Measuring kiteboard jump height

Hey y'all.

I'm looking to ground truth how high kitesurf jumps are. We use apps and sensors on our boards that are basically accelleratomoter readers ,but they are inaccurate. I'm looking for an externally referenced capturing method. Idk, maybe a laser?

the kite jump's i'd measure are between 5-15m high, and the riders might be 100m away, but I can get closer to them if necessary.

thought y'all might have some good ideas!