A 3-D Attitude Measurement Method using Spread Spectrum Modulated Ultrasonic Wave

The local position and attitude measurement method is necessary for the navigation of autonomous robots and the other applications. In this report, a three-dimensional attitude measurement method is proposed. This method uses the spread spectrum modulated ultrasonic wave for the measurement of the pseudo-distance of each pathway between transmitter and receiver elements which are arranged in an array. The relative attitude between transmitter and receiver unit could be calculated from the relationship between these pseudo-distances. The use of spread spectrum modulation enables the high accuracy, noise tolerance, and coexistence of multiple transmitter devices by code division multiple access (CDMA) between each transmitter and receiver elements. A pair of transmitter and receiver prototype for proposed method was manufactured, and the fundamental performance was examined in experiments. As a result, accuracy of sigma=0.78 [mm] was confirmed in the pseudo-distance measurement of each pathway between transmitter and receiver elements, and resolution of about 0.01 [rad] was also confirmed in the attitude measurement