Underwater GPS

[100days-a-year]

uhhh,Runvus ULF sound waves or ULF radio waves.Milatary has used ULF radio for decades to communicate with subs.ULF sound(a lond distance sonar form)has been implicated in beachings and deaths.It is a relatively new technology now mostly unneeded due to our far superior hunter/killer subs and some other toys we have.The EyeSea and similar are pretty cool ,but if you need that to know where you are in relation to the boat I'll pass on having you dive with me.

 

[runvus4]

I was talking about ULF sound waves as I know that those can penetrate the water on a trans-oceanic scale. I don't know enough about ULF radio waves... aside from what I've seen on sci-fi tv shows and in movies.... Whats the straight dope on the Eyesea?

 

[darkmoon3d]

Found this site doing a web search: http://www.wadespage.com/D800DS07RF00.shtml

I guess this might work as an alternative for underwater gps.

 

[gaudencio]

For me I still use the old and dependable compass nothing else. gps would be too expensive.
Jimmy T.

 

[DJ69]

The signal GPS's are using can't penetrate more then 50cm of water.
Other thing is the whole technolegy is based on sertin wave length's at special modelations and digital coding. (actually very similar to CDMA celphones). And the thing uses the fact that both the sat's are moving all the time, as well as the hand unit's (that's why is's more acurate then in motion then in standing).
So it's not that simple to modify.
Probably more simple is to create somthing new on the lines of the Neverlost but on larger scale, with 3+ larg beacons.....

If you ask me, when arriving to a new dive site, take a local guide for your first dives.

 

[otobmark]

Our Navy still depends on inertial navigation which is updated by other means when possible (can't be jammed). Most long range (transatlanic etc.) aircraft also use inertial navigation (Supplimented w/ GPS, -civilian gps easy to jam). Subs can float an antenna to get a GPS fix. The VLF radio wavelengths are so long that it takes enormous time to send messages (extremely low bandwidth). I would guess that getting an accurate fix on source for triangulation would be difficult--I don't know. The inertial systems can be amazingly accurate, especially in something as stable as a sub. Perhaps a compact pocket size inertial system will someday be available. We used accelerometers in onboard telemetry in race cars and one trip around the track would draw a very accurate picture of the course. The sensor pack was not large and I could see the technology reaching personal size at some not too distant point.

 

[j-valve]

Has anyone ever taken their cell phone under with them in an enclosure while turned on? Do you still have cell signal?
If so you can probably get an Assisted GPS signal from your provider or even a fix from GPS One CDMA network if it's available in your area.

 

[SMan]

I did some looking around last fall. A company has a patent on a gps device for underwater use. I don't remember the company's name off the top of my head but I did find a pdf file of a flyer that talked about them demoing the product with a California dive club in the late 90's. The company did not have a toll free number and I did not feel like making a long distance phone about a product not out in the public. Their website still talks about the product. If I can find my information again I will post it.

S

 

[Braunbehrens]

j-valve once bubbled...
Has anyone ever taken their cell phone under with them

yeah, I make calls all the time while doing deco. It passes the time.

Seriously though, I've had my cellphone in my pocket before, so it was pressurized to about 150 fsw. Still works. I didn't get any calls while I was under

Here is a link for UW gps:

http://www.underwater-gps.com/

If anyone is seriously interested in this, I recommend learning how to use a reel. It's cheaper and easier.

Before you learn that, learn how to navigate under water (admittedly a difficult skill, at least for me).

 

[jeremyrfoster]

Granted, GPS signal will not penetrate the water. Has anyone considered a surface receiver (similar to mounting a traditional receiver as I've heard mentioned) to the dive flag connected to a device that CAN penetrate water and sends the signals to a unit that the diver carries? I know this is a complex setup and would probably have to be commercially engineered.

We know that the satellite signals are very weak. The device I'm thinking of would basically act like a repeater... not only strengthening the signal, but also changing it to a different medium (ULF? Sonar?)

Jeremy