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hcso1510
(@hcso1510)
Active Member

Rolf,
Thank you for the ADCP intro link. It seems quite interesting and something I may read up on a bit more for some general knowledge. I totally understood your initial post and some of the responses.
At some point I became totally lost. ADCP technology seems like it is something that would come with a hefty price tag? Is this something that you have used specifically to detect the location of a mobile?

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Posted : 31/01/2017 7:31 pm
RolfGutmann
(@rolfgutmann)
Community Legend

The main process splits into three steps 1. splash zone (mobile into water), 2. riverbed topography (underwater landscape and flow parameters) and 3. underwater LiDAR (find the mobile).

Step 2. consists of first getting an understanding of how it looks underwater. The riverbed or riverground is the vertical limitation. We need these parameters also for Step 3. to not needless damage the LiDAR.

ADCP delivers us the landscape, how it looks underwater. You can imagine that it has a great influence on the mobile's way on riverground.

Step 2. includes the riverbed AND the flow parameters. The flow parameters with substream direction, speed and acceleration. By running the riverbed topography and the flow parameters in the Geomatics Simulation Platform GSP we calculate priority zones based on Phone Finding Probability PFP.

The quality of Step 2. is crucial for the overall success. Searching on the wrong place you lose time and spend resources wrongly.

I am bound. Strictly forbidden to show our animated graphical visualization and concept.

Hope you get a sense -)

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Posted : 31/01/2017 9:14 pm
RolfGutmann
(@rolfgutmann)
Community Legend

Just learned that the dual-rope cable system is technically named

Temporary Bank-Operated Cableway TBC

Do you have a better term?

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Posted : 01/02/2017 12:03 pm
RolfGutmann
(@rolfgutmann)
Community Legend

The proj runs fine in all phases. We just face problems of getting up from underwater the geospatioal (absolute position in space) position of the underwater LiDAR. As not GPS positioning is possible we actually transmit from landside GNSS terrestrial referencies the distance 2D towards the underwater LiDAR. All trials of bringing up an exact position from underwater failed. The last trail was of setting a cable-based overwater float ball and taking into calcualtion the speed of water (m/s) and actual water direction parameters (compass-based).

Does anybody know a more accurate/precise method of getting from underwater up the geospatial position by any Radio Frequency RF based signalling?

Any help very much appreciated. Thank you.

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Posted : 19/04/2017 10:25 pm
RolfGutmann
(@rolfgutmann)
Community Legend

Who is familiar with Underwater High Accuracy Location Finding?

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Posted : 06/07/2017 3:49 pm
jaclaz
(@jaclaz)
Community Legend

Who is familiar with Underwater High Accuracy Location Finding?

Here, complete with a couple new acronyms, UWSN and (terrestrial) WSN, but also many more like DETs, AUV's, etc., and more than anything else, HLS
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3304154/#b4-sensors-12-02026

jaclaz

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Posted : 06/07/2017 6:38 pm
RolfGutmann
(@rolfgutmann)
Community Legend

Grazie!

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Posted : 06/07/2017 6:41 pm
RolfGutmann
(@rolfgutmann)
Community Legend

Got today the information of a professional diver (outside Police) who mentioned that he had mobile broadband access 10 meters under water.

Who is expert? Water has a heterogeneity and absorbs RF signals. Is this possible?

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Posted : 29/08/2017 6:16 pm
jaclaz
(@jaclaz)
Community Legend

Got today the information of a professional diver (outside Police) who mentioned that he had mobile broadband access 10 meters under water.

Who is expert? Water has a heterogeneity and absorbs RF signals. Is this possible?

Sea (salted) or river/lake?

I would say possible under fresh water, more unlikely in sea water, unless maybe in the immediate vicinity of a tower/near the shore, or anyway in exceptionally high signal spots.

I have seen other reports of phones still having signal at around 35 feet, just like with Faraday cages, very likely text/sms can "go through" much better than voice, however, mobile broadband is likely to become narrowband.

jaclaz

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Posted : 29/08/2017 7:24 pm
RolfGutmann
(@rolfgutmann)
Community Legend

River

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Posted : 29/08/2017 7:41 pm
jaclaz
(@jaclaz)
Community Legend

River

Then it is plausible.
I would expect (very roughly) something like 3-4, maybe 5 dB attenuation per meter of depth, so if the signal is very strong in the area a "sensible" phone might do it.

Some anecdotal evidence, JFYI
http//www.undercurrent.org/UCnow/dive_magazine/2010/CellPhoneDiving201001.html

jaclaz

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Posted : 29/08/2017 8:41 pm
RolfGutmann
(@rolfgutmann)
Community Legend

Worth reading about ADCP in Hydro International

https://issuu.com/geomarespublishing/docs/hydro-international-january-februar_e7992384f33b6d/10

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Posted : 06/09/2017 10:11 am
RolfGutmann
(@rolfgutmann)
Community Legend

For the underwater location finding we partnered with DesertStar.com.

http//www.desertstar.com/page/southstar

The project runs fine and we plan the version 2 with size-reduced components -)

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Posted : 13/11/2017 2:13 pm
RolfGutmann
(@rolfgutmann)
Community Legend

Just got our Endura from Aquabotix - great fun to test -)

https://f2.blick.ch/img/aktuell/origs560953/6805562603-w644-h429/Unfall-Winterthur-Mini-Toess.jpg
This was the past - the next time little green diver goes down…

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Posted : 03/01/2018 10:25 am
RolfGutmann
(@rolfgutmann)
Community Legend

For the USBL we trust on the X150

http//www.blueprintsubsea.com/pages/product.php?PN=BP00795

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Posted : 04/01/2018 9:02 am
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