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Improvements to Mode A/C display

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Allow a greater range and negative values for Mode C (down to -1200
feet)

Stop attempting to feed ModeA/C data to SBS Output stream.

Allow Mode A only matches to Mode-S squawks when the Mode A code does
not conflict with any possible (legal) Mode C code.

Allow Mode C matches to track aircraft climbing and descending
relatively slowly. This also helps when trying to match Mode-S altitudes
which are 25 foot increments, with Mode C altitudes which are in 100
foot increments.
This commit is contained in:
Malcolm Robb 2013-04-24 00:13:18 +01:00
parent d63ac81a6a
commit b78b60677c
1 changed files with 26 additions and 20 deletions
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46
dump1090.c
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@ -56,7 +56,7 @@
// MinorVer changes when additional features are added, but not for bug fixes (range 00-99) // MinorVer changes when additional features are added, but not for bug fixes (range 00-99)
// DayDate & Year changes for all changes, including for bug fixes. It represent the release date of the update // DayDate & Year changes for all changes, including for bug fixes. It represent the release date of the update
// //
#define MODES_DUMP1090_VERSION "1.02.2204.13" #define MODES_DUMP1090_VERSION "1.02.2304.13"
#define MODES_DEFAULT_RATE 2000000 #define MODES_DEFAULT_RATE 2000000
#define MODES_DEFAULT_FREQ 1090000000 #define MODES_DEFAULT_FREQ 1090000000
@ -287,8 +287,11 @@ struct modesMessage {
int um; /* Request extraction of downlink request. */ int um; /* Request extraction of downlink request. */
int identity; /* 13 bits identity (Squawk). */ int identity; /* 13 bits identity (Squawk). */
// DF32 ModeA & Mode C
int modeC;
/* Fields used by multiple message types. */ /* Fields used by multiple message types. */
int altitude, unit, modeC; int altitude, unit;
}; };
void interactiveShowData(void); void interactiveShowData(void);
@ -1008,9 +1011,8 @@ int ModeAToModeC(unsigned int ModeA )
unsigned int FiveHundreds = 0; unsigned int FiveHundreds = 0;
unsigned int OneHundreds = 0; unsigned int OneHundreds = 0;
if ( (ModeA & 0xFFFF888B) // D1 set is illegal. D2 set is > 62700ft which is unlikely if ( (ModeA & 0xFFFF888B) // D1 set is illegal. D2 set is > 62700ft which is unlikely
|| ((ModeA & 0x000000F0) == 0) // C1,,C4 cannot be Zero || ((ModeA & 0x000000F0) == 0) ) // C1,,C4 cannot be Zero
|| ((ModeA & 0xFFFFFB0F) == 0) ) // Whilst legal, indicates an altitude less than -200 feet
{return -9999;} {return -9999;}
if (ModeA & 0x0010) {OneHundreds ^= 0x007;} // C1 if (ModeA & 0x0010) {OneHundreds ^= 0x007;} // C1
@ -1067,11 +1069,7 @@ void decodeModeAMessage(unsigned int ModeA, struct modesMessage *mm)
// Convert ModeA to ModeC and use as an altitude // Convert ModeA to ModeC and use as an altitude
mm->modeC = ModeAToModeC(ModeA); mm->modeC = ModeAToModeC(ModeA);
mm->altitude = 0; mm->altitude = mm->modeC * 100;
// Limit the altitude to sensible values
if ( (mm->modeC < 460) && (mm->modeC >= 0))
{mm->altitude = mm->modeC * 100;}
// Not much else we can tell from a Mode A/C reply. // Not much else we can tell from a Mode A/C reply.
// Just fudge up a few bits to keep other code happy // Just fudge up a few bits to keep other code happy
@ -2136,7 +2134,10 @@ void useModesMessage(struct modesMessage *mm) {
