-
Notifications
You must be signed in to change notification settings - Fork 21
/
track.c
1243 lines (1067 loc) · 39.3 KB
/
track.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
// Part of dump1090, a Mode S message decoder for RTLSDR devices.
//
// track.c: aircraft state tracking
//
// Copyright (c) 2014-2016 Oliver Jowett <oliver@mutability.co.uk>
//
// This file is free software: you may copy, redistribute and/or modify it
// under the terms of the GNU General Public License as published by the
// Free Software Foundation, either version 2 of the License, or (at your
// option) any later version.
//
// This file is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
// This file incorporates work covered by the following copyright and
// permission notice:
//
// Copyright (C) 2012 by Salvatore Sanfilippo <antirez@gmail.com>
//
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//
// * Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#include "dump1090.h"
#include <inttypes.h>
/* #define DEBUG_CPR_CHECKS */
uint32_t modeAC_count[4096];
uint32_t modeAC_lastcount[4096];
uint32_t modeAC_match[4096];
uint32_t modeAC_age[4096];
//
// Return a new aircraft structure for the linked list of tracked
// aircraft
//
struct aircraft *trackCreateAircraft(struct modesMessage *mm) {
static struct aircraft zeroAircraft;
struct aircraft *a = (struct aircraft *) malloc(sizeof(*a));
int i;
// Default everything to zero/NULL
*a = zeroAircraft;
// Now initialise things that should not be 0/NULL to their defaults
a->addr = mm->addr;
a->addrtype = mm->addrtype;
for (i = 0; i < 8; ++i)
a->signalLevel[i] = 1e-5;
a->signalNext = 0;
// defaults until we see a message otherwise
a->adsb_version = -1;
a->adsb_hrd = HEADING_MAGNETIC;
a->adsb_tah = HEADING_GROUND_TRACK;
// prime FATSV defaults we only emit on change
// start off with the "last emitted" ACAS RA being blank (just the BDS 3,0
// or ES type code)
a->fatsv_emitted_bds_30[0] = 0x30;
a->fatsv_emitted_es_acas_ra[0] = 0xE2;
a->fatsv_emitted_adsb_version = -1;
a->fatsv_emitted_addrtype = ADDR_UNKNOWN;
// don't immediately emit, let some data build up
a->fatsv_last_emitted = a->fatsv_last_force_emit = messageNow();
// Copy the first message so we can emit it later when a second message arrives.
a->first_message = *mm;
// initialize data validity ages
#define F(f,s,e) do { a->f##_valid.stale_interval = (s) * 1000; a->f##_valid.expire_interval = (e) * 1000; } while (0)
F(callsign, 60, 70); // ADS-B or Comm-B
F(altitude_baro, 15, 70); // ADS-B or Mode S
F(altitude_geom, 60, 70); // ADS-B only
F(geom_delta, 60, 70); // ADS-B only
F(gs, 60, 70); // ADS-B or Comm-B
F(ias, 60, 70); // ADS-B (rare) or Comm-B
F(tas, 60, 70); // ADS-B (rare) or Comm-B
F(mach, 60, 70); // Comm-B only
F(track, 60, 70); // ADS-B or Comm-B
F(track_rate, 60, 70); // Comm-B only
F(roll, 60, 70); // Comm-B only
F(mag_heading, 60, 70); // ADS-B (rare) or Comm-B
F(true_heading, 60, 70); // ADS-B only (rare)
F(baro_rate, 60, 70); // ADS-B or Comm-B
F(geom_rate, 60, 70); // ADS-B or Comm-B
F(squawk, 15, 70); // ADS-B or Mode S
F(airground, 15, 70); // ADS-B or Mode S
F(nav_qnh, 60, 70); // Comm-B only
F(nav_altitude, 60, 70); // ADS-B or Comm-B
F(nav_heading, 60, 70); // ADS-B or Comm-B
F(nav_modes, 60, 70); // ADS-B or Comm-B
F(cpr_odd, 60, 70); // ADS-B only
F(cpr_even, 60, 70); // ADS-B only
F(position, 60, 70); // ADS-B only
F(nic_a, 60, 70); // ADS-B only
F(nic_c, 60, 70); // ADS-B only
F(nic_baro, 60, 70); // ADS-B only
F(nac_p, 60, 70); // ADS-B only
F(nac_v, 60, 70); // ADS-B only
F(sil, 60, 70); // ADS-B only
F(gva, 60, 70); // ADS-B only
F(sda, 60, 70); // ADS-B only
#undef F
Modes.stats_current.unique_aircraft++;
return (a);
}
//
//=========================================================================
//
// Return the aircraft with the specified address, or NULL if no aircraft
// exists with this address.
