船载高频地波雷达(High Frequency Surface Wave Radar, HFSWR)的平台机动运动会使目标回波信号发生展宽,引起目标回波幅度和信噪比降低,进而对目标波达方向估计(Direction of Arrival, DOA)产生不利的影响。针对船载地波雷达展宽目标DO...船载高频地波雷达(High Frequency Surface Wave Radar, HFSWR)的平台机动运动会使目标回波信号发生展宽,引起目标回波幅度和信噪比降低,进而对目标波达方向估计(Direction of Arrival, DOA)产生不利的影响。针对船载地波雷达展宽目标DOA估计问题,本文提出了一种基于时频信息Toeplitz协方差重构的展宽目标DOA估计方法。该方法首先采用结合航向补偿的时频分析处理,来提取展宽目标信号的脊线,可为充分利用展宽目标时频信息来构建协方差矩阵奠定基础。然后对构建的协方差矩阵进行Toeplitz化,实现了非平稳噪声的抑制,提高了目标信噪比,解决了展宽目标信噪比下降的问题,从而实现目标的方位角估计。最后,通过仿真和实测数据对本文提出的方法进行验证,结果表明本文所提方法在相同信噪比和目标展宽程度下均方根误差比单峰值MUSIC和DBF方法减小了1.2°,证明了本文所提方法的有效性。展开更多
针对高频地波雷达(High frequency surface wave radar,HFSWR)在探测中产生的回波数据,传统的人工识别和分类方法存在工作量大、效率低和主观性强等问题,本研究在分析一阶海杂波、电离层杂波和射频干扰的回波数据特性的基础上,创新性地...针对高频地波雷达(High frequency surface wave radar,HFSWR)在探测中产生的回波数据,传统的人工识别和分类方法存在工作量大、效率低和主观性强等问题,本研究在分析一阶海杂波、电离层杂波和射频干扰的回波数据特性的基础上,创新性地提出了基于YOLOv5识别模型的HFSWR杂波和干扰识别分类方法。该方法旨在帮助研究人员在海量实验数据中快速筛选出符合其科学研究需求的数据集,从而提高研究效率和数据准确性。在具体实施过程中,通过采用批量实测距离-多普勒(Range-Doppler,RD)谱数据对所提出模型进行训练和分析,使该方法能够在频域范围内对杂波和干扰进行有效识别。本研究以该识别分类算法为核心,进一步基于Python语言设计了一款地波雷达智能杂波和干扰识别分类软件。经过严格的批量实测数据测试验证,该软件能够满足设计需求,具有良好的可靠性,极大地提高了研究人员筛选有效实测数据的工作效率,为科学研究工作提供了有力的技术支撑。展开更多
High frequency surface wave radar (HFSWR) is well proved to have over the horizon (OTH) detection capability to weak aerial targets, such as concealed airplanes or cruise missiles. The most important problem of detect...High frequency surface wave radar (HFSWR) is well proved to have over the horizon (OTH) detection capability to weak aerial targets, such as concealed airplanes or cruise missiles. The most important problem of detection of fast and small targets using HFSWR is earlier warning, i.e. enlargement of detection range oftargets. Therefore, the detection threshold should be decreased as low as possible, but numerous false alarms are brought about at the same time. On this condition, conventional track initiation techniques, which normally require the probability of false alarm to be at the level of 10-6, will initiate enormous false tracks and lead to abnormal operation of tracking system. An adaptive modified hough transform (AMHT) track initiator is proposed accordingly and the relation of detection range to the performance of track initiator is analyzed in this paper. Simulations are performed to confirm the capability of track initiation to fast and small targets in dense clutter by AMHT track initiator. The tolerable probability of false alarm of detector can reach the level of 10 -3 . And it performs better than track initiator based on modified hough transform (MHT).展开更多
This paper studies the development on the first order sea clutter cross section for bistatic high frequency surface wave radar (HFSWR). Based on the received first order electric field expression, a closed-form of cro...This paper studies the development on the first order sea clutter cross section for bistatic high frequency surface wave radar (HFSWR). Based on the received first order electric field expression, a closed-form of cross sections is derived to account for the case of receiving antenna array being mounted on the shipborne platform. The uniform linear motion and sway motion components are assumed to be responsible for the observed differences in comparison with the bistatic fixed antenna case. Correspondingly, simulations are conducted to study the sea clutter spectral characteristics for these two cases versus different system parameters and sea state conditions. It is shown numerically that the forward motion component will spread the Bragg lines severely and the influence triggered by the sway motion can be explained as the Bessel function modulation of the ordinary sea clutter spectra. The obtained results have important implications in the application of shipborne HFSWR technology to ocean remote sensing and target detection.展开更多
