Research on GNSS-R model and delay-Doppler characteristics of reflected signal from sea surface
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摘要: GNSS海面反射信号的建模对全球导航卫星系统反射测量(Global Navigation Satellite System-Reflectometry,GNSS-R)遥感应用具有重要意义. 针对海面GNSS反射信号建模问题,本文采用Z-V模型研究了GNSS反射信号的时延一维相关功率和时延-多普勒二维相关功率特征,分析了不同风速下一维相关功率的变化情况,讨论了时延间隔和多普勒间隔对时延-多普勒图(delay-Doppler map,DDM)的影响. 数值结果表明:海面GNSS反射信号的相关功率对海面风速具有敏感性,在DDM波形仿真中,应选择合适的时延与多普勒间隔参数. 该模型可模拟不同海况下海面GNSS反射信号的相关功率,为GNSS-R反射信号模拟及海洋遥感应用提供理论模型支撑.
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关键词:
- 全球导航卫星系统反射测量( GNSS-R) /
- Z-V模型 /
- 时延 /
- 多普勒 /
- 时延-多普勒图(DDM)
Abstract: The modeling of sea surface reflected signal of GNSS is of great significance for Global Navigation Satellite System-Reflectometry (GNSS-R) remote sensing applications. Aiming at the modeling problem of GNSS reflected signal on the sea surface, the Z-V model is adopted in this paper to study the characteristics of one-dimensional time delay correlation power and two-dimensional delay-Doppler correlation power of GNSS reflected signal. The variation of one-dimensional correlation power is analyzed under different wind speeds, and the influence of time-delay interval and Doppler interval on delay-Doppler map (DDM) is also discussed in detail. Numerical results show that the correlation power of GNSS reflected signal is sensitive to sea surface wind speed, and appropriate time delay and Doppler interval parameters should be selected in DDM waveform simulation. The GNSS-R model can simulate the correlation power of GNSS reflected signal under different sea conditions, which is able to provide theoretical model support for GNSS-R reflected signal simulation and marine remote sensing applications. -
表 1 主要输入参数
参数 数值/范围 发射信号频率/MHz 1 561.098 卫星高度/km 35 786 接收机高度/km 682 地球半径/km 6 378.137 海水温度/℃ 15 海水盐度/psu 35 海面风速(m·s−1) 6.0 海面风向/(°) 0.0 接收天线增益/dB 14.205 相干积分时间/ms 1.0 信号损耗/dB 3.0 噪声功率/dBm –134.719 -
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