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在未来军事电磁频谱战中,雷达通常工作于复杂电磁环境中,主瓣干扰作为一种典型的干扰形式,已经严重降低了雷达系统性能。在目标角度测量方面,大功率主瓣干扰的存在极大影响了目标到达方向(direction of arrival, DOA)估计的准确性。因此,如何在强主瓣干扰环境中精确估计目标DOA是亟需解决的问题,具有重要的理论价值和实际意义。
文献[1]提出了一种干扰阻塞方法(interference jamming method, IJM)来获取变换矩阵与干扰噪声矩阵抑制的关系,进而使用空间谱估计算法(multiple signal classification, MUSIC)或其他频谱估计方法估计目标DOA。文献[2-3]通过构造阻塞矩阵,实现干扰对消,从而有效估计目标的DOA。但上述方法均需要精确已知干扰信号的角度信息。文献[4]提出了一种基于扩展噪声子空间的强干扰条件下目标DOA估计方法,该方法首先对噪声子空间进行扩展,然后使用常规MUSIC方法估计目标DOA。文献[5]通过构造干扰子空间的正交投影矩阵对接收阵列信号做预处理,再利用基于旋转不变技术的信号参数估计(estimating signal parameter via rotational invariance techniques, ESPRIT)算法实现目标DOA估计。但上述两种方法均需要先验已知干扰信号的数量。文献[6-8]研究了子阵列以及自适应波束成形设计方法来抑制干扰并估计目标DOA,但主要针对旁瓣干扰,当存在大功率主瓣干扰时,算法失效。文献[9]提出了一种基于迭代最小二乘和空间差分平滑的混合信号DOA估计算法,可以有效估计多个源信号的DOA,但无法区分目标与干扰。文献[10]利用盲源分离算法分离目标成分与干扰成分,并重构干扰信号,然后利用CLEAN算法在空间谱上对消干扰,实现目标DOA估计。在此基础上,文献[11]研究了一种特定的子阵配置结构,利用子阵滑窗机制,在每个子阵内实现目标与干扰分离,最后联合各子阵分离的目标回波,利用稀疏信号的重构算法有效估计目标DOA,解决了主瓣干扰存在情况下相干源目标DOA估计问题。但上述两种算法计算量较大,不利于工程化实现。
随着高性能数字硬件和数字处理技术的不断发展,灵活、高性能、低成本的数字阵列雷达逐渐走向实用。本文针对数字子阵体制雷达,提出了一种主瓣干扰下和差波束测角方法。首先,对每个子阵列采用盲源分离算法分离目标回波与干扰信号;然后,联合各子阵分离得到的估计目标/干扰信号构建和差信号,并利用单脉冲和差波束测角方法实现目标/干扰的DOA估计。
Digital Sub-Array Radar Sum-Difference DOA Estimation Method in the Presence of Mainlobe Following Jamming
doi: 10.12178/1001-0548.2022283
- Received Date: 2022-09-21
- Rev Recd Date: 2023-02-03
- Available Online: 2023-09-06
- Publish Date: 2023-07-07
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Key words:
- blind source separation /
- digital sub-array /
- estimation of the direction of arrival /
- mainlobe following jamming /
- sum-difference beams
Abstract: Aiming at the estimation problem of the Direction of Arrival (DOA) of weak targets in the presence of strong mainlobe interference for digital sub-array radar, this paper proposes a sum-difference beam angle measurement method. Firstly, a receiving model of the mainlobe interference and target echo under the multi-subarray sum-difference beam structure is established. Then, according to the uncorrelated characteristics of the target echo and the interference signal in the time domain, blind source separation is used for each sub-array to separates the target echo and interference signal, and monopulse angle measurement technology is used to achieve target/interference DOA estimation via combining the target echo/interference signal separated by each sub-array. Finally, the effectiveness and analysis performance of this method is verified by numerical simulation experiment.
Citation: | YU Xianxiang, YAN Zhengxin, PAN Bunian, WANG Bing, CUI Guolong. Digital Sub-Array Radar Sum-Difference DOA Estimation Method in the Presence of Mainlobe Following Jamming[J]. Journal of University of Electronic Science and Technology of China, 2023, 52(4): 498-505. doi: 10.12178/1001-0548.2022283 |