GB1003390A - Improvements in or relating to radar systems - Google Patents

Abstract

1,003,390. Radar. TELEFUNKEN PATENVER-WERTUNGS G.m.b.H. Oct. 13, 1961 [Oct. 13, 1960], No. 36902/61. Drawings to Specification. Heading H4D. In a pulse radar system having a rotating antenna a predictor computer (not described) estimates the probable future position of a moving target from previous target positions. Signals from targets not within the predicted zone are rejected. The received signals are fed to a digital detector, the output of which supplies a buffer store which feeds the signals, uniformly distributed in time, to the visual display. To prevent overloading of the store, the signals applied to it are subjected to two restrictions, first only those above a threshold value are used and secondly, of these, only those from the most probable target zone are selected. The choice of signals from threshold and zone considerations is effected in a filter, which feeds the store and which is subject to control from the computer. Each probable target position, calculated by the computer, generates two further values, in the filter, by the addition and subtraction of an increment 8. A new target signal is compared, in the filter, with a series of such previously calculated expected values, representing a zone of target positions, and a target signal for which coincidence with a calculated value occurs, is passed through the filter to the store. To prevent overloading of the system where a large number of targets are encountered in a narrow sector of the antenna scan angle, the target echoes are accepted into an additional store preceding the filter. A first echo is erased from the store when the following echoes fail to appear twice in succession and a known target is erased when echoes fail to appear four times. At each antenna bearing, the range is divided into 1,000 discrete units and 10,000 bearing units are scanned thereby providing 10<SP>7</SP> separate swept polar co-ordinates.