We’ve bought a BlueBoat to test out building a survey vessel for construction projects.
Right now we just use a single beam echo sounder connected to a data collector to get a rough cut/fill for construction purposes. We’re just doing that from an open boat.
I’d like to get a little more accuracy with our data. We’ll need to get good sound velocity data to do that.
Anyone here using some sort of profiler on a blueboat or USV? What options are there for getting accurate data?
Hi @dpittman -
What depths are you working in, and what is the beam angle of your single beam? A sound speed profile is typically more important for multibeam data correction, or if a large thermocline exists in the water column you’re surveying through…
There has been some discussion of a winch, and Blue Robotics has an early prototype that has been tested.a few times, but there’s not yet any good solutions for conducting casts with a CTD or SV sensor…
He @tony-white. Thanks for taking the time to respond.
This is for mainly harbour construction projects. Depths range from 1m - 20m. Using a single beam AirMar SS510 200kHz echosounder. Beam is 9 degrees.
After some thought about the issue, perhaps the right solution here is to use water temperature and salinity to estimate the sound velocity.
Accuracy is important, but so is ease of use and functionality. There’s no point in having a super accurate system that nobody in the field understands how to use. No point in making it more complicated than it needs to be.
Most of the work we do that requires hydrographic surveying is going to have tolerances of +/- 100 to 200mm. Some types of work need more accuracy, but for construction purposes if we had some level of confidence that our data was within 150mm that would be fine.
If we were to put a temperature sensor on the bottom of the boat like the BlueRobotics one, and then mount a salinity sensor as well, we could record that data and use it to estimate the velocity of sound.
From what I understand that should get us within an acceptable level of accuracy.
This sound reasonable?
Hi @dpittman -
That certainly does seem reasonable! I believe the Cerulean Surveyor Multibeam will eventually support this with an onboard temperature sensor - the salinity typically varies considerably less, at least in the open ocean.
Your AirMar may provide means to enter the speed of sound int he medium, as does PingViewer, however I don’t believe a profile of sound speed is usable in PingViewer or SonarView.