The path generator will continuously update the demand position even if there is no new track command received in the SlewAndTrack sub-state. The initial suspect is that this comes from the non-zero target velocity in the final received track command. This will continue to update the position command. The initial idea to fix this is to reset the velocity command to be zero if no new track command received.

The following figure (x-axis: time in seconds, y-axis: value such as position in degree) shows this problem. There are two targets (positions = 1.2 degree and 3 degree. velocity = 0.01 deg/sec and -0.01 deg/sec). The track command does not continue after the time equals 6 seconds. We could see the rotator position is at 3 degree when time is at 8 seconds but the demand position is decreasing after time=8 seconds (rotator's position keeps the same) because of the second target has the velocity of -0.01 deg/sec.