check message age

axis-ptz-controller/object.py

@@ -188,6 +188,13 @@ def recompute_location(self) -> None:
  logging.debug(f"Object msg age: {msg_age} [s]")
  time_delta += msg_age
 
+
+ if (time_delta < 0.0) or (msg_age < 0.0):
+ logging.error(
+ f"Time delta: {time_delta} [s] or msg age: {msg_age} [s] is negative"
+ )
+ self.object_lock.release()
+ return
  # Compute position and velocity in the topocentric (ENz)
  # coordinate system of the object relative to the tripod at
  # time zero, and position at slightly later time one