Array radar complex terrain low elevation angle estimation method based on beam space

Abstract

The invention discloses an array radar complex terrain low elevation angle estimation method based on beam space. The method comprises the following steps of constructing a beam forming matrix; converting a received signal from an array element space to a beam space by using the beam forming matrix to obtain a converted received signal; and judging whether the converted received signal contains amultipath signal or not through gate limitation of the multipath signal, if the converted received signal contains the multipath signal, performing low elevation estimation by using an RML algorithm,and if the converted received signal does not contain the multipath signal, performing low elevation estimation by using an RML algorithm. A sum-difference monopulse angle measurement method is adopted to estimate the low elevation angle. According to the estimation method, the more data information is utilized, and the angle measurement performance can be improved.

Description

technical field [0001] The invention belongs to the field of radar technology, in particular to a method for estimating low elevation angles of array radar complex terrain based on beam space. Background technique [0002] When performing array radar (especially meter-wave radar) low-elevation angle estimation, the signals received by the radar include target direct signals, multipath signals such as specular reflection and diffuse reflection, and background noise. The existence of multipath signals will cause the lobe splitting and upturning in the vertical plane of the radar, which not only affects the detection of target signals, but also seriously affects the measurement performance of the target's elevation angle. [0003] The use of array super-resolution technology is an important means to improve the performance of elevation angle estimation, which includes multiple signal classification MUSIC algorithm and maximum likelihood ML algorithm, etc. The angle measurement...

AI Technical Summary

Problems solved by technology

The RML algorithm uses the prior information of the reflection coefficient ρ, replaces the conventional steering vector in free space with the composite steering vector under multipath conditions, and then uses the maximum likelihood method to estimate the DOA in the direction of arrival angle. This algorithm has fewer parameters to be estimated. The estimation accuracy is high, but there are still situations where it is not suitable for complex reflective surfaces, and when the number of array elements is large, the amount of calculation and data will be large, which is not conducive to engineering implementation

[0004] Aiming at the defects of the existing technology, an existing patent proposes a method for estimating the low elevation angle of meter-wave radar based on the beam space, in order to reduce the amount of computation while ensuring the accuracy of the angle measurement, but the number of beams used by this method is limited. Only three sum beams are utilized, so the scan function sidelobe is high, which will lead to a decrease in the robustness of the angle measurement. At the same time, it does not consider the fact that the complex target echo of the reflector does not contain multipath signals, resulting in the accuracy and robustness of the angle measurement. The performance is reduced, which is not conducive to engineering applications

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