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Complete the bFlags decoding

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Update the bFlags structure member to indicate which other structure
members contain decoded values.

Also, trim out mm structure members that are simple bitwise ands from
the raw data, unless the results are used in lots of places whereby
decoding them once is more efficient.
This commit is contained in:
Malcolm Robb 2013-05-09 15:29:25 +01:00
parent a3d62f96b7
commit fc7d1e27c9
1 changed files with 112 additions and 80 deletions
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dump1090.c
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@ -106,6 +106,14 @@
#define MODES_USER_LATLON_VALID (1<<0)
#define MODES_ACFLAGS_LATLON_VALID (1<<0) // Aircraft Lat/Lon is known
#define MODES_ACFLAGS_ALTITUDE_VALID (1<<1) // Aircraft altitude is known
#define MODES_ACFLAGS_HEADING_VALID (1<<2) // Aircraft heading is known
#define MODES_ACFLAGS_SPEED_VALID (1<<3) // Aircraft speed is known
#define MODES_ACFLAGS_VERTRATE_VALID (1<<4) // Aircraft vertical rate is known
#define MODES_ACFLAGS_SQUAWK_VALID (1<<5) // Aircraft Mode A Squawk is known
#define MODES_ACFLAGS_CALLSIGN_VALID (1<<6) // Aircraft Callsign Identity
#define MODES_ACFLAGS_EWSPEED_VALID (1<<7) // Aircraft East West Speed is known
#define MODES_ACFLAGS_NSSPEED_VALID (1<<8) // Aircraft North South Speed is known
#define MODES_ACFLAGS_AOG (1<<9) // Aircraft is On the Ground
#define MODES_ACFLAGS_LATLON_REL_OK (1<<15) // Indicates it's OK to do a relative CPR
@ -279,34 +287,26 @@ struct modesMessage {
unsigned char signalLevel; // Signal Amplitude
// DF 11
int ca; // Responder capabilities
int iid;
int ca; // Responder capabilities
int iid;
// DF 17
int metype; // Extended squitter message type.
int mesub; // Extended squitter message subtype.
int heading_is_valid;
int heading; // Reported by aircraft, or computed from from EW and NS velocity
int fflag; // 1 = Odd, 0 = Even CPR message.
int tflag; // UTC synchronized?
int raw_latitude; // Non decoded latitude.
int raw_longitude; // Non decoded longitude.
int metype; // Extended squitter message type.
int mesub; // Extended squitter message subtype.
int heading; // Reported by aircraft, or computed from from EW and NS velocity
int raw_latitude; // Non decoded latitude.
int raw_longitude; // Non decoded longitude.
char flight[16]; // 8 chars flight number.
int ew_dir; // 0 = East, 1 = West.
int ew_velocity; // E/W velocity.
int ns_dir; // 0 = North, 1 = South.
int ns_velocity; // N/S velocity.
int vert_rate_source; // Vertical rate source.
int vert_rate_sign; // Vertical rate sign.
int vert_rate; // Vertical rate.
int velocity; // Reported by aircraft, or computed from from EW and NS velocity
int tasflag; // TAS or IAS
int ew_velocity; // E/W velocity.
int ns_velocity; // N/S velocity.
int vert_rate; // Vertical rate.
int velocity; // Reported by aircraft, or computed from from EW and NS velocity
// DF4, DF5, DF20, DF21
int fs; // Flight status for DF4,5,20,21
int dr; // Request extraction of downlink request.
int um; // Request extraction of downlink request.
int modeA; // 13 bits identity (Squawk).
int fs; // Flight status for DF4,5,20,21
int dr; // Request extraction of downlink request.
int um; // Request extraction of downlink request.
int modeA; // 13 bits identity (Squawk).
// Fields used by multiple message types.
