GB1367600A - Radar systems - Google Patents

Abstract

1367600 Radar SIEMENS AG 30 July 1973 [15 Sept 1972] 36132/73 Heading H4D A radar system is provided with means for initially operating in a target acquisition mode and for automatically switching to a target tracking mode. The system comprises a receiver, echo-processing circuits provided with a plurality of range gates, a displaceable range window for use in the tracking mode, and a store to mark the range gate involved after acquisition of a target. The marking serves to displace the range window in time by means of a followup circuit, which remains operative until an echo signal from the target appears in said window, when a stop signal is applied to said circuit. As described, a transmitter and receiver are combined in a unit RG connected to an aerial AT which during the acquisition mode is circularly scanned, and which during the tracking mode is conically scanned. The received echo signals are supplied from the unit RG to a first bank of range gates ET1, which has separate range channels K1 to Kn. A second bank of range gates ET2, to which the echo signals are also applied, splits part of the range span of the range gate bank ET1 into a number of smaller range channels, K1a to K1f. As shown, the time position of an echo pulse E1 is within the range channel K1 of the range gate bank ET1. From information obtained from channel K1, the range gate bank ET2 is so placed that it definitely covers said channel. The outputs from the range channels K1a to K1f are connected to a store SP for marking purposes, this store retaining information as to which range channel in the bank ET2 has picked up an echo signal during the acquisition mode (in this case, channel K1d). A target tracking circuit GEF has a displaceable range window EF, and is also supplied with the received echo signals. A follow up circuit NS displaces the timing of the range window EF towards the marked channel K1d until they coincide, when output EA from said range window switches off said follow up circuit. Tracking then continues conventionally, information passing from the range window EF and the circuit GEF to an analyser or indicator circuit AS. The store SP may be arranged to retain only a signal corresponding to a target of shortest range, should there be more than one, as a counter to simulation of pulses by enemy jammers.