Optimal space-time signal processing algorithms are considered in radars with discrete, discrete-continuous or continuous antenna aperture for cases of practical importance in the context of target acquisition-jammer under conditions of active noise and pulse interferences produced by other sources.
Object of this paper is to develop and evaluate quality of optimal signal processing algorithms in network radar systems with discrete, discrete-continuous or continuous antenna aperture in the presence of «self-defenses» noise jamming as well as active noise and pulse interferences produced by other sources.
Using unit for space-time function sampling, there were proposed continuous signal and jamming models in radar systems with discrete, discrete-continuous or continuous antenna aperture. As applied to the models developed, unlike the known statements, problem of synthesizing optimal space-time signal processing algorithms under conditions of noise and pulse interferences was set and solved within the class of multialternative detection problems. It was shown that several thresholds are generated in optimal (according to the Neumann-Pearson criterion) multialternative space-time receiver-detector and stabilization of false alarms is provided across all alternative signals.
In the statement different from the known ones by representation of a useful signal as the sum of target return signal and active noise jamming to be produced by it, optimal space-time signal processing algorithms under conditions of external narrow-band interference sources in radar systems with discrete-continuous apertures of two-way antennas were synthesized. Expressions for reference signals of optimal processing system were obtained and it was shown that in this case basic part of the reference signal provides optimal signal processing in the presence of active jamming (powers are summed up) and compensating part of the reference signal is “set” to narrow-band interference.
There were performed calculations of signal-to-noise ratio in the receiving systems realizing optimal space-time information processing algorithms that enabled to establish that:
increase in number of jamming sources leads to reduction of signal-to-noise ratio which is the more significant, the less level of interference cross-correlation is; with 3–4 jamming sources and their cross-correlation coefficient no better than 0,5, signal-to-interference ratio decreases more than by 4…4,5 times;
increase of cross-correlation coefficient for signal and noise interference results in substantial reduction of signal-to-noise ratio; so at increase of cross-correlation coefficient for signal and interference from с 0,3 to 0,7 signal-to-noise ratio decreases by 3,5…7 times;
advantage of optimal processing as compared to consistent one decreases strongly with increase in number of jamming sources and gives no more 2…2,7 dB at Jуп ≥ 4;
It was demonstrated that effect of signal-to-noise ratio reduction at the output of optimal processing system with increase of cross-correlation coefficient for signal and interference as well as with increase in number of jamming sources is caused by rise of the number of “parasitic” cross correlation relationships of interference produced by various sources, between itself and signal and by corresponding increase of residual interfering component level.
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