Distance blur clutter suppression method based on pitch frequency diversity STAP

Abstract

The invention discloses a distance blur clutter suppression method based on pitch frequency diversity STAP. The method comprises the steps that down-conversion and matched filtering are sequentially carried out on a detected received signal to sequentially acquire the pitch-azimuth-time three-dimensional clutter snapshot model of each range gate, the pitch frequency expression of each range gate and the corresponding clutter compensation item; an appropriate clutter compensation item is used to separate distance blur clutters of different distance rings; due to the fact that pitch frequencies of different distance blur clutters are separated from each other, the distance blur clutter of each distance ring needs a filter with corresponding coefficients for filtering, and then all distance blur clutters are inhibited to solve the problem of distance blur; and finally, after the pitch distance blur clutters are separated, pitch frequency spectrum distribution and digital frequency periodicity are used to acquire the selection criteria of frequency increment. According to the invention, the freedom of a system and the operation complexity are not increased.

Description

technical field [0001] The invention belongs to the technical field of radar signal clutter suppression, in particular to a range ambiguous clutter suppression method based on pitch frequency diversity STAP, that is, a range ambiguous clutter suppression method based on pitch frequency diversity STAP (Space-Time Adaptive Processing, STAP) The wave suppression method is mainly applicable to the separation and suppression of range-ambiguous clutter in practical engineering. Background technique [0002] In recent years, ground moving target detection (Ground Moving Target Indication, GMTI) of airborne / spaceborne radar system has attracted widespread attention in urban traffic control and target tracking and detection; for the application background of strong clutter in airborne / spaceborne radar, Especially under the application background of background noise and interference, scholars at home and abroad have proposed space-time adaptive processing (STAP) algorithm and its corr...

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Problems solved by technology

[0004]The traditional space-time adaptive processing (STAP) algorithm generally adopts the method of adding fixed weights in the pitch dimension to synthesize the area array into a line array, and then in the azimuth dimension and time domain Adaptive processing in dimension to suppress clutter, that is, space-time two-dimensional adaptive signal processing (2D-STAP). Adding a fixed weight in the pitch direction will cause the clutter spectrum to spread, and it is difficult to completely eliminate the clutter with a large amount of distance ambiguity

[0005] On high-speed moving platforms such as airborne / spaceborne radars, in order to avoid severe Doppler ambiguity caused by Doppler frequency propagation, the actual space-time adaptive processing (STAP) algorithm usually adopts high pulse repetition frequency (HighPulseRepetitionFrequence, HPRF), high pulse repetition frequency (HPRF) is seriously ambiguous in distance, not ambiguous in speed, and has good detection performance for high-speed targets, which will make the secondary data of the test unit It is more difficult to obtain; seriously, except for the side-looking radar, the array radar will have a distance dependence problem and cannot satisfy the independent and identically distributed (IID) condition of the clutter. adaptive processing

Also, the range ambiguity usually introduced by high pulse repetition frequency (HPRF) can make the clutter increasingly non-uniform; The most important is sea level, so that clutter with different statistical values ​​will be superimposed over the distance, this complication will lead to errors in estimating the clutter covariance matrix, and cause serious degradation of the performance of the space-time adaptive processing (STAP) algorithm

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