scholarly journals POINTING ANGLE CALIBRATION OF ZY3-02 SATELLITE LASER ALTIMETER USING TERRAIN MATCHING

2017 ◽  
Vol XLII-1/W1 ◽  
pp. 205-210 ◽  
Author(s):  
G. Li ◽  
X. Tang ◽  
X. Gao ◽  
J. P. Huang ◽  
J. Chen ◽  
...  
Keyword(s):  
Altimetry Data ◽  
Laser Altimetry ◽  
Angle Error ◽  
Laser Altimeter ◽  
Geometric Calibration ◽  
Pointing Error ◽  
The Public ◽  
Ice Cloud ◽  
Laser Data ◽  
Terrain Matching

After GLAS (Geo-science Laser Altimeter System) loaded on the ICESat (Ice Cloud and land Elevation Satellite), satellite laser altimeter attracts more and more attention. ZY3-02 equipped with the Chinese first satellite laser altimeter has been successfully launched on 30<sup>th</sup> May, 2016. The geometric calibration is an important step for the laser data processing and application. The method to calculate the laser pointing angle error based on existed reference terrain data is proposed in this paper. The public version terrain data, such as 90m-SRTM and 30m-AW3D30, can be used to estimate the pointing angle of laser altimeter. The GLAS data with simulated pointing error and actual ZY3-02 laser altimetry data is experimented to validate the algorithm. The conclusion will be useful for the future domestic satellite laser altimeter.

scholarly journals ANALYSIS OF INFLUENCING FACTORS OF CURVE MATCHING BASED GEOMETRIC CALIBRATION FOR ZY3-02 ALTIMETER DATA

2019 ◽  
Vol IV-2/W7 ◽  
pp. 221-226
Author(s):  
M. Zhou ◽  
L. S. Chen ◽  
J. H. Wang ◽  
G. E. Teng ◽  
C. R. Li ◽  
...  
Keyword(s):  
Control Point ◽  
Altimeter Data ◽  
Curve Matching ◽  
Altimetry Data ◽  
Laser Altimetry ◽  
Step Size ◽  
Laser Altimeter ◽  
Geometric Calibration ◽  
Calibration Methods ◽  
Initial Control

<p><strong>Abstract.</strong> High-precision on-orbit geometric calibration of spaceborne laser altimetry data is essential to its effective applications. Firstly, the existing calibration methods for laser altimeter data are analyzed. Then, a geometric calibration method based on curve matching is proposed. Compared to the existing methods, the proposed method does not rely on ground calibration field. Thus, it is efficiency in expense and time. Notably, three factors, i.e. matching method, initial control point selection and the step size of matching step, which significantly affect the results of calibration are analyzed respectively. The analysis was validated based on the original laser altimetry data obtained by ZY3-02 satellite. According to the results, the following conclusions can be drawn preliminarily: (1) Both the correlation coefficient maximum (COR) criterion and the mean square error minimum (MSD) criterion in the curve matching can be used to correct the systematic error in altimetry data. (2) The initial control points of the selected track should have a significant change trend and the slope within the laser footprints should be less than 15&amp;deg;. (3) Current experimental data show that the best step size for matching search is 10&amp;thinsp;m. The relevant conclusions can provide reference for the research of geometrical calibration and data processing of the same type of laser altimetry satellite.</p>

scholarly journals IMPROVE THE ZY-3 HEIGHT ACCURACY USING ICESAT/GLAS LASER ALTIMETER DATA

2016 ◽  
Vol XLI-B1 ◽  
pp. 37-42
Author(s):  
Guoyuan Li ◽  
Xinming Tang ◽  
Xiaoming Gao ◽  
Chongyang Zhang ◽  
Tao Li
Keyword(s):  
High Resolution ◽  
Bundle Adjustment ◽  
Experimental Result ◽  
Altimeter Data ◽  
Surface Model ◽  
Laser Altimetry ◽  
Laser Altimeter ◽  
Ice Cloud ◽  
Elevation Data ◽  
Polar Ice Sheets

ZY-3 is the first civilian high resolution stereo mapping satellite, which has been launched on 9th, Jan, 2012. The aim of ZY-3 satellite is to obtain high resolution stereo images and support the 1:50000 scale national surveying and mapping. Although ZY-3 has very high accuracy for direct geo-locations without GCPs (Ground Control Points), use of some GCPs is still indispensible for high precise stereo mapping. The GLAS (Geo-science Laser Altimetry System) loaded on the ICESat (Ice Cloud and land Elevation Satellite), which is the first laser altimetry satellite for earth observation. GLAS has played an important role in the monitoring of polar ice sheets, the measuring of land topography and vegetation canopy heights after launched in 2003. Although GLAS has ended in 2009, the derived elevation dataset still can be used after selection by some criteria. <br><br> In this paper, the ICESat/GLAS laser altimeter data is used as height reference data to improve the ZY-3 height accuracy. A selection method is proposed to obtain high precision GLAS elevation data. Two strategies to improve the ZY-3 height accuracy are introduced. One is the conventional bundle adjustment based on RFM and bias-compensated model, in which the GLAS footprint data is viewed as height control. The second is to correct the DSM (Digital Surface Model) straightly by simple block adjustment, and the DSM is derived from the ZY-3 stereo imaging after freedom adjustment and dense image matching. The experimental result demonstrates that the height accuracy of ZY-3 without other GCPs can be improved to 3.0 meter after adding GLAS elevation data. What’s more, the comparison of the accuracy and efficiency between the two strategies is implemented for application.

