Solid state methods of sonar calibration

Abstract

In application to sonars and underwater transducers a variety of waterless 'solid state' calibration methods can be performed in continuous wave mode (CW). Multi-echo effects arising in such acoustical system are negligibly small due to the large dynamic range of sonar. Sytematic errors can be further eliminated by direct measurements in water. Having test probe scanned or comprised of 1-3 composite it is possible to 'photoprint' aperture function of multi-element, electrically shaded transducers to evaluate cross-coupling and predict sonar performance in the far field.The plates are in acoustical contact with the small probe of the diameter p < < L through the layer of liquid. Thickness of the layer is h. The probe E s positioned over the radiating surfaces by the vector r={x,hp}, where hp=Const..

Metering Method and Measurement Uncertainty Evaluation of Underwater Positioning System in Six Degrees of Freedom Space

“…Nowadays, there are many effective methods have been proposed to measure and calibrate the underwater acoustic equipment, such as standard target method, electrical calibration, comparison calibration method, solid state method [10]- [13], while all these methods should be implemented on a measurement and control platform which is closely related to the schemes of these methods, especially for the underwater acoustic positioning system. This is because the located targets are usually doing real-time motions, and the positioning systems are generally applied on ships or some platforms that propelling at sea experiences three translational and three rotational motions each of which are surge, heave, sway and pitch, roll, yaw respectively [14].…”