Integrable ultra-compact, high-resolution, real-time MEMS LADAR for the individual soldier

Abstract

Laser radar (LADAR) has many advantages over other methods of target detection and analysis, both in combat and commercial applications. Because it uses a shorter wavelength than microwave radar and has significantly greater angular resolution, it is capable of a greater degree of accuracy and more precise target resolution to a level that allows for high-resolution image acquisition. The development of a next generation LADAR unit that is lightweight, ultra-compact, portable, and power-efficient real-time 3D LADAR unit would be a significant advance with many potential military and civilian applications. This paper describes a novel LADAR device that would be small, compact, field practical, eye safe, and integrable into a soldier's helmet. This would be achieved by using a 2-axis MEMS (micro-electro-mechanical system) scanner with an optical system that will extend the field of view (FOV). This next generation time-of-flight (TOF) LADAR design utilizes a novel angle amplification mechanism that uses a pre-compensating positive lens and a subsequent negative lens to overcome the small scanning range of MEMS mirrors where scan angles as small as 6° can be increased to over 40°. Also, with conventional digital zoom, a portion of an image is used to create a larger but much lower resolution image, while the LADAR zoom technology discussed in this paper will have a tighter field of view for a high-resolution zoom image. Other innovation is a relatively inexpensive and compact laser driver that can generate subnanosecond pulses of varying repetition frequency. Our analyses demonstrate that this portable LADAR device would work in close proximities as well as distances over 100 meters, could have a range resolution of less than a centimeter and a FOV greater than 40°, and be able to display 320×240 pixel real-time images at a frame rate of 15. Such a LADAR unit could be enhanced to also record and transmit range, intensity, and GPS/vector data to a remote computer. By using the same soldier for capturing LADAR images and data from multiple locations or multiple soldiers, a computer program could analyze and integrate the data so as to build a 3D survey of the combat field with in-depth target information. In this potential scenario even occluded (camouflaged) targets could be revealed and identified with appropriate signal processing. Also, as the intensity (amplitude) and range (time interval) data are being quickly processed, graphically enhanced 3D images could he transmitted hack to the soldiers in the field.