Anybody having success with Cerulean Surveyor 240-16?

Third Party Products Sonar and Acoustics
21

Thanks Larry, thats a good link. I see in that data set depths down to ~85m, do you know if the MBES has been used in much deeper water?

22

We rate it at 100m, I’ve got a couple files where it’s looking fine at 150m+. Not at my computer at the moment to access but LMK if you’d like to see them.

23

Yeah that would be great if you had the opportunity to share.

Do you know of any being use in Australia? Doesn’t looks like any dealers in Western Australia.

Would be great to see and test on in person.

24

I recently used the Cerulean Surveyor 240-16 to capture data using HydroMagic, you need to purchase the MBES addon for it to work as a multibeam. Since the Surveyor has an onboard IMU, is the data that is captured already corrected for pitch/roll? Would adding an additional IMU to the system cause it to double correct the data?

25

Hi everyone,

I am preparing for an upcoming bathymetric survey using the Cerulean Surveyor 240-16 mounted on a BlueBoat, and I have a few questions regarding the calibration and patch test workflow.

Calibration: Regarding the onboard IMU calibration, should it be performed with the Surveyor 240-16 mounted on the fully equipped BlueBoat (with batteries powered on) to properly compensate for magnetic interferences? Or is an off-board calibration recommended?

Patch Test: While I understand a patch test is necessary to ensure data accuracy, it is not explicitly detailed in the documentation for this setup. Could you confirm if a patch test is mandatory? Furthermore, if I obtain the patch test angular offsets (roll, pitch, yaw), where should these be entered in the workflow? Do they go directly into SonarView, or are they exclusively handled in the post-processing software (e.g., BeamworX)?

Feedback: Has anyone here noticed systematic errors in their data ? Particularly with roll and pitch—that could be attributed to the absence of a proper patch test or specific installation challenges?

Any guidance on the recommended workflow for this integration would be greatly appreciated. Thanks in advance for your help!

Corentin

26

Hi @Eloi -

Happy to help. In answer to your questions -

Yes, calibrate with the system mounted and sitting on a level surface, on land.

SonarView does not support patch test functionality, so anything you do for that process with third party software like BeamWorX will have to be handled from the data that is collected by default. Exporting to a CSV may be necessary, I’m not sure what format that software ingests best!

I’ve not noticed any issues with roll and pitch compensation in the data! With that said, you’ll get better data in calm waters vs. rough! Have you reviewed the datasets at sonarview.io ? There are 2x from the Surveyor 240…

What depth range is your upcoming survey targeting?

27

Thank you for your response.

Is it common practice to perform a patch test in post-processing (e.g., using BeamWorX) with the Surveyor 240-16, or do you consider this sonar a ‘plug-and-play’ solution that (most in the time) doesn’t require one? It obviously depends of the targeting precision and the water depth.

My upcoming survey is in a lake, targeting a depth range of 1 to 10 meters.

Thanks in advance for your help!

Corentin

28

Hi @Eloi -

I’ve never completed a patch test, nor do I have access to expensive software like BeamWorx - I typically export point-cloud data to CloudCompare or ReefMaster, and from there export to QGIS.

Maybe @ljlukis has some experience or thoughts on how necessary such a procedure is.

29

It is common practice in hydrography in general to do a patch test and to do so you’ll need professional hydrographic s/w like BeamworX. It is very much less common with the low cost Surveyor solution. We do have some customers who consider 20 cm a big error, and we have others that say “Surveyor just saved our town $20k because we did a quick survey and realized that we don’t need to dredge the harbor entry this year!”

30

Hi @ljlukis ,

We do understand the intrinsic limitations of the low cost Surveyor 240-16. However we want to quantitatively evaluate its performance, to know when it is fit for purpose and when we need to go back to a more accurate solution, hence our whish to put it through as much of a standard workflow as possible.

