Oculus M750d multibeam sonar

Overview

Introduction
Installing the multibeam
How to use the multibeam
Troubleshooting
Example videos
User manual
Specifications

1. Introduction

The Oculus M-Series offers single and dual-frequency models, unparalleled image quality in a compact, rugged form factor, and a depth rating of 500 m. The Oculus M750d multibeam sonar from Blueprint Subsea is an excellent sensor helping the operator navigate, identify objects and increase situational awareness under the surface.

The sensor is handy when diving in murky waters, for search and rescue missions, or for jobs where you cannot rely on a camera solely to locate your target of interest.

2. How to install

All guest ports can be used, although we recommend using GP1 as this will make the cable routing easier.

WARNING: Always power off the ROV before connecting or disconnecting external equipment to prevent damage, also when using the Quick Connect.

The M750d in the removable Blueye multibeam skid. Attach the skid in mount in the front and the back of the drone.

Slide the drone onto the hook mount in front then attach the screw in the back.

Slide the drone into the front mounting bracket, make sure the cables are not pinched.

Attach the back mount by inserting an M5x12 screw and tightening it "hand tight".

Connect the cable to GP1 and attach the cable with a zip tie to the black plastic mount.

Make sure to route the cable in in the grooves of the aluminium plate to the zip tie mount and back again. Adding a zip tie to the left thruster connector makes it easier to get the cable to stay in place.

3. How to use the multibeam

Make sure to switch on the surface unit before powering on the drone, which powers the multibeam.

3.1 Powering on the system

Powering the surface unit before the drone when using the M750d multibeam is important. Otherwise, the multibeam might not get an IP address, and the software won't be able to discover it. Once the surface unit and drone are fully powered on, connect your Blueye app, then connect a Windows computer or tablet running the Oculus ViewPoint software to the Blueye WiFi.

If you accidentally power on the drone first, reboot the drone, and the multibeam should appear in the ViewPoint software.

3.2 Connect to the ViewPoint software

Using the Oculus M750d with a Blueye X3 is very simple. The only requirements are:

A Windows computer connected to the Surface Unit Wi-Fi.
Download the latest ViewPoint software from Blueprint.

Once connected to the Wi-Fi and launching the program, click on the top left icon, as shown in the picture below, then press the small window that appears with the multibeam info.

Open the Oculus ViewPoint software and press the top left corner on the sonar icon.

Once the sonar icon is clicked, you should be able to see the details of your M750d. Click on the M750d picture to activate the sonar view.

Once connected, press the settings icon (4) in the bottom left corner and make sure the bandwidth limit is set to all the way down to Min.

Sonar view interface. 1: Range settings, 2: Gain control, 3: Frequency, 4: Settings

Always make sure Min. Bandwidth is set in the settings before diving.

Always make sure Bandwith is set to Min. in the settings before diving.

3.3 Using the sonar

The sonar is also integrated with the Blueye system enabling the operator to tilt the vertical sonar angle directly from the Blueye app. You can tilt the multibeam with the volume buttons while in the app. While diving with the app you will also be able to see a sonar tilt icon in the top status bar, showing you the current angle of the multibeam.

tilting the sonar inside the Blueye App menu while diving.

A good rule of thumb when searching the seabed is to use a 10-15 degrees downward facing angle and maintain an altitude above the seabed of 10% of the selected range.

Blueye-Oculus_sonar_illustrations-seabed_mapping-2_2x.png — The altitude should be adjusted according to the range for optimum seabed coverage.

Frequency and range

Use the low-frequency mode when searching for a target, and once located, switch over to high-frequency mode to get a more detailed view of the target. Remember that high-frequency mode will reduce the viewing angle from 130 to 80 degrees.

The range affects the update rate of the image. The longer the range, the slower the update rate, and increased battery usage, so use it wisely.

Gain control works like a volume controller. If details are hard to see, the gain increases the "volume" of the signal, and details will be clearer. However, this can also saturate the image, making some details disappear.

Low gain vs. high gain. Notice the details get lost if the gain is too high.

3.4 Limitations

The M750d is a heavy and powerful payload, so the drone will automatically limit the maximum boost to 90% to maintain stability. In terms of power, the maximum boost will slowly decrease as the battery percentage goes down, and when the drone battery gets under 20%, the boost will be disabled to maintain the sonar's power. If the sonar stops working during a dive, it is most likely due to the low drone battery voltage.

4. Troubleshooting

The multibeam is not discovered by the ViewPoint software

The multibeam gets an automatically assigned IP address. If the drone were started long before the surface unit, the multibeam would not get a valid IP address. Try to restart the drone while keeping the surface unit powered. Remember to always turn on your surface unit before the multibeam.

This known bug in the Oculus firmware has been fixed. For instructions on how to update the Oculus firmware, please see this article.

The multibeam stopped working during a dive

If the multibeam stops working during a dive, it is likely due to the drone battery being too low. If the drone has external lights or other power-hungry accessories, it is recommended not to run them at 100% brightness. To re-establish the connection, the drone needs to be restarted.

The drone won't boost

When a M750d is connected, the boost function is limited during the dive to prevent voltage drops and maintain the drone's stability in the water. Below 20% battery, the boosting functionality is disabled.

5. Example videos

The following videos are demonstrations of the 720im attached to a Blueye X3 drone.

6. User manual

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7. Specifications

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