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Compute ADS-B v0 NACp/SIL from position message type

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This commit is contained in:
Oliver Jowett 2018-09-19 17:09:11 +01:00
parent 3c02e8419d
commit c8501cb41c
1 changed files with 92 additions and 0 deletions
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92
track.c
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@ -790,6 +790,81 @@ static unsigned compute_rc(unsigned metype, unsigned version, unsigned nic_a, un
}
}
// Map ADS-B v0 position message type to NACp value
// returned computed NACp, or -1 if not a suitable message type
static int compute_v0_nacp(struct modesMessage *mm)
{
if (mm->msgtype != 17 && mm->msgtype != 18) {
return -1;
}
// ED-102A Table N-7
switch (mm->metype) {
case 0: return 0;
case 5: return 11;
case 6: return 10;
case 7: return 8;
case 8: return 0;
case 9: return 11;
case 10: return 10;
case 11: return 8;
case 12: return 7;
case 13: return 6;
case 14: return 5;
case 15: return 4;
case 16: return 1;
case 17: return 1;
case 18: return 0;
case 20: return 11;
case 21: return 10;
case 22: return 0;
default: return -1;
}
}
// Map ADS-B v0 position message type to SIL value
// returned computed SIL, or -1 if not a suitable message type
static int compute_v0_sil(struct modesMessage *mm)
{
if (mm->msgtype != 17 && mm->msgtype != 18) {
return -1;
}
// ED-102A Table N-8
switch (mm->metype) {
case 0:
return 0;
case 5:
case 6:
case 7:
case 8:
case 9:
case 10:
case 11:
case 12:
case 13:
case 14:
case 15:
case 16:
case 17:
return 2;
case 18:
return 0;
case 20:
case 21:
return 2;
case 22:
return 0;
default:
return -1;
}
}
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);
@ -875,6 +950,23 @@ struct aircraft *trackUpdateFromMessage(struct modesMessage *mm)
}
}
// fill in ADS-B v0 NACp, SIL from position message type
if (a->adsb_version == 0 && !mm->accuracy.nac_p_valid) {
int computed_nacp = compute_v0_nacp(mm);
if (computed_nacp != -1) {
mm->accuracy.nac_p_valid = 1;
mm->accuracy.nac_p = computed_nacp;
}
}
if (a->adsb_version == 0 && mm->accuracy.sil_type == SIL_INVALID) {
int computed_sil = compute_v0_sil(mm);
if (computed_sil != -1) {
mm->accuracy.sil_type = SIL_UNKNOWN;
mm->accuracy.sil = computed_sil;
}
}
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) {