In this paper,we study the accuracy of delay-Doppler parameter estimation of targets in a passive radar using orthogonal frequency division multiplexing(OFDM)signal.A coarse-fine joint estimation method is proposed to...In this paper,we study the accuracy of delay-Doppler parameter estimation of targets in a passive radar using orthogonal frequency division multiplexing(OFDM)signal.A coarse-fine joint estimation method is proposed to achieve better estimation accuracy of target parameters without excessive computational burden.Firstly,the modulation symbol domain(MSD)method is used to roughly estimate the delay and Doppler of targets.Then,to obtain high-precision Doppler estimation,the atomic norm(AN)based on the multiple measurement vectors(MMV)model(MMV-AN)is used to manifest the signal sparsity in the continuous Doppler domain.At the same time,a reference signal compensation(RSC)method is presented to obtain highprecision delay estimation.Simulation results based on the OFDM signal show that the coarse-fine joint estimation method based on AN-RSC can obtain a more accurate estimation of target parameters compared with other algorithms.In addition,the proposed method also possesses computational advantages compared with the joint parameter estimation.展开更多
Orthogonal frequency division multiplexing(OFDM) radar with multicarrier phase-coded waveforms has been recently introduced to achieve high range resolution.The conventional method for obtaining the high resolution ...Orthogonal frequency division multiplexing(OFDM) radar with multicarrier phase-coded waveforms has been recently introduced to achieve high range resolution.The conventional method for obtaining the high resolution range profile(HRRP) is based on matched filters.A method of synthesizing HRRP based on the fast Fourier transform(FFT) and decoding is proposed.The mathematical expressions of HRRP are derived by assuming an elementary scenario of point-scattering targets.Based on the characteristic of OFDM multicarrier signals,it mainly analyzes the influence on HRRP exerted by several factors,such as velocity compensation errors,the sampling frequency offset,and so on.The conclusions are significant for the design of the OFDM imaging radar.Finally,the simulation results demonstrate the validity of the conclusions.展开更多
Sparse-array Synthetic Impulse and Aperture Radar (SIAR) can isotropically radiate by employing multiple frequencies (synthetic pulse) and multiple antennas (synthetic antenna). According to Ambiguity Function(AF), it...Sparse-array Synthetic Impulse and Aperture Radar (SIAR) can isotropically radiate by employing multiple frequencies (synthetic pulse) and multiple antennas (synthetic antenna). According to Ambiguity Function(AF), its range resolution depends only on bandwidth of transmitted signals, however, the distance grating lobes emerge when increasing the time-bandwidth product of transmitted signals. The performance of pulse compression is analyzed with the transmitted signals modulated by phase-coded sequences. It is seen that greater ratio of pulse compression and suppression of range sidelobe in SIAR can be obtained, and its effective range and range resolution is increased as well.展开更多
To obtain the radar High Range Resolution (HRR) profile of the slowly moving ground target in strong clutter background, the Phase-Coded Hopped-Frequency (PCHF) waveform is proposed. By multiple-bursts coherent proces...To obtain the radar High Range Resolution (HRR) profile of the slowly moving ground target in strong clutter background, the Phase-Coded Hopped-Frequency (PCHF) waveform is proposed. By multiple-bursts coherent processing, the HRR profile synthesis, target velocity compensation and clutter compression can be accomplished simultaneously. The new waveform is shown to have good ability to suppress ground clutter and good Electronic Counter-CounterMeasures (ECCM) ability as well. The clutter compression performance of the proposed method is verified by the numerical results.展开更多
随着外辐射源雷达技术的快速发展和逐步应用,干扰问题日渐受到关注。本文以对OFDM外辐射源雷达工作性能带来极大影响的线性调频(Linear Frequency Modulation,LFM)干扰为研究对象,根据线性调频干扰信号模型,从理论上分析了多周期线性调...随着外辐射源雷达技术的快速发展和逐步应用,干扰问题日渐受到关注。本文以对OFDM外辐射源雷达工作性能带来极大影响的线性调频(Linear Frequency Modulation,LFM)干扰为研究对象,根据线性调频干扰信号模型,从理论上分析了多周期线性调频干扰对OFDM外辐射源雷达的干扰形态和特性,并推导了干扰带宽与相关时延宽度的关系,进而提出了一种自适应多周期线性调频干扰抑制方法。所提干扰抑制方法首先在频域进行干扰检测并估计线性调频干扰带宽,然后根据干扰带宽在距离多普勒谱上选取慢时间维序列构造干扰子空间,最后通过干扰子空间正交投影实现对多周期线性调频干扰的抑制。在不同干扰强度、干扰带宽以及线性调频周期条件下,以基底改善因子作为评估指标,仿真验证了所提方法的有效性和鲁棒性。展开更多
