SONAR hydrophones, active, doppler, ADCP, ADP, DVL, Fan Beam




in several of the forums I've read posts about pingers and hydrophones that might be used for a variety of reasons, navigation, eaves dropping on whale karaoke, sonars, control, modems, etc.

I’m currently in the concept design phase for a simple wide band hydrophone, that will be light weight, low profile, and can be outboard of the ROV housing and independent of ROV power, electronics and/or the ROV communications.

As I progress through the gap analysis of this design, I'd love to read about the needs of OpenROV users (and others) as to how and/or why a pinger, hydrophone, or a fully integrated sonar will be helpful for fun & science.

Please reply with your story. What do you hope to achieve with a hydrophone or sonar on your openROV? Perhaps you have a need for a hydrophone by itself, to hear songs of marine mammals, or perhaps as an array as part of USBL or LBL network or as a DVL integrated with an IMU. For whale song observation, will it be helpful to integrate with a cell phone to record sound?

I've 12 years of sonar design experience for a major sonar manufacturer. We had fun designing, building, testing, integrating, supporting and sometimes flooding retiring tens of thousands of sonar systems. Many hundreds of these sonars were unique variations of Doppler Velocity Logs (DVL), Acoustic Doppler Current Profilers (ADCP), Acoustic Doppler Flow meters (ADFM) and Hydrographic multi-fan-beams integrated with a variety of other sensors. All of these systems cost tens of thousands of dollars. Perhaps they could cost far less.

Please, I welcome reading about what you'd like to do with your sonar or hydrophone! Perhaps we can design a simple, inexpensive open system that will meet your needs.

John Braman


Greetings John

Personally i would love to see opensource forward facing sonar and side scan sonar out there, there are several options for terrestrial robots however none are available at least on an opensource level for aquatic projects, Our area has multiple low visibility dive sites and would be great to be able to use the sonar for locating objects and obstical avoidince.




Dear Mr John,
My name is Ahmed Kotb and I'm a senior mechanical engineering student from Egypt. For our final year project, my friends and I decided to build an ROV that performs underwater inspection for internal cracks in metal pipelines and bridges or/and other form of underwater metal structures. I couldn't help but notice that you said that you have more than 12 years of experience in sonar design and that is why I'm writing this reply. We're having difficulties finding the correct sonar or whichever device that can be used for this mission and I wonder if you could help us with it if you may.
I know that my reply might be off the topic but I couldn't send you a message since you and me are not friends so please accept my apologies. I really hope you can help us whichever way you can.

best regards,

Ahmed Kotb.


Hi Ahmed,

you have an ambitious project! Please reach out to me by email or invite me as a friend we can discuss your needs over phone, it may be faster than attempting to write all of this here.

Does your ROV need sonar navigation capabilities? i.e. do you need a sonar that will help to guide and orient the ROV relative to the structure?


Do you intend to use the sonar to aid in the inspection of the structure directly? i.e. do you anticipate that using sonar, or a high frequency emitter coupled directly to the structure you will be able to characterize the quality of the structure?

Can you describe in more detail what you want to achieve with the sonar? Navigation and/or detection of internal cracks, or both?

Both of these tasks are very challenging. Can we limit the problem in some way to make baby steps?

thank you,

John Braman


Has anyone thought of using one of the “cast-able” fish finders as an altimeter? They’re relatively in expensive and all self contained.


Hi John, I am to interestted in this and actually researching this as my interest in hobby and also presently working as a software engineer in this area. My thought is to have somthing compatible where 2 or more underwater ROVs can play a search and hide type game with actual range predictions interfaces and such... I am searching for something that can be cheaply purchased and interfaced to the existing I/O slots for both passive/active sonars...


Hello john,

It is now more than à year that i search the solution to the following problem :

I wish to use the open rov to inspect underwater devices in waters with very few, and sometimes absolutely no visibility. Water chambers of hydro electric plants, water treatment plants, sewers, for instance.

In some cases, the camera can not be used, even at very short distance. I do think that sonar can be used to position the rov. But can it be used for the inspection itself ? What i call inspection is the equivalent of a visual check that a diver could do, without specific tools, if there was visibility ? Could a sonar produce images with a resolution of around 1 mm ? Structural analysis ( thickness measurement, welding quality, for instance) is not in the scope of my need. I am actualy searching a way to get detailed images in very troubled waters.

Do you think that could be possible ?

Thank you for your attention.



Hi Marc,

searching thru OpenROV on the word sonar I came across this:

5. Scanning Sonar: Although the Tritech Micron is vastly out of my range ($15,000), new less expensive technology is becoming available as used in the Lowrance Spotlightscan and Humminbird bow mounted AC 360 scanning sonars. Very useful for picking objects out of the seabed if we can somehow integrate this technology.

How far away (range) from the object did you want to achieve 1mm? Will the ROV be say < 1 meter from the object of interest?


