This is ArduSub forum, ArduSub is part of the ArduPilot project but does not uses apsync or Mission Planner.
Probably you’ll find help in ArduPilot ApSync forum: https://discuss.ardupilot.org/c/apsync-companion-computers
oh,i’m sorry.That’s so embarrassed ,and thank you ,man.I will ask for help from ArduPilot ApSync forum .
@huanyre , it appears to be a baudrate mismatch between the serial port configuration on your autopilot and mavproxy. Try it with
--baudrate 57600 or 115200. If this helps, be sure to follow up your question on another forum if you posted elsewhere also.