MEMS-scanned ladar sensor for small ground robots

The Army Research Laboratory (ARL) is researching a short-range ladar imager for small unmanned ground vehicles for navigation, obstacle/collision avoidance, and target detection and identification. To date, commercial ladars for this application have been flawed by one or more factors including, low pixelization, insufficient range or range resolution, image artifacts, no daylight operation, large size, high power consumption, and high cost. In the prior year we conceived a scanned ladar design based on a newly developed but commercial MEMS mirror and a pulsed Erbium fiber laser. We initiated construction, and performed in-lab tests that validated the basic ladar architecture. This year we improved the transmitter and receiver modules and successfully tested a new low-cost and compact Erbium laser candidate. We further developed the existing software to allow adjustment of operating parameters on-the-fly and display of the imaged data in real-time. For our most significant achievement we mounted the ladar on an iRobot PackBot and wrote software to integrate PackBot and ladar control signals and ladar imagery on the PackBot's computer network. We recently remotely drove the PackBot over an inlab obstacle course while displaying the ladar data real-time over a wireless link. The ladar has a 5-6 Hz frame rate, an image size of 256 (h) x 128 (v) pixels, a 60 degrees x 30 degrees field of regard, 20 m range, eyesafe operation, and 40 cm range resolution (with provisions for super-resolution or accuracy). This paper will describe the ladar design and update progress in its development and performance.