A wide angle bistatic scanning lidar for navigation

Abstract

Scanning LIDARs are widely used as 3D sensors for navigation due to their ability to provide 3D information of terrains and obstacles with a high degree of precision. The optics of conventional scanning LIDARs are generally monostatic, i.e. launch beam and return beam share the same optical path in scanning optics. As a consequence, LIDARs with monostatic optics suffer poor performance at short range (<5m) due to scattering from internal optics and insufficient dynamic range of a LIDAR receiver to cover both short range and long range (1km) . This drawback is undesirable for rover navigation since it is critical for low profile rovers to see well at short range. It is also an issue for LIDARs used in applications involving aerosol penetration since the scattering from nearby aerosol particles can disable LIDARs at short range. In many cases, multiple 3D sensors have to be used for navigation. To overcome these limitations, Neptec has previously developed a scanning LIDAR (called TriDAR) with specially designed triangulation optics that is capable of high speed scanning. In this paper, the reported WABS (Wide Angle Bistatic Scanning) LIDAR has demonstrated a few major advances over the TriDAR design. While it retains the benefit of bistatic optics as seen from TriDAR, in which launch beam path and return beam path are separated in space, it significantly improves performance in term of field-of-view, receiving optical aperture and sensor size. The WABS LIDAR design was prototyped under a contract with the Canadian Space Agency. The LIDAR prototype was used as the 3D sensor for the navigation system on a lunar rover prototype. It demonstrated good performance of FOV (45°×60°) and minimum range spec (1.5m); both are critical for rover navigation and hazard avoidance. The paper discusses design concept and objective of the WABS LIDAR; it also presents some test results.