Radar sidelobe cancellation, saying it was not a means to improve the performance of the radar itself, but an anti-jamming. Very often, the victim radar is irradiated from the other non-radar jammer over the direction of the main lobe, herein described for this form of interference.
1. Radar interference irradiation
Radar, the most difficult to deal with interference is active jamming, active jamming radar can only enter from the main lobe of the radar, you can also enter the side lobe. In general, the radar in the search state, the interference signal is very difficult to directly irradiated from the radar mainlobe coming, into the radar receiver is by sidelobes, as shown in FIG. To reduce the amplitude of the interference signal into the radar signal receiver, antenna sidelobe reduction is an important means of interference, it may generally take ultralow sidelobes, sidelobe cancellation (the SLC), sidelobe blackout (SLB) , etc., to enhanced anti-jamming capability of the radar.
2. The principle side lobes and side lobe cancellation of blackout
The antenna has a main lobe and sidelobes, if an additional auxiliary antenna, it receives the interference signal and the interference signal received by the radar antenna weighted sum, to obtain new radar pattern, form a null in the interference direction, thereby suppressing the side lobe interference. The auxiliary antenna directivity is generally weak or non-directional, the antenna gain is much lower than the main lobe, the side lobe considerable . Thus the introduction of the corresponding auxiliary antenna main lobe of the antenna less affected, and its main role is to influence the antenna side lobe properties.
Weight change adaptively adjusted in real time based on the interference direction, is formed such that the antenna is always null in FIG synthesis interference direction - that is adaptive sidelobe cancellation techniques . It is mainly used to eliminate interference continuous active.
Sidelobe blackout , mainly used to eliminate pulsed interference, the principle is very simple: when the signal entering the antenna main lobe, a level which is far greater than the incoming signal level from the auxiliary antenna; when the signal entering the antenna sidelobes which level lower than the level of the incoming signal from the auxiliary antenna, and thus is considered to be interference. In this case a main channel is closed, the interference is blocked.
