GPS Accuracy Underwater

This is an outdoor camera. Not an underwater camera.

GPS signals cannot penetrate salt water, or fresh water, for that matter.

You'd have to have a receiver on the surface.

Thank you for the GPS information Lyn. Since the specs say "Waterproof to five meters" I believe I can indeed take it under water.

I'm sorry. I didn't read that far. You are, of course correct about the underwater part.

Unfortunately, GPS signals still stop at the surface.

......which is why submarines need to surface to use radio communication....

I don't think it would be a big deal. Either the pic's are tagged as you shoot them, with GPS coordinates updated when you surface. Or in a worst case scenario, you waste a shot when you surface, and share the GPS attributes with the underwater pictures you've just taken...................this would give you an accurate coordinate for your underwater shots.

I think the question has been answered sufficiently, but it is interesting to note from the Owner's Manual that underwater isn't the only place the GPS feature may not work...

The camera may be unable to receive GPS data if the antenna is obstructed or when underground, underwater, under a bridge or overpass, inside a vehicle, building, tunnel, or metal briefcase, between tall buildings, or in the vicinity of cell phones or other devices that broadcast in the 1.5 GHz band.

... Note that the use of GPS devices is restricted in some countries, including the People's Republic of China. Before going abroad, consult with the embassy or a travel agent.

LOL... consult with the embassy before bringing your camera... wow... What is this world coming to???

When I go back to the farm outside of Hot Springs, my GPS quits working because the road is overgrown with Oak trees and they block the signal.

My GPS has quit updating during heavy cloud cover while driving across nearly treeless central Nebraska on I-80. What the GPS may then do is use the last speed to keep updating its position until it gets a new signal.

If you go underwater, it will likely display the last position that it had a signal, typically when the camera break's the surface going down. If position is critical resurface above the area of interest.

It is true the GPS should not work under water, however, to answer the original question, the signal will reach down somewhat. The signal degradation will not affect the accuracy until the unit can no longer resolve at least 3 signals from 3 different satellites.

GPS operates at about 1/2 the wavelength of a microwave oven or WiFi at 1500Mhz.

This will penetrate the ambient materials for a meter or so but that's it. 2400-2700MHz water is opaque, and will absorb the signal strongly. 1500MHz is not far from that point and so the water will deteriorate the signal. The satellites you see will not be the ones near the horizon due to the increased length of travel through the water. You are deeper to the line of sight from the horizon than you are from the line of sight from directly above at the same depth.

But if you get a signal (3 signals), then the accuracy should not be affected.

The only correct answer to the original question, "does the air-water interface degrade the GPS signal or accuracy in any way" would be yes.

Unless you are speaking from actual experience and you have actually submerged a GPS unit and observed the signal I doubt that anything you say is correct.

The air water interface degrades the signal, but not the accuracy until less than 3 signals can be seen.

And I say the air water interface stops the signal, period.

Fine. It ain't gonna work at depth any way.

I feel a sandwich bag and some water may be in the future of my GPS.

Make sure you double or triple bag it!