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added parsing of surface position messages

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Skip Tavakkolian
2013-06-05 12:29:18 -07:00
committed by antirez
parent 7d03c180a0
commit 9c42492103
1 changed files with 104 additions and 0 deletions
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dump1090.c
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@ -1063,6 +1063,49 @@ void decodeModesMessage(struct modesMessage *mm, unsigned char *msg) {
mm->flight[6] = ais_charset[((msg[9]&15)<<2)|(msg[10]>>6)];
mm->flight[7] = ais_charset[msg[10]&63];
mm->flight[8] = '\0';
} else if (mm->metype >= 5 && mm->metype <= 8) {
/* Surface Position Message */
int mvt = ((msg[0] & 3) << 4) | (msg[1] >> 4) ;
if (mvt == 0) {
mm->velocity = 0; /* unknown */
} else if (mvt == 1) {
/* less than 0.125 kt */
mm->velocity = 0.125 * 1.6878099 / 2; /* kt to f/s */
} else if (mvt == 124) {
mm->velocity = 175 * 1.6878099;
} else if (mvt >= 2 && mvt <= 8) {
mm->velocity = 0.125 * 1.6878099;
mm->velocity += (mvt-2) * 0.125 * 1.6878099;
} else if (mvt >= 9 && mvt <= 12) {
mm->velocity = 1.6878099;
mm->velocity += (mvt-9) * 0.25 * 1.6878099;
} else if (mvt >= 13 && mvt <= 38) {
mm->velocity = 2 * 1.6878099;
mm->velocity += (mvt-13) * 0.5 * 1.6878099;
} else if (mvt >= 39 && mvt <= 93) {
mm->velocity = 15 * 1.6878099;
mm->velocity += (mvt-39) * 1.0 * 1.6878099;
} else if (mvt >= 94 && mvt <= 108) {
mm->velocity = 70 * 1.6878099;
mm->velocity += (mvt-94) * 2.0 * 1.6878099;
} else if (mvt >= 109 && mvt <= 123) {
mm->velocity = 100 * 1.6878099;
mm->velocity += (mvt-109) * 5.0 * 1.6878099;
}
mm->heading_is_valid = msg[1] & (1<<3);
if(mm->heading_is_valid){
int track = ((msg[1] & 7) << 4)|
(msg[2] >> 4);
mm->heading = track * 360 / 128; /* 360/128 degrees increments */
}
mm->fflag = msg[6] & (1<<2);
mm->tflag = msg[6] & (1<<3);
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];
} else if (mm->metype >= 9 && mm->metype <= 18) {
/* Airborne position Message */
mm->fflag = msg[6] & (1<<2);
@ -1686,6 +1729,10 @@ double cprDlonFunction(double lat, int isodd) {
return 360.0 / cprNFunction(lat, isodd);
}
double cprDlonFunction_surface(double lat, int isodd) {
return 90.0 / cprNFunction(lat, isodd);
}
/* This algorithm comes from:
* http://www.lll.lu/~edward/edward/adsb/DecodingADSBposition.html.
*
@ -1734,6 +1781,44 @@ void decodeCPR(struct aircraft *a) {
if (a->lon > 180) a->lon -= 360;
}
void decodeCPR_surface(struct aircraft *a) {
const double AirDlat0 = 90.0 / 60;
const double AirDlat1 = 90.0 / 59;
double lat0 = a->even_cprlat;
double lat1 = a->odd_cprlat;
double lon0 = a->even_cprlon;
double lon1 = a->odd_cprlon;
/* Compute the Latitude Index "j" */
int j = floor(((59*lat0 - 60*lat1) / 131072) + 0.5);
double rlat0 = AirDlat0 * (cprModFunction(j,60) + lat0 / 131072);
double rlat1 = AirDlat1 * (cprModFunction(j,59) + lat1 / 131072);
if (rlat0 >= 270) rlat0 -= 360;
if (rlat1 >= 270) rlat1 -= 360;
/* Check that both are in the same latitude zone, or abort. */
if (cprNLFunction(rlat0) != cprNLFunction(rlat1)) return;
/* Compute ni and the longitude index m */
if (a->even_cprtime > a->odd_cprtime) {
/* Use even packet. */
int ni = cprNFunction(rlat0,0);
int m = floor((((lon0 * (cprNLFunction(rlat0)-1)) -
(lon1 * cprNLFunction(rlat0))) / 131072) + 0.5);
a->lon = cprDlonFunction_surface(rlat0,0) * (cprModFunction(m,ni)+lon0/131072);
a->lat = rlat0;
} else {
/* Use odd packet. */
int ni = cprNFunction(rlat1,1);
int m = floor((((lon0 * (cprNLFunction(rlat1)-1)) -
(lon1 * cprNLFunction(rlat1))) / (131072*1.0)) + 0.5);
a->lon = cprDlonFunction_surface(rlat1,1) * (cprModFunction(m,ni)+lon1/131072);
a->lat = rlat1;
}
if (a->lon < 90) a->lon -= 180;
}
/* Receive new messages and populate the interactive mode with more info. */
struct aircraft *interactiveReceiveData(struct modesMessage *mm) {
uint32_t addr;
@ -1775,6 +1860,25 @@ struct aircraft *interactiveReceiveData(struct modesMessage *mm) {
} else if (mm->msgtype == 17) {
if (mm->metype >= 1 && mm->metype <= 4) {
memcpy(a->flight, mm->flight, sizeof(a->flight));
} else if (mm->metype >= 5 && mm->metype <= 8) {
a->speed = mm->velocity;
if(mm->heading_is_valid){
a->track = mm->heading;
}
if (mm->fflag) {
a->odd_cprlat = mm->raw_latitude;
a->odd_cprlon = mm->raw_longitude;
a->odd_cprtime = mstime();
} else {
a->even_cprlat = mm->raw_latitude;
a->even_cprlon = mm->raw_longitude;
a->even_cprtime = mstime();
}
/* If the two data is less than 10 seconds apart, compute
* the position. */
if (abs(a->even_cprtime - a->odd_cprtime) <= 10000) {
decodeCPR_surface(a);
}
} else if (mm->metype >= 9 && mm->metype <= 18) {
a->altitude = mm->altitude;
if (mm->fflag) {