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首页> 外文期刊>Radio Science >An ambiguity-function-based method for analysis of Doppler decompressed radar signals applied to EISCAT measurements of oblique UHF-VHF meteor echoes
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An ambiguity-function-based method for analysis of Doppler decompressed radar signals applied to EISCAT measurements of oblique UHF-VHF meteor echoes

机译：一种基于模糊函数的多普勒解压缩雷达信号分析方法，该方法应用于斜超高频-甚高频流星回波的EISCAT测量

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摘要

Binary phase modulation using Barker codes as the modulating sequences is often used as a pulse compression technique in incoherent scatter radar measurements of the ionospheric E region. Demodulation of the compressed signal is usually accomplished by matched filtering techniques. If the target has appreciable velocity, the resulting Doppler shift detunes the scattered signal relative to the filter, and the target response spreads over a large range interval. The paper describes the development of a new data analysis method, based on an ambiguity function description of radar total-power measurements, which uses the characteristic Doppler decompression signatures to identify, extract, and analyze high-velocity events from conventional Barker-coded power profile type incoherent scatter (IS) measurements. Data sets recorded with the European Incoherent Scatter UHF (931 MHz) and VHF (224 MHz) radars during the 1990–1991 Geminid and 1993 Perseid showers are shown to contain many events which are associated with individual meteors crossing the radar beams over a wide range of aspect angles, including a few near-radial cases. Line-of-sight velocities and effective cross sections are derived for some of the best dual radar events. The cross sections are very small and increase with decreasing wavelength, something not observed before. It is suggested that this is indicative of a scattering mechanism different from the one operating at near-normal incidence at VHF, and Rayleigh scatter from compact “balls” of plasma contained within the meteor coma is proposed as a possible candidate, in qualitative agreement with the observations. Finally, some signal-processing related aspects of the method are discussed. It is shown that most IS radars should be able to apply it to their existing programs with very little effort and without having to compromise the performance in normal E region applications. The method could therefore become a powerful tool for studies of meteor statistics at UHF frequencies.
机译：在电离层E区域的非相干散射雷达测量中，使用巴克码作为调制序列的二进制相位调制通常用作脉冲压缩技术。压缩信号的解调通常通过匹配滤波技术来完成。如果目标具有明显的速度，则产生的多普勒频移会使散射信号相对于滤波器失谐，并且目标响应会散布在较大的范围间隔内。本文基于雷达总功率测量的模糊函数描述，描述了一种新的数据分析方法的开发，该方法使用特征性的多普勒减压特征来识别，提取和分析常规巴克编码功率剖面中的高速事件。类型非相干散射（IS）测量。 1990-1991年双子星雨和1993年英仙座阵雨期间，使用欧洲非相干散射UHF（931 MHz）和VHF（224 MHz）雷达记录的数据集包含许多事件，这些事件与单个流星在大范围内越过雷达波束有关角度，包括一些近径向的情况。对于某些最佳的双雷达事件，得出了视线速度和有效横截面。横截面非常小，并且随着波长的减小而增加，这是以前从未观察到的。有证据表明，这表明一种散射机制不同于在VHF处接近法线入射的一种散射机制，与定性一致的是，建议将流星昏迷内血浆的紧密“球”的瑞利散射作为可能的候选者。观察。最后，讨论了该方法的一些信号处理相关方面。事实证明，大多数IS雷达应能够毫不费力地将其应用到现有程序中，而不必在普通E区域应用中牺牲性能。因此，该方法可能成为研究UHF频率流星统计的有力工具。

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