A pseudo random (PR) code based ultrasonic navigation system (UNS)

An ultrasonic navigation system (UNS) has been designed and tested for marker-less AGV navigation. This solution is based on pseudo random (PR) coding on the transmitter side and coherent correlation on the receiver side, to achieve higher positioning accuracy, much longer detection range and better robustness to the environment acoustic noise, compared to a traditional short pulse UNS. The system concept is quite similar to a GPS pseudolite system, except that RF propagation is replaced by ultrasonic waves here. Such a change makes the UNS easier to implement, and thus more cost-effective for the proposed application, compared to a GPS pseudolite solution. Prototypes have been built to verify the design concept and performance capability. 0.72 cm pseudo range measurement error and 30 m detection range have been achieved in the lab testing.