Your project sounds very interesting. Do you realize/understand the limitations of RF in water? One inch of water would attenuate a GPS signal to the point that it would be undetectable. Even the US Navy must raise a snorkel/antenna to the surface to receive a "GPS" signal. Nevertheless, if you have idea(s), I would certainly be interested and I would be happy to provide the info you request (above). Best Regards, Kent
PS: I have been diving for 35 year. I have dove many places around the world; favorite probably being the New Guinea area. I am in Colorado, and I have a pretty extensive background in RF.
Steve, I showed your thoughts to a friend of mine who is both a diver and an RF engineer. Here is what he said:
It's impossible to use GPS or other low-powered ultra-high-frequency RF device under water. Only VLF works there in the realm of 100-300KHz. These take impossibly long wire antennas to make work. They have to trail a long wire for it to work underwater on Subs and that will only give them 30-60 bits per minute for data speeds. This compared to the 1100mhz GPS signal that is transmitted from 250 miles up and passes large quantities of data (9600baud or 9600 bits per minute)
He's barking up the wrong tree and using flawed logic here even thinking that it will work. An underwater navigational device would have to work in the ultrasonic realm like our pingers.