Direct wave interference suppression method
A technology of interference suppression and direct wave, applied in the direction of radio wave measurement system, instrument, etc., can solve the problems of RLS filter with large calculation amount, reduced calculation amount, and inability to realize long-distance clutter remaining problems, etc.
Inactive Publication Date: 2014-04-09
BEIJING INSTITUTE OF TECHNOLOGYGY
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Problems solved by technology
[0033] The purpose of the present invention is to solve the problem that the RLS filter has a large amount of calculation and cannot realize the long-distance clutter remaining caused by higher-order real-time processing, and the problem that the NLMS filter cannot take into account the convergence speed and target energy loss at the same time, and proposes a A new direct wave interference suppression method, which combines the RLS filter and the NLMS filter. When the external radiation source radar echo antenna rotates, the method can have a faster convergence speed, better tracking performance, and better The steady-state accuracy and small target energy loss not only greatly reduce the amount of calculation, but also improve the cancellation effect of long-distance clutter
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[0073] The actual collected data is 165,000 points for the direct wave and 165,000 points for the echo, the target point is at the time delay of 65, the frequency shift is 45, and there is strong interference at the time delay of 52 and 87. Perform 24th-order RLS cancellation, 9th-order RLS filter and 85th-order NLMS filter on the data, respectively, and perform two-dimensional correlation processing. The side views of the mutual ambiguity functions are as follows: Figure 4 and Figure 5 shown.
[0074] The adaptive filter algorithm flow chart of RLS filter of the present invention and NLMS filter combination is as attached image 3 As shown, used in this embodiment, it includes the following steps:
[0075] 1) Filter parameter initialization, take M=94, M RLS =9, M NLMS =85, u(0)=0(u RLS (0)=0, u NLMS (0)=0), P(0)=I, δ=1, λ=0.979, n=0;
[0076] 2) Update the tap input vector u(n), u RLS (n) and u NLMS (n), add the value u(n) of the direct wave at time n to the...
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The invention, pertaining to a field of radar technology, particularly relates to a direct wave interference suppression method which combines a RLS filter and an NLMS filter. The method comprises the following steps of: (1) initializing filter parameters which comprise a cancellation filter parameter, a RLS filter parameter and an NLMS filter parameter; (2) updating input vectors of u (n), uRLS (n) and uNLMS (n); (3) calculating an estimation error e (n) at an n moment, that is, a cancellation result of the filters at the n moment; (4) updating weight coefficient of the RLS filter; and (5) updating weight coefficient of the NLMS filter. The method of the invention reduces order of the RLS filter, reduces real-time processing amount, has a fast convergence rate, good tracking performance, good steady precision and low target energy loss, and at the same time improves direct wave interference suppression effect.
Description
technical field [0001] The invention relates to a direct wave interference suppression method, in particular to a direct wave interference suppression method combining an RLS filter and an NLMS filter, and belongs to the technical field of radar signal processing. Background technique [0002] The external radiation source radar usually has two receiving antennas, one is the direct wave antenna, which points to the radiation source to receive the transmitted signal; the other is the echo antenna, which points to the search airspace to receive the echo signal reflected by the moving target. It is configured as figure 1 As shown, in addition to being reflected by the target, the signal emitted by the radiation source can also enter the echo antenna through other paths, such as the direct wave interference directly entering from the side lobe of the echo antenna and the clutter entering the main lobe of the echo antenna through the ground reflection interference etc. Therefor...
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IPC IPC(8): G01S7/36
Inventor 冯远单涛陶然卓智海
Owner BEIJING INSTITUTE OF TECHNOLOGYGY