Compact lidars able to scan underwater terrain

Bathymetric lidars are devices that use powerful lasers to scan beneath the water's surface, which are commonly used to map coastal waters. These systems are large and heavy, weighing roughly 272kg, and they require costly, piloted aircraft to carry them. Now, a team at the Georgia Tech Research Institute (GTRI) has come up with a way to develop bathymetric lidars that are much smaller and more efficient than the full-size systems presently available.

The novel technology, developed under the Active Electro-Optical Intelligence, Surveillance and Reconnaissance (AEO-ISR) project, would let modest-sized unmanned aerial vehicles (UAVs) carry bathymetric lidars, lowering costs substantially. And, unlike existing systems, AEO-ISR technology is geared to gather and transmit data in real time, allowing it to produce high-resolution 3D undersea imagery with greater speed, accuracy and usability.

The GTRI lightweight lidar prototype system uses a special green laser that penetrates water to considerable depths. GTRI researchers use it to study the best methods for producing accurate images of objects on the pool floor.

These advanced capabilities could support a range of military uses such as anti-mine and anti-submarine intelligence and nautical charting, as well as civilian mapping tasks. In addition, GTRI's lidar could probe forested areas to detect objects under thick canopies.

"Lidar has completely revolutionised the way that ISR is done in the military, and also the way that precision mapping is done in the commercial world," said Grady Tuell, a principal research scientist who is leading the work. "GTRI has extensive experience in atmospheric lidar going back 30 years, and we're now bringing that knowledge to bear on a growing need for small, real-time bathymetric lidar systems."

Tuell and his team have developed a GTRI lightweight lidar, a prototype that has successfully demonstrated AEO-ISR techniques in the laboratory. The team has also completed a design for a deployable mid-size bathymetric device that is less than half the size and weight of current systems and needs half the electric power.

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