FEATURES OF CONSTRUCTION OF A BISTATIC RADAR SYSTEM FOR COVERED SURVEILLANCE OF THE PROTECTION ZONE OF IMPORTANT STATE OBJECTS

The article discusses the issues of building bistatic radar systems, which are supposed to be used in the National Guard of Ukraine to perform tasks for the protection of important state facilities. The peculiarities of the construction of this system are associated with the absence of its own transmitter in its composition and the use of the «translucent» location effect. A general configuration of bistatic coherent radar systems is proposed and the main problems of signal processing in such a radar system are considered. The central problem of constructing this bistatic radar system is the effect of an interfering direct signal from a radiation source (usually continuous), penetrating into the receiving path along the side lobes of its antenna. Using analytical expressions, the dependences of the ratio of the power of the useful and penetrating signals for delivery vehicles and intruders on the azimuth of the target relative to the receiver at various fixed ranges are obtained. The analysis of the dependences showed that at ranges to the target less than 5 km, the ratio of the signal capability does not depend on the target azimuth. With an increase in the detection range and an increase in the azimuth of the target, the signal power ratio tends, respectively, to -65 dB for delivery vehicles and -90 dB for intruders. Ways of suppressing the direct signal are considered. To improve the suppression of such a signal, an adaptive compensator as part of the receiver is proposed. It consists of a feedback control system and takes into account the ratio of the useful and penetrating signals, information about their delay and structure. The general structure of a receiver with a compensation system for a penetrating signal and a block diagram of an adaptive compensation device are presented. Direction for further research. Particular attention should be paid to defining the characteristics of the bistatic covert surveillance system in terms of compensating for the influence of the underlying surface and local objects.