High-resolution monopulse piezopolymer sonar sensor

A novel sonar sensor is described which utilizes two coincident, distributed, shaded polyvinylidene fluoride (PVDF) piezopolymer sensors to provide high-resolution target bearing estimates. Sensor shading is accomplished by suitably shaping the charge collection electrodes deposited on the sensing layer. When these two sensor shadings are matched via a derivative in space, the ratio of their signal outputs is linearly proportional to the direction cosine of an incident acoustic field; this is an extension of the well-known monopulse concept. A hardware implementation of the sensor is also described. The influence of ambient noise level on bearing resolution is addressed. The sensor concept developed provides a means of obtaining high-spatial-resolution sonar data for applications such as sea floor profiling, sea floor mapping, mine detection, and precision homing. In particular, the concept is pertinent to size- and weight-constrained platforms such as autonomous underwater vehicles.<
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