Orthogonal frequency division multiplexing (OFDM) waveform enables radar and communication functions simultaneously, which encounters low angle resolution and poor data rate for traditional single input single output ...Orthogonal frequency division multiplexing (OFDM) waveform enables radar and communication functions simultaneously, which encounters low angle resolution and poor data rate for traditional single input single output (SISO) systems. To solve these problems, an integrated radar and communication system (IRCS) with multiple input multiple output (MIMO) OFDM waveform is proposed. The different limitations of radar and communication in designing such a system are investigated. Then, an optimization problem is devised to obtain suitable system parameters, including the number of subcarriers, subcarrier spacing, number of symbols, pulse repetition frequency (PRF) and length of cyclic prefix (CP). Finally, to satisfy the requirements of both radar and communication, the IRCS parameters are derived in three typical cases. Several numerical results are presented to illustrate the demands of radar and communication, inconsistent or consistent, for the IRCS parameters and the superiority of the proposed system.展开更多
随着雷达系统和通信系统的快速发展,二者之间相互融合,能够凸显一体化系统设计和应用便利优势,如在通信系统方面,高数据速率传输能够更好地满足信号大带宽拓展需求,在一定程度上推动通信工作频段往高频段方向发展,有利于进行一体化的信...随着雷达系统和通信系统的快速发展,二者之间相互融合,能够凸显一体化系统设计和应用便利优势,如在通信系统方面,高数据速率传输能够更好地满足信号大带宽拓展需求,在一定程度上推动通信工作频段往高频段方向发展,有利于进行一体化的信号设计和应用。为此,从正交频分复用(Orthogonal Frequency Division Multiplexing,OFDM)信号的峰值平均功率比(Peak to Average Power Ratio,PAPR)性能问题出发,通过仿真分别研究和探讨不同子载波数目以及调制方式对于OFDM一体化信号的PAPR特性的影响,列举两种改善PAPR性能的技术方法,以期达到预设的研究目标。展开更多
该文利用武汉大学新近研制的全数字主被动一体化高频地波雷达硬件平台,开展了短波通信与雷达探测的一体化实验研究。结合高频电波特定传播环境,首先从通信角度介绍了正交频分复用(Orthogonal Frequency Division Multiplexing,OFDM)在...该文利用武汉大学新近研制的全数字主被动一体化高频地波雷达硬件平台,开展了短波通信与雷达探测的一体化实验研究。结合高频电波特定传播环境,首先从通信角度介绍了正交频分复用(Orthogonal Frequency Division Multiplexing,OFDM)在短波通信中的关键技术,然后从雷达探测角度分析了OFDM参数设计准则及其对超视距雷达探测性能的影响,最后说明了通信信号解调与探测信息获取的处理流程及部分关键技术,并介绍了硬件平台、参数配置及实验结果。结果表明OFDM波形是一种良好的雷达通信一体化信号,该技术对超视距雷达(Over-The-Horizon Radar,OTHR)组网探测研究具有重要意义。展开更多
基金supported by the National Natural Science Foundation of China(6193101562071335)+1 种基金the Technological Innovation Project of Hubei Province of China(2019AAA061)the Natural Science F oundation of Hubei Province of China(2021CFA002)。
文摘In this paper,we study the accuracy of delay-Doppler parameter estimation of targets in a passive radar using orthogonal frequency division multiplexing(OFDM)signal.A coarse-fine joint estimation method is proposed to achieve better estimation accuracy of target parameters without excessive computational burden.Firstly,the modulation symbol domain(MSD)method is used to roughly estimate the delay and Doppler of targets.Then,to obtain high-precision Doppler estimation,the atomic norm(AN)based on the multiple measurement vectors(MMV)model(MMV-AN)is used to manifest the signal sparsity in the continuous Doppler domain.At the same time,a reference signal compensation(RSC)method is presented to obtain highprecision delay estimation.Simulation results based on the OFDM signal show that the coarse-fine joint estimation method based on AN-RSC can obtain a more accurate estimation of target parameters compared with other algorithms.In addition,the proposed method also possesses computational advantages compared with the joint parameter estimation.
基金supported by the National Natural Science Foundation of China (6087213461072117)
文摘Orthogonal frequency division multiplexing(OFDM) radar with multicarrier phase-coded waveforms has been recently introduced to achieve high range resolution.The conventional method for obtaining the high resolution range profile(HRRP) is based on matched filters.A method of synthesizing HRRP based on the fast Fourier transform(FFT) and decoding is proposed.The mathematical expressions of HRRP are derived by assuming an elementary scenario of point-scattering targets.Based on the characteristic of OFDM multicarrier signals,it mainly analyzes the influence on HRRP exerted by several factors,such as velocity compensation errors,the sampling frequency offset,and so on.The conclusions are significant for the design of the OFDM imaging radar.Finally,the simulation results demonstrate the validity of the conclusions.