//
struct aircraft *trackFindAircraft(uint32_t addr) {
struct aircraft *a = Modes.aircrafts;
while(a) {
if (a->addr == addr) return (a);
a = a->next;
}
return (NULL);
}
// Should we accept some new data from the given source?
// If so, update the validity and return 1
static int accept_data(data_validity *d, datasource_t source)
{
if (messageNow() < d->updated)
return 0;
if (source < d->source && messageNow() < d->stale)
return 0;
d->source = source;
d->updated = messageNow();
d->stale = messageNow() + (d->stale_interval ? d->stale_interval : 60000);
d->expires = messageNow() + (d->expire_interval ? d->expire_interval : 70000);
return 1;
}
// Given two datasources, produce a third datasource for data combined from them.
static void combine_validity(data_validity *to, const data_validity *from1, const data_validity *from2) {
if (from1->source == SOURCE_INVALID) {
*to = *from2;
return;
}
if (from2->source == SOURCE_INVALID) {
*to = *from1;
return;
}
to->source = (from1->source < from2->source) ? from1->source : from2->source; // the worse of the two input sources
to->updated = (from1->updated > from2->updated) ? from1->updated : from2->updated; // the *later* of the two update times
to->stale = (from1->stale < from2->stale) ? from1->stale : from2->stale; // the earlier of the two stale times
to->expires = (from1->expires < from2->expires) ? from1->expires : from2->expires; // the earlier of the two expiry times
}
static int compare_validity(const data_validity *lhs, const data_validity *rhs) {
if (messageNow() < lhs->stale && lhs->source > rhs->source)
return 1;
else if (messageNow() < rhs->stale && lhs->source < rhs->source)
return -1;
else if (lhs->updated > rhs->updated)
return 1;
else if (lhs->updated < rhs->updated)
return -1;
else
return 0;
}
//
// CPR position updating
//
// Distance between points on a spherical earth.
// This has up to 0.5% error because the earth isn't actually spherical
// (but we don't use it in situations where that matters)
static double greatcircle(double lat0, double lon0, double lat1, double lon1)
{
double dlat, dlon;
lat0 = lat0 * M_PI / 180.0;
lon0 = lon0 * M_PI / 180.0;
lat1 = lat1 * M_PI / 180.0;
lon1 = lon1 * M_PI / 180.0;
dlat = fabs(lat1 - lat0);
dlon = fabs(lon1 - lon0);
// use haversine for small distances for better numerical stability
if (dlat < 0.001 && dlon < 0.001) {
double a = sin(dlat/2) * sin(dlat/2) + cos(lat0) * cos(lat1) * sin(dlon/2) * sin(dlon/2);
return 6371e3 * 2 * atan2(sqrt(a), sqrt(1.0 - a));
}
// spherical law of cosines
return 6371e3 * acos(sin(lat0) * sin(lat1) + cos(lat0) * cos(lat1) * cos(dlon));
}
static void update_range_histogram(double lat, double lon)
{
if (Modes.stats_range_histo && (Modes.bUserFlags & MODES_USER_LATLON_VALID)) {
double range = greatcircle(Modes.fUserLat, Modes.fUserLon, lat, lon);
int bucket = round(range / Modes.maxRange * RANGE_BUCKET_COUNT);
if (bucket < 0)
bucket = 0;
else if (bucket >= RANGE_BUCKET_COUNT)
bucket = RANGE_BUCKET_COUNT-1;
++Modes.stats_current.range_histogram[bucket];
}
}
// 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, int surface)
{
uint64_t elapsed;
double distance;
double range;
int speed;
int inrange;
if (!trackDataValid(&a->position_valid))
return 1; // no reference, assume OK
elapsed = trackDataAge(&a->position_valid);
if (trackDataValid(&a->gs_valid))
speed = a->gs;
else if (trackDataValid(&a->tas_valid))
speed = a->tas * 4 / 3;
else if (trackDataValid(&a->ias_valid))
speed = a->ias * 2;
else
speed = surface ? 100 : 600; // guess
// Work out a reasonable speed to use:
// 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 {
if (speed < 200)
speed = 200;
}
// 100m (surface) or 500m (airborne) base distance to allow for minor errors,
// plus distance covered at the given speed for the elapsed time + 1 second.