文摘船载高频地波雷达(High Frequency Surface Wave Radar, HFSWR)的平台机动运动会使目标回波信号发生展宽,引起目标回波幅度和信噪比降低,进而对目标波达方向估计(Direction of Arrival, DOA)产生不利的影响。针对船载地波雷达展宽目标DOA估计问题,本文提出了一种基于时频信息Toeplitz协方差重构的展宽目标DOA估计方法。该方法首先采用结合航向补偿的时频分析处理,来提取展宽目标信号的脊线,可为充分利用展宽目标时频信息来构建协方差矩阵奠定基础。然后对构建的协方差矩阵进行Toeplitz化,实现了非平稳噪声的抑制,提高了目标信噪比,解决了展宽目标信噪比下降的问题,从而实现目标的方位角估计。最后,通过仿真和实测数据对本文提出的方法进行验证,结果表明本文所提方法在相同信噪比和目标展宽程度下均方根误差比单峰值MUSIC和DBF方法减小了1.2°,证明了本文所提方法的有效性。
文摘针对高频地波雷达(High frequency surface wave radar,HFSWR)在探测中产生的回波数据,传统的人工识别和分类方法存在工作量大、效率低和主观性强等问题,本研究在分析一阶海杂波、电离层杂波和射频干扰的回波数据特性的基础上,创新性地提出了基于YOLOv5识别模型的HFSWR杂波和干扰识别分类方法。该方法旨在帮助研究人员在海量实验数据中快速筛选出符合其科学研究需求的数据集,从而提高研究效率和数据准确性。在具体实施过程中,通过采用批量实测距离-多普勒(Range-Doppler,RD)谱数据对所提出模型进行训练和分析,使该方法能够在频域范围内对杂波和干扰进行有效识别。本研究以该识别分类算法为核心,进一步基于Python语言设计了一款地波雷达智能杂波和干扰识别分类软件。经过严格的批量实测数据测试验证,该软件能够满足设计需求,具有良好的可靠性,极大地提高了研究人员筛选有效实测数据的工作效率,为科学研究工作提供了有力的技术支撑。
文摘High frequency surface wave radar (HFSWR) is well proved to have over the horizon (OTH) detection capability to weak aerial targets, such as concealed airplanes or cruise missiles. The most important problem of detection of fast and small targets using HFSWR is earlier warning, i.e. enlargement of detection range oftargets. Therefore, the detection threshold should be decreased as low as possible, but numerous false alarms are brought about at the same time. On this condition, conventional track initiation techniques, which normally require the probability of false alarm to be at the level of 10-6, will initiate enormous false tracks and lead to abnormal operation of tracking system. An adaptive modified hough transform (AMHT) track initiator is proposed accordingly and the relation of detection range to the performance of track initiator is analyzed in this paper. Simulations are performed to confirm the capability of track initiation to fast and small targets in dense clutter by AMHT track initiator. The tolerable probability of false alarm of detector can reach the level of 10 -3 . And it performs better than track initiator based on modified hough transform (MHT).
基金supported by the National Natural Science Foundation of China(61471144)
文摘This paper studies the development on the first order sea clutter cross section for bistatic high frequency surface wave radar (HFSWR). Based on the received first order electric field expression, a closed-form of cross sections is derived to account for the case of receiving antenna array being mounted on the shipborne platform. The uniform linear motion and sway motion components are assumed to be responsible for the observed differences in comparison with the bistatic fixed antenna case. Correspondingly, simulations are conducted to study the sea clutter spectral characteristics for these two cases versus different system parameters and sea state conditions. It is shown numerically that the forward motion component will spread the Bragg lines severely and the influence triggered by the sway motion can be explained as the Bessel function modulation of the ordinary sea clutter spectra. The obtained results have important implications in the application of shipborne HFSWR technology to ocean remote sensing and target detection.