|| (Modes.stat_sbs_connections > 0) // or if sbs connections are established || (Modes.stat_sbs_connections > 0) // or if sbs connections are established
|| (Modes.mode_ac) ) { // or if mode A/C decoding is enabled || (Modes.mode_ac) ) { // or if mode A/C decoding is enabled
struct aircraft *a = interactiveReceiveData(mm); struct aircraft *a = interactiveReceiveData(mm);
if (a && Modes.stat_sbs_connections > 0) modesSendSBSOutput(mm, a); // Feed SBS output clients if ( (a)
&& (mm->msgtype < 32) // don't even try to send ModesA/C to SBS clients
&& (Modes.stat_sbs_connections > 0) )
{modesSendSBSOutput(mm, a);} // Feed SBS output clients
} }
// In non-interactive mode, and non-quiet mode, display messages on // In non-interactive mode, and non-quiet mode, display messages on
@ -2228,11 +2229,11 @@ void interactiveUpdateAircraftModeA(struct aircraft *a) {
if (a->squawk == b->squawk) { // If a 'real' Mode S ICAO exists using this Squawk if (a->squawk == b->squawk) { // If a 'real' Mode S ICAO exists using this Squawk
b->modeAcount++; b->modeAcount++;
if ((b->modeAcount > 0) && (b->modeCcount > 1)) if ( (b->modeAcount > 0) &&
((b->modeCcount > 1) || (a->modeC < -12)) )
{a->modeACflags |= MODEAC_MSG_MODES_HIT;} // flag that this ModeA/C probably belongs to a known Mode S {a->modeACflags |= MODEAC_MSG_MODES_HIT;} // flag that this ModeA/C probably belongs to a known Mode S
} else if ( (a->altitude) // If this ModeC altitude is valid and... } else if (a->modeC == b->modeC) // If a 'real' Mode S ICAO exists at this Altitude
&& (a->modeC == b->modeC) ) // ...a 'real' Mode S ICAO exists at this Altitude
{ {
b->modeCcount++; b->modeCcount++;
if ((b->modeAcount > 0) && (b->modeCcount > 1)) if ((b->modeAcount > 0) && (b->modeCcount > 1))
@ -2410,6 +2411,11 @@ struct aircraft *interactiveReceiveData(struct modesMessage *mm) {
a->messages++; a->messages++;
if (mm->msgtype == 0 || mm->msgtype == 4 || mm->msgtype == 20) { if (mm->msgtype == 0 || mm->msgtype == 4 || mm->msgtype == 20) {
if ( (a->modeCcount) // if we've a modeCcount already
&& (a->modeC != mm->modeC ) // 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->altitude = mm->altitude; a->altitude = mm->altitude;
a->modeC = mm->modeC; a->modeC = mm->modeC;
} else if(mm->msgtype == 5 || mm->msgtype == 21) { } else if(mm->msgtype == 5 || mm->msgtype == 21) {
@ -2421,9 +2427,11 @@ struct aircraft *interactiveReceiveData(struct modesMessage *mm) {
if (mm->metype >= 1 && mm->metype <= 4) { if (mm->metype >= 1 && mm->metype <= 4) {
memcpy(a->flight, mm->flight, sizeof(a->flight)); memcpy(a->flight, mm->flight, sizeof(a->flight));
} else if (mm->metype >= 9 && mm->metype <= 18) { } else if (mm->metype >= 9 && mm->metype <= 18) {
if (a->modeC != mm->modeC) { if ( (a->modeCcount) // if we've a modeCcount already
a->modeCcount = 0; // Altitude has changed, so zero the hit count && (a->modeC != mm->modeC ) // 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->altitude = mm->altitude; a->altitude = mm->altitude;
a->modeC = mm->modeC; a->modeC = mm->modeC;
if (mm->fflag) { if (mm->fflag) {
@ -2450,9 +2458,7 @@ struct aircraft *interactiveReceiveData(struct modesMessage *mm) {
a->modeACflags = MODEAC_MSG_FLAG; a->modeACflags = MODEAC_MSG_FLAG;
a->squawk = mm->identity; a->squawk = mm->identity;
a->modeC = mm->modeC; a->modeC = mm->modeC;
if (mm->altitude > -1300) { a->altitude = mm->altitude;
a->altitude = mm->altitude;
}
interactiveUpdateAircraftModeA(a); interactiveUpdateAircraftModeA(a);
} }
return a; return a;