Estimation method of arbitrary array weak signal source angle under strong interference

Abstract

The invention discloses an estimation method of an arbitrary array weak signal source angle under strong interference, i.e., a modified projection blocking method, which is used for researching estimation of the weak signal angle under strong interference. The method does not need to accurately know an interference angle, has no array limit, is suitable for an arbitrary array, and has good estimation performance under the condition with array errors. Compared with the interference blocking method, the method saves the problem that different arrays need to construct different blocking matrixes, and does not lose the degree of freedom during blocking interference. Compared with the traditional noise subspace expansion method, the method has higher angle-measuring accuracy under the condition of a low signal to noise ratio.

Description

technical field [0001] The invention belongs to the technical field of array antennas, and in particular relates to a method for estimating the angle of a weak signal source in an arbitrary formation under the background of strong interference. Background technique [0002] At present, weak signal detection and parameter estimation methods based on array antennas are being widely used in many fields such as radar, communication, navigation, sonar and seismic detection. Array antenna technology has the advantages of flexible beam control, high signal gain, strong anti-interference ability and high super-resolution ability, so it has attracted great attention. [0003] Strong interference and low SNR environment will directly affect the detection and estimation of weak signals. Especially in the case of strong interference, the signal is very weak relative to the interference, and the weak signal is submerged by the strong interference, which cannot be detected accurately. E...

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Problems solved by technology

[0005] Domestic research on this problem can be mainly divided into three categories: the first category is to use the improved beamforming method to perform beamforming nulling on the subarray to resist interference. The characteristic beamforming method is mainly based on Chai Ligong [3] , Xu Liang [4] et al., in which literature [3] requires the number of interference sources and the direction of incidence to be known accurately, but when strong and weak signals coexist, there will be a large deviation in the estimated signal source; literature [4] does not need to know the interference wave direction of arrival, and only one eigenvalue decomposition is required, but its disadvantage is that its scope of application is limited, and it is only suitable for one-dimensional uniform linear arrays

The second type is the interference blocking method (JJM), which constructs a blocking matrix based on prior knowledge to preprocess the interference, mainly based on Chen Hui [5] , Wang Shu [6] , Su Chengxiao [7] Represented by et al., this method can effectively suppress the influence of the strong interference of the spatially known azimuth and realize the correct estimation of the weak signal, but the estimation error of the guidance vector of the strong interference will lead to the leakage of the strong interference, and it will also suppress the interference while suppressing the interference. drop part of the desired signal

[0007] 1. RELAX (relaxation algorithm), the estimation of each step of this method needs to be realized through repeated iterations, especially when the angle between strong interference and weak signal is small, the convergence speed is very slow, so the amount of calculation is quite large, which is very important in practical applications. Difficult to achieve

[0008] 2. The eigenbeam forming method and the interference blocking method require the number of interference sources and the incident direction to be known accurately, and are applied to the situation without array errors, which is also difficult to achieve in practical applications

[0009] 3. The defect of the noise subspace expansion method is that only the traditional MUSIC estimation method can be used to estimate the angle of the output signal after the subspace expansion, which then brings about the problem of high complexity of two-dimensional or multi-dimensional spectral peak search

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