range = (surface ? 0.1e3 : 0.5e3) + ((elapsed + 1000.0) / 1000.0) * (speed * 1852.0 / 3600.0);
// find actual distance
distance = greatcircle(a->lat, a->lon, lat, lon);
inrange = (distance <= range);
#ifdef DEBUG_CPR_CHECKS
if (!inrange) {
fprintf(stderr, "Speed check failed: %06x: %.3f,%.3f -> %.3f,%.3f in %.1f seconds, max speed %d kt, range %.1fkm, actual %.1fkm\n",
a->addr, a->lat, a->lon, lat, lon, elapsed/1000.0, speed, range/1000.0, distance/1000.0);
}
#endif
return inrange;
}
static int doGlobalCPR(struct aircraft *a, struct modesMessage *mm, double *lat, double *lon, unsigned *nic, unsigned *rc)
{
int result;
int fflag = mm->cpr_odd;
int surface = (mm->cpr_type == CPR_SURFACE);
// derive NIC, Rc from the worse of the two position
// smaller NIC is worse; larger Rc is worse
*nic = (a->cpr_even_nic < a->cpr_odd_nic ? a->cpr_even_nic : a->cpr_odd_nic);
*rc = (a->cpr_even_rc > a->cpr_odd_rc ? a->cpr_even_rc : a->cpr_odd_rc);
if (surface) {
// surface global CPR
// find reference location
double reflat, reflon;
if (trackDataValid(&a->position_valid)) { // Ok to try aircraft relative first
reflat = a->lat;
reflon = a->lon;
} else if (Modes.bUserFlags & MODES_USER_LATLON_VALID) {
reflat = Modes.fUserLat;
reflon = Modes.fUserLon;
} else {
// No local reference, give up
return (-1);
}
result = decodeCPRsurface(reflat, reflon,
a->cpr_even_lat, a->cpr_even_lon,
a->cpr_odd_lat, a->cpr_odd_lon,
fflag,
lat, lon);
} else {
// airborne global CPR
result = decodeCPRairborne(a->cpr_even_lat, a->cpr_even_lon,
a->cpr_odd_lat, a->cpr_odd_lon,
fflag,
lat, lon);
}
if (result < 0) {
#ifdef DEBUG_CPR_CHECKS
fprintf(stderr, "CPR: decode failure for %06X (%d).\n", a->addr, result);
fprintf(stderr, " even: %d %d odd: %d %d fflag: %s\n",
a->cpr_even_lat, a->cpr_even_lon,
a->cpr_odd_lat, a->cpr_odd_lon,
fflag ? "odd" : "even");
#endif
return result;
}
// check max range
if (Modes.maxRange > 0 && (Modes.bUserFlags & MODES_USER_LATLON_VALID)) {
double range = greatcircle(Modes.fUserLat, Modes.fUserLon, *lat, *lon);
if (range > Modes.maxRange) {
#ifdef DEBUG_CPR_CHECKS
fprintf(stderr, "Global range check failed: %06x: %.3f,%.3f, max range %.1fkm, actual %.1fkm\n",
a->addr, *lat, *lon, Modes.maxRange/1000.0, range/1000.0);
#endif
Modes.stats_current.cpr_global_range_checks++;
return (-2); // we consider an out-of-range value to be bad data
}
}
// for mlat results, skip the speed check
if (mm->source == SOURCE_MLAT)
return result;
// check speed limit
if (trackDataValid(&a->position_valid) && a->pos_nic >= *nic && a->pos_rc <= *rc && !speed_check(a, *lat, *lon, surface)) {
Modes.stats_current.cpr_global_speed_checks++;
return -2;
}
return result;
}
static int doLocalCPR(struct aircraft *a, struct modesMessage *mm, double *lat, double *lon, unsigned *nic, unsigned *rc)
{
// relative CPR
// find reference location
double reflat, reflon;
double range_limit = 0;
int result;
int fflag = mm->cpr_odd;
int surface = (mm->cpr_type == CPR_SURFACE);
if (fflag) {
*nic = a->cpr_odd_nic;
*rc = a->cpr_odd_rc;
} else {
*nic = a->cpr_even_nic;
*rc = a->cpr_even_rc;
}
if (trackDataValid(&a->position_valid)) {
reflat = a->lat;
reflon = a->lon;
if (a->pos_nic < *nic)
*nic = a->pos_nic;
if (a->pos_rc < *rc)
*rc = a->pos_rc;
range_limit = 50e3;
} else if (!surface && (Modes.bUserFlags & MODES_USER_LATLON_VALID)) {
reflat = Modes.fUserLat;
reflon = Modes.fUserLon;
// The cell size is at least 360NM, giving a nominal
// max range of 180NM (half a cell).
