一种天波超视距雷达电离层相位污染的校正算法
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摘要
时变电离层的相位污染使天波超视距雷达高频回波谱展宽,影响对舰船等低速目标的检测。针对长相干积累时回波谱受到电离层大幅度相位调制导致正负Bragg峰重叠的情况,提出一种联合小波变换和基于模型假设的校正方法(即WTM法)。该方法首先利用小波变换补偿回波相位,使得正负Bragg峰可以初步区分,然后利用基于功率比的自适应滑窗信号提取方法取出初步校正后的标校信号,最后在时域根据假设的模型对回波信号进行精确的相位污染校正。仿真结果表明,该方法对于电离层大幅度相位污染导致的高频回波谱正负Bragg峰重叠的情况具有明显的去污染效果,性能优于改进的MESA法。
The significant Doppler spread of over-the-horizon radar(OTHR)echoes induced by the timevariant phase modulation of ionosphere limits the detection performance for low-speed targets,such as ships.Considering the spreading and overlapping Bragg peaks caused by ionospheric phase contamination with large amplitude in long coherent integration time(CIT),ajoint correction scheme based on wavelet transform and the method of hypothetical model is proposed in this paper.In the scheme,wavelet transform is firstly used to compensate the echo phase so that the positive and negative Bragg peaks can be roughly distinguished.Then an adaptive sliding window filter based on power ratio is applied to extract the calibration signal,and accurate phase contamination correction is carried out based on the hypothetical model in time domain.The simulation results show that the scheme is effective for the situation of the two Bragg peaks overlapping caused by ionospheric phase contamination with large amplitude,and has a better performance than the improved maximum entropy spectrum analysis(MESA)method.
The significant Doppler spread of over-the-horizon radar(OTHR)echoes induced by the timevariant phase modulation of ionosphere limits the detection performance for low-speed targets,such as ships.Considering the spreading and overlapping Bragg peaks caused by ionospheric phase contamination with large amplitude in long coherent integration time(CIT),ajoint correction scheme based on wavelet transform and the method of hypothetical model is proposed in this paper.In the scheme,wavelet transform is firstly used to compensate the echo phase so that the positive and negative Bragg peaks can be roughly distinguished.Then an adaptive sliding window filter based on power ratio is applied to extract the calibration signal,and accurate phase contamination correction is carried out based on the hypothetical model in time domain.The simulation results show that the scheme is effective for the situation of the two Bragg peaks overlapping caused by ionospheric phase contamination with large amplitude,and has a better performance than the improved maximum entropy spectrum analysis(MESA)method.
引文
[1]胡进峰,艾慧,李万阁,等.基于匹配傅里叶变换的相位解污染算法[J].雷达科学与技术,2015,13(3):291-295.
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[9]LIU Y,NIE Z,ZHAO Z,et al.A Cascaded Correction Method to Reduce the Contamination of Ionospheric Frequency Modulation for HF Skywave Radars[C]∥Antennas and Propagation Society International Symposium,Charleston,SC:IEEE,2009:1-4.
[10]罗欢,陈建文,鲍拯.一种天波超视距雷达电离层相位污染联合校正方法[J].电子与信息学报,2013,35(12):2829-2835.
[11]刘清艳,杨强,姜维.基于CMOR小波的雷达信号解相位污染方法[J].微计算机信息(测控自动化),2009,25(4-1):305-307.
[12]LIU Y,NIE Z,ZHAO Z.A Method to Adaptively Compensate for Ionospheric Layer Movement in HF Sky Wave Radar Systems[J].Journal of University of Electronic Science and Technology of China,2008,37(3):335-338.
[13]PARENT J,BOURDILLON A.A Method to Correct HF Skywave Backscattered Signals for Ionospheric Frequency Modulation[J].IEEE Trans on Antennas and Propagation,1988,36(1):127-135.
[14]赵志国,陈建文,鲍拯.分时波束空间MIMO天波雷达发射ADBF方法[J].华中科技大学学报(自然科学版),2013,41(2):64-69.
[2]LU K,WANG J,LIU X.A Piecewise Parametric Method Based on Polynomial Phase Model to Compen sate Ionospheric Phase Contamination[C]∥IEEE International Conference on Acoustics,Speech,and Signal Processing,New York:IEEE,2003:405-408.
[3]BO C,GU H,SU W,et al.Ionosphere Phase Decontamination Method Based on Subspace in Sky-Wave OTHR[J].Electronics Letters,2014,50(24):1874-1875.
[4]罗欢,陈建文,鲍拯.同时校正电离层幅度和相位污染的MLE方法[J].华中科技大学学报(自然科学版),2013,41(9):17-21.
[5]邢孟道,保铮.电离层电波传播相位污染校正[J].电波科学学报,2002,17(2):129-133.
[6]BOURDILLON A,GAUTHIER F,PARENT J.Use of Maximum Entropy Spectral Analysis to Improve Ship Detection by Over-the-Horizon Radar[J].Radio Science,1987,22(2):313-320.
[7]ANDERSON S J,ABRAMOVICH Y I.A Unified Approach to Detection Classification,and Correction of Ionospheric Distortion in HF Sky Wave Radar Systems[J].Radio Science,1998,33(4):1055-1067.
[8]李钢,杨仕文,刘颜回,等.天波超视距雷达电离层大幅度相位污染校正算法研究[J].宇航学报,2008,29(2):670-674.
[9]LIU Y,NIE Z,ZHAO Z,et al.A Cascaded Correction Method to Reduce the Contamination of Ionospheric Frequency Modulation for HF Skywave Radars[C]∥Antennas and Propagation Society International Symposium,Charleston,SC:IEEE,2009:1-4.
[10]罗欢,陈建文,鲍拯.一种天波超视距雷达电离层相位污染联合校正方法[J].电子与信息学报,2013,35(12):2829-2835.
[11]刘清艳,杨强,姜维.基于CMOR小波的雷达信号解相位污染方法[J].微计算机信息(测控自动化),2009,25(4-1):305-307.
[12]LIU Y,NIE Z,ZHAO Z.A Method to Adaptively Compensate for Ionospheric Layer Movement in HF Sky Wave Radar Systems[J].Journal of University of Electronic Science and Technology of China,2008,37(3):335-338.
[13]PARENT J,BOURDILLON A.A Method to Correct HF Skywave Backscattered Signals for Ionospheric Frequency Modulation[J].IEEE Trans on Antennas and Propagation,1988,36(1):127-135.
[14]赵志国,陈建文,鲍拯.分时波束空间MIMO天波雷达发射ADBF方法[J].华中科技大学学报(自然科学版),2013,41(2):64-69.