| 摘要 |
To improve the accuracy of angular measurements in a radar or sonar system by suppressing noise due to target glint, an angular-deviation signal epsilon derived from the output signals SIGMA and DELTA of a sum channel and a difference channel is multiplied with a gain-control signal K(t) before being subjected to recursive filtering. Signal K(t) is obtained, also by recursive filtering, from a weighting function P(t) which goes to zero during periods when the measurement of the angular deviation is unreliable as determined from a low value of sum signal SIGMA and from a peaking of a quadrature deviation signal epsilon q, function P(t) being proportional to the product SIGMA nx(S-¦ epsilon q¦) where the exponent n is at least equal to 1 and S is a predetermined threshold. The recursive filter processing the deviation signal epsilon has two cross-connected stages, both controlled by signal K(t), respectively emitting a corrected deviation measurement epsilon and an estimated time differential tau d epsilon /dt, tau being a delay introduced in a recursive loop of each stage. Prior to being multiplied with gain-control signal K(t), the deviation signal epsilon may be additively combined with an angular-orientation signal theta r of a radar antenna to yield an angular value theta c which can then be multiplied by a measured target distance D to provide a transverse-deviation signal d; in that case the two filter stages respectively emit a corrected deviation signal d and a target-velocity estimate v. |
