基于长合成孔径的辐射源成像定位算法

考虑到单平台测角的定位精度随目标的距离增加而下降、远距离处的方位定位精度有待提高的问题，该文提出了一种基于长合成孔径的辐射源定位算法。该算法将合成孔径成像的概念引入到辐射源无源定位中，通过平台的移动形成长的虚拟孔径，以合成孔径雷达的方式处理数据，获得很高的方位定位精度。对于单频辐射源，接收信号在方位上等效为线性调频信号，其调频率与辐射源的距离成反比，通过距离搜索和方位聚焦的方法在距离-方位域完成信号聚焦，直接获得辐射源2维成像定位结果。针对宽波束侦察的特点，分析了低采样率下调频率距离-方位的耦合关系，并提出了信号角度估计和2维成像定位的方法。理论推导和实测数据处理结果验证了该定位算法的有效性。 

Passive Localization Algorithm for Radiation Source Based on Long Synthetic Aperture

When the direction-of-arrival estimation is made by a single platform,the localization accuracy decreases with increases in the distance from the radiation source,which means the localization accuracy of the azimuth of the radiation source at long distances must be improved.To address this problem,we propose a radiation-source localization algorithm based on a long synthetic aperture.This algorithm introduces the use of synthetic aperture imaging to the passive localization of radiation sources.A long virtual aperture is obtained by movement of the platform,and received data is processed in the form of synthetic aperture radar to obtain high azimuth localization accuracy.For a single-frequency radiation source,the received signal is equivalent to a linear frequency-modulation signal in the azimuth domain,and its chirp rate is inversely proportional to the distance from the radiation source.A range search and azimuth-focusing method are used to perform signal focusing in the range–azimuth domain,and the localization of the radiation source is obtained directly by two-dimensional imaging.Moreover,with respect to the characteristics of wide-beam reconnaissance,we analyzed the range–azimuth coupling relationship of the chirp rate at a low sampling frequency.On this basis,methods for direction-of-arrival estimation and two-dimensional imaging localization are proposed.Our theoretical derivation and experimental data processing results verify the validity of this algorithm.