The Investigations of Imaging for Midwater Autonomous Platforms (i2MAP) vehicle is an AUV for running video transects in the midwater which historically were done using ROVs. The advantages of this approach are the reduced effort to run the transects since the AUV can do these tasks autonomously while the ROV requires constant control by trained personnel. Additionally, it is simpler and less expensive to run transects at night, outside of working hours for operators and scientists. Another benefit was the reduced noise level of an AUV that is propelled by one low-power electric motor versus an ROV which has a slew of loud hydraulic systems to move through the water. The higher speed of the AUV also allows to catch animals in the video frames which are fast enough to escape the ROV.

In 2018, the i2MAP vehicle was upgraded to also collect bio-acoustic data using two sets of transducers, one set looking forward and one looking downward. Combining the camera and acoustics allowed researching how animals react to the lights and noise of the AUV since the acoustics have a significantly longer range than the camera can capture.

Additional Information

Vehicle Specifications

Dorado-class AUV, flooded fairing design with electronics, payload and batteries in sealed glass-spheres or separate metal pressure housings.

Length: 19.5 ft
Mass: 1350 lbs (Mass at recovery with entrained water: xxxx lbs)
Weight in water: -4 lbs (4 lbs buoyant)
Propulsion and control: single propeller with duct on 2-axis gimbal, allowing for rudder and elevator function, oil compensated
Batteries: 14.5 kWh LiIon batteries in 3 glass spheres
Navigation: RDI Workhorse 1200kHz in water track mode and VectorNav VN100 MEMS compass
Acoustic Comms: Sonardyne AvTrak 6 tracking beacon with SMS feature
Camera: 2k Video camera systems in underwater housing with aspherical dome
Lights: 4x DSP&L lights with up to 9000 lm each
Bioacoustics: Downward and forward looking acoustic transducers (200 and 333 kHz)
Water Sensors: Seabird Conductivity, Temperature and Oxygen sensor as well as transmissometer

i2MAP Research

MBARI has been running video transects in the midwater out in Monterey Bay for the last 25 years. These efforts have historically involved ROVs that have been manually driven to a particular depth and through the transects. This required a whole day of operations on a large ship with a work-class ROV to get just a few transects lines covered. In 2014 the i2MAP project was started to move task of the recording of these video transects to an AUV. At that point, MBARI had been deploying deep-water AUVs for at least 15 years so a new nose payload with a high resolution camera and a solid-state recorder was built to be tested on an existing AUV.

The advantage of using an AUV for running video transects is not just limited to the reduced work effort. Since after deployment the vehicle operates without supervision for around 24 hours, it can run many more transects that would be possible in a typical day of ROV operations, including transects all the way through the night.

The i2MAP transects start at 25m and stretch all the way to 1000m. The maximum depth the vehicle can operate in is 1500m.

In 2018 the i2MAP vehicle got updated with an additional sensor suite as part of MBARIs interest in bioacoustic research, which uses sonars to detect and even identify biology in the water column using their acoustic signature. Now the i2MAP vehicle has a set of forward and downward looking sonars that work around 200 kHz and 333 kHz.

Combining these instruments with the camera-equipped vehicle allowed to see the influence the vehicle and especially the lights have on the animals around the vehicle. The acoustic system has a much larger range than what can be seen in the camera pictures which allows the study of avoidance and attraction behavior of the creatures. Furthermore, the vehicle is repeating transects without the lights and camera on at all, which can tell the researchers something about if the animals react to the vehicle based on noise or if it is just the super-bright lights.