<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div></div><div>Cliff,</div><div>yes looks like I am re-inventing the wheel a bit here.</div><div>the tag transponder for the Subsonus is US $2430. I would hate to</div><div>think what the Subsonus costs, & prices for it are only available by request.</div><div>My system is a bit different in that the transducer hanging from the buoy</div><div>would send data on it's GPS position to a receiver on the submarine. The</div><div>electronics on the sub would calculate its distance from the buoy by the</div><div>time it takes for various signals to arrive from the buoy, then calculate it's</div><div>GPS position by trilateration. </div><div>It is not outside the realms of someone who tinkers with electronics to</div><div>put something like this together, as a lot of the components to it could</div><div>be bought cheaply.</div><div>Alan</div><div><br></div><div><br>On 1/09/2019, at 1:29 AM, Cliff Redus via Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>> wrote:<br><br></div><blockquote type="cite"><div><div class="ydp2e3398a7yahoo-style-wrap" style="font-family: times new roman, new york, times, serif; font-size: 16px;"><div></div>
<div dir="ltr" data-setdir="false">Alan, an alternative would be to order an off-the-shelf USBL <span><a href="https://en.wikipedia.org/wiki/Short_baseline_acoustic_positioning_system" rel="nofollow" target="_blank">https://en.wikipedia.org/wiki/Short_baseline_acoustic_positioning_system</a> </span>system like <span><a href="https://www.advancednavigation.com/product/subsonus" rel="nofollow" target="_blank" class="enhancr_card_7801585810">Subsonus | Advanced Navigation</a></span><div><br></div></div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false"><br></div><div><br></div>
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On Saturday, August 31, 2019, 05:54:47 AM CDT, Alan via Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>> wrote:
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<div><div dir="ltr">I was looking at GPS receivers for my sub, mainly for estimating my<br></div><div dir="ltr">surface speed & determining my range based on my power consumption.<br></div><div dir="ltr">But it occurred to me that you could make a similar system to GPS for<br></div><div dir="ltr">underwater navigation.<br></div><div dir="ltr">Have 4 buoys placed around your intended dive location that have GPS<br></div><div dir="ltr">receivers & ultrasonic transmitters. With a bit of electronics the submarine <br></div><div dir="ltr">could locate itself with trilateration ( as in GPS) in relation to the 4 bouys.<br></div><div dir="ltr">The 4 buoys in turn are locating their position off satellites & relaying this<br></div><div dir="ltr">information via the ultrasonic transmitters to the sub. This way the pilot<br></div><div dir="ltr">could use charts to plot where they were & where they had been. <br></div><div dir="ltr">It wouldn't matter too much if the buoys were blown about or if they moved <br></div><div dir="ltr">in the current as they would update their position.<br></div><div dir="ltr">It may be helpful for grid searching.<br></div><div dir="ltr">If you wanted to get more serious you could put small motors on the buoys<br></div><div dir="ltr">that automatically held them in position as Minnkota are now doing with<br></div><div dir="ltr">their radio controlled motor.<br></div><div dir="ltr">Or is this already done?<br></div><div dir="ltr">Alan<br></div><div dir="ltr"><br></div><div dir="ltr" data-setdir="false">You bolt this unit to the top of your sub and drop the corresponding tender transponder into the water and the sub (as well as the tender) knows its submerged GPS location real time. Tender knows it's GPS location and the surface unit calculates the relative location of the sub then sends the calculated GPS location back to the sub real time. There are a number of these USBL systems. For the Psub community, the trick would be to standardize on one that does not cost an arm and a leg.<br></div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">Cliff</div><div dir="ltr"><br></div><div dir="ltr"><br></div><div dir="ltr">_______________________________________________<br></div><div dir="ltr">Personal_Submersibles mailing list<br></div><div dir="ltr"><a href="mailto:Personal_Submersibles@psubs.org" rel="nofollow" target="_blank">Personal_Submersibles@psubs.org</a><br></div><div dir="ltr"><a href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles" rel="nofollow" target="_blank">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a><br></div></div>
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