Re: [PSUBS-MAILIST] Once again

["George Slaterpryce" <gslaterp@hotmail.com>]

Ohhhh that's a shiney piece of kit that is.


George Slaterpryce
----- Original Message ----- 
From: "Sean T. Stevenson" <cast55@telus.net>
To: <personal_submersibles@psubs.org>
Sent: Friday, April 07, 2006 1:40 PM
Subject: Re: [PSUBS-MAILIST] Once again


> I was toying with the idea of a relatively low cost inertial navigation 
> system using a 3DM-GX1 sensor from Microstrain.  Essentially, GPS would 
> provide a position reference when surfaced, and the inertial system 
> would take over once GPS position data is lost.  Of course, with an 
> inertial system, error accumulates the more time elapses between GPS 
> positions, but then some sort of hybrid GPS on a tether like you 
> describe could limit that error to a maximum of the current submersion 
> depth.  Realistically though, I think that sonar in conjunction with 
> bathymetric maps are more reliable than electronic dead reckoning.
>
> -Sean
>
>
> George Slaterpryce wrote:
>
> > Once again I come unto you the great PSubbers community with my 
> > Thoughts, Musings and questions. Ye, Verilly... or something.
> >
> > First thought, Problem, location underwater. How to ascertain the 
> > exact (or as near as exact) location of an object under water such as 
> > a sub. Problem is I don't know how deep you can reliabley get a GPS 
> > signal. So I thought of this solution that may not be the most elegant 
> > but I think it would get the job done pretty well.
> >
> > GPS Bouy on a teather released form depth to the surface.
> > You know the depth to the surface, so whatever line you released over 
> > the depth would be your varience. From there you could get the GPS 
> > location, calculate two more points on a circle path, then find the 
> > center point of that, which would give you your GPS location. 
> > (Illustration below)
> >
> > (or if you can't see them) 
> > http://www.captovis.com/marine/designsketches/uwloco.png and 
> > http://www.captovis.com/marine/designsketches/uwloco2.png
> >
> > Seem like a good idea to anybody else? comments? Detractions? 
> > Improvements?
> >
> > George Slaterpryce
>
>
>
>
>
>
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