Method for estimating direction of arrival of MIMO radar based on nested array

Abstract

The invention discloses a method for estimating the direction of arrival of MIMO radar based on a nested array, which mainly solves a problem that the early radar is low in resolution for the direction of arrival and small in number of recognized signal sources. Implementation of the method comprises the steps of 1) building a nested array based MIMO radar model, and acquiring a target return signal; 2) performing snapshot sampling, matched filtering and vectorization on the target return signal in sequence, and acquiring vectorized receiving data y; 3) estimating a covariance matrix Ryy of the receiving data y, and performing vectorization on the covariance matrix Ryy to acquire an observation vector z; 4) removing repeated elements of the observation vector z to acquire virtual differential array receiving data z1; 5) dividing the virtual differential array receiving data z1 into N1 pieces of subarray receiving data, and acquiring a rank-recovery receiving data covariance matrix Rss; 6) performing eigenvalue decomposition on the rank-recovery receiving data covariance matrix Rss to acquire a noise subspace EN; and 7) acquiring the direction of arrival according to a spectral function formed by the noise subspace EN. The method disclosed by the invention improves the degree of freedom and the resolution of an MIMO radar system, and can be applied to radar target orientation detection.

Description

technical field [0001] The invention relates to the technical field of radar, in particular to a method for estimating direction of arrival of MIMO radar, which can be used for estimating the azimuth of a target source. Background technique [0002] Multiple-input and multiple-output MIMO systems were used in mobile communication systems in the early days, and have only been applied to radar systems in recent years, and a new radar system - MIMO radar - has been born. Compared with early radars, it has many unique advantages, such as breaking through the restriction that the antenna element spacing of early radars must be less than or equal to half a wavelength, enhancing the angular resolution of antennas, increasing the degree of freedom of radar systems, and improving radar The performance of anti-interference and suppression of clutter, etc., therefore, MIMO radar has gradually received extensive attention from radar researchers at home and abroad, and has become one of ...

AI Technical Summary

Problems solved by technology

However, under the limited number of transmitting and receiving array elements, the degree of freedom obtained by the virtual array constructed by uniform linear array is relatively limited. When the number of targets is greater than the product of the number of transmitting and receiving array elements, the early MIMO radar based on uniform linear array will not be able to accurately distinguish

At the same time, when the estimation accuracy of the direction of arrival is very high, the equivalent antenna array aperture needs to be quite large. At this time, if the antenna array is continued to be a uniform linear array, a lot of antenna resources will be used, resulting in The increase in cost and complexity cannot be realized in engineering

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