how to set the auto-tracking antenna with wireless video data link.

Aĉetanto: I would like to ask you a technical question about the automatic tracking of the gimbal:
We currently hold the flight controller by hand, pri 2 meters higher than the automatic tracking gimbal. Tamen, the height displayed on the automatic tracking gimbal screen is always negative, and the value is still relatively large. According to our understanding of reading the automatic tracking gimbal documentation, this Alt parameter should be the altitude difference calculated by calculating the GPS information of the flight control end and the automatic tracking gimbal end, so the current Alt parameter shows a negative number, what is the reason?

Aĉetanto: ExtGPS is currently enabled, and the ALT interpretation of the protocol also selects GPS.

iVcan: If it is Baro, change it to GPS.

Aĉetanto: ExtGPS is currently enabled, and the ALT interpretation of the protocol also selects GPS.

iVcan: That’s right, how much is negative? Seventy or eighty?

Aĉetanto: Is the working current normal after the machine is powered on?

iVcan: It is correct.

Aĉetanto: This is our flight controller, with a GPS module.

https://item.taobao.com/item.htm?spm=a1z09.2.0.0.438c2e8dvtnqOH&id=537550757674&_u=o75g5m97e74

Aĉetanto: We went downstairs to test again, and now the height is -4.

iVcan: That’s probably within the margin of error, fly the plane to see the effect.

Aĉetanto: Looks like it should be fine.