Natural terrain hazard detection with a laser rangefinder

This paper presents a laser-based hazard detection system for rovers traveling over natural terrain. This system, which complements an existing stereo vision system, is based on a line-scanning laser ranger viewing the area just in front of the rover. This configuration of the laser yields a fast response time and very high precision, but due to the short look-ahead only an emergency stop can be commanded. The system consists of a data acquisition module and a hazard detection module. The acquisition module retrieves and validates range data, performing integrity checks of the laser system and correcting minor problems if necessary. The detection module evaluates the elevation profile of the terrain looking for evidence of three different hazards: step, ditch, and belly. The laser system has been tested in lunar-like terrain with excellent performance: zero misses and few false alarms operating at 4 Hz