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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 simulated echo waveforms of different surface targets are of great significance for the design of altimeter system parameters, while the parameters of oceanic echoes are rarely studied after Tsai. According to the Fresnel diffraction theory, the specular reflection properties of the ocean surface and the ocean surface wave height and slope statistics, the analytical expression of the output of the satellite-borne ocean altimeter detector when the near-zenith direction is different from the Tsai result is derived And the total number of photons of the echo; and using the result of the derivation to establish the echo analytic formula suitable for the sub-millimeter arc divergence angle of the laser altimeter. Comparing the simulated waveforms with the real ocean echoes of GLAS, the energy, pulse width, amplitude and shape are very close and the errors are both less than 6%. It is concluded that the echo of the altimeter The high system parameters are related to the average wind speed above the sea level. Taking GLAS parameters as an example, it is very difficult to receive valid ocean echoes at wind speeds greater than 12 m / s. This conclusion provides an important theoretical basis for the system design parameters of ocean laser altimeter and the inversion of wind speed above the sea level.