Positioning systems that use ultrasonic sensors can measure position with a high degree of accuracy. For this reason, they are an attractive option for use in indoors, where the level of accuracy required is higher than that needed outdoors. This study aims to make possible a practical ultrasonic positioning system based on what is called an inverse GPS method. To be practical, positioning systems should be able to cover a wide area and identify the positions of multiple objects. This paper discusses the positioning methodology and system structure to achieve these objectives. It presents the results of verification tests with static and moving objects conducted using an experimental model. It was confirmed that the positioning error is less than 100 mm, and that the proposed system satisfies the required accuracy. In addition, as a possible application of the method, an experiment in ‘pedestrian navigation’ was conducted using a moving robot, and the effectiveness of the proposed system was confirmed.

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