低信噪比(signal-to-noise ratio,SNR)或小接收快拍数条件下,经典的二维(two-dimensional,2D)波达方向(direction of arrival,DOA)算法存在估计精度低的缺点。针对该问题,充分利用L型阵列接收数据的自、互相关信息,提出一种适用于低SNR...低信噪比(signal-to-noise ratio,SNR)或小接收快拍数条件下,经典的二维(two-dimensional,2D)波达方向(direction of arrival,DOA)算法存在估计精度低的缺点。针对该问题,充分利用L型阵列接收数据的自、互相关信息,提出一种适用于低SNR及小接收快拍数环境下的2D DOA估计新方法。该方法首先通过解析优化2D谱峰搜索问题,获得方位角与仰角之间的特定约束关系,进而将包含2D角度参量的目标函数转化为只包含一维(one-dimensional,1D)角度参量,即可通过1D谱峰搜索获得方位角(或仰角)估计值,最后再次利用该约束关系求得与之对应的仰角(或方位角)估计值。该方法只需1D谱峰搜索,而且所得2D角度估计参数可自动实现配对。计算机仿真验证了该方法在低SNR及小接收快拍数情况下的有效性。展开更多
Ubiquitous radar is a new radar system that provides continuous and uninterrupted multifunction capability within a coverage volume. Continuous coverage from close-in ＂pop-up＂ targets in clutter to long-range target...Ubiquitous radar is a new radar system that provides continuous and uninterrupted multifunction capability within a coverage volume. Continuous coverage from close-in ＂pop-up＂ targets in clutter to long-range targets impacts selection of waveform parameters. The coherent processing interval （CPI） must be long enough to achieve a certain signal-to-noise ratio （SNR） that ensures the efficiency of detection. The condition of detection in the case of low SNR is analyzed, and three different cases that would occur during integration are discussed and a method to determine the CPI is presented. The simulation results show that targets detection with SNR as low as -26 dB in the experimental system can possibly determine the CPI.展开更多
基于分数阶傅里叶变换(Fractional Fourier Transform,FRFT)对线性调频(Linear Frequency Modulated,LFM)信号参数进行估计,问题关键是确定FRFT最佳阶数,根据误差迭代思想提出新的参数估计算法,该算法利用归一化带宽和旋转角的转化关系...基于分数阶傅里叶变换(Fractional Fourier Transform,FRFT)对线性调频(Linear Frequency Modulated,LFM)信号参数进行估计,问题关键是确定FRFT最佳阶数,根据误差迭代思想提出新的参数估计算法,该算法利用归一化带宽和旋转角的转化关系,由估计误差推算角度差值,有效降低了运算量,不需要调频斜率正负的先验信息,改进的对数搜索算法可以进一步提高参数估计结果的稳定性和可靠性。仿真结果表明,信噪比在-8 dB以上时该方法在高效率的前提下仍具有良好的参数估计性能,平均估计误差在1%以内,估计结果接近Cramer-Rao下限,满足工程实时处理需求。展开更多
文摘低信噪比(signal-to-noise ratio,SNR)或小接收快拍数条件下,经典的二维(two-dimensional,2D)波达方向(direction of arrival,DOA)算法存在估计精度低的缺点。针对该问题,充分利用L型阵列接收数据的自、互相关信息,提出一种适用于低SNR及小接收快拍数环境下的2D DOA估计新方法。该方法首先通过解析优化2D谱峰搜索问题,获得方位角与仰角之间的特定约束关系,进而将包含2D角度参量的目标函数转化为只包含一维(one-dimensional,1D)角度参量,即可通过1D谱峰搜索获得方位角(或仰角)估计值,最后再次利用该约束关系求得与之对应的仰角(或方位角)估计值。该方法只需1D谱峰搜索,而且所得2D角度估计参数可自动实现配对。计算机仿真验证了该方法在低SNR及小接收快拍数情况下的有效性。
文摘Ubiquitous radar is a new radar system that provides continuous and uninterrupted multifunction capability within a coverage volume. Continuous coverage from close-in ＂pop-up＂ targets in clutter to long-range targets impacts selection of waveform parameters. The coherent processing interval （CPI） must be long enough to achieve a certain signal-to-noise ratio （SNR） that ensures the efficiency of detection. The condition of detection in the case of low SNR is analyzed, and three different cases that would occur during integration are discussed and a method to determine the CPI is presented. The simulation results show that targets detection with SNR as low as -26 dB in the experimental system can possibly determine the CPI.
