How to setup ardupilot antenna tracker woth sitl

i have a antenna tracker with ardupilot tracker 4.6 firmware installed in cube orange and here3 gps, using 2 servos 360,90 degrees,

when i set mode to scan after arming it only moves the pitch back and forth and little bit of yaw,

i want to test my antenna tracker using ardupilot sitl, please someone guide me on setup and testing