Re: [PSUBS-MAILIST] UW-DGPS

["Adam Lawrence" <adteleka@in-tch.com>]

I find the topic of underwater positioning quite interesting. Like Phil and
Vance mentioned though I would suspect the price tag of the equipment alone
to be very high. A conventional land system last I heard runs at least 16K
and forget taking it even two inches under water. This number alone puts the
crunch to us backyard fellows.

The interesting part of it though is how a moving support vessel's position
and a moving sub's position can be instantaneously calculated along with the
four or more needed satalites to pinpoint  the sub's position and an
instantaneous position of the sub can be given through a realtime reading.
Whew! This must all be possible with fast computers and the right setup. But
what I am curious about is how the initial position of the moving support
vessel is found as to have a base point for the positioning of the sub? I
imagine that this type of arrangment would give tolerances within a few
meters which might be satisfactory.
This might also incorporate transponders placed on the ocean floor therefore
providing a stationary position.

This is interesting stuff and would be valuable knowlege for any of us who
want to be a tech for Phil or go into the business. I would like to
understand it but I can't see myself bying the system for a psub.

Regards,
Adam