int altitude;
@ -1048,7 +1048,8 @@ void decodeModeAMessage(struct modesMessage *mm, int ModeA)
mm->addr = 0x00FF0000 | (ModeA & 0x0000FF7F);
// Set the Identity field to ModeA
mm->modeA = ModeA & 0x7777;
mm->modeA = ModeA & 0x7777;
mm->bFlags |= MODES_ACFLAGS_SQUAWK_VALID;
// Flag ident in flight status
mm->fs = ModeA & 0x0080;
@ -1465,7 +1466,11 @@ void decodeModesMessage(struct modesMessage *mm, unsigned char *msg) {
// Fields for DF5, DF21 = Gillham encoded Squawk
if (mm->msgtype == 5 || mm->msgtype == 21) {
mm->modeA = decodeID13Field((msg[2] << 8) | msg[3]);
int ID13Field = ((msg[2] << 8) | msg[3]) & 0x1FFF;
if (ID13Field) {
mm->bFlags |= MODES_ACFLAGS_SQUAWK_VALID;
mm->modeA = decodeID13Field(ID13Field);
}
}
// Fields for DF0, DF4, DF16, DF20 13 bit altitude
@ -1473,19 +1478,21 @@ void decodeModesMessage(struct modesMessage *mm, unsigned char *msg) {
mm->msgtype == 16 || mm->msgtype == 20) {
int AC13Field = ((msg[2] << 8) | msg[3]) & 0x1FFF;
if (AC13Field) { // Only attempt to decode if a valid (non zero) altitude is present
mm->bFlags |= MODES_ACFLAGS_ALTITUDE_VALID;
mm->altitude = decodeAC13Field(AC13Field, &mm->unit);
}
}
// Fields for DF17 squitter
if (mm->msgtype == 17) {
mm->metype = msg[4] >> 3; // Extended squitter message type
mm->mesub = msg[4] & 7; // Extended squitter message subtype
int metype = mm->metype = msg[4] >> 3; // Extended squitter message type
int mesub = mm->mesub = msg[4] & 7; // Extended squitter message subtype
// Decode the extended squitter message
if (mm->metype >= 1 && mm->metype <= 4) { // Aircraft Identification and Category
if (metype >= 1 && metype <= 4) { // Aircraft Identification and Category
uint32_t chars;
mm->bFlags |= MODES_ACFLAGS_CALLSIGN_VALID;
chars = (msg[5] << 16) | (msg[6] << 8) | (msg[7]);
mm->flight[3] = ais_charset[chars & 0x3F]; chars = chars >> 6;
@ -1501,65 +1508,70 @@ void decodeModesMessage(struct modesMessage *mm, unsigned char *msg) {
mm->flight[8] = '\0';
} else if (mm->metype >= 5 && mm->metype <= 18) { // Position Message
mm->fflag = msg[6] & (1<<2);
mm->tflag = msg[6] & (1<<3);
} else if (metype >= 5 && metype <= 18) { // Position Message
mm->raw_latitude = ((msg[6] & 3) << 15) | (msg[7] << 7) | (msg[8] >> 1);
mm->raw_longitude = ((msg[8] & 1) << 16) | (msg[9] << 8) | (msg[10]);
if (mm->metype >= 9) { // Airborne
if (metype >= 9) { // Airborne
int AC12Field = ((msg[5] << 4) | (msg[6] >> 4)) & 0x0FFF;
if (AC12Field) {// Only attempt to decode if a valid (non zero) altitude is present
{mm->altitude = decodeAC12Field(AC12Field, &mm->unit);}
mm->bFlags |= MODES_ACFLAGS_ALTITUDE_VALID;
mm->altitude = decodeAC12Field(AC12Field, &mm->unit);
}
} else { // Ground
int movement = ((msg[4] << 4) | (msg[5] >> 4)) & 0x007F;
if ((movement) && (movement < 125))
{mm->velocity = decodeMovementField(movement);}
mm->bFlags |= MODES_ACFLAGS_AOG;
if ((movement) && (movement < 125)) {
mm->bFlags |= MODES_ACFLAGS_SPEED_VALID;
mm->velocity = decodeMovementField(movement);
}
mm->heading_is_valid = (msg[5] & 0x08);
if (mm->heading_is_valid) {
if (msg[5] & 0x08) {
mm->bFlags |= MODES_ACFLAGS_HEADING_VALID;
mm->heading = ((((msg[5] << 4) | (msg[6] >> 4)) & 0x007F) * 45) >> 4;
}
}
} else if (mm->metype == 19) { // Airborne Velocity Message
} else if (metype == 19) { // Airborne Velocity Message
if ( (mm->mesub >= 1) && (mm->mesub <= 4) ) {
if ( (mesub >= 1) && (mesub <= 4) ) {
int vert_rate = ((msg[8] & 0x07) << 6) | (msg[9] >> 2);
if (vert_rate) {
mm->vert_rate_source = (msg[8] & 0x10) >> 4;
mm->vert_rate_sign = (msg[8] & 0x08) >> 3;
mm->vert_rate = vert_rate - 1;
--vert_rate;
if (msg[8] & 0x08)
{vert_rate = 0 - vert_rate;}
mm->vert_rate = vert_rate * 64;
mm->bFlags |= MODES_ACFLAGS_VERTRATE_VALID;
}
}
if ((mm->mesub == 1) || (mm->mesub == 2)) {
if ((mesub == 1) || (mesub == 2)) {
int ew_raw = ((msg[5] & 0x03) << 8) | msg[6];
int ew_vel = ew_raw - 1;
int ns_raw = ((msg[7] & 0x7F) << 3) | (msg[8] >> 5);