scholarly journals IMPROVE THE ZY-3 HEIGHT ACCURACY USING ICESAT/GLAS LASER ALTIMETER DATA

2016 ◽  
Vol XLI-B1 ◽  
pp. 37-42 ◽  
Author(s):  
Guoyuan Li ◽  
Xinming Tang ◽  
Xiaoming Gao ◽  
Chongyang Zhang ◽  
Tao Li
Keyword(s):  
High Resolution ◽  
Bundle Adjustment ◽  
Experimental Result ◽  
Altimeter Data ◽  
Surface Model ◽  
Laser Altimetry ◽  
Laser Altimeter ◽  
Ice Cloud ◽  
Elevation Data ◽  
Polar Ice Sheets

ZY-3 is the first civilian high resolution stereo mapping satellite, which has been launched on 9th, Jan, 2012. The aim of ZY-3 satellite is to obtain high resolution stereo images and support the 1:50000 scale national surveying and mapping. Although ZY-3 has very high accuracy for direct geo-locations without GCPs (Ground Control Points), use of some GCPs is still indispensible for high precise stereo mapping. The GLAS (Geo-science Laser Altimetry System) loaded on the ICESat (Ice Cloud and land Elevation Satellite), which is the first laser altimetry satellite for earth observation. GLAS has played an important role in the monitoring of polar ice sheets, the measuring of land topography and vegetation canopy heights after launched in 2003. Although GLAS has ended in 2009, the derived elevation dataset still can be used after selection by some criteria. &lt;br&gt;&lt;br&gt; In this paper, the ICESat/GLAS laser altimeter data is used as height reference data to improve the ZY-3 height accuracy. A selection method is proposed to obtain high precision GLAS elevation data. Two strategies to improve the ZY-3 height accuracy are introduced. One is the conventional bundle adjustment based on RFM and bias-compensated model, in which the GLAS footprint data is viewed as height control. The second is to correct the DSM (Digital Surface Model) straightly by simple block adjustment, and the DSM is derived from the ZY-3 stereo imaging after freedom adjustment and dense image matching. The experimental result demonstrates that the height accuracy of ZY-3 without other GCPs can be improved to 3.0 meter after adding GLAS elevation data. What’s more, the comparison of the accuracy and efficiency between the two strategies is implemented for application.

Estimating Mass Balance of White Glacier using ICESat-2

2021 ◽  
Author(s):  
Rachel Lackey
Keyword(s):  
Mass Balance ◽  
Laser Beams ◽  
Altimeter Data ◽  
Altimetry Data ◽  
Laser Altimeter ◽  
Ice Cloud ◽  
Geodetic Technique ◽  
Travel Restrictions ◽  
The Difference ◽  
Satellite Altimetry Data

White Glacier is located on Axel Heiberg Island in Nunavut, Canada, and has had its mass balance actively monitored since 1960. Due to COVID-19 travel restrictions it not possible for researchers to travel to White Glacier and perform the measurements required. This results in gaps in data required to determine the mass balance for 2018-2020. In this study we aim to collect and process laser altimeter data to be interpolated to calculate an estimate of the Mass Balance of White Glacier. This study will be completed using a geodetic technique that utilizes the Ice Cloud and Elevation-2 (ICESat-2) satellite altimetry data. ICESat-2 is carrying ATLAS which is an Advanced Topographic Laser Altimeter that is equipped with six laser beams divided into three pairs that measure lidar altimetry to derive surface height. The longitude, latitude, datetime, and land ice height values were extracted over the Expedition fjord region using MATLAB. The land ice tracks were brought into ArcGIS for analysis, three repeat tracks in the Expedition Fjord region were selected for analysis to determine the difference in elevation between the premelt seasons of 2019 and 2020 as well as one track comparing the premelt and melt seasons of 2019. These elevation differences will be interpolated as accumulation or ablation dependant on the location on the glacier and used to estimate mass balance.

scholarly journals Iterative Pointing Angle Calibration Method for the Spaceborne Photon-Counting Laser Altimeter Based on Small-Range Terrain Matching

2019 ◽  
Vol 11 (18) ◽  
pp. 2158
Author(s):  
Nan ◽  
Feng ◽  
Liu ◽  
Li
Keyword(s):  
Photon Counting ◽  
Calibration Method ◽  
High Repetition Rate ◽  
Search Method ◽  
Airborne Lidar ◽  
Altimeter Data ◽  
Small Range ◽  
Laser Altimeter ◽  
Ice Cloud ◽  
Terrain Matching

