Looking for a waterproof sensor to measure ground clearance under a 4wd

Hi All, first time here.
What I'm trying to do is find a sensor/s that can cope with being mounted on the body of a 4wd car/truck. Given the poor operating environment (dirt, mud, water, under water, vibration, temperature range, etc)
So that a warning can be given to the operater if the vehicle under body is going to hit something?
I know that there are waterproof ultasonic senors and aslo radar, I've seen lots of part numbers.

Has anybody done anything like this or could offer models?
Has anybody measured like a sonar map with a sensor under water?

Thanks
Cheers
Mark

I would go with a TOF optical sensor.

Thanks
Something I had not even thought of

IF the vehicle is moving, then it is too late for a warning!!!
Paul

What you want is to connect that to your hydraulic jacks, so you can lift the car over the bump!