文摘Sparse-array Synthetic Impulse and Aperture Radar (SIAR) can isotropically radiate by employing multiple frequencies (synthetic pulse) and multiple antennas (synthetic antenna). According to Ambiguity Function(AF), its range resolution depends only on bandwidth of transmitted signals, however, the distance grating lobes emerge when increasing the time-bandwidth product of transmitted signals. The performance of pulse compression is analyzed with the transmitted signals modulated by phase-coded sequences. It is seen that greater ratio of pulse compression and suppression of range sidelobe in SIAR can be obtained, and its effective range and range resolution is increased as well.
基金Supported by the National Natural Science Foundation of China (No.60302009).
文摘To obtain the radar High Range Resolution (HRR) profile of the slowly moving ground target in strong clutter background, the Phase-Coded Hopped-Frequency (PCHF) waveform is proposed. By multiple-bursts coherent processing, the HRR profile synthesis, target velocity compensation and clutter compression can be accomplished simultaneously. The new waveform is shown to have good ability to suppress ground clutter and good Electronic Counter-CounterMeasures (ECCM) ability as well. The clutter compression performance of the proposed method is verified by the numerical results.
文摘随着外辐射源雷达技术的快速发展和逐步应用,干扰问题日渐受到关注。本文以对OFDM外辐射源雷达工作性能带来极大影响的线性调频(Linear Frequency Modulation,LFM)干扰为研究对象,根据线性调频干扰信号模型,从理论上分析了多周期线性调频干扰对OFDM外辐射源雷达的干扰形态和特性,并推导了干扰带宽与相关时延宽度的关系,进而提出了一种自适应多周期线性调频干扰抑制方法。所提干扰抑制方法首先在频域进行干扰检测并估计线性调频干扰带宽,然后根据干扰带宽在距离多普勒谱上选取慢时间维序列构造干扰子空间,最后通过干扰子空间正交投影实现对多周期线性调频干扰的抑制。在不同干扰强度、干扰带宽以及线性调频周期条件下,以基底改善因子作为评估指标,仿真验证了所提方法的有效性和鲁棒性。
基金supported by the National Natural Science Foundation of China(6123101761671352)
文摘Orthogonal frequency division multiplexing (OFDM) waveform enables radar and communication functions simultaneously, which encounters low angle resolution and poor data rate for traditional single input single output (SISO) systems. To solve these problems, an integrated radar and communication system (IRCS) with multiple input multiple output (MIMO) OFDM waveform is proposed. The different limitations of radar and communication in designing such a system are investigated. Then, an optimization problem is devised to obtain suitable system parameters, including the number of subcarriers, subcarrier spacing, number of symbols, pulse repetition frequency (PRF) and length of cyclic prefix (CP). Finally, to satisfy the requirements of both radar and communication, the IRCS parameters are derived in three typical cases. Several numerical results are presented to illustrate the demands of radar and communication, inconsistent or consistent, for the IRCS parameters and the superiority of the proposed system.
文摘随着雷达系统和通信系统的快速发展,二者之间相互融合,能够凸显一体化系统设计和应用便利优势,如在通信系统方面,高数据速率传输能够更好地满足信号大带宽拓展需求,在一定程度上推动通信工作频段往高频段方向发展,有利于进行一体化的信号设计和应用。为此,从正交频分复用(Orthogonal Frequency Division Multiplexing,OFDM)信号的峰值平均功率比(Peak to Average Power Ratio,PAPR)性能问题出发,通过仿真分别研究和探讨不同子载波数目以及调制方式对于OFDM一体化信号的PAPR特性的影响,列举两种改善PAPR性能的技术方法,以期达到预设的研究目标。
文摘该文利用武汉大学新近研制的全数字主被动一体化高频地波雷达硬件平台,开展了短波通信与雷达探测的一体化实验研究。结合高频电波特定传播环境,首先从通信角度介绍了正交频分复用(Orthogonal Frequency Division Multiplexing,OFDM)在短波通信中的关键技术,然后从雷达探测角度分析了OFDM参数设计准则及其对超视距雷达探测性能的影响,最后说明了通信信号解调与探测信息获取的处理流程及部分关键技术,并介绍了硬件平台、参数配置及实验结果。结果表明OFDM波形是一种良好的雷达通信一体化信号,该技术对超视距雷达(Over-The-Horizon Radar,OTHR)组网探测研究具有重要意义。