为了提高电离层虚高测量精度,介绍了利用电离层回波相位实现高精度虚高测量的方法,并以CADI (Canadian Advanced Digital Ionosonde)电离层数字测高仪为研究平台,进行组合脉冲控制和回波相位测量分析,开展了一系列虚高测量实验,并与传...为了提高电离层虚高测量精度,介绍了利用电离层回波相位实现高精度虚高测量的方法,并以CADI (Canadian Advanced Digital Ionosonde)电离层数字测高仪为研究平台,进行组合脉冲控制和回波相位测量分析,开展了一系列虚高测量实验,并与传统的利用回波时间延迟的虚高测量方法进行了分析比较．实验结果表明,基于回波相位的测量分析方法与回波时延测量分析方法相比,其虚高测量精度高一个量级以上,这对精确反演电离层峰下电子浓度剖面及研究电离层精细结构具有重要意义．展开更多
Underwater acoustic scattering echoes have time–space structures and are aliasing in time and frequency domains. Different series of echoes properties are not identified when incident angle is unknown. This article i...Underwater acoustic scattering echoes have time–space structures and are aliasing in time and frequency domains. Different series of echoes properties are not identified when incident angle is unknown. This article investigates variations in target echoes of monostatic sonar to address this problem. The mother wavelet with similar structures has been proposed on the basis of preprocessing signal waveform using matched filter, and the theoretical expressions between delay factor and incident angle are derived in the wavelet domain. Analysis of simulation data and experimental results in free-field pool show that this method can effectively separate geometrical scattering components of target echoes. The time delay estimation obtained from geometrical echoes at a single angle is consistent with target geometrical features, which provides a basis for object recognition without angle information. The findings provide valuable insights for analyzing elastic scattering echoes in actual ocean environment.展开更多
文摘为了提高电离层虚高测量精度,介绍了利用电离层回波相位实现高精度虚高测量的方法,并以CADI (Canadian Advanced Digital Ionosonde)电离层数字测高仪为研究平台,进行组合脉冲控制和回波相位测量分析,开展了一系列虚高测量实验,并与传统的利用回波时间延迟的虚高测量方法进行了分析比较．实验结果表明,基于回波相位的测量分析方法与回波时延测量分析方法相比,其虚高测量精度高一个量级以上,这对精确反演电离层峰下电子浓度剖面及研究电离层精细结构具有重要意义．
基金Foundation item： Supported by the National Natural Science Foundation of China（Grant No.51279033） and Natural Science Foundation of Heilongjiang Province, China（Grant No.F201346 ）
文摘Underwater acoustic scattering echoes have time–space structures and are aliasing in time and frequency domains. Different series of echoes properties are not identified when incident angle is unknown. This article investigates variations in target echoes of monostatic sonar to address this problem. The mother wavelet with similar structures has been proposed on the basis of preprocessing signal waveform using matched filter, and the theoretical expressions between delay factor and incident angle are derived in the wavelet domain. Analysis of simulation data and experimental results in free-field pool show that this method can effectively separate geometrical scattering components of target echoes. The time delay estimation obtained from geometrical echoes at a single angle is consistent with target geometrical features, which provides a basis for object recognition without angle information. The findings provide valuable insights for analyzing elastic scattering echoes in actual ocean environment.
