Side scan sonar

payloads

#1

Hi everyone

Just wonder if it is possible to use the spare aux cables on the rov to connect a side scan sonar module to the rov?
Has anyone looked into this?

Would have been cool to be able to see bottom “image” in the search for wrecks and stuff.


Using a Humminbird Side Scan Sonar not to the bottom but to ahead of the ROV
#2

My take is that you would need full Ethernet which the current wiring isn’t really set up to do (although I know a few people have been trying different things eg U/W WiFi with its 100mm range) as most of the systems that could be “bolted on” do need to transfer large amounts of data back into the ROV and then up the tether

Have a look at what RV Seeker has been doing

and also what @Jim_Trezzo has been developing (it can in time be extended to this sort of operation)

Regards

Scott


#3

I think communication could be done but the problem is that a side scan “fish” need be towed in a regular pathway with constant speed and direction and altitude. Depending of visibility and environment would be not feasible for a tethered ROV.


#4

You don’t necessarily need a towfish, there are quite a few examples of fixed mounting systems out there, and you wouldn’t use an OpenROV (small observation class ROV) for the grunt of broad scale survey work with regular pathway (as you rightly indicate) but some sort of SSS to just to home in on a target.

But some form of extended underwater sensing (via sound or something else) to detect objects (say nominal 30m off) would be nice either via a scanning “sounder” (eg similar to the Lowrance SpotlightScan) or something similar to the Tritech unit on the deeptrekker

(Grunt survey work mmmmmmm that’s a dream for the nice cost effective autonomous open source AUV a cheap and dirty REMUS equivalent mmmmmm )

Scott


#5

Have you seen the Starfish OEM sidescan unit?

http://www.blueprintsubsea.com/pages/product.php?PN=BP00755

I’ve been drooling over this and thinking of ways to use it for some time…

E


#6

Check out some of the projects on the Humminbird Side Imaging forums:

http://forums.sideimagingsoft.com/index.php

People have successfully extended the transducer cable to 30 meters or longer.


#7

Eric that’s just being downright mean :heart_eyes: Who wouldn’t wont one?

But back in the real world yep it would be great but some of the scanning units out there might be better suited on the smaller observation class unit (PS the Starfish units in your link are made by tritech (the unit on the deeptrekker unit) so an off the shelf solution with only some integration small?? to get it onto OpenROV may be possible)
http://www.tritech.co.uk/product/small-rov-mechanical-sector-scanning-sonar-tritech-micron

And now a couple of consumer level providers are getting into the market
http://www.lowrance.com/en-US/Products/Sonar/SpotlightScan-Sonar-en-us.aspx


there may be the possibility of a hack (or even integration with Jim’s work) to get this form of technology down to a more affordable system

A couple of people I know have been using 100m cables on these hybrid systems and finding new shipwrecks - If you do go this route do everything you can to take the wobble out of the fish (a heavy fish / a long and lean balance fish/ depressors and 2 part tow systems) to get the best possible results (alternatively I’ve got a couple of Klein 595 I can sell with 100m cables if your getting serious)


#8

Mounting a side scanning sonar on a mini ROV probably won’t net you the kind of information you’re looking for. The problem is that in order to print a recognizable image, side scanning sonar needs accurate position data. Without that, all you’ll see is jiberish on the screen.

The Micron sector scanning sonar is a different bird all together and isn’t cheap. You’re looking at roughly $10-12K for one. Imaginex used to make a cheaper model but I’m not sure if they still do.

The cheapest sonar solution I’ve found is the Humminbird 360 scan with an appropriate sonar display. Total cost is around $2300USD. Unlike the Lawrence unit, the Humminbird 360 uses a servo motor to automatically scan sectors or an entire 360 degree circle, much like a Blueview Sonar ( http://www.blueview.com/ ). Mounting it on a ROV wouldn’t be easy, but a better option might be to lower it to just above the ocean floor as explained here

http://forums.sideimagingsoft.com/index.php?topic=8029.msg48843#msg48843

And track your ROV’s movements from a fixed sonar position.


#9

Just took another look at the Lowrance Spotlight Scan unit. I’m not sure how deep the transducer is rated for, but that might be an option if all you want is an imaging sonar with “look ahead” capabilities. Looks like the transducer connects using CAT5 cable so shouldn’t be too hard to extend.

EDIT: Nope. Lowrance Spotlight Scan won’t work if mounted to an ROV. It requires input from a manually operated heading sensor slaved to the sonar transducer. If the transducer (and heading sensor) aren’t moved, nothing will appear on the sonar display.

One other option worth considering might be to use “Down Scanning Sonar” which both Lowrance and Humminbird offer. This sonar takes a vertical slice of the area ahead, below and behind. In its normal orientation it might offer a look at what the bottom beneath the ROV looks like. Rotated 90 degrees, it may offer a form of “look ahead” sonar. Might be worth experimenting with.


#10

This maybe an option http://store12459.americommerce.com/store/p/26-SP100-T-POD.aspx
while it would not be connected to the ROV it could be deployed prior to investigate the area


#11

Hi Stretch

Agree with what you’re saying but you could also look at the data being sent via the heading sensor (most likely a glorified compass on the Lowrance unit - just a guess) and see if it can be simulated by the ROV’s IMU not married to any unit just giving options

Hi James
Yep the “cheap and dirty” sounders are interesting and in principle any sounder can be turned sideways to provide a scan of the bottom (either side scan or forward looking or if mounted and rotationg radar like) rather than just the depth (just need to be able to give it a fixed range rather than an auto range similar to the old Burton units http://www.burtonelectronics.com/) and which is also one of the reasons why the work @Jim_Trezzo is doing is so interesting

Not trying to give it even more complexity but also the consumer multibeams that Garmin (stuff all real detail about the real specs yet eg number of beams beam angles etc) would also work in concept on a small ROV
http://sites.garmin.com/en-US/panoptix/

Sorry @Tom_Vidar_Salangli hope we are not hijacking your thread

Scott


#12

Hi everyone

No problem. It is great to follow this discussion.
All info is good info :wink:

Tom-Vidar


#13

The heading sensor is even lower tech than you think. Looks like it might just be a lever connected to a potentiometer.

That Garmin Panoptix looks like it might be the solution we’re looking for. The key is that it doesn’t require the transducer to be moving. The “RealVu 3D Forward” display would be very useful on an ROV!

Thanks for the tip!