//
// If the receiver range is more than half a cell
// then we must limit this range further to avoid
// ambiguity. (e.g. if we receive a position report
// at 200NM distance, this may resolve to a position
// at (200-360) = 160NM in the wrong direction)
if (Modes.maxRange == 0) {
return (-1); // Can't do receiver-centered checks at all
} else if (Modes.maxRange <= 1852*180) {
range_limit = Modes.maxRange;
} else if (Modes.maxRange < 1852*360) {
range_limit = (1852*360) - Modes.maxRange;
} else {
return (-1); // Can't do receiver-centered checks at all
}
} else {
// No local reference, give up
return (-1);
}
result = decodeCPRrelative(reflat, reflon,
mm->cpr_lat,
mm->cpr_lon,
fflag, surface,
lat, lon);
if (result < 0) {
return result;
}
// check range limit
if (range_limit > 0) {
double range = greatcircle(reflat, reflon, *lat, *lon);
if (range > range_limit) {
Modes.stats_current.cpr_local_range_checks++;
return (-1);
}
}
// check speed limit
if (trackDataValid(&a->position_valid) && a->pos_nic >= *nic && a->pos_rc <= *rc && !speed_check(a, *lat, *lon, surface)) {
#ifdef DEBUG_CPR_CHECKS
fprintf(stderr, "Speed check for %06X with local decoding failed\n", a->addr);
#endif
Modes.stats_current.cpr_local_speed_checks++;
return -1;
}
return 0;
}
static uint64_t time_between(uint64_t t1, uint64_t t2)
{
if (t1 >= t2)
return t1 - t2;
else
return t2 - t1;
}
static void updatePosition(struct aircraft *a, struct modesMessage *mm)
{
int location_result = -1;
uint64_t max_elapsed;
double new_lat = 0, new_lon = 0;
unsigned new_nic = 0;
unsigned new_rc = 0;
int surface;
surface = (mm->cpr_type == CPR_SURFACE);
if (surface) {
++Modes.stats_current.cpr_surface;
// Surface: 25 seconds if >25kt or speed unknown, 50 seconds otherwise
if (mm->gs_valid && mm->gs.selected <= 25)
max_elapsed = 50000;
else
max_elapsed = 25000;
} else {
++Modes.stats_current.cpr_airborne;
// Airborne: 10 seconds
max_elapsed = 10000;
}
// If we have enough recent data, try global CPR
if (trackDataValid(&a->cpr_odd_valid) && trackDataValid(&a->cpr_even_valid) &&
a->cpr_odd_valid.source == a->cpr_even_valid.source &&
a->cpr_odd_type == a->cpr_even_type &&
time_between(a->cpr_odd_valid.updated, a->cpr_even_valid.updated) <= max_elapsed) {
location_result = doGlobalCPR(a, mm, &new_lat, &new_lon, &new_nic, &new_rc);
if (location_result == -2) {
#ifdef DEBUG_CPR_CHECKS
fprintf(stderr, "global CPR failure (invalid) for (%06X).\n", a->addr);
#endif
// 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++;
a->cpr_odd_valid.source = a->cpr_even_valid.source = a->position_valid.source = SOURCE_INVALID;
return;
} else if (location_result == -1) {
#ifdef DEBUG_CPR_CHECKS
if (mm->source == SOURCE_MLAT) {
fprintf(stderr, "CPR skipped from MLAT (%06X).\n", a->addr);
}
#endif
// No local reference for surface position available, or the two messages crossed a zone.
// Nonfatal, try again later.
