Ultrasonic Position Measurement using Phased Array Microsensors with Resonant Frequency Variation

A new type of signal processing method for position measurement using ultrasonic array sensors has been proposed. The proposed method can detect wavefronts as phase or amplitude changes in a received waveform using a simple signal processing, by eliminating a long tail of dumping oscillation caused by high-Q mechanical resonance of a sensor element. The obtained waveforms corresponding to the detected wavefronts can be synthesized by delay-and-summation method for position measurement regardless the resonant frequencies of the sensor elements. Plural object positions in almost the same distance have been successfully determined by the method using resonant frequency-scattered sensors.