Bathymetric Lidar for UAS

The following is a summary of an article written by Ben Coxworth of Gizmag.com:

Bathymetric Lidar for UAS

A team of researchers at Georgia Tech University, led by Dr. Grady Tuell, are in the process of developing a bathymetric lidar system which may be small enough to be carried by an unmanned aerial system (UAS). Lidar, which stands for Light Detection and Ranging, utilizes lasers to emit pulsating beams of light which reflect off of the surface below. The lidar receiving unit then monitors the beam’s rate-of-return to accurately determine the distance from the sensor to the surface below.  By combining millions of these data points, lidar systems are able to produce precise 3D terrain models.

Bathymetric lidar systems transmit two laser beams. One beam in the infrared and another in the higher frequency green spectrum which is capable penetrating columns of water to produce 3D imagery of the ocean floor. Typical bathymetric systems are bulky and weigh in the range of 600 pounds, therefore limiting their use to manned aircraft which have the ability to handle a payload of that size. The Georgia Tech team has developed a CAD model of their system which would be about half the size of current systems. The group hopes to develop an even smaller device which could perhaps be deployed on small UAS platforms. 

The Georgia Tech system also offers significant advancements in bathymetric lidar processing speeds. Their system utilizes a computing technique called “total propagated uncertainty” (TPU) and is capable of processing up to 37 million data points per second. Comparatively, some current systems are only capable of processing approximately one thousand points per second.

As of December 2014, the system was deployed on a gantry apparatus and was being tested over a pool for further evaluation. Possible applications for the system include seaborne mine and submarine detection, under water mapping, and land management applications- as the sensor is also capable of penetrating foliage to detect objects beneath the forest canopy.

  

The continued miniaturization of sensor technologies, both exteroceptive and proprioceptive, lends well to future implementation of UAS and will ultimately lead to increased efficiencies and cost reductions across a wide array of industries.  

Reference:

Coxworth, B. (2014, December 8).  UAVs Could Map The Bottom of the Sea, Using New Lidar Tech. Retrieved from http://www.gizmag.com/uav-bathymetric-lidar/35113/

NOAA (2014). Lidar. Retrieved from http://www.nauticalcharts.noaa.gov/hsd/lidar.html