中国激光, 2015, 42 (4): 0413002, 网络出版: 2015-04-08
激光测高仪平顶高斯光束条件下的回波参数模型
Model of Waveform Parameters for Laser Altimeter System Under Flattened Gaussian Beams
遥感 激光测高 平顶高斯光束 波形宽度 测距误差 remote sensing laser altimeter flattened Gaussian beam waveform width range error
摘要
星载激光测高仪通过提取激光回波参数计算卫星与地表的距离,结合轨道和姿态信息生成激光脚点的三维坐标。普通高斯光束的空间能量分布随光斑半径增加迅速衰减,不利于探测复杂和分层的地表目标,而平顶高斯光束可以克服这一缺点。根据平顶高斯光束和激光测高回波的相关理论推导得出平顶高斯激光模式下回波波形主要参数的解析式,并使用波形模拟器、波形处理算法,以及地球科学激光测高系统(GLAS)真实回波对所得理论模型进行了验证,结果显示不同阶数激光脉冲的对比偏差都小于3%,且随着目标斜率或阶数的增加,回波宽度和距离误差也随之增加,4阶平顶高斯光束目标斜率0.05时对应的距离误差超过10 cm。
Abstract
The distance between satellite and target is calculated through extracting parameters of received waveforms, combined with orbit and attitude information, the accurate location and elevation of laser footprint are acquired. For common Gaussian laser beam, the spatial distribution of energy decays rapidly with the increase of laser spot radius, which is not suitable for detecting the complicated and layered ground target, while the flattened Gaussian beam can overcome this drawback. According to the theory of flattened Gaussian beam and waveform model of laser altimeter, the primary parameters of received waveform are derived and verified using laser altimetry waveform simulator, waveform processing algorithm and actual geoscience laser altimeter system (GLAS) waveforms. The results show that the contrast deviations of different order laser pulses are all less than 3%, the waveform width and range error increase with the rising of target slope or order number, and the corresponding range error of the 4th order flattened Gaussian beam under target stope of 0.05 is more than 10 cm range error.
马跃, 李松, 阳凡林, 周辉. 激光测高仪平顶高斯光束条件下的回波参数模型[J]. 中国激光, 2015, 42(4): 0413002. Ma Yue, Li Song, Yang Fanlin, Zhou Hui. Model of Waveform Parameters for Laser Altimeter System Under Flattened Gaussian Beams[J]. Chinese Journal of Lasers, 2015, 42(4): 0413002.