Re: [PSUBS-MAILIST] UW-DGPS

[Ray Keefer <Ray.Keefer@ebay.sun.com>]

Hi,

But I am curious. If the GPS receiver is on the surface, what good is it? Sending
the location of the receiver via acoustics to the sub does not tell the sub where
the sub is. It tell the sub where the receiver is.

Now if the sub could take a bearing off the GPS receiver acoustical transmiter and
is able to figure out the distance then you might have something. You will know the
offset from a know GPS location.

Problems. 

The GPS location will be know down to how many 10's of feet? Civilian
GPS receivers are not all that accurate.

The acoustical signal from the GPS receiver's acoustical transmitter is subject
to the usual problems with sound underwater. Refraction. Stratified desenty layers....
Fortunate most PSUBS don't go so deep so these issues may not be major. They are
something to consider though.

Regards,
Ray

> From: VBra676539@aol.com
> Date: Sat, 18 Mar 2000 19:21:40 EST
> Subject: Re: [PSUBS-MAILIST] UW-DGPS
> To: personal_submersibles@psubs.org
> MIME-Version: 1.0
> Content-Transfer-Encoding: 7bit
> 
> Carsten & Pat,
> 
> I know there is an integral system on the market, PC driven, which connects 
> the GPS link and an acoustic link from a tracking system by computer and then 
> tells everybody where everybody is. Trust me, we can't afford it. Woods Hole 
> uses it, and IFREMER, but not Harbor Branch (too many $$$).
> 
> I have used radios, both VHF and CB to about 50 fsw, but not deeper. There 
> has to be a way to convert the GPS signal to acoustic and broadcast to the 
> sub, but all that stuff was mighty Flash Gordon in my operational day. Maybe 
> Phil will read this and chip in. He uses computers to control the DWs, and 
> will be up to snuff on current events along these lines (if there are any).
> 
> Best Regards,
> Vance