| 摘要: |
| 无源探测作为一种经济安全的被动探测手段近年来获得学术界的广泛关注，在非合作外辐射无源雷达系统中，准确快速地估计直达波的参数是无源探测的前提。本文以基于非合作chirp雷达的无源雷达系统为平台，围绕直达波参数估计问题展开研究。对于工程上常见的时频混叠，且时间不同步的多分量chirp信号，提出一种基于分数阶傅里叶域滤波的chirp信号参数估计方法。该方法根据时频域滤波的原理，首先通过分数阶傅里叶变换估计chirp分量的调频斜率；然后通过逆分数阶傅里叶变换将多分量chirp信号分离为若干个单分量chirp信号，并在时域估计每个chirp分量的脉冲宽度；最后构造dechirp滤波器，对分离后的chirp分量进行解线性调频，估计每个chirp分量的中心频率。仿真实验证明，本方法相较于时频图像的方法，具有更高的估计精度和计算效率，而且本方法可以实时处理，易于工程化实现。 |
| 关键词: 非合作 无源雷达 chirp信号 参数估计 分数阶傅里叶变换 时频滤波 信号分离 |
| DOI：DOI:10.3969/j.issn.1672-2337.2020.06.012 |
| 分类号:TN958.97 |
| 基金项目:国家自然科学基金（No.61401489） |
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| Research on Parameter Estimation Method of Direct-Arrival Wave of Passive Radar |
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SU Hanning， BAO Qinglong， WANG Sen， SUN Yupeng
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School of Electronic Science and Technology, National University of Defense Technology, Changsha 410073, China
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| Abstract: |
| Passive detection, as an economical and safe passive detection method, has gained wide attention in recent years. In non-cooperative external illuminator-passive radar system, accurate and rapid estimation of the parameters of direct-arrival waves is a prerequisite for passive detection. In this paper, a non-cooperative chirp radar based passive radar system is used as the platform to study the problem of direct-arrival wave parameter estimation. For multi-component chirp signals with time-frequency aliasing and time unsynchronized, which is common in engineering, a chirp signal parameters estimation method based on fractional Fourier domain filtering is proposed. Based on the principle of time-frequency filtering, the proposed method firstly estimates the chirp components chirp rate by fractional Fourier transform. Then, the multi-component chirp signals are separated into several mono-component chirp signals by inverse fractional Fourier transform, and afterwards, the pulse width of each chirp component is estimated in the time domain. Finally, a dechirp filter is constructed to dechirp the separated chirp components and estimate the centroid frequency of each chirp component. Simulation results show that the method has higher estimation accuracy and computational efficiency than the time-frequency image method and can realize real time processing, which is beneficial for engineering realization. |
| Key words: non-cooperative passive radar chirp signal parameter estimation fractional Fourier transform time-frequency filtering signal separation |
