Photon-counting multikilohertz microlaser altimeters for airborne and spaceborne topographic measurements
Photon-counting multikilohertz microlaser altimeters for airborne and spaceborne topographic measurements
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DOI：
10.1016/s0264-3707(02)00045-5
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发表时间：
2002-10-01
影响因子：
2.3
通讯作者：
Degnan, JJ
中科院分区：
文献类型：
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作者：
Degnan, JJ
我们认为光子计数微型激光高度计的最佳设计工作在白天和夜间条件下从机载和星载平台。极其紧凑的被动Q开关微激光发射器以几kHz的速率产生一系列低能量脉冲，并且可以轻松地产生用于精确测距的亚纳秒脉冲宽度。为了指导设计，我们模拟了太阳噪声背景，并开发了简单的算法，基于后检测泊松滤波（PDPF），以最佳的方式提取弱高度计信号从高噪声背景在白天的操作。讨论了光子计数探测器阵列和多通道定时接收器在高分辨率地形测绘中的优势。实际的技术问题，如检测器和/或接收器的死区时间及其对信号检测和测距精度和分辨率的影响，也被认为是在分析中。根据NASA的仪器孵化器计划开发的机载微激光高度计的数据加强了理论结果。后一种仪器从飞机巡航高度到6.7公里以几kHz的速率工作，激光脉冲能量大约为几微焦耳。该仪器成功地记录了分米精度或更好的人造结构、树冠和底层地形的单光子回波，并展示了几米深处的浅水测深。我们通过分析光子计数仪器来结束讨论，该仪器设计用于在3年的使命寿命内从300公里的高度产生具有5米水平分辨率和分米垂直精度的火星表面的全球连续地图。所需的发射机功率-接收孔径积与地球科学激光高度计系统相当，但对地面的单个距离测量的数量增加了三到四个数量级。对于更普通的科学目标，与传统的高信噪比星载高度计的能力相当，可以通过使用光子计数技术来建造更紧凑和功率效率更高的仪器。出版社：Elsevier Science Ltd
We consider the optimum design of photon-counting microlaser altimeters operating from airborne and spaceborne platforms under both day and night conditions. Extremely compact, passively Q-switched microlaser transmitters produce trains of low energy pulses at multi-kHz rates and can easily generate subnanosecond pulsewidths for precise ranging. To guide the design, we have modeled the solar noise background and developed simple algorithms, based on post-detection Poisson filtering (PDPF), to optimally extract the weak altimeter signal from a high noise background during daytime operations. The advantages of photon-counting detector arrays followed by multichannel timing receivers for high resolution topographic mapping are discussed. Practical technology issues, such as detector and/or receiver dead times and their impact on signal detection and ranging accuracy and resolution, have also been considered in the analysis. The theoretical results are reinforced by data from an airborne microlaser altimeter, developed under NASA's Instrument Incubator Program. The latter instrument has operated at several kHz rates from aircraft cruise altitudes up to 6.7 km with laser pulse energies on the order of a few microjoules. The instrument has successfully recorded decimeter accuracy or better single photon returns from man-made structures, tree canopies and underlying terrain and has demonstrated shallow water bathymetry at depths to a few meters. We conclude the discussion by analyzing a photon counting instrument designed to produce, over a mission life of 3 years, a globally contiguous map of the Martian surface, with 5 m horizontal resolution and decimeter vertical accuracy, from an altitude of 300 km. The transmitter power-receive aperture product required is comparable to the Geoscience Laser Altimeter System (GLAS) but the number of individual range measurements to the surface is increased by three to four orders of magnitude. For more modest scientific goals, on a par with the capabilities of conventional high SNR spaceborne altimeters, significantly more compact and power efficient instruments can be constructed through the use of photon-counting techniques. Published by Elsevier Science Ltd.