MAVLINK Altitude Message For RC Truck Jump Height

I have been trying to measure jump height of an rc truck using altitude messages returned from an mRo Pixracer R14 running ArduPilot firmware. I have recently asked a more focused question about baro altitude in another post, but I would be looking for more general advice.

I have been using altitude from GLOBAL_POSITION_INT/VFR_HUD. They both seem to mostly provide GPS altitude. GPS altitude often appears to drift mid jump, leading to an innaccurate jump height reading. For this application, I would need an altitude message that accurately measures small/quick relative changes in altitude close to the ground.

Is there a MAVLINK message that would work well for this purpose? I was thinking baro or IMU fusion altitude would work well.

If you have a recommended MAVLINK message that doesn’t stream by default on QGC on ArduPilot firmware, I would appreciate advice on how to get it to stream.

Thanks for the help.