Cerulean Support Page

Frequent Asked Questions

ROV Locator:

Can I purchase the Receiver and transmitter separately?

Yes, you can purchase the Transmitter and Receiver separately. Go and visit or Online-Store and select either of these two product items.

How can I mount the ROV locator unto the vessel?

You can purchase the Cerulean ROV mounting bracket, or if you want to construct the part, you can download the sheet metal bracket drawing here.

Where can I find the ROV Locator Manual?

You can download the ROV Locator manual here.

Can an external Depth/Pressure sensor be used to aid positioning?

Yes, but the computations need to be done separately. Use the ROVL’s slant range and the external depth sensor’s depth estimate to compute the horizontal range. See also the math examples in the user manual.

Can we use the Receiver in responder mode? (not 1s ping, but to reply only when an electrical signal is sent via a tether)

No. The reason has to do with automatic gain control, which is needed to improve angular accuracy.

Is it possible to input a Sound velocity profile or an average sound velocity to the application?

The Receiver can be given an average sound speed, which it will store in non-volatile memory. The factory-default default speed of sound is 1484 m/s.

How often do I need to recalibrate to achieve accuracy?

For slant range accuracy, as noted in the user manual, we recommend calibrating for clock drift when initially putting the system into service and about every three months after that. If this is done, we expect a typical slant range accuracy drift of under 2m/hour. If you know the average speed of sound in your water body, you can get a slight improvement in accuracy by loading that value into the Receiver.

Does the application include an external navigation screen? Is it possible to input a georeferenced dwg/dxf drawing?

The ROVL application is not intended to be a workhorse user interface or operating tool. It is meant as a basic tool to test your system components and get familiar with them. For everyday system operation, we recommend using our QGroundControl plug-in found on this link.

Does the Rov Locator compensate for movements (roll and pitch) of the vessel?

Yes, the ROVL IMU data is used to compensate for the vessel’s roll and pitch movement.

Can the Receiver be installed in the ROV instead of the surface vessel?

Perhaps, but putting the pinger on the ROV is preferred for maximum range. The reason for this is that ROV thrusters tend to be electrically noisy, so if the USBL receive head is on the ROV, it has less sensitivity due to the increased electrical noise environment.

What is Cerulean Sonar warranty policy?

Please refer to this link  for our warranty policy.

What is Cerulean Sonar refund policy?

Please refer to this link  for our refund policy.

Can I run the Companion and ROVL Windows app at the same time?

The main ROVL software and the Companion App can not be running at the same time.

How is medium accuracy defined?

For a distance of 100 meters, position accuracy should be planned on +/- 2% of distance.

Can I use QGroundControl

Testing has been completed using QGroundControl to communicate with our ROVL product. The Cerulean team has created a sample utility (Cerulean Companion) that enables the ROV's location to be displayed in the map view of QGroundControl. The user can then create a waypoint in QGroundControl and drive to it.

The Cerulean Companion is an open-source program, which allows customers with Python knowledge to customize/add functionality to match their requirements.

The following link ( https://ceruleansonar.github.io/Cerulean-Companion/) provides the steps to getting the ROVL to work with QGroundControl. These instructions currently support the ROVL Rx on the topside connected to a laptop and the ROVL Tx on the ROV.

ROV Locator appears to be jumping to arbitrary locations and directions under QGroundControl?

Most customers connect power and ground to the ROVL Tx unit and leave the serial data lines floating. Some ROVs are noisier than others, and in the noisy units, the ROVL TX picks up noise on the serial receive line and interprets it as commands. After enough time, the ROVL Tx gets a pattern it interprets as a request to reboot, and it does so, which causes loss of distance sync.


Connect the serial receive wire (green wire) in the ROVL TX power/data cable to power ground (connect the green wire to the same place you connected the black wire). Leave the serial send wire (the white wire) unconnected (i.e., floating).

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