A novel method based on zoom fast Fourier transform（FFT） is proposed for minimizing the burden processing of cross-ambiguity functions without affecting performance. The low-pass anti-aliasing filter in zoom FFT is ...A novel method based on zoom fast Fourier transform（FFT） is proposed for minimizing the burden processing of cross-ambiguity functions without affecting performance. The low-pass anti-aliasing filter in zoom FFT is realized by using the multistage filtering technique and the weighting processing is employed in the first stage filter to get rid of the redundancy of the computation. In practical systems, the input data is divided into overlapped data frames to avoid loss of detection ability which results in the rapid increase of computational complexity. A segment technique is also proposed in which CAF calculation of overlapped data frames is viewed as slide window FFT to decrease the computational complexity. The experimental results show that compared to the conventional methods, the proposed method can lower computational complexity and is consistent with the real time implementation in existing high-speed digital processors.展开更多
多载波信号具有丰富的频域信息,相参积累能够拓宽信号的有效带宽,克服单载波信号带宽窄导致时差(time difference of arrival,TDOA)、频差(frequency difference of arrival,FDOA)参数估计精度不高的问题。以多载波信号的检测定位为背景...多载波信号具有丰富的频域信息,相参积累能够拓宽信号的有效带宽,克服单载波信号带宽窄导致时差(time difference of arrival,TDOA)、频差(frequency difference of arrival,FDOA)参数估计精度不高的问题。以多载波信号的检测定位为背景,研究了基于多个载波信号互模糊函数(cross ambiguity function,CAF)相参积累的TDOA/FDOA参数估计算法,为多载波信号的无源定位提供高精度的定位参数估计方法。基于接收信号模型,推导了多载波信号的互模糊函数,从TDOA/FDOA两个维度分析了不同载波信号CAF的相位关系,通过相位补偿实现了多载波信号CAF的相参积累,并从理论上分析了TDOA/FDOA参数估计的性能改善情况。蒙特卡罗仿真表明,提出的多载波信号相参积累TDOA/FDOA估计算法性能明显优于单载波信号的估计性能,性能改善情况与理论分析一致。展开更多
Passive radar detects moving targets by Cross Ambiguity Function (CAF), which is based on the cross correlation process of the direct-path signal in reference channel and echo signal in receive channel. Thus, the perf...Passive radar detects moving targets by Cross Ambiguity Function (CAF), which is based on the cross correlation process of the direct-path signal in reference channel and echo signal in receive channel. Thus, the performance of direct-path signal is important to system performance for this type of radar. While the Signal to Noise Ratio (SNR) of direct-path signal is low, it will deteriorate the detection performance. In this paper, how SNR of direct-path signal induces degradation on the SNR of CAF, and how the integration gain affects by integration time are analyzed, both with theoretical analysis and numerical simulation, which are valuable for the R&D of passive radar.展开更多
In this paper, a novel anti-interference direction finding(DF)method for amplitude comparison method based on cyclostationarity is proposed. With the periodic properties of the communication signals, the desired signa...In this paper, a novel anti-interference direction finding(DF)method for amplitude comparison method based on cyclostationarity is proposed. With the periodic properties of the communication signals, the desired signal’s amplitude value can be effectively obtained even though there is an interference signal whose frequency spectrum overlaps with the desired signal in the environment,and the corresponding incident angle can be estimated accurately with the amplitude comparison method. The influence of interference signal on the amplitude comparison method is discussed and the proposed method’s theoretical feasibility is also analyzed. Compared with the conventional method,simulations are provided to demonstrate the anti-interference capability of the proposed method. The amplitude comparison DF system working at 2.44 GHz and 5.8 GHz is also constructed to verify its feasibility.展开更多
基金Sponsored by the Excellent Young Scholar Research Fund of Beijing Institute of Technology (000Y01-5)BIT(UBF 200501F4208.4)
文摘A novel method based on zoom fast Fourier transform（FFT） is proposed for minimizing the burden processing of cross-ambiguity functions without affecting performance. The low-pass anti-aliasing filter in zoom FFT is realized by using the multistage filtering technique and the weighting processing is employed in the first stage filter to get rid of the redundancy of the computation. In practical systems, the input data is divided into overlapped data frames to avoid loss of detection ability which results in the rapid increase of computational complexity. A segment technique is also proposed in which CAF calculation of overlapped data frames is viewed as slide window FFT to decrease the computational complexity. The experimental results show that compared to the conventional methods, the proposed method can lower computational complexity and is consistent with the real time implementation in existing high-speed digital processors.
文摘多载波信号具有丰富的频域信息,相参积累能够拓宽信号的有效带宽,克服单载波信号带宽窄导致时差(time difference of arrival,TDOA)、频差(frequency difference of arrival,FDOA)参数估计精度不高的问题。以多载波信号的检测定位为背景,研究了基于多个载波信号互模糊函数(cross ambiguity function,CAF)相参积累的TDOA/FDOA参数估计算法,为多载波信号的无源定位提供高精度的定位参数估计方法。基于接收信号模型,推导了多载波信号的互模糊函数,从TDOA/FDOA两个维度分析了不同载波信号CAF的相位关系,通过相位补偿实现了多载波信号CAF的相参积累,并从理论上分析了TDOA/FDOA参数估计的性能改善情况。蒙特卡罗仿真表明,提出的多载波信号相参积累TDOA/FDOA估计算法性能明显优于单载波信号的估计性能,性能改善情况与理论分析一致。
文摘Passive radar detects moving targets by Cross Ambiguity Function (CAF), which is based on the cross correlation process of the direct-path signal in reference channel and echo signal in receive channel. Thus, the performance of direct-path signal is important to system performance for this type of radar. While the Signal to Noise Ratio (SNR) of direct-path signal is low, it will deteriorate the detection performance. In this paper, how SNR of direct-path signal induces degradation on the SNR of CAF, and how the integration gain affects by integration time are analyzed, both with theoretical analysis and numerical simulation, which are valuable for the R&D of passive radar.
基金the National Natural Science Foundation of China(62001291)the National Natural Science Foundation of China(61901263)+1 种基金the Joint Foundation of Key Laboratory of Shanghai Jiao Tong universityXidian University,Ministry of Education(LHJJ/2021-09)the Shanghai Science and Technology Innovation Action Plan(20511106605)。
文摘In this paper, a novel anti-interference direction finding(DF)method for amplitude comparison method based on cyclostationarity is proposed. With the periodic properties of the communication signals, the desired signal’s amplitude value can be effectively obtained even though there is an interference signal whose frequency spectrum overlaps with the desired signal in the environment,and the corresponding incident angle can be estimated accurately with the amplitude comparison method. The influence of interference signal on the amplitude comparison method is discussed and the proposed method’s theoretical feasibility is also analyzed. Compared with the conventional method,simulations are provided to demonstrate the anti-interference capability of the proposed method. The amplitude comparison DF system working at 2.44 GHz and 5.8 GHz is also constructed to verify its feasibility.