  1. Could you please clarify how you use the “9-axis IMU” you mention here Overview | Surveyor 240-16 | Cerulean Sonar Docs? Is this just for pitch and roll or do you also use a heading from this? If not using the heading, why going to the expense of a “9-axis IMU” instead of using just a “6-axis IMU”?
  2. In sonarview, what do you mean by “calibrate pitch & roll”. Is this just finding the levelled zero (offsets) or a “real” calibration?
  3. If we do a full patch test I guess the initial “calibrate pitch & roll” is overridden by the patch test?
  4. If we do not do a full patch test, we should probably perform both a “calibrate pitch & roll” in sonarview and a misalignment-angle calculation between the X-axis of the Surveyor and the X-axis of the external heading (magnetic compass from blueboat or GNSS compass). I We often do that misalignment-angle calculation between ADCP and external heading, but I am not sure how you would do that in bathymetry. Do you have a simple procedure or is patch-test the only real way for this.
  5. SonarView exports XYZ data but also raw data. Can you confirm it is, in theory, possible to perform a patch test using .svlog data
  6. What do you think of SPH Engineering work here : https://www.youtube.com/watch?v=LcAvbU7HRQA. The workflow looks usual, however what do you make of the pitch “mounting angle” of 3.4°? Is this:
    • typical angular offsets between IMU and Sonar ?
    • coming from a pitch & roll calibration in sonarview which may not have been done correctly?
    • coming from their specific application where Surveyor is held by a UAV at the end of foldable arm… I am not sure if they use external pitch and roll but I think they use an external heading.

Cheers

Eloi

31

Good questions all, and your point about understanding “fit for purpose” is well taken.

  1. Although there is a magnetometer on board, it is ignored. Thus the device IMU data is used for pitch and roll angle only. Position and heading must be supplied from external sources.
  2. Calibration comprises zero offset only for Surveyor. Surveyor is expected to be used in that orientation with modest pitch and roll variations.
  3. I’m not exactly sure how BeamworX applies their patch-test-derived mounting offsets, or if the IMU pitch and roll are used in that scenario.
  4. In SonarView it is assumed that the Surveyor is mounted in alignment with the heading provided.
  5. BeamworX handles raw (svlog) data with a live connection and/or in post processing. You wouldn’t be able to do a patch test with the xyz exported data.
  6. Looks like that’s the BeamworX work flow for executing the patch test. In SonarView there is no need (or possibility) to enter pitch or roll mount offsets because these are provided by the device anyway. You can of course enter x,y,z offsets relative to the position sensor.

One thing to keep in mind also is that Surveyor only has about an 80 degree swath width, and is generally used in relatively shallow water. This diminishes the affect of pitch and roll errors on point accuracy as compared to a higher end multibeam with a much wider swath width.

Cheers,

Larry

32

Hi @ljlukis

Many thanks for your detailed reply.

@tony-white and @Eloi (Corentin), Tony mentionned “Yes, calibrate with the system mounted and sitting on a level surface, on land.” however Quick Start | Surveyor 240-16 | Cerulean Sonar Docs states that “Make the necessary connections for power and Ethernet. Don’t mount the sonar to your vessel quite yet, we need to calibrate the accelerometers on a level surface first.” I guess the documentation makes sense in that the pitch and roll are zeroed relatively to the instrument (and therefore sonar) axes.

Eloi

33

Hi @ljlukis ,

In Quick Start | Surveyor 240-16 | Cerulean Sonar Docs it also says :

    1. Enable “Waterfall” on the right side and start pinging. Some points should appear in the 3D viewer.
    1. If all is well, you are ready to do your first in-water test. Refer to the SonarView docs for general information on how to use SonarView.

Does that mean the Surveyor can ping in air without damage? For just a few seconds or indefinitely?

34

The manual is more explicit and correct. It’s the sonar device itself that has to be on the level surface.

You can ping without damage in air. Don’t do it indefinitely, but 5 minutes should be fine.