check receiver distance when adding to existing sync points

mlat/server/clocktrack.py

@@ -185,7 +185,6 @@ def receiver_sync(self, receiver,
  if abs(candidate.interval - interval) < 1e-3:
  # interval matches within 1ms, close enough.
  self._add_to_existing_syncpoint(candidate, receiver, tA, tB)
- receiver.sync_range_exceeded = 0
  return
 
  # No existing match. Validate the messages and maybe create a new sync point
@@ -233,30 +232,30 @@ def receiver_sync(self, receiver,
  # CPR failed
  return
 
- receiver.sync_range_exceeded = 1 #unset when everything checks out
-
  # convert to ECEF, do range checks
  even_ecef = geodesy.llh2ecef((even_lat,
  even_lon,
  even_message.altitude * constants.FTOM))
  if geodesy.ecef_distance(even_ecef, receiver.position) > config.MAX_RANGE:
  # suppress this spam, can't help if ppl give a wrong location
  # logging.info("{a:06X}: receiver range check (even) failed".format(a=even_message.address))
+ receiver.sync_range_exceeded = 1
  return
 
  odd_ecef = geodesy.llh2ecef((odd_lat,
  odd_lon,
  odd_message.altitude * constants.FTOM))
- if geodesy.ecef_distance(odd_ecef, receiver.position) > config.MAX_RANGE:
+
+ # checking range for the even position and intermessage distance is sufficient
+ #if geodesy.ecef_distance(odd_ecef, receiver.position) > config.MAX_RANGE:
  #logging.info("{a:06X}: receiver range check (odd) failed".format(a=odd_message.address))
- return
+ #return
 
  if geodesy.ecef_distance(even_ecef, odd_ecef) > config.MAX_INTERMESSAGE_RANGE:
  #logging.info("{a:06X}: intermessage range check failed".format(a=even_message.address))
  return
 
  #valid, do some extra bookkeeping before sync stuff
- receiver.sync_range_exceeded = 0
 
  ac = self.coordinator.tracker.aircraft.get(even_message.address)
  if ac:
@@ -290,9 +289,19 @@ def _add_to_existing_syncpoint(self, syncpoint, r0, t0A, t0B):
  # and a flag indicating if this receiver actually managed to sync
  # with another receiver using this syncpoint (used for stats)
 
+ receiverDistA = geodesy.ecef_distance(syncpoint.posA, r0.position)
+ receiverDistB = geodesy.ecef_distance(syncpoint.posB, r0.position)
+
+ # add receiver distance check here
+ if receiverDistA > config.MAX_RANGE or receiverDistB > config.MAX_RANGE:
+ r0.sync_range_exceeded = 1
+ return
+
+ r0.sync_range_exceeded = 0
+
  # propagation delays, in clock units
- delay0A = geodesy.ecef_distance(syncpoint.posA, r0.position) * r0.clock.freq / constants.Cair
- delay0B = geodesy.ecef_distance(syncpoint.posB, r0.position) * r0.clock.freq / constants.Cair
+ delay0A = receiverDistA * r0.clock.freq / constants.Cair
+ delay0B = receiverDistB * r0.clock.freq / constants.Cair
 
  td0A = t0A - delay0A
  td0B = t0B - delay0B