Australian Navy Experiments with Mine Hunting Drones

23 Agustus 2020

Defence personnel recovering a uninhabited underwater vehicle (photos : MarineLink)

Mine-hunting robots get smart

Whether providing a bird’s eye view of the battlefield or searching the ocean for mines, it’s well known robotic systems are ideally suited to dull, dirty and dangerous jobs.

The operator of an uninhabited aerial vehicle can remotely control a drone using radio or satellite communications. 

However, communicating through water is more difficult, driving a need to incorporate a greater degree of autonomy in uninhabited underwater vehicles (UUVs).

Defence is experimenting with deploying UUVs to undertake mine countermeasures operations. Hunting for naval mines is obviously dangerous work, and the task of interpreting vast amounts of sonar imagery is monotonous and tiring for humans.

There are a range of technological solutions that can be used to seek out mines in the ocean, but Navy primarily relies on sonar.

As it moves through the water, a sonar device sends out pulses of sound and listen for echoes to bounce back. From this data, sonar produces acoustically generated images that should reveal any mines that might be lurking on the seabed.

Defence scientist Dr Phil Chapple has developed software that processes sonar imagery automatically detecting any objects of interest.

Known as SonarDetect, the software can be used to carry out post-mission analysis, including processing data all at once after it has been collected. But the software can also work in real time as a sonar-equipped UUV moves around the ocean.

“These robotic vehicles are normally programmed to follow certain fixed paths,” Dr Chapple said. 

“They will cover an area of the seabed and go backwards and forwards to cover an area and provide images of all of the seabed.

“Those images are sent back for analysis later by the naval operator but we are trying to make that more autonomous so vehicles can respond immediately if they see something of interest.

“To do that, you have to get a good detection rate and a low false-alarm rate and that’s the challenge. If they respond to every rock on the seabed, or every fish, you’ll never get anywhere.”

Once it detects something, the vehicle might pause its predetermined search pattern to take a closer look at the object, capturing images from different angles to help identification.

The UUV might return to the surface and alert the operator of what it has found, and to await instructions.

“The software is replicating what a human would do, but a trained operator could generally do better,” Dr Chapple said. 

“Humans have an ability to recognise certain objects and they know what is likely to be in certain places, so there’s a whole lot of contextual understanding that a human has which is difficult to program.”

Dr Chapple said human operators were prone to getting tired and could be distracted by other tasks.

“They start off being quite good at processing data but after a while they get fatigued and they miss things, whereas the software will just keep going,” he said.

“The software alerts the human to look at certain objects and make a decision, so it’s still a teaming between what the both can do.”

Dr Chapple said robotic vehicles were not intended to replace naval personnel but envisaged UUVs being deployed as part of a team to enhance Navy’s mine countermeasures capability.

“We’re trying to build in autonomy because it will enhance the ability of the naval operator to conduct a mission,” he said. 

“If they can send out robotic vehicles, trust what they’re going to do and rely on them to come back safely then that will be a force multiplier going forward.”

(Aus DoD)