Ya. O. Areshin, D. L. Belotserkovsky, E. A. Selmenev
Some applications concerned with the signal filtering in the multistatic radar with quasi-continuous radiation mode are considered in this paper.
One of the problems shown in this article is the extraction of the echo-signal reflected from the target against the background of ground clutter and the power direct penetrating signal of transmitter. The available methods are described and their imperfections while applying to the model of multistatic radar, such as high computational intensity and complexity of algorithm hardware implementation, are shown in the article. The authors introduce quite simple in realization method of echo-signal extraction, which has insignificant energy loss in comparison with the methods described in the other papers. The proposed method is based on spectral estimation of the received signal parameters and background returns compensation with the help of the signals modeled with the estimated parameters. The weighting algorithms are applied to improve the side-lob suppression. Theoretical and experimental results of the researching of the proposed method are shown in this paper.
The second problem is related to the correlation processing of the received echo-signal and the radiated signal. The correlation processing results in the estimation of the time delay of the received echo-signal relative to the radiated signal and the Doppler frequency shift for each receiving position (“primary coordinates”). The measurements of the “primary coordinates” are computationally intensive as the correlation integral depends on two variables (time delay and Doppler frequency shift).
The using of a combined probing signal is proposed in the article for decreasing the computing power. The combined signal consists of narrow-band and wideband signals followed by each other. The whole signal Doppler frequency shift is estimated with the help of narrow-band part of the combined signal. When the Doppler frequency shift is estimated the time delay of received echo-signal is calculated with the help of wide-band part of the combined signal. The authors show that using of the combined signal helps to reduce total number of multiplication actions for the receiving position more than to 20 times as compared with using only the wide-band signal.
The third problem of the signal processing in the model of multistatic radar is the forming of resulting sample, i.e. the estimation of target coordinates based on “primary coordinates” measured by each receiving position. This problem is considered in the other papers in theory without measurement errors. The elliptical method for calculating target coordinates described in this article in details. Also the influence of the “primary coordinates” calculation error on the target position estimation procedure is analyzed.
The solutions for each problem mentioned above are proposed in this article. These solutions suitable for practical applying under the conditions close to operating conditions of the multistatic radar model.