自测速频率跳变合成带宽波形设计及处理算法
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摘要
合成带宽信号通过脉冲间频率跳变与相干处理,等效地合成大带宽,可获得高距离分辨能力。但是,当目标相对于雷达具有径向运动分量时,径向速度引起的多普勒效应会在回波信号中产生相应的一次相位项和二次相位项,严重影响目标一维高分辨距离像的成像质量。通常雷达需额外发射一组窄带脉冲用来辅助测速,极大浪费雷达资源。本文提出一种自测速频率跳变合成带宽波形设计及处理算法,该算法可以在低信噪比下有效估计目标速度信息,相比于现有算法具有更好的普适性和灵活性。同时,可以通过改变相关参数快捷、灵活地改变波形跳变形式,具有较强的抗干扰能力,蕴藏较大的实用潜力与价值。
Synthetic bandwidth waveform yields high range resolution with equivalent wide bandwidth by applying hopped frequency and coherent processing between different pulses. However, when a moving target is concerned, the quality of the high range resolution profile would degrade seriously because of the Doppler effect in the linear and quadratic phase items of the echo signal, which is caused by radial velocity of the target. Generally, radar needs to emit another waveform with narrow bandwidth to help measure the target speed but at a cost of added hardware resources. In this paper, a frequency hopped synthetic bandwidth waveform design and processing algorithm for self-speed measurement is proposed. Speed of the target can be effectively measured in low SNR environment, which is superior to many existing methods. In addition, the hopped frequency can be flexibly designed by changing several parameters, which presents good anti-interference performance.
Synthetic bandwidth waveform yields high range resolution with equivalent wide bandwidth by applying hopped frequency and coherent processing between different pulses. However, when a moving target is concerned, the quality of the high range resolution profile would degrade seriously because of the Doppler effect in the linear and quadratic phase items of the echo signal, which is caused by radial velocity of the target. Generally, radar needs to emit another waveform with narrow bandwidth to help measure the target speed but at a cost of added hardware resources. In this paper, a frequency hopped synthetic bandwidth waveform design and processing algorithm for self-speed measurement is proposed. Speed of the target can be effectively measured in low SNR environment, which is superior to many existing methods. In addition, the hopped frequency can be flexibly designed by changing several parameters, which presents good anti-interference performance.
引文
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[13] Liu Z,Wei X,Li X.Low sidelobe robust imaging in random frequency-hopping wideband radar based on compressed sensing[J].Journal of Central South University,2013,20(3):702-714.
[14] Isoda K,Hara T.Doppler Velocity Measurement Method with a Second-Time-Around Echoes Suppression for Synthetic Bandwidth Radars[C]//Proceedings of the 8th European Radar Conference,2011:134-137.
[15] Sun Y,Liu Q,Cai J,et al.A Novel Weighted Mismatched Filter for Reducing Range Sidelobes[J].IEEE Transactions on Aerospace and Electronic Systems (Early Access),2018:1-1.
[16] Sun Y,Liu Q,Cai J,et al.A Novel Method for Designing General Window Functions with Flexible Spectral Characteristics[J].Sensors,2018,18(9):3081.
[2] 刘一民.合成带宽雷达高分辨成像与目标速度估计[D].北京:清华大学,2009:1-2.Liu Yimin.High Range Resolution Profiling and Velocity Estimation in Synthetic Bandwidth Radar[D].Beijing:Tsinghua University,2009:1-2.(in Chinese)
[3] Liu Y,Shan T,Feng Y.Research on the range side lobe suppression method for modulated stepped frequency radar signals[C]//AIP Conference Proceedings,2018:1967.
[4] Huang X,Yang M,Liu M,et al.An efficient and robust frequency estimator dealing with short-observation under-sampled waveforms[J].IEEE Access,2018(6):48021- 48029.
[5] Wang F,Du S,Sun W,et al.A method of velocity estimation using composite hyperbolic frequency-modulated signals in active sonar[J].Journal of the Acoustical Society of America,2017,141(5):3117-3122.
[6] Gill G S.Simultaneous pulse compression and Doppler processing with step frequency waveform[J].Electronic Letters,1996,32(23):2178-2179.
[7] 刘峥,张守宏.步进频率雷达目标的运动参数估计[J].电子学报,2000(3):43- 45.Liu Zheng,Zhang Shouhong.Estimation of Target Motion Parameter in a Stepped Frequency Pulses Radar[J].Acta Electronica Sinica,2000(3):43- 45.(in Chinese)
[8] Wang F,Long T.A new method of velocity estimation for inverse V-shape stepped frequency signal[C]//2006 CIE International Conference on Radar,2006:1-3.
[9] Chen H,Liu Y,Jiang W,et al.A New Approach for Synthesizing the Range Profile of Moving Targets via Stepped-Frequency Waveforms[J].IEEE Geoscience and Remote Sensing Letters,2006,3(3):406- 409.
[10] Yang L,Su W,Gu H.Synthetic Ultra-wideband Radar Range Profile Based on Stepped Frequency Pulse Trains[C]//Proceedings of 2010 IEEE International Conference on Ultra-Wideband,2010.
[11] Kathree U,Nel W,Van Rensburg V,et al.Investigation of Hopped Frequency Waveforms for Range and Velocity Measurements of Radar Targets[C]//2015 IEEE Radar Conference,2015:475- 480.
[12] Ma C,Xu X.A Motion Compensation Technique for Stepped-frequency Radar with Phase Slope Analysis[C]//Proceedings of 2011 IEEE CIE International Conference on Radar,2011(2):1543-1546.
[13] Liu Z,Wei X,Li X.Low sidelobe robust imaging in random frequency-hopping wideband radar based on compressed sensing[J].Journal of Central South University,2013,20(3):702-714.
[14] Isoda K,Hara T.Doppler Velocity Measurement Method with a Second-Time-Around Echoes Suppression for Synthetic Bandwidth Radars[C]//Proceedings of the 8th European Radar Conference,2011:134-137.
[15] Sun Y,Liu Q,Cai J,et al.A Novel Weighted Mismatched Filter for Reducing Range Sidelobes[J].IEEE Transactions on Aerospace and Electronic Systems (Early Access),2018:1-1.
[16] Sun Y,Liu Q,Cai J,et al.A Novel Method for Designing General Window Functions with Flexible Spectral Characteristics[J].Sensors,2018,18(9):3081.