抄録
We develop an ultrasonic positioning system for navigation of automated guided vehicles (AGV) available to be used not only indoors but also outdoors and adaptable to a temporary route. Then AGV drives along setup route, the sonar system mounted on AGV communicating with the land marker composed of ultrasonic transducers by the handshake protocol and measuring relative position against the marker at same time. The sonar system is equipped with the phased array of the ultrasonic sensors to improve the signal-to-noise ratio. Assignment of the 7-bits ID to the land marker reduces the influence of the ultrasonic interference. We need more improvement of the system performance under the degradation, such as false detection and reduction of estimate accuracy of the marker position, ascribable to superposition of multiply-reflected signal. In this paper, we investigate the response of the marker with the long time delay to suppress the influence of the multiple reflections. We compare experimental results for the land markers with the short and long time delays and confirm the effectiveness of our proposal.