Modes.stats_current.cpr_global_skipped++;
} else {
Modes.stats_current.cpr_global_ok++;
combine_validity(&a->position_valid, &a->cpr_even_valid, &a->cpr_odd_valid);
}
}
// Otherwise try relative CPR.
if (location_result == -1) {
location_result = doLocalCPR(a, mm, &new_lat, &new_lon, &new_nic, &new_rc);
if (location_result < 0) {
Modes.stats_current.cpr_local_skipped++;
} else {
Modes.stats_current.cpr_local_ok++;
mm->cpr_relative = 1;
if (mm->cpr_odd) {
a->position_valid = a->cpr_odd_valid;
} else {
a->position_valid = a->cpr_even_valid;
}
}
}
if (location_result == 0) {
// If we sucessfully decoded, back copy the results to mm so that we can print them in list output
mm->cpr_decoded = 1;
mm->decoded_lat = new_lat;
mm->decoded_lon = new_lon;
mm->decoded_nic = new_nic;
mm->decoded_rc = new_rc;
// Update aircraft state
a->lat = new_lat;
a->lon = new_lon;
a->pos_nic = new_nic;
a->pos_rc = new_rc;
update_range_histogram(new_lat, new_lon);
}
}
static unsigned compute_nic(unsigned metype, unsigned version, unsigned nic_a, unsigned nic_b, unsigned nic_c)
{
switch (metype) {
case 5: // surface
case 9: // airborne
case 20: // airborne, GNSS altitude
return 11;
case 6: // surface
case 10: // airborne
case 21: // airborne, GNSS altitude
return 10;
case 7: // surface
if (version == 2) {
if (nic_a && !nic_c) {
return 9;
} else {
return 8;
}
} else if (version == 1) {
if (nic_a) {
return 9;
} else {
return 8;
}
} else {
return 8;
}
case 8: // surface
if (version == 2) {
if (nic_a && nic_c) {
return 7;
} else if (nic_a && !nic_c) {
return 6;
} else if (!nic_a && nic_c) {
return 6;
} else {
return 0;
}
} else {
return 0;
}
case 11: // airborne
if (version == 2) {
if (nic_a && nic_b) {
return 9;
} else {
return 8;
}
} else if (version == 1) {
if (nic_a) {
return 9;
} else {
return 8;
}
} else {
return 8;
}
case 12: // airborne
return 7;
case 13: // airborne
return 6;
case 14: // airborne
return 5;
case 15: // airborne
return 4;
case 16: // airborne
if (nic_a && nic_b) {
return 3;
} else {
return 2;
}
case 17: // airborne
return 1;
default:
return 0;
}
}
static unsigned compute_rc(unsigned metype, unsigned version, unsigned nic_a, unsigned nic_b, unsigned nic_c)
{
switch (metype) {
case 5: // surface
case 9: // airborne
case 20: // airborne, GNSS altitude
return 8; // 7.5m
case 6: // surface
case 10: // airborne
case 21: // airborne, GNSS altitude
return 25;
case 7: // surface
if (version == 2) {
if (nic_a && !nic_c) {
return 75;
} else {
return 186; // 185.2m, 0.1NM
}
} else if (version == 1) {
if (nic_a) {
return 75;
} else {
return 186; // 185.2m, 0.1NM
}
} else {
return 186; // 185.2m, 0.1NM
}
case 8: // surface
if (version == 2) {
if (nic_a && nic_c) {
return 371; // 370.4m, 0.2NM
} else if (nic_a && !nic_c) {
return 556; // 555.6m, 0.3NM
} else if (!nic_a && nic_c) {
return 926; // 926m, 0.5NM
} else {
return RC_UNKNOWN;
}
} else {
return RC_UNKNOWN;
}
case 11: // airborne
if (version == 2) {
if (nic_a && nic_b) {
return 75;
} else {
return 186; // 370.4m, 0.2NM
}
} else if (version == 1) {
if (nic_a) {
return 75;
} else {
return 186; // 370.4m, 0.2NM
}
} else {
return 186; // 370.4m, 0.2NM
}
case 12: // airborne
return 371; // 370.4m, 0.2NM
case 13: // airborne
if (version == 2) {
if (!nic_a && nic_b) {
return 556; // 555.6m, 0.3NM
} else if (!nic_a && !nic_b) {
return 926; // 926m, 0.5NM
} else if (nic_a && nic_b) {