int ns_vel = ew_raw - 1;
if (mm->mesub == 2) { // If (supersonic) unit is 4 kts
if (mesub == 2) { // If (supersonic) unit is 4 kts
ns_vel = ns_vel << 2;
ew_vel = ew_vel << 2;
}
if (ew_raw) { // Do East/West
mm->ew_velocity = ew_vel;
mm->ew_dir = (msg[5] & 0x04) >> 2;
if (mm->ew_dir)
mm->bFlags |= MODES_ACFLAGS_EWSPEED_VALID;
if (msg[5] & 0x04)
{ew_vel = 0 - ew_vel;}
mm->ew_velocity = ew_vel;
}
if (ns_raw) { // Do North/South
mm->ns_velocity = ns_vel;
mm->ns_dir = (msg[7] & 0x80) >> 7;
if (mm->ns_dir)
mm->bFlags |= MODES_ACFLAGS_NSSPEED_VALID;
if (msg[7] & 0x80)
{ns_vel = 0 - ns_vel;}
mm->ns_velocity = ns_vel;
}
if (ew_raw && ns_raw) {
// Compute velocity and angle from the two speed components
mm->bFlags |= (MODES_ACFLAGS_SPEED_VALID | MODES_ACFLAGS_HEADING_VALID);
mm->velocity = (int) sqrt((ns_vel * ns_vel) + (ew_vel * ew_vel));
if (mm->velocity) {
@ -1569,19 +1581,19 @@ void decodeModesMessage(struct modesMessage *mm, unsigned char *msg) {
}
}
} else if (mm->mesub == 3 || mm->mesub == 4) {
} else if (mesub == 3 || mesub == 4) {
int airspeed = ((msg[7] & 0x7f) << 3) | (msg[8] >> 5);
if (airspeed) {
mm->bFlags |= MODES_ACFLAGS_SPEED_VALID;
--airspeed;
if (mm->mesub == 4) // If (supersonic) unit is 4 kts
if (mesub == 4) // If (supersonic) unit is 4 kts
{airspeed = airspeed << 2;}
mm->velocity = airspeed;
mm->tasflag = (msg[7] & 0x80);
}
mm->heading_is_valid = msg[5] & 0x04;
if (mm->heading_is_valid) {
mm->heading = ((((msg[5] & 0x03) << 8) | msg[6]) * 45) >> 7;
if (msg[5] & 0x04) {
mm->bFlags |= MODES_ACFLAGS_HEADING_VALID;
mm->heading = ((((msg[5] & 0x03) << 8) | msg[6]) * 45) >> 7;
}
}
}
@ -1592,6 +1604,7 @@ void decodeModesMessage(struct modesMessage *mm, unsigned char *msg) {
if (msg[4] == 0x20) { // Aircraft Identification
uint32_t chars;
mm->bFlags |= MODES_ACFLAGS_CALLSIGN_VALID;
chars = (msg[5] << 16) | (msg[6] << 8) | (msg[7]);
mm->flight[3] = ais_charset[chars & 0x3F]; chars = chars >> 6;
@ -1720,25 +1733,30 @@ void displayModesMessage(struct modesMessage *mm) {
//} else if (mm->metype >= 5 && mm->metype <= 8) { // Surface position
} else if (mm->metype >= 9 && mm->metype <= 18) { // Airborne position Baro
printf(" F flag : %s\n", mm->fflag ? "odd" : "even");
printf(" T flag : %s\n", mm->tflag ? "UTC" : "non-UTC");
printf(" F flag : %s\n", (mm->msg[6] & 0x04) ? "odd" : "even");
printf(" T flag : %s\n", (mm->msg[6] & 0x08) ? "UTC" : "non-UTC");
printf(" Altitude : %d feet\n", mm->altitude);
printf(" Latitude : %d (not decoded)\n", mm->raw_latitude);
printf(" Longitude: %d (not decoded)\n", mm->raw_longitude);
} else if (mm->metype == 19) { // Airborne Velocity
if (mm->mesub == 1 || mm->mesub == 2) {
printf(" EW direction : %d\n", mm->ew_dir);
printf(" EW status : %s\n", (mm->bFlags & MODES_ACFLAGS_EWSPEED_VALID) ? "Valid" : "Unavailable");
printf(" EW velocity : %d\n", mm->ew_velocity);
printf(" NS direction : %d\n", mm->ns_dir);
printf(" NS status : %s\n", (mm->bFlags & MODES_ACFLAGS_NSSPEED_VALID) ? "Valid" : "Unavailable");
printf(" NS velocity : %d\n", mm->ns_velocity);
printf(" Vertical rate src : %d\n", mm->vert_rate_source);
printf(" Vertical rate sign: %d\n", mm->vert_rate_sign);
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 if (mm->mesub == 3 || mm->mesub == 4) {
printf(" Heading status: %d", mm->heading_is_valid);
printf(" Heading: %d", mm->heading);
printf(" Heading status : %s\n", (mm->bFlags & MODES_ACFLAGS_HEADING_VALID) ? "Valid" : "Unavailable");
printf(" Heading : %d\n", mm->heading);
printf(" Airspeed status : %s\n", (mm->bFlags & MODES_ACFLAGS_SPEED_VALID) ? "Valid" : "Unavailable");
printf(" Airspeed : %d\n", mm->velocity);
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);
@ -2482,11 +2500,12 @@ void decodeCPR(struct aircraft *a, int fflag, int surface) {
* Note: text of document describes trunc() functionality for deltaZI calculation
* but the formulae use floor().
