宽带信号测向与定位算法研究

发布时间：2018-04-10 23:39

本文选题：长基线宽带测向 + 时差校正　；参考：《南京航空航天大学》2014年博士论文

【摘要】：随着电子技术的不断发展,现代雷达发射的信号通常采用宽带调制,因此研究宽带信号的测向(Direction Finding,DF)和定位是一个具有现实意义的课题。本文针对宽带信号的测向与定位的一些关键技术和环节,如单信号的高精度测向算法、诱饵背景下的相干多信号个数估计及测向算法、宽带干扰源测向、双站测向交叉定位算法、宽带信号测向算法的硬件FPGA(Field Programmable Gate Array)实现等进行了研究,主要创新性成果如下:(1)在高精度宽带信号时差估计算法基础上,系统地研究了长基线宽带信号测向算法,提出了基于时差校正的宽带长基线测向及解模糊算法,并且对它们的性能和使用条件作了详细的分析。在该算法中,利用时差初估计值,对信号进行相位校正,利用干涉仪算法对剩余相位差进行估计及相位解模糊,从而进一步提高测向精度。基线长度不受相位解模糊条件的限制。(2)研究了诱饵背景下宽带相干多辐射源个数估计与测向算法。对于位置靠近的多个相干信号源,仅采用两个天线阵元组成的单基线系统,利用它们的频谱相关特征实现辐射源个数估计,并同时对多个辐射源进行精确测向。在电子侦察和情报截获等场合具有一定的应用价值,并且对继续深入研究诱饵信号测向与定位有参考价值。(3)研究了宽带噪声干扰源测向算法,对干扰源信号进行检测,进而对单噪声辐射源进行高精度测向。其次,结合阵列信号处理的MUSIC(Multiple Signal Classification)算法,实现对多噪声辐射源的测向。在干扰信号与雷达信号混杂并存的环境中,实现宽带信号的准确识别和测向。算法考虑在频域上,根据短时傅里叶变换(Short Time Fourier Transform,STFT)的谱线模值最大值和均方值来对信号进行检测和识别,然后截取各信号有用数据段进行时差测向。(4)在高精度波达角(Direction of Arrival,DOA)估计值的基础上,研究了双站测向交叉定位算法,构建角度观测方程组,进而解算出辐射源位置。对测向交叉定位算法的定位误差进行分析,并讨论了在什么条件下定位精度最高。(5)研究了宽带信号测向的FPGA硬件实现。在多相滤波信道化体制下,数据经过抽取后时间分辨率降低,运用传统的到达时间估计得到的时差精度较低。在宽带信号测向算法中,经过时域和频域的对应关系将时差估计问题转换为频率估计问题,其精度不受采样时间间隔的限制。该算法运算简单,适于硬件实现,可以实时进行处理,能达到较高的测向精度。(6)研究了捷变频雷达信号分选及基准频率估计算法。先对接收到的捷变频雷达信号进行高精度频率估计,然后利用相邻两个信号频率差相除,在一定的搜索范围内,通过比较相除结果的小数部分,来分选出不同雷达的信号。根据同一雷达的信号,估计出信号分频系数,从而估计出雷达的基准频率。该算法可以抑制错误分选问题的产生,可以对特定辐射源进行准确识别。
[Abstract]:With the development of electronic technology, the signals transmitted by modern radar usually adopt wideband modulation. Therefore, the research on direction finding and location of wideband signals is of practical significance.This paper aims at some key techniques and links of direction finding and location of wideband signals, such as high precision direction finding algorithm of single signal, estimation and direction finding algorithm of coherent multi-signal in decoy background, direction finding of wideband interference source.The bistatic direction finding cross location algorithm and the hardware FPGA(Field Programmable Gate Arrayof wideband signal direction finding algorithm are studied. The main innovative achievements are as follows: 1) on the basis of high precision wideband signal time difference estimation algorithm,The algorithm of wideband direction finding for long baseline wideband signals is studied systematically. A wideband long baseline direction finding and deblurring algorithm based on time difference correction is proposed, and their performance and application conditions are analyzed in detail.In this algorithm, the initial estimation of time difference is used to correct the phase of the signal, the interferometer algorithm is used to estimate the residual phase difference and the phase is deblurred, thus the precision of direction finding is further improved.The base-line length is not restricted by the phase ambiguity condition. (2) the estimation and direction finding algorithm of the number of wideband coherent multiple emitters in the decoy background is studied.A single baseline system consisting of only two antenna array elements is used to estimate the number of emitter sources and to accurately detect the direction of multiple emitter sources.It has certain application value in electronic reconnaissance and intelligence interception, and has reference value for further research on direction finding and location of decoy signal. (3) this paper studies the algorithm of wideband noise jamming source direction finding, and detects the interference source signal.Furthermore, the direction finding of single noise emitter is carried out with high precision.Secondly, combining the MUSIC(Multiple Signal Classification algorithm of array signal processing, the direction finding of multi-noise emitter is realized.In the mixed environment of jamming signal and radar signal, the accurate recognition and direction finding of wideband signal can be realized.The algorithm considers the detection and recognition of signals in frequency domain according to the maximum and mean square values of spectral mode values of short Time Fourier transform (STFT).Based on the high-precision DOA Direction of Arrivalo estimation, the bistatic cross-locating algorithm is studied, and the angle observation equations are constructed, and the emitter position is solved.The location error of the direction finding cross location algorithm is analyzed, and the FPGA hardware implementation of wideband signal direction finding is discussed under what conditions the positioning accuracy is the highest.In the multiphase filtering channelization system, the time resolution of the data is reduced after extraction, and the time difference accuracy obtained by the traditional time of arrival estimation is low.In the wideband signal direction finding algorithm, the time difference estimation problem is transformed into the frequency estimation problem through the corresponding relation between the time domain and the frequency domain, and its precision is not limited by the sampling time interval.The algorithm is simple in operation, suitable for hardware implementation, and can be processed in real time. It can achieve high precision of direction finding.) the algorithm of signal sorting and reference frequency estimation for frequency agility radar is studied.The frequency of the received frequency agile radar signal is estimated with high accuracy, then the frequency difference of two adjacent signals is divided. In a certain search range, different radar signals are sorted by comparing the fractional parts of the division results.According to the signal of the same radar, the frequency division coefficient of the signal is estimated and the reference frequency of the radar is estimated.The algorithm can suppress the problem of error sorting and identify the specific emitter accurately.
【学位授予单位】：南京航空航天大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TN957.51

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