Abstract: A tracking system uses a road mounted microwave reflector as an alignment tool. The system can be used to provide primary or supplemental guidance and alignment for a self-driving vehicle, or it can be used to provide warning signals for a manually controlled vehicle. The disclosed reflector is economical and easily installed. A preferred corner reflector includes both a microwave retro reflector and an embedded tuned circuit. The system is optimized to operate reliability and accurately in conditions of inclement weather and poor visibility, particularly where GPS signals, conventional road markers and visual aids fail.

Abstract: A tracking system uses a road mounted microwave reflector as an alignment tool. The system can be used to provide primary or supplemental guidance and alignment for an self-driving vehicle, or it can be used to provide warning signals for a manually controlled vehicle. The disclosed reflector is economical and easily installed. A preferred corner reflector contains both a microwave retro reflector and an embedded tuned circuit. The system is optimized to operate reliability and accurately in conditions of inclement weather and poor visibility, particularly where GPS signals, conventional road markers and visual aids fail.