Saw on CNN that the AUW (autonomous underwater) sidescan sonar that is being used to search for MH370 in the south indian ocean is equipped with a GPS sensor. Just wondering if GPS is abailable under the sea?
I think the position would be calculated from GNSS observations from a ship that it is connected to, much like a tailfish used in hydrographic work. Just my 2 cents. The connection could be cable, via radar, or acoustics? It would be interesting to see how the set up works!
The GPS radio frequencies are close enough to microwave oven frequencies that I would expect sea water to absorb most of the signal at a very shallow depth.
No
Possibly GPS is used to initialize the IMU while on the surface.
Correct. GPS only works from the surface up. It takes mathematics to penetrate the water in a meaningful way. 😀
I am wondering why if they are dropping multiple sonobouys with GPS aren't they triangulating a more precise location than 15,000 square miles?