Hi John,
Tank you very much for your answer. I looked at some videos on you tube about Lawrence Spotlightscan. Looks promising, but i am wondering what the result would be at short range. The sensor is pretty big, compared with the tritech micron. But as you said, price is a problem. The rov CAN be pretty close from the object, 1 m or 0.5 m.


what angular field of vision were you reasonably hoping to achieve?

Altitude (vertical):

Azimuth (horizontal):

How many views per second?

Do you have access to any older model ultrasound equipment for in womb baby monitoring?

If you wanted to do inspections, can you describe the ideal or novel approach, that might be used that wouldn't require such high resolution? Is there some anomaly, caused by a fault, in the material under inspection that can be sensed in some other way other than using sound imaging?


Is an american Lincoln penny about 19mm in diameter? The column's on the back of the penny are about 1mm apart... hmm...


Does anybody know how the Hummingbird 360 scans? I assume it is mechanical - not a sonar expert.

The smartphone connected sonars look pretty interesting. Perhaps we can find the transducer on alibaba. I see there are some off the shelf sonar range IC's. We could scale the data for water and create a basic x,y,z array for distance at first. I'm confident we can create the hardware for a hummingbird-like experience, although I have so clue about the data processing algorithm department.


1) I don't know about the size of an american Lincoln penny, but 1 mm is about 1/25 inch.

2) A field of vision of 90°, in the horizontal and vertical direction, is more than enough.

3) I didn't think of the number of view per second. I would say that if the conditions allow the ROV to remain steady, 1 view every 5 or even 10 seconds is perfect. The need could be higher in a stream, where real steady position of the ROV could be harder to achieve.

4) The inspections I deal with are most of the time performed visualy, after emptying the water chamber. The great advantage of an inspection by ROV is to avoid this process. If 5 mm resolution allows to find a solution, I would say this is acceptable. More could be a problem. The typical type of defects I would like to detect are cavitation damages on a water turbine (turbine being idle during inspection, of course), or lack of a welded joint on a pipe support for instance, in extremely turbid water.


Wondering if the smartphone sonar apps would work on a Droid tablet.


It is my understanding that they would. My thought was to have an android “virtual” computer running on the control laptop and a USB serial device server on the vehicle itself. This would also open up more USB slots for camera, manipulators etc.


I use a Samsung Droid tablet to monitor and control UAVs via 900-mHz telemetry uplink over a Bluetooth bridge. The reason behind asking if the apps would work in the Android environment was that I believe Android to be much more user and developer friendly that Apple iOS and the device in one of the pics (in the link to the Cabela's product page) appeared to be an iPhone.

I'd be interested to see a manipulator arm operate over USB. Seems like the power requirements could exceed USB specs. I have however seen cameras operated over USB using PWM (I think) for zoom and shutter controls. Even my large-frame Olympus DSLR will work over USB...and it will stream a live view as well. All of the functions of the camera are available using Olympus Studio software. Too bad they discontinued it. I have an older copy that still works really well.

Maybe my idea is a bit ambitious, but I'd like to see OROV capable of carrying a payload of water chem instruments and have them all transmit data over a tether cable simultaneously, much like a HydroLab Quanta or something similar, for real-time display and data logging. Something like that, coupled with a live video feed (already available) and a hydrophone feed would be a real asset to marine scientists.

If there were a way to bring the live video feed into this little gizmo then superimpose the water data over the AV, that would be REALLY cool.


Here's a way to connect 4 sensors to the Arduino via I2C


Would like to design a DVL sensor :blush:


Hi Tamergeorgy:
Pls T, reply with a few more details about the desired design? Do u or ur freinds enjoy electronics? If you could put a team together what skills do u have, or are you willing to acquire? If you can reply w more details about the design goals that’s a huge step. A Doppler Velocity Log can quickly become a complicated beast. Let’s take it little by little. Will the DVL use the bottom echo, or a return from the water? How often do we need to return a velocity measurement? What shall we use for determining the orientation? Compass? Or is this DVL held in a fixed position and surveying a conveyor belt? Pls tell me more about how the DVL will be used? Would it be possible to use an old school boat speedometer? (A little paddle wheel?)j


Not sure if this is a good thread to ask this, I may create a new one. But…

Along the lines of poor man’s sonar, I’ve decided to pick the Garmin Striker Plus 4cv fish finder.

For those of you familiar with side scan sonar, though this is not a side scan, it is an affordable chirp down ping that provides high detail line scan. Has anyone had experience with using a medium grade fish finder for bathymetry and archaeology work? I will be using this kit to look at the HMS Betsy cofferdam here in the York River. I have to figure out a way to tap into the data stream to build 3D contour map of the wrecks from the unit, but hay, that’s why I’m paid the big bucks. And by big bucks I mean no bucks since I don’t have to 2k to spend on a decent sidescan hummingbird or Raymarine unit.


In addition, I’ve been doing some poor man hydrophone work as well. Check out the Chesapeake SMART Bay ARC expedition page for links to some clips. More to come this weekend.