Universal two-channel STAP filter
First Claim
1. A method of filtering radar source data comprising distance Doppler matrices X1 and X2 of two receiving channels, by Space-Time Adaptive Processing (STAP), wherein the data of the distance/Doppler matrices X1 and X2 of individual adjacent channels (left/right) as well as of sum and difference signals (Σ
- /Δ
) are processed according to the same procedure, and wherein both computation of filter coefficients α
(i) and β
(i), and filtering take place in the frequency domain, said method comprising;
determining auto-correlations r11 and r22 and cross-correlations r12 of the signals X1 and X2 of both receiving channels, according to the following equations;
wherein X1 (i, j) is a complex range/Doppler matrix of a first of the two channels, X2 (i, j) is a complex range/Doppler matrix of a second of the two channels, NDZ is a number of Doppler cells, NRG is a number of range gates, and 1≦
i≦
NDZ;
determining whether the first channel has the better signal-to-noise ratio according to the following condition applying a selection rule which provides that if the first channel has the better signal-to-noise ratio, the filtering coefficients a (i) and b (i) are determined according to
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Abstract
To suppress interfering stationary targets in radar source data, a STAP filtering method is used. Filtering coefficients are determined, and filtering of the data takes place, in the frequency domain; the process is therefore limited to a few computing operations per matrix element of the range/Doppler matrix. Since, by means of the STAP filter according to the invention, the optimal filtering characteristics can be implemented, the stationary target suppression also functions in the range of the minor lobes of the antenna. Therefore, data of individual adjacent channels (L/R, left/right) can be processed as well as summation and difference signals (Σ/Δ).
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Citations
3 Claims
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1. A method of filtering radar source data comprising distance Doppler matrices X1 and X2 of two receiving channels, by Space-Time Adaptive Processing (STAP), wherein the data of the distance/Doppler matrices X1 and X2 of individual adjacent channels (left/right) as well as of sum and difference signals (Σ
- /Δ
) are processed according to the same procedure, and wherein both computation of filter coefficients α
(i) and β
(i), and filtering take place in the frequency domain, said method comprising;determining auto-correlations r11 and r22 and cross-correlations r12 of the signals X1 and X2 of both receiving channels, according to the following equations;
wherein X1 (i, j) is a complex range/Doppler matrix of a first of the two channels, X2 (i, j) is a complex range/Doppler matrix of a second of the two channels, NDZ is a number of Doppler cells, NRG is a number of range gates, and 1≦
i≦
NDZ;determining whether the first channel has the better signal-to-noise ratio according to the following condition applying a selection rule which provides that if the first channel has the better signal-to-noise ratio, the filtering coefficients a (i) and b (i) are determined according to - View Dependent Claims (2, 3)
- /Δ
Specification