DECISION OF REMOTE FIELD CHARACTERISTIC FOR SEISMIC CENTER OR THE LIKE

摘要

A method is provided of ascertaining the far field signature of an array of sound source units, each of which is small compared with the wavelength of the highest frequency of interest. The units are fired so that the interactions between them is negligible. This is achieved by firing the units sequentially so that each generates all its significant radiation before the next is fired, and/or by firing more than one unit at a time and separating the units by at least one wavelength of the lowest frequency of interest. The far field signature of each unit is measured by a pressure-sensitive detector close to the unit but in a region where the phase spectrum of the pressure field is independent of azimuth and range. The far field signature of the array is derived from the measured signatures by summation.