invalidate CPRs when reaching position reliability zero

track.c

@@ -483,7 +483,7 @@ static int speed_check(struct aircraft *a, datasource_t source, double lat, doub
  )
  ) {
  mm->pos_ignore = 1; // don't decrement pos_reliable
- } else if (a->pos_reliable_odd < 0.2 || a->pos_reliable_even < 0.2) {
+ } else if (a->pos_reliable_odd < 0.01f || a->pos_reliable_even < 0.01f) {
  override = 1;
  } else if (now - a->position_valid.updated > POS_RELIABLE_TIMEOUT) {
  override = 1; // no reference or older than 60 minutes, assume OK
@@ -1230,7 +1230,7 @@ static void setPosition(struct aircraft *a, struct modesMessage *mm, int64_t now
 }
 
 static int64_t cpr_global_airborne_max_elapsed(int64_t now, struct aircraft *a) {
- if (trackDataAge(now, &a->gs_valid) > 20 * SECONDS) {
+ if (!trackDataValid(&a->gs_valid) || trackDataAge(now, &a->gs_valid) > 20 * SECONDS) {
  return 10 * SECONDS;
  }
  int speed = imax((int64_t) a->gs, 1);
@@ -3726,9 +3726,18 @@ static void position_bad(struct modesMessage *mm, struct aircraft *a) {
  }
 
  a->pos_reliable_odd -= 0.26f;
- a->pos_reliable_odd = fmax(0, a->pos_reliable_odd);
  a->pos_reliable_even -= 0.26f;
- a->pos_reliable_even = fmax(0, a->pos_reliable_even);
+
+ if (a->pos_reliable_odd < 0.1f || a->pos_reliable_even < 0.1f) {
+
+ // when we reach zero, reset reliable state
+ a->pos_reliable_odd = 0;
+ a->pos_reliable_even = 0;
+
+ // invalidate CPRs to start fresh
+ a->cpr_even_valid.source = SOURCE_INVALID;
+ a->cpr_odd_valid.source = SOURCE_INVALID;
+ }
 
 
  if (0 && a->addr == Modes.cpr_focus)