Thank you very much for your reply. I once thought of contacting you for help after reading your thread “Mini Ardupilot Antenna Tracker”.
I changed the pitch PID values according to your recommendation, and also tried both “0” and “1” for the SERVO2_REVERSED value(Servo 2 is for pitch). Both did not make the pitch servo work in SITL mode. At one time, while decent during landing(SITL), the tracker pitched up and down violently. But I can’t reproduce it.
“Using the compass on-board the Pixhawk”, I suppose you meant the built-in magnetometer inside the Pixhawk. I have been using the built-in mag for a long time until 1 week ago when I exhausted all the ways , then I decided to try an external compass, as suggested in another thread saying mounting an external compass along the pitch axis makes it work.
Regarding losing satellites when plane flies overhead, do you mean when the plane flies overhead, the antenna , and thus the tracker (with the GPS module mounted on top) points vertical up, the GPS thus faces sideway or horizontally, and loses satelites ? If yes, this makes sense.
I admire you guys who succeed in making the tracker work. With the yaw working, It seems I am not too far from success. But I have to keep on trying. Meanwhile, if you think of any clue, please let me know. Really appreciate your assistance in advance.