // difference between HAE and baro alt
// DF 18
int cf; // Control Field

31
mode_s.c
View file

@ -846,6 +846,11 @@ static void decodeExtendedSquitter(struct modesMessage *mm)
}
}
if (msg[10] != 0) {
mm->bFlags |= MODES_ACFLAGS_HAE_DELTA_VALID;
mm->hae_delta = ((msg[10] & 0x80) ? -25 : 25) * ((msg[10] & 0x7f) - 1);
}
break;
}
@ -910,9 +915,18 @@ static void decodeExtendedSquitter(struct modesMessage *mm)
}
if (AC12Field) {// Only attempt to decode if a valid (non zero) altitude is present
mm->altitude = decodeAC12Field(AC12Field, &mm->unit);
if (mm->altitude != INVALID_ALTITUDE)
mm->bFlags |= MODES_ACFLAGS_ALTITUDE_VALID;
if (metype == 20 || metype == 21 || metype == 22) {
// Position reported as HAE
mm->altitude_hae = decodeAC12Field(AC12Field, &mm->unit);
if (mm->altitude_hae != INVALID_ALTITUDE) {
mm->bFlags |= MODES_ACFLAGS_ALTITUDE_HAE_VALID;
}
} else {
mm->altitude = decodeAC12Field(AC12Field, &mm->unit);
if (mm->altitude != INVALID_ALTITUDE) {
mm->bFlags |= MODES_ACFLAGS_ALTITUDE_VALID;
}
}
}
if (metype == 0 || metype == 18 || metype == 22)
@ -1011,15 +1025,22 @@ static void displayExtendedSquitter(struct modesMessage *mm) {
printf(" Vertical status : %s\n", (mm->bFlags & MODES_ACFLAGS_VERTRATE_VALID) ? "Valid" : "Unavailable");
printf(" Vertical rate src : %d\n", ((mm->msg[8] >> 4) & 1));
printf(" Vertical rate : %d\n", mm->vert_rate);
} else {
printf(" Unrecognized ME subtype: %d subtype: %d\n", mm->metype, mm->mesub);
}
if (mm->bFlags & MODES_ACFLAGS_HAE_DELTA_VALID) {
printf(" HAE - Barometric : %d ft\n", mm->hae_delta);
} else {
printf(" HAE - Barometric : not valid\n");
}
} else if (mm->metype >= 5 && mm->metype <= 22) { // Airborne position Baro
printf(" F flag : %s\n", (mm->msg[6] & 0x04) ? "odd" : "even");
printf(" T flag : %s\n", (mm->msg[6] & 0x08) ? "UTC" : "non-UTC");
if (mm->bFlags & MODES_ACFLAGS_ALTITUDE_VALID)
printf(" Altitude : %d feet\n", mm->altitude);
printf(" Altitude : %d feet barometric\n", mm->altitude);
else if (mm->bFlags & MODES_ACFLAGS_ALTITUDE_HAE_VALID)
printf(" Altitude : %d feet HAE\n", mm->altitude_hae);
else
printf(" Altitude : not valid\n");
if (mm->bFlags & MODES_ACFLAGS_LATLON_VALID) {

31
track.c
View file

@ -522,9 +522,34 @@ struct aircraft *trackUpdateFromMessage(struct modesMessage *mm)
a->altitude = mm->altitude;
a->modeC = (mm->altitude + 49) / 100;
a->seenAltitude = now;
// reporting of HAE and baro altitudes is mutually exclusive
// so if we see a baro altitude, assume the HAE altitude is invalid
// we will recalculate it from baro + HAE delta below, where possible
a->bFlags &= ~MODES_ACFLAGS_ALTITUDE_HAE_VALID;
}
}
// If a (new) HAE altitude has been received, copy it to the aircraft structure
if (mm->bFlags & MODES_ACFLAGS_ALTITUDE_HAE_VALID) {
a->altitude_hae = mm->altitude_hae;
// reporting of HAE and baro altitudes is mutually exclusive
// if you have both, you're meant to report baro and a HAE delta,
// so if we see explicit HAE then assume the delta is invalid too
a->bFlags &= ~(MODES_ACFLAGS_ALTITUDE_VALID | MODES_ACFLAGS_HAE_DELTA_VALID);
}
// If a (new) HAE/barometric difference has been received, copy it to the aircraft structure
if (mm->bFlags & MODES_ACFLAGS_HAE_DELTA_VALID) {
a->hae_delta = mm->hae_delta;
// reporting of HAE and baro altitudes is mutually exclusive
// if you have both, you're meant to report baro and a HAE delta,
// so if we see a HAE delta then assume the HAE altitude is invalid
a->bFlags &= ~MODES_ACFLAGS_ALTITUDE_HAE_VALID;
}
// If a (new) SQUAWK has been received, copy it to the aircraft structure
if (mm->bFlags & MODES_ACFLAGS_SQUAWK_VALID) {
if (a->modeA != mm->modeA) {
@ -559,6 +584,12 @@ struct aircraft *trackUpdateFromMessage(struct modesMessage *mm)
// Update the aircrafts a->bFlags to reflect the newly received mm->bFlags;
a->bFlags |= mm->bFlags;
// If we have a baro altitude and a HAE delta from baro, calculate the HAE altitude
if ((a->bFlags & MODES_ACFLAGS_ALTITUDE_VALID) && (a->bFlags & MODES_ACFLAGS_HAE_DELTA_VALID)) {
a->altitude_hae = a->altitude + a->hae_delta;
a->bFlags |= MODES_ACFLAGS_ALTITUDE_HAE_VALID;
}
// Update mlat flags. The mlat flags indicate which bits in bFlags
// were last set based on a mlat-derived message.
if (mm->bFlags & MODES_ACFLAGS_FROM_MLAT)

4
track.h
View file

@ -64,7 +64,9 @@ struct aircraft {
uint32_t addr; // ICAO address
char flight[16]; // Flight number
double signalLevel[8]; // Last 8 Signal Amplitudes
int altitude; // Altitude
int altitude; // Altitude (Baro)
int altitude_hae; // Altitude (HAE)
int hae_delta; // Difference between HAE and Baro altitudes
int speed; // Velocity
int track; // Angle of flight
int vert_rate; // Vertical rate.