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光束空间分布是影响星载激光测高仪测距指标的重要因素。根据星载激光测高仪接收脉冲回波分布特点,通过对椭圆高斯足印及线性目标的理论建模,基于接收脉冲回波信号时间重心及其方差的基本定义,构建了椭圆高斯足印对星载激光测高仪测距值及其误差的影响模型。以GLAS星载激光测高仪为输入条件,利用数值仿真分析的方法,针对倾斜度和粗糙度分别为(3°,1.7 m)、(12.5°,8.9 m)和(28.2°,14.5 m)的三种典型观测目标,系统论述了椭圆高斯足印的椭圆率与方位角对测距值及其误差的影响规律。结果表明,激光测距值基本与椭圆高斯足印的椭圆率和方位角无关,其测距值余量最大值不超过1 mm,但是,激光测距误差会随着椭圆高斯足印的椭圆率和方位角的增加产生起伏变化,其测距误差余量最大值达到了47.04 cm。所得结论对于星载激光测高仪的硬件设计和性能评估具有一定实际应用价值。
The spatial distribution of light beam is an important factor that affects the distance measurement of spaceborne laser altimeters. According to the characteristics of pulse laser echo received by satellite laser altimeter, based on the theoretical modeling of ellipse Gaussian footprints and linear target, based on the basic definition of the time center of gravity of the received pulse echo signal and its variance, an elliptical Gaussian footprint pair Influence Model of Spaceborne Laser Altimeter Ranging Value and Its Error. Taking the GLAS satellite laser altimeter as the input condition and the numerical simulation analysis method, the slope and roughness are respectively (3 °, 1.7 m), (12.5 °, 8.9 m) and (28.2 °, 14.5 m) The paper discusses systematically the influence of ellipticity and azimuth of elliptic Gaussian footprints on distance measurement and its error. The results show that the laser ranging value basically has nothing to do with the ellipticity and azimuth of the elliptic Gaussian footprints, and the maximum value of the measured value margin does not exceed 1 mm. However, the laser ranging error will vary with the ellipticity of elliptic Gaussian footprints And the azimuth increases with the ups and downs, the maximum error of ranging error reaches 47.04 cm. The conclusion is of practical value for hardware design and performance evaluation of spaceborne laser altimeters.