return 1112; // 1111.2m, 0.6NM
} else {
return RC_UNKNOWN; // bad combination
}
} else if (version == 1) {
if (nic_a) {
return 1112; // 1111.2m, 0.6NM
} else {
return 926; // 926m, 0.5NM
}
} else {
return 926; // 926m, 0.5NM
}
case 14: // airborne
return 1852; // 1.0NM
case 15: // airborne
return 3704; // 2NM
case 16: // airborne
if (version == 2) {
if (nic_a && nic_b) {
return 7408; // 4NM
} else {
return 14816; // 8NM
}
} else if (version == 1) {
if (nic_a) {
return 7408; // 4NM
} else {
return 14816; // 8NM
}
} else {
return 18520; // 10NM
}
case 17: // airborne
return 37040; // 20NM
default:
return RC_UNKNOWN;
}
}
static void compute_nic_rc_from_message(struct modesMessage *mm, struct aircraft *a, unsigned *nic, unsigned *rc)
{
int nic_a = (trackDataValid(&a->nic_a_valid) && a->nic_a);
int nic_b = (mm->accuracy.nic_b_valid && mm->accuracy.nic_b);
int nic_c = (trackDataValid(&a->nic_c_valid) && a->nic_c);
*nic = compute_nic(mm->metype, a->adsb_version, nic_a, nic_b, nic_c);
*rc = compute_rc(mm->metype, a->adsb_version, nic_a, nic_b, nic_c);
}
static int altitude_to_feet(int raw, altitude_unit_t unit)
{
switch (unit) {
case UNIT_METERS:
return raw / 0.3048;
case UNIT_FEET:
return raw;
default:
return 0;
}
}
//
//=========================================================================
//
// Receive new messages and update tracked aircraft state
//
struct aircraft *trackUpdateFromMessage(struct modesMessage *mm)
{
struct aircraft *a;
if (mm->msgtype == 32) {
// Mode A/C, just count it (we ignore SPI)
modeAC_count[modeAToIndex(mm->squawk)]++;
return NULL;
}
if (mm->addr == 0) {
// junk address, don't track it
return NULL;
}
_messageNow = mm->sysTimestampMsg;
// Lookup our aircraft or create a new one
a = trackFindAircraft(mm->addr);
if (!a) { // If it's a currently unknown aircraft....
a = trackCreateAircraft(mm); // ., create a new record for it,
a->next = Modes.aircrafts; // .. and put it at the head of the list
Modes.aircrafts = a;
}
if (mm->signalLevel > 0) {
a->signalLevel[a->signalNext] = mm->signalLevel;
a->signalNext = (a->signalNext + 1) & 7;
}
a->seen = messageNow();
a->messages++;
// update addrtype, we only ever go towards "more direct" types
if (mm->addrtype < a->addrtype)
a->addrtype = mm->addrtype;
// if we saw some direct ADS-B for the first time, assume version 0
if (mm->source == SOURCE_ADSB && a->adsb_version < 0)
a->adsb_version = 0;
// category shouldn't change over time, don't bother with metadata
if (mm->category_valid) {
a->category = mm->category;
}
// operational status message
// done early to update version / HRD / TAH
if (mm->opstatus.valid) {
a->adsb_version = mm->opstatus.version;
if (mm->opstatus.hrd != HEADING_INVALID) {
a->adsb_hrd = mm->opstatus.hrd;
}
if (mm->opstatus.tah != HEADING_INVALID) {
a->adsb_tah = mm->opstatus.tah;
}
}
if (mm->altitude_baro_valid && accept_data(&a->altitude_baro_valid, mm->source)) {
int alt = altitude_to_feet(mm->altitude_baro, mm->altitude_baro_unit);
if (a->modeC_hit) {
int new_modeC = (a->altitude_baro + 49) / 100;
int old_modeC = (alt + 49) / 100;
if (new_modeC != old_modeC) {
a->modeC_hit = 0;
}
}
a->altitude_baro = alt;
}
if (mm->squawk_valid && accept_data(&a->squawk_valid, mm->source)) {
if (mm->squawk != a->squawk) {
a->modeA_hit = 0;
}
a->squawk = mm->squawk;
#if 0 // Disabled for now as it obscures the origin of the data
