Influence of Atmospheric Scattering on the Accuracy of Laser Altimetry of the GF-7 Satellite and Corrections

Yao, Jiaqi; Tang, Xinming; Li, Guoyuan; Jiyi, Chen; Zuo, Zhiqiang; Ai, Bo; Zhang, Shuaitai; Guo, Jinquan

doi:10.3390/rs14010129

Cited by 4 publications

(2 citation statements)

References 23 publications

(31 reference statements)

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“…For the satellite laser altimetry system, the external environment has a great influence on the measurement accuracy of the plane and elevation of laser footprints [33]. Yao et al found that the multiple scattering effect caused by cloud has a significant influence on the ranging accuracy of GF-7 data [15,34], but in addition, when the area covered by cloud coincides with the area where the light spot is located, it will affect the original internal characteristics, thus affecting the laser pointing and energy distribution monitoring accuracy. In addition to clouds, glaciers, deserts and other highly reflective features will also have the same impact.…”

Section: Discussionmentioning

confidence: 99%

“…During the data processing of the GF-7 satellite, we found that the laser pointing changed little every month, so we randomly selected one track from the night data obtained every month as experimental data to analyze the plane accuracy of laser footprints in long time series. The experimental results show that the laser pointing jitter is about 0.3 , and the corresponding laser footprint positioning accuracy is about 5 m. Compared with complex surface, ideally, the accuracy of satellite laser altimetry in water should have higher internal consistency, but meteorological factors such as wind speed may introduce additional observation errors [34]. According to the monthly meteorological data provided by NOAA's National Centers for Environmental Information (NCEI) during data collection [35], we found that the wind speed was less than 3 m/s, which would not cause waves on the lake.…”

Section: Discussionmentioning

confidence: 99%

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Evaluation of the Emissions State of a Satellite Laser Altimeter Based on Laser Footprint Imaging

Yao

Zhai

et al. 2022

Remote Sensing

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The GaoFen-7(GF-7) satellite is equipped with China’s first laser altimeter for Earth observation; it has the capability of full waveform recording, which can obtain global high-precision three-dimensional coordinates over a wide range. The laser is inevitably affected by platform tremors, random errors in the laser pointing angle, laser state, and other factors, which further affect the measurement accuracy of the laser footprint. Therefore, evaluation of the satellite laser launch state is an important process. This study contributes to laser emission state evaluations based on the laser footprint image in terms of two main two aspects: (1) Monitoring changes in the laser pointing angle—laser pointing is closely related to positioning accuracy, which mainly results from monitoring the change in the laser spot centroid. We propose a threshold constraint algorithm that extracts the centroid of an ellipse-fitting spot. (2) Analysis of the energy distribution state—directly obtaining the parameters used in the traditional evaluation method is a challenge for the satellite. Therefore, an index suitable for evaluating the laser emissions state of the GF-7 satellite was constructed according to the data characteristics. Based on these methods, long time-series data were evaluated and analyzed. The experimental results show that the proposed method can effectively evaluate the emissions state of the laser altimeter, during which the laser pointing angle changes monthly by 0.434″. During each continuous operation of the laser, the energy state decreased gradually, with a small variation range; however, both were generally in a stable state.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%