Altitude hold upon the water

Hello everyone
I want to perform “altitude hold” mode upon the water,but i have no idea about what kind of sensor should i use.I’ve heard that the Ultrasonic module can’t work well under this environment and GPS have big bias for the altitude hold.SO do you guys have any good advice or can you suggest a sensor to make it well.

hi, david.
Have you tested the altctl mode?

I don’t dare to test the altctl mode upon the water,because i cannot find any reliable ways to perform it.So do you have any ideas?

You can refit you quadrotor to water scooter.
You only add a foam boat body under your quadrotor.
It sounds exciting.
You can try it.:smiley:

Your FlightController should be equipped with a Barometer Sensor. So there should be no worry it should perform as over land.

If you want a more precise flight over water you should add a distance sensor module. Avoid the laser one on the water, Ultrasound should work.