星载激光测高仪海洋表面回波计算的理论模型  

Received Waveform Model for Satellite Laser Altimeter Measuring Ocean Surface

作　　者：马跃[1] 李松[1] 周辉[1] 郑国兴[1] 

机构地区：[1]武汉大学电子信息学院,湖北武汉430079

出　　处：《中国激光》2012年第12期219-225,共7页Chinese Journal of Lasers

基　　金：国家自然科学基金(40901165);"十二五"民用航天预研项目(卫星激光测量数据处理及冰层高度变化反演)资助课题

摘　　要：不同地表目标的模拟回波波形对测高仪系统参数设计具有重要意义,而海洋回波参数在Tsai之后很少被研究。根据菲涅耳衍射理论、海洋表面镜面反射性质以及海洋表面波高和斜率的统计规律,推导出与Tsai结果不同的近天顶方向入射时星载海洋测高仪探测器输出的回波解析表达式和回波总光子数;并用该推导结果建立了适用于激光测高仪亚毫弧度量级发散角的回波解析式。将模拟波形与地球科学激光测高系统(GLAS)真实海洋回波做对比,其能量、脉宽、振幅和形状都非常接近,误差均小于6%;分析得出海洋测高仪回波与测高系统参数和海平面上方平均风速有关,以GLAS参数为例,在风速大于12m/s的条件下将很难收到有效海洋回波。该结论对海洋激光测高仪的系统设计参数及海平面上方风速的反演提供了重要的理论依据。The received waveform model for different earth surfaces is significant for altimeter system design, and the model of ocean surface is rarely researched after Tsai. According to the theory of Fresnel diffraction, the character of specular reflection and statistical regularity of the ocean surface profile, the analytic expression of detector output and the average received photons are deduced which are used for ocean altimeter and different from the results of Tsai under the condition of near-normal incidence. The simulated waveform is established for laser altimeter with microradian beam divergence and compared with the real geoscience laser altimeter system （GLAS） received signal. The energy, root mean square （RMS） width, amplitude and shape are very similar and the errors between simulated and real waveforms are all less than 6%. The parameters of received signal are related to the altimeter systems and the wind speed over the ocean surface, and taking the GLAS parameters for example, the valid ocean waveforms can he hardly got when the wind speed exceeds 12 m/s. The analysis and conclusion are important theory basis for the design of laser altimeter system and the wind speed calculation over the ocean surface.

关 键 词：遥感 回波模型 菲涅耳衍射 海洋表面模型 地球科学激光测高系统 

分 类 号：TH821[机械工程—仪器科学与技术]