underwater GPS?

[Precht,Bill]

			In response to the GPS querry -

> 		Presently Trimble Navigation makes a GPS unit for the US
> Military (Navy Seals). This system known as the MUGR (Miniature
> Underwater GPS Receiver) is a 6-channel, P(Y) code, SA/AS performance
> hand held unit.  It is waterproof up to 2 atmospheres (66 feet) and
> weighs 1.2 pounds.  It is designed "to be very easy to use even under
> duress".  The P(Y) code indicates a military code. Users licences  for
> commercial/scientific use are available. However, with the recent and
> ongoing declassification of military technology I understand this
> equipment may be readily available to the scientific community sooner
> than later and with non-military codes.
> 
> 		Since this equipment has been heretofore unavailable to
> general users, and because of the need for accurate underwater surveys
> in the case of ship groundings etc...,  We  have  also  adapted a
> survey-grade, Trimble RTK - GPS rover unit for U/W data collection.
> We float the receiver directly above the diver doing the survey.  The
> diver has the antenna mounted on a pole with a waterproof coaxial
> cable connecting the antenna with the receiver.  With teams of as
> little as three field personnel we are able to cover a large area with
> excellent precision and accuracy (cm scale).  Limitations include
> water depth and sea state.  The calmer the conditions and the
> shallower the depth - the better the results.  It is difficult to near
> impossible to use this technique in rough seas.  If you have any
> additional questions on this technique...  please don't hesitate to
> drop me a line. In addition, our firm has a working (partnering)
> relationship with the firm SSR (Search, Survey & Recovery) out of
> Jupiter FL.  They have a system entitled the IVMS (Integrated Video
> Mapping System) that incorporates a constant GPS location on their U/W
> video surveys.  This system is further being refined with the advent
> of digital video cameras. 
> 
> 		I hope this clarifies any questions as to the present
> State-of-the-Art with U/W GPS. 
> 
> 
> 		Cheers,
> 
> 		Bill Precht
> 
> 		LAW Engineering & Environmental Services Inc.
> 		5845 NW 158th Street
> 		Miami Lakes, FL  33014
> 		ph (305) 826-5588
> 		fax (305) 826-1799
> 
> 			-----Original Message-----
> 			From:	eric roach [SMTP:ericroach at hotmail.com]
> 			Sent:	Tuesday, June 23, 1998 5:33 PM
> 			To:	coral-list at coral.aoml.noaa.gov
> 			Subject:	underwater GPS?
> 
> 			Does anyone possess product information for any
> sort of underwater GPS 
> 			or any ideas of how to make one?
> 
> 			Eric Roach
> 
> 	
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