*/
int decodeCPRrelative(struct aircraft *a, int fflag, int surface, double latr, double lonr) {
int decodeCPRrelative(struct aircraft *a, int fflag, int surface) {
double AirDlat;
double AirDlon;
double lat;
double lon;
double lonr, latr;
double rlon, rlat;
int j,m;
@ -2613,18 +2632,31 @@ struct aircraft *interactiveReceiveData(struct modesMessage *mm) {
if (mm->metype >= 1 && mm->metype <= 4) {
memcpy(a->flight, mm->flight, sizeof(a->flight));
} else if (mm->metype >= 9 && mm->metype <= 18) {
if ( (a->modeCcount) // if we've a modeCcount already
&& (a->altitude != mm->altitude ) ) // and Altitude has changed
// && (a->modeC != mm->modeC + 1) // and Altitude not changed by +100 feet
// && (a->modeC + 1 != mm->modeC ) ) // and Altitude not changes by -100 feet
{
a->modeCcount = 0; //....zero the hit count
a->modeACflags &= ~MODEAC_MSG_MODEC_HIT;
}
a->altitude = mm->altitude;
a->modeC = (mm->altitude + 49) / 100;
if (mm->fflag) {
} else if (mm->metype >= 5 && mm->metype <= 18) {
int fflag = mm->msg[6] & 0x04;
if ((a->bFlags ^ mm->bFlags) & MODES_ACFLAGS_AOG) {
a->odd_cprtime = a->even_cprtime = 0; // Change airborne = change CPR scale need new pair
a->bFlags ^= MODES_ACFLAGS_AOG; // Ground = metype 5-8, Airborne = metype 9-18
}
if (mm->metype >= 9) { // Airborne
if ( (a->modeCcount) // if we've a modeCcount already
&& (a->altitude != mm->altitude ) ) // and Altitude has changed
// && (a->modeC != mm->modeC + 1) // and Altitude not changed by +100 feet
// && (a->modeC + 1 != mm->modeC ) ) // and Altitude not changes by -100 feet
{
a->modeCcount = 0; //....zero the hit count
a->modeACflags &= ~MODEAC_MSG_MODEC_HIT;
}
a->altitude = mm->altitude;
a->modeC = (mm->altitude + 49) / 100;
} else { // Ground
a->speed = mm->velocity;
a->track = mm->heading;
}
if (fflag) {
a->odd_cprlat = mm->raw_latitude;
a->odd_cprlon = mm->raw_longitude;
a->odd_cprtime = mstime();
@ -2634,16 +2666,16 @@ struct aircraft *interactiveReceiveData(struct modesMessage *mm) {
a->even_cprtime = mstime();
}
// Try relative CPR first
if (decodeCPRrelative(a, mm->fflag, 0, 0, 0)) {
if (decodeCPRrelative(a, fflag, (mm->bFlags & MODES_ACFLAGS_AOG))) {
// If it fails then try global if the two data are less than 10 seconds apart, compute
// the position.
if (abs((int)(a->even_cprtime - a->odd_cprtime)) <= 10000) {
decodeCPR(a, mm->fflag, 0);
decodeCPR(a, fflag, (mm->bFlags & MODES_ACFLAGS_AOG));
}
}
} else if (mm->metype == 19) {
if (mm->mesub == 1 || mm->mesub == 2) {
if ((mm->mesub >= 1) && (mm->mesub <= 4)) {
a->speed = mm->velocity;
a->track = mm->heading;
}