초록 ▼

The velocity measuring correlation sonar disclosed employs a planar array of receiving transducers spaced in the directions along which velocity components parallel to the plane of the array are to be measured, and includes means for transmitting a series of two or more identical pulses which are se

The velocity measuring correlation sonar disclosed employs a planar array of receiving transducers spaced in the directions along which velocity components parallel to the plane of the array are to be measured, and includes means for transmitting a series of two or more identical pulses which are separated by a time interval selected in accordance with transducer separation and the estimated velocity components so as to place the expected point of maximum correlation of the echo return from one pulse with that from a following pulse within the boundaries of a set of spatial sample points representing relative spacings between pairs of receiving transducers. Correlation measurements are made corresponding to these relative spacings of the receiving transducers, with each such measurement being treated as a sample of a space-time correlation function of predetermined shape. The location of the peak of this function in each of the directions of interest is estimated by curve fitting techniques, and yields the velocity vector in that direction scaled by the inter-pulse time interval. The velocity component normal to the plane of the array may be derived by estimating the location of the correlation peak as a function of time and/or phase, using similar curve fitting techniques.

대표청구항 ▼

Apparatus for measuring the relative velocity of a wave energy source-sensor combination with respect to a field of scatterers separated therefrom by a medium through which the wave energy is propagated, comprising: (a) a plurality of wave energy transducers included in said source-sensor combinatio

Apparatus for measuring the relative velocity of a wave energy source-sensor combination with respect to a field of scatterers separated therefrom by a medium through which the wave energy is propagated, comprising: (a) a plurality of wave energy transducers included in said source-sensor combination, said transducers having directivity in the general direction of the scattering field and comprising an array of at least two receiving transducers separated from each other by known distances in a plane perpendicular to the major axis of directivity; (b) means for energizing at least one of said transducers to emit a wave energy pulse train comprising first and second pulses having a predetermined pulse repetition period; (c) means for sampling simultaneously the echo returns from said scatterer field to the receiving transducers of said array at predetermined sampling intervals; (d) means for computing a set of measured values of complex correlation using time-delayed samples of echo returns from said first pulse and undelayed samples of echo returns from said second pulse, as sensed at a selected plurality of said receiving transducers, the period of delay of said time-delayed samples being equal to an integral number of sampling intervals and equal to said predetermined pulse repetition period; (e) means for processing each of said measured values of complex correlation as a sample of a continuous function of position with each such sample being associated with a location equal to the vector spacing between the pair of receiving transducers from which the samples were obtained, and curve fitting such samples to said continuous function to provide an estimate of the location in vector space of the peak value of correlation magnitude; and (f) means for deriving an output measure of velocity in each of two directions of relative motion by dividing the components of the location of the correlation magnitude peak along each of said directions by twice said predetermined interpulse interval.