[PSUBS-MAILIST] New Generation Inertial Sensors - Twice as Accurate

Fri Mar 24 16:48:13 EDT 2017

Jim,
just had a look in Sea Technology magazine March edition, ( free online magazine)
& saw this...
http://www.link-quest.com/html/intro2.htm
It is a small module that tracks an underwater vehicle, has GPS & communicates
to the vehicle via an onboard PC or whatever. Haven't studied it, but I am sure
it could translate the underwater vehicles position to maps on the vehicles PC.
These days you have GPS mapping apps on your cel phone, so it wouldn't be too
hard. The next stage would be using the position signal from the submarine to
control motors on the buoy to follow it. On quad copters they have GPS & return
to start functions that return the quad copter to it's launch position should it's
transmitter lose contact. So the sought of technology to control the buoy thrusters
through position signals is alive & well & cheap.
   I won't be pursuing it, as I need to make my sub first :)
Alan

Sent from my iPad

> On 25/03/2017, at 6:53 AM, Alan via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
> Jim,
> yes. Just an intermittent signal every 10 seconds or so. I have
> read about text type communication systems.
> Here is a passage from a paper that talks about a buoy device.
> 
> An underwater GPS is primarily a combination of a GPS and an acoustic positioning system and consists of two types [12-19]: a sea surface buoy system using a long baseline and carrying a GPS receiver, which can track, monitor, and dynamically position underwater targets from a sea surface, coastal land, and a plane and has a large operating range but can only position underwater targets that carry acoustic transponders in certain waters; and a system which uses a mother ship equipped with a short baseline or ultra short baseline transceiver and a GPS receiver, which is mobile and flexible but also can only position targets equipped with acoustic transponders. Therefore, this paper proposes a way of positioning combining an ultra short baseline, a forward-looking sonar and a GPS receiver, overcoming the limitation of the existing underwater GPS positioning technology that it can only position targets equipped with acoustic transponders and realizing the real-time positioning of the longitude and latitude coordinates of any unknown targets in any waters in the WGS84 ellipsoidal coordinate system, and it is also highly mobile.
> 
> Alan 
> 
> Sent from my iPad
> 
>> On 25/03/2017, at 6:06 AM, via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>> 
>> Alan,
>> Transmit GPS positions wirelessly where?  You didn't mean down to the sub, did you?
>> Jim
>>  
>> In a message dated 3/23/2017 10:07:37 P.M. Central Daylight Time, personal_submersibles at psubs.org writes:
>> Jim,
>> re the tow behind buoy (pronounced boy); it would be possible to make a 
>> buoy with motors on it that tracked your sub & transmitted GPS positions
>> wirelessly. Minn kota have a system that controls their thruster to keep
>> a boat steady on a certain coordinate. 
>> Alan
>> 
>> Sent from my iPad
>> 
>>> On 24/03/2017, at 3:43 PM, via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>>> 
>>> Here's a link that gives quite a bit of information including a reference to their Windows-based software.  Once you open the link, the more you scroll down the more you will see; it goes a long way! http://www.seismic.com.au/assets/pdf/SBG_Systems-Ellipse_Series_Brochure.pdf
>>>  
>>> GPS is great as a starting point before you submerge and for telling you where you are once you surface.  Too bad radio signals don't propagate so well under water.  In the past we've discussed mounting a GPS antenna on a Diver Below buoy with a cable running to the sub.  I don't recall what was said regarding theoretical depth limitations for such a setup as well as the hydrodynamics of towing it.
>>>  
>>> It would be really interesting to see how well your INS position matches up with your GPS when you resurface.  I like the idea of knowing just where you are with reasonable precision when submerged, being able to return to a precise location on another day, being able to search or survey methodically, navigating from A to B to C, etc.
>>>  
>>> Jim T.
>>>  
>>> In a message dated 3/23/2017 7:55:50 P.M. Central Daylight Time, personal_submersibles at psubs.org writes:
>>>> On 3/23/2017 6:40 PM, Brian Cox via Personal_Submersibles wrote:
>>>> There needs to be an underwater GPS  !!
>>> 
>>> I remember a discussion, long ago, about a GPS antenna on a mast.  I don't recall any resolution.
>>> 
>>> 
>>> Mike
>>> 
>>> 	Virus-free. www.avast.com
>>> 
>>> 
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>> 
>> 
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