| 摘要 |
PURPOSE:To reduce a calculation quantity without lowering position measurement accuracy by dividing the reception band of noises from a moving target into two, selecting their center frequencies and band widths under specific conditions, and performing arithmetic operations. CONSTITUTION:Radiation noises of the moving target which are received by receivers 11-13 are limited by band-limiting filters 21 and 22 to proper reception bands. Here, the center frequencies fC and f'C and band widths W and W' of the filters 21 and 22 are so selected that an inequality I holds. A signal of a 1st reception band is inputted to the circuit composed of mutual correlator 241 and 242, maximum point detectors 261 and 262, interpolators 281 and 282, and maximum point detectors 301 and 302, and a 1st estimated value of arrival time difference is obtained through the detectors 301 and 302. The mutual correlators 231 and 232 calculates a mutual function from a 2nd reception band within a range of delay time difference centered on the arrival time difference. Then the maximum value detectors 291 and 292 obtains time difference which maximizes the mutual function and a target position calculator 8 calculates the position of the moving target from said value.
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