雷达系统在临近目标分辨中存在近区旁瓣过高的问题,导致了弱目标淹没、临近目标回波主旁瓣混叠等现象。针对这一问题,该文提出了一种抑制近区距离旁瓣的正交频分复用(orthogonal frequency division multiplexing,OFDM)多输入多输出雷...雷达系统在临近目标分辨中存在近区旁瓣过高的问题,导致了弱目标淹没、临近目标回波主旁瓣混叠等现象。针对这一问题,该文提出了一种抑制近区距离旁瓣的正交频分复用(orthogonal frequency division multiplexing,OFDM)多输入多输出雷达波形设计方法。首先,构造一组基于相位编码调制的OFDM发射波形集,在此基础上,以极小化极大原理和近区积分旁瓣水平建立目标函数,令发射波形恒模为约束条件;然后,借助发射波形与相位的对应关系,将波形设计转化为无约束优化问题,并利用Broyden-Fletcher-Goldfarb-Shanno算法求解。理论分析和仿真结果表明,该文方法较现有方法具有更好的近区旁瓣抑制特性和更低的运算复杂度。展开更多
With the emergence of location-based applications in various fields, the higher accuracy of positioning is demanded. By utilizing the time differences of arrival （TDOAs） and gain ratios of arrival （GROAs）, an effi...With the emergence of location-based applications in various fields, the higher accuracy of positioning is demanded. By utilizing the time differences of arrival （TDOAs） and gain ratios of arrival （GROAs）, an efficient algorithm for estimating the position is proposed, which exploits the Broyden-Fletcher-Goldfarb-Shanno （BFGS） quasi-Newton method to solve nonlinear equations at the source location under the additive measurement error. Although the accuracy of two-step weighted-least-square （WLS） method based on TDOAs and GROAs is very high, this method has a high computational complexity. While the proposed approach can achieve the same accuracy and bias with the lower computational complexity when the signal-to-noise ratio （SNR） is high, especially it can achieve better accuracy and smaller bias at a lower SNR. The proposed algorithm can be applied to the actual environment due to its real-time property and good robust performance. Simulation results show that with a good initial guess to begin with, the proposed estimator converges to the true solution and achieves the Cramer-Rao lower bound （CRLB） accuracy for both near-field and far-field sources.展开更多
文摘雷达系统在临近目标分辨中存在近区旁瓣过高的问题,导致了弱目标淹没、临近目标回波主旁瓣混叠等现象。针对这一问题,该文提出了一种抑制近区距离旁瓣的正交频分复用(orthogonal frequency division multiplexing,OFDM)多输入多输出雷达波形设计方法。首先,构造一组基于相位编码调制的OFDM发射波形集,在此基础上,以极小化极大原理和近区积分旁瓣水平建立目标函数,令发射波形恒模为约束条件;然后,借助发射波形与相位的对应关系,将波形设计转化为无约束优化问题,并利用Broyden-Fletcher-Goldfarb-Shanno算法求解。理论分析和仿真结果表明,该文方法较现有方法具有更好的近区旁瓣抑制特性和更低的运算复杂度。
基金supported by the Major National Science&Technology Projects(2010ZX03006-002-04)the National Natural Science Foundation of China(61072070)+4 种基金the Doctorial Programs Foundation of the Ministry of Education(20110203110011)the"111 Project"(B08038)the Fundamental Research Funds of the Ministry of Education(72124338)the Key Programs for Natural Science Foundation of Shanxi Province(2012JZ8002)the Foundation of State Key Laboratory of Integrated Services Networks(ISN1101002)
文摘With the emergence of location-based applications in various fields, the higher accuracy of positioning is demanded. By utilizing the time differences of arrival （TDOAs） and gain ratios of arrival （GROAs）, an efficient algorithm for estimating the position is proposed, which exploits the Broyden-Fletcher-Goldfarb-Shanno （BFGS） quasi-Newton method to solve nonlinear equations at the source location under the additive measurement error. Although the accuracy of two-step weighted-least-square （WLS） method based on TDOAs and GROAs is very high, this method has a high computational complexity. While the proposed approach can achieve the same accuracy and bias with the lower computational complexity when the signal-to-noise ratio （SNR） is high, especially it can achieve better accuracy and smaller bias at a lower SNR. The proposed algorithm can be applied to the actual environment due to its real-time property and good robust performance. Simulation results show that with a good initial guess to begin with, the proposed estimator converges to the true solution and achieves the Cramer-Rao lower bound （CRLB） accuracy for both near-field and far-field sources.
