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Speed check improvements. Entirely invalidate position messages that look wrong.

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This commit is contained in:
Oliver Jowett 2015-02-18 18:26:23 +00:00
parent 44302bb199
commit 7cc9438b2d
1 changed files with 56 additions and 43 deletions
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99
track.c
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@ -130,7 +130,7 @@ static double greatcircle(double lat0, double lon0, double lat1, double lon1)
// return true if it's OK for the aircraft to have travelled from its last known position
// to a new position at (lat,lon,surface) at a time of now.
static int speed_check(struct aircraft *a, double lat, double lon, uint64_t now, int surface)
static int speed_check(struct aircraft *a, struct modesMessage *mm, double lat, double lon, uint64_t now, int surface)
{
uint64_t elapsed;
double distance;
@ -143,24 +143,28 @@ static int speed_check(struct aircraft *a, double lat, double lon, uint64_t now,
elapsed = now - a->seenLatLon;
if ((mm->bFlags & MODES_ACFLAGS_SPEED_VALID) && (a->bFlags & MODES_ACFLAGS_SPEED_VALID))
speed = (mm->velocity + a->speed) / 2;
else if (mm->bFlags & MODES_ACFLAGS_SPEED_VALID)
speed = mm->velocity;
else if (a->bFlags & MODES_ACFLAGS_SPEED_VALID)
speed = a->speed;
else
speed = surface ? 100 : 600; // guess
// Work out a reasonable speed to use:
// current speed + 50%
// surface speed min 30kt, max 150kt
// airborne speed min 300kt, no max
if ((a->bFlags & MODES_ACFLAGS_SPEED_VALID)) {
speed = a->speed * 3 / 2;
if (surface) {
if (speed < 30)
speed = 30;
if (speed > 150)
speed = 150;
} else {
if (speed < 300)
speed = 300;
}
// current speed + 1/3
// surface speed min 20kt, max 150kt
// airborne speed min 200kt, no max
speed = speed * 4 / 3;
if (surface) {
if (speed < 20)
speed = 20;
if (speed > 150)
speed = 150;
} else {
// Guess.
speed = surface ? 150 : 1000;
if (speed < 200)
speed = 200;
}
// 100m (surface) or 500m (airborne) base distance to allow for minor errors,
@ -181,9 +185,11 @@ static int speed_check(struct aircraft *a, double lat, double lon, uint64_t now,
return inrange;
}
static int doGlobalCPR(struct aircraft *a, int fflag, int surface, uint64_t now, double *lat, double *lon, unsigned *nuc)
static int doGlobalCPR(struct aircraft *a, struct modesMessage *mm, uint64_t now, double *lat, double *lon, unsigned *nuc)
{
int result;
int fflag = (mm->bFlags & MODES_ACFLAGS_LLODD_VALID) != 0;
int surface = (mm->bFlags & MODES_ACFLAGS_AOG) != 0;
*nuc = (a->even_cprnuc < a->odd_cprnuc ? a->even_cprnuc : a->odd_cprnuc); // worst of the two positions
@ -236,7 +242,7 @@ static int doGlobalCPR(struct aircraft *a, int fflag, int surface, uint64_t now,
}
// check speed limit
if ((a->bFlags & MODES_ACFLAGS_LATLON_VALID) && a->pos_nuc >= *nuc && !speed_check(a, *lat, *lon, now, surface)) {
if ((a->bFlags & MODES_ACFLAGS_LATLON_VALID) && a->pos_nuc >= *nuc && !speed_check(a, mm, *lat, *lon, now, surface)) {
Modes.stats_current.cpr_global_speed_checks++;
return -2;
}
@ -244,15 +250,17 @@ static int doGlobalCPR(struct aircraft *a, int fflag, int surface, uint64_t now,
return result;
}
static int doLocalCPR(struct aircraft *a, int fflag, int surface, uint64_t now, double *lat, double *lon, unsigned *nuc)
static int doLocalCPR(struct aircraft *a, struct modesMessage *mm, uint64_t now, double *lat, double *lon, unsigned *nuc)
{
// relative CPR
// find reference location
double reflat, reflon;
double range_limit = 0;
int result;
int fflag = (mm->bFlags & MODES_ACFLAGS_LLODD_VALID) != 0;
int surface = (mm->bFlags & MODES_ACFLAGS_AOG) != 0;
*nuc = (fflag ? a->odd_cprnuc : a->even_cprnuc);
*nuc = mm->nuc_p;
if (a->bFlags & MODES_ACFLAGS_LATLON_REL_OK) {
reflat = a->lat;
@ -286,8 +294,8 @@ static int doLocalCPR(struct aircraft *a, int fflag, int surface, uint64_t now,
}
result = decodeCPRrelative(reflat, reflon,
fflag ? a->odd_cprlat : a->even_cprlat,
fflag ? a->odd_cprlon : a->even_cprlon,
mm->raw_latitude,
mm->raw_longitude,
fflag, surface,
lat, lon);
if (result < 0)
@ -297,17 +305,13 @@ static int doLocalCPR(struct aircraft *a, int fflag, int surface, uint64_t now,
if (range_limit > 0) {
double range = greatcircle(reflat, reflon, *lat, *lon);
if (range > range_limit) {
#ifdef DEBUG_CPR_CHECKS
fprintf(stderr, "Local position ambiguous: %06x: %.3f,%.3f -> %.3f,%.3f, max range %.1fkm, actual %.1fkm\n",
a->addr, reflat, reflon, *lat, *lon, range_limit/1000.0, range/1000.0);
#endif
Modes.stats_current.cpr_local_range_checks++;
return (-1);
}
}
// check speed limit
if ((a->bFlags & MODES_ACFLAGS_LATLON_VALID) && a->pos_nuc >= *nuc && !speed_check(a, *lat, *lon, now, surface)) {
if ((a->bFlags & MODES_ACFLAGS_LATLON_VALID) && a->pos_nuc >= *nuc && !speed_check(a, mm, *lat, *lon, now, surface)) {
Modes.stats_current.cpr_local_speed_checks++;
return -1;
}
@ -348,17 +352,26 @@ static void updatePosition(struct aircraft *a, struct modesMessage *mm, uint64_t
// If we have enough recent data, try global CPR
if (((mm->bFlags | a->bFlags) & MODES_ACFLAGS_LLEITHER_VALID) == MODES_ACFLAGS_LLBOTH_VALID && abs((int)(a->even_cprtime - a->odd_cprtime)) <= max_elapsed) {
location_result = doGlobalCPR(a, (mm->bFlags & MODES_ACFLAGS_LLODD_VALID), (mm->bFlags & MODES_ACFLAGS_AOG), now,
&new_lat, &new_lon, &new_nuc);
location_result = doGlobalCPR(a, mm, now, &new_lat, &new_lon, &new_nuc);
if (location_result == -2) {
// Global CPR failed because an airborne position produced implausible results.
