Robust navigation through rocky terrain by small mobile robots is important for maximizing science return from missions to Mars. We are addressing this problem at multiple levels through the development of intelligent sequencing, sensor constrained path planning, natural terrain visual localization, and real-time state estimation. Each of these techniques is described and their complementary aspects discussed. Experimental results are provided from implementation on our Mars rover prototype operating in realistic scenarios.

With the success of Mars Pathfinder's Sojourner rover, a new era of planetary exploration has opened, with demand for highly capable mobile robots. These robots must be able to traverse long distances over rough, unknown terrain autonomously, under severe resource constraints. This paper reviews issues which are critical for successful autonomous navigation of planetary rovers. We report on the "Wedgebug" algorithm for planetary rover navigation. This algorithm is complete, correct, requires minimal memory for storage of its world model, and uses only on-board sensors, which are guided by the algorithm to efficiently sense only the data needed for motion planning. The implementation of a version of Wedgebug on the Rocky7 Mars rover prototype at the Jet Propulsion Laboratory is described, and experimental results from operation in simulated martian terrain are presented.

Much prior work in mobile robot path planning has been based on assumptions that are unrealistic for exploration of planetary terrains. Based on the first author's experience with the Mars Pathfinder mission, this paper reviews issues that are critical for successful autonomous navigation of planetary rovers. No currently proposed methodology accurately addresses all of these issues. We report on an extension of the recently proposed "TangentBug" algorithm. The implementation of this extended algorithm on the Rocky 7 Mars Rover prototype at the Jet Propulsion Laboratory is described and experimental results are presented. In addition, limitations encountered by the Sojourner rover in actual Martian terrain suggest that terrain traversability is a key issue for future interplanetary rover autonomous planning algorithms.

This paper describes the design and implementation at the Jet Propulsion Laboratory of a small rover for future Mars missions requiring long traverses and rover-based science experiments. The small rover prototype, called Rocky 7, is capable of long traverses, autonomous navigation, and science instrument control. This rover carries three science instruments, and can be commanded from any computer platform from any location using the World Wide Web. In this paper we describe the mobility system, the sampling system, the sensor suite, navigation and control, onboard science instruments, and the ground command and control system. We also present key accomplishments of a recent field test of Rocky 7 in the Mojave Desert in California.