// Handle 7x00 without a corresponding emergency status
if (!mm->emergency_valid) {
emergency_t squawk_emergency;
switch (mm->squawk) {
case 0x7500:
squawk_emergency = EMERGENCY_UNLAWFUL;
break;
case 0x7600:
squawk_emergency = EMERGENCY_NORDO;
break;
case 0x7700:
squawk_emergency = EMERGENCY_GENERAL;
break;
default:
squawk_emergency = EMERGENCY_NONE;
break;
}
if (squawk_emergency != EMERGENCY_NONE && accept_data(&a->emergency_valid, mm->source)) {
a->emergency = squawk_emergency;
}
}
#endif
}
if (mm->emergency_valid && accept_data(&a->emergency_valid, mm->source)) {
a->emergency = mm->emergency;
}
if (mm->altitude_geom_valid && accept_data(&a->altitude_geom_valid, mm->source)) {
a->altitude_geom = altitude_to_feet(mm->altitude_geom, mm->altitude_geom_unit);
}
if (mm->geom_delta_valid && accept_data(&a->geom_delta_valid, mm->source)) {
a->geom_delta = mm->geom_delta;
}
if (mm->heading_valid) {
heading_type_t htype = mm->heading_type;
if (htype == HEADING_MAGNETIC_OR_TRUE) {
htype = a->adsb_hrd;
} else if (htype == HEADING_TRACK_OR_HEADING) {
htype = a->adsb_tah;
}
if (htype == HEADING_GROUND_TRACK && accept_data(&a->track_valid, mm->source)) {
a->track = mm->heading;
} else if (htype == HEADING_MAGNETIC && accept_data(&a->mag_heading_valid, mm->source)) {
a->mag_heading = mm->heading;
} else if (htype == HEADING_TRUE && accept_data(&a->true_heading_valid, mm->source)) {
a->true_heading = mm->heading;
}
}
if (mm->track_rate_valid && accept_data(&a->track_rate_valid, mm->source)) {
a->track_rate = mm->track_rate;
}
if (mm->roll_valid && accept_data(&a->roll_valid, mm->source)) {
a->roll = mm->roll;
}
if (mm->gs_valid) {
mm->gs.selected = (a->adsb_version == 2 ? mm->gs.v2 : mm->gs.v0);
if (accept_data(&a->gs_valid, mm->source)) {
a->gs = mm->gs.selected;
}
}
if (mm->ias_valid && accept_data(&a->ias_valid, mm->source)) {
a->ias = mm->ias;
}
if (mm->tas_valid && accept_data(&a->tas_valid, mm->source)) {
a->tas = mm->tas;
}
if (mm->mach_valid && accept_data(&a->mach_valid, mm->source)) {
a->mach = mm->mach;
}
if (mm->baro_rate_valid && accept_data(&a->baro_rate_valid, mm->source)) {
a->baro_rate = mm->baro_rate;
}
if (mm->geom_rate_valid && accept_data(&a->geom_rate_valid, mm->source)) {
a->geom_rate = mm->geom_rate;
}
if (mm->airground != AG_INVALID) {
// If our current state is UNCERTAIN, accept new data as normal
// If our current state is certain but new data is not, only accept the uncertain state if the certain data has gone stale
if (mm->airground != AG_UNCERTAIN ||
(mm->airground == AG_UNCERTAIN && !trackDataFresh(&a->airground_valid))) {
if (accept_data(&a->airground_valid, mm->source)) {
a->airground = mm->airground;
}
}
}
if (mm->callsign_valid && accept_data(&a->callsign_valid, mm->source)) {
memcpy(a->callsign, mm->callsign, sizeof(a->callsign));
}
// prefer MCP over FMS
// unless the source says otherwise
if (mm->nav.mcp_altitude_valid && mm->nav.altitude_source != NAV_ALT_FMS && accept_data(&a->nav_altitude_valid, mm->source)) {
a->nav_altitude = mm->nav.mcp_altitude;
} else if (mm->nav.fms_altitude_valid && accept_data(&a->nav_altitude_valid, mm->source)) {
a->nav_altitude = mm->nav.fms_altitude;
}
if (mm->nav.heading_valid && accept_data(&a->nav_heading_valid, mm->source)) {
a->nav_heading = mm->nav.heading;
}
if (mm->nav.modes_valid && accept_data(&a->nav_modes_valid, mm->source)) {