// Global CPR failed because the position produced implausible results.
// This is bad data. Discard both odd and even messages and wait for a fresh pair.
// Also disable aircraft-relative positions until we have a new good position (but don't discard the
// recorded position itself)
Modes.stats_current.cpr_global_bad++;
mm->bFlags &= ~(MODES_ACFLAGS_LATLON_VALID | MODES_ACFLAGS_LLODD_VALID | MODES_ACFLAGS_LLEVEN_VALID);
a->bFlags &= ~(MODES_ACFLAGS_LATLON_REL_OK | MODES_ACFLAGS_LLODD_VALID | MODES_ACFLAGS_LLEVEN_VALID);
// Also discard the current message's data as it is suspect - we don't want
// to update any of the aircraft state from this.
mm->bFlags &= ~(MODES_ACFLAGS_LATLON_VALID | MODES_ACFLAGS_LLODD_VALID | MODES_ACFLAGS_LLEVEN_VALID |
MODES_ACFLAGS_ALTITUDE_VALID |
MODES_ACFLAGS_SPEED_VALID |
MODES_ACFLAGS_HEADING_VALID |
MODES_ACFLAGS_NSEWSPD_VALID |
MODES_ACFLAGS_VERTRATE_VALID |
MODES_ACFLAGS_AOG_VALID |
MODES_ACFLAGS_AOG);
return;
} else if (location_result == -1) {
// No local reference for surface position available, or the two messages crossed a zone.
@ -371,7 +384,7 @@ static void updatePosition(struct aircraft *a, struct modesMessage *mm, uint64_t
// Otherwise try relative CPR.
if (location_result == -1) {
location_result = doLocalCPR(a, (mm->bFlags & MODES_ACFLAGS_LLODD_VALID), (mm->bFlags & MODES_ACFLAGS_AOG), now, &new_lat, &new_lon, &new_nuc);
location_result = doLocalCPR(a, mm, now, &new_lat, &new_lon, &new_nuc);
if (location_result == -1) {
Modes.stats_current.cpr_local_skipped++;
@ -420,6 +433,16 @@ struct aircraft *trackUpdateFromMessage(struct modesMessage *mm)
a->seen = now;
a->messages++;
// if the Aircraft has landed or taken off since the last message, clear the even/odd CPR flags
if ((mm->bFlags & MODES_ACFLAGS_AOG_VALID) && ((a->bFlags ^ mm->bFlags) & MODES_ACFLAGS_AOG)) {
a->bFlags &= ~(MODES_ACFLAGS_LLBOTH_VALID | MODES_ACFLAGS_AOG);
}
// If we've got a new cprlat or cprlon
if (mm->bFlags & MODES_ACFLAGS_LLEITHER_VALID) {
updatePosition(a, mm, now);
}
// If a (new) CALLSIGN has been received, copy it to the aircraft structure
if (mm->bFlags & MODES_ACFLAGS_CALLSIGN_VALID) {
memcpy(a->flight, mm->flight, sizeof(a->flight));
@ -463,16 +486,6 @@ struct aircraft *trackUpdateFromMessage(struct modesMessage *mm)
a->vert_rate = mm->vert_rate;
}
// if the Aircraft has landed or taken off since the last message, clear the even/odd CPR flags
if ((mm->bFlags & MODES_ACFLAGS_AOG_VALID) && ((a->bFlags ^ mm->bFlags) & MODES_ACFLAGS_AOG)) {
a->bFlags &= ~(MODES_ACFLAGS_LLBOTH_VALID | MODES_ACFLAGS_AOG);
}
// If we've got a new cprlat or cprlon
if (mm->bFlags & MODES_ACFLAGS_LLEITHER_VALID) {
updatePosition(a, mm, now);
}
// Update the aircrafts a->bFlags to reflect the newly received mm->bFlags;
a->bFlags |= mm->bFlags;