The satellite, Ice, Cloud and Land Elevation Satellite-2 (ICESat-2) has been equipped with a new type of spaceborne laser altimeter, which has the benefits of having small footprints and a high repetition rate, and it can produce dense footprints on the ground. Focusing on the pointing angle calibration of this new spaceborne laser altimeter, this paper proposes a fast pointing angle calibration method using only a small range of terrain surveyed by airborne lidar. Based on the matching criterion of least elevation difference, an iterative pointing angle calibration method was proposed. In the experiment, the simulated photon-counting laser altimeter data and the Ice, Cloud and Land Elevation Satellite-2 data were used to verify the algorithm. The results show that when 1 km and 2.5 km lengths of track were used, the pointing angle error after calibration could be reduced to about 0.3 arc-seconds and less than 0.1 arc-seconds, respectively. Meanwhile, compared with the traditional pyramid search method, the proposed iterative pointing angle calibration method does not require well-designed parameters, which are important in the pyramid search method to balance calculation time and calibration result, and the iterative pointing angle calibration method could significantly reduce the calibration time to only about one-fifth of that of the pyramid search method.

scholarly journals Assessment of ICESat-2’s Horizontal Accuracy Using Precisely-Surveyed Terrains in McMurdo Dry Valleys, Antactica

2021 ◽  
Author(s):  
Anton Schenk ◽  
Beata Csatho ◽  
Thomas Neumann
Keyword(s):  
Mcmurdo Dry Valleys ◽  
Dry Valleys ◽  
Laser Altimetry ◽  
Matching Method ◽  
Laser Altimeter ◽  
Optimal Position ◽  
Planar Surfaces ◽  
Accuracy And Precision ◽  
Rugged Topography ◽  
Terrain Matching

This paper presents an assessment of the horizon-tal accuracy and precision of the laser altimetry observations collected by NASA's ICESat-2 mission. We selected the terrain-matching method to determine the position of laser altimeter profiles within a precisely knownn surface, represented by a DEM. We took this classical approach a step further, approx-imated the DEM by planar surfaces and calculated the optimal position of the laser profile by minimizing the square sum of the elevation differences between reference DEMs and ICESat-2 profiles. We found the highly accurate DEMs of the McMurdo Dry Valleys, Antarctica, ideal for this research because of their stable landscape and rugged topography. We computed the 3D shift parameters of 379 different laser altimeter profiles along two reference ground tracks collected within the first two years of the mission. Analyzing these results revealed a total geolocation error (mean + 1 sigma) of 4.93 m for release 3 and 4.66 m for release 4 data. These numbers are the averages of the six beams, expressed as mean + 1 sigma and lie well within the mission requirement of 6.5 m.

scholarly journals High-Precision Digital Surface Model Extraction from Satellite Stereo Images Fused with ICESat-2 Data

2021 ◽  
Vol 14 (1) ◽  
pp. 142
Author(s):  
Jiang Ye ◽  
Yuxuan Qiang ◽  
Rui Zhang ◽  
Xinguo Liu ◽  
Yixin Deng ◽  
...  
Keyword(s):  
Surface Model ◽  
Stereo Pair ◽  
Control Points ◽  
Altimetry Data ◽  
Stereo Images ◽  
Laser Altimetry ◽  
Ice Cloud ◽  
Ground Control Points ◽  
Surface Models ◽  
Abnormal Points

The lack of ground control points (GCPs) affects the elevation accuracy of digital surface models (DSMs) generated by optical satellite stereo images and limits the application of high-resolution DSMs. It is a feasible idea to use ICESat-2 (Ice, Cloud, and land Elevation Satellite-2) laser altimetry data to improve the elevation accuracy of optical stereo images, but it is necessary to accurately match the two types of data. This paper proposes a DSM registration strategy based on terrain similarity (BOTS), which integrates ICESat-2 laser altimetry data without GCPs and improves the DSM elevation accuracy generation from optical satellite stereo pairs. Under different terrain conditions, Worldview-2, SV-1, GF-7, and ZY-3 stereo pairs were used to verify the effectiveness of this method. The experimental results show that the BOTS method proposed in this paper is more robust when there are a large number of abnormal points in the ICESat-2 data or there is a large elevation gap between DSMs. After fusion of ICESat-2 data, the DSM elevation accuracy extracted from the satellite stereo pair is improved by 73~92%, and the root mean square error (RMSE) of Worldview-2 DSM reaches 0.71 m.

scholarly journals Assessment of ICESat-2’s Horizontal Accuracy Using Precisely-Surveyed Terrains in McMurdo Dry Valleys, Antactica

2021 ◽  
Author(s):  
Anton Schenk ◽  
Beata Csatho ◽  
Thomas Neumann
Keyword(s):  
Mcmurdo Dry Valleys ◽  
Dry Valleys ◽  
Laser Altimetry ◽  
Matching Method ◽  
Laser Altimeter ◽  
Optimal Position ◽  
Planar Surfaces ◽  
Accuracy And Precision ◽  
Rugged Topography ◽  
Terrain Matching

This paper presents an assessment of the horizon-tal accuracy and precision of the laser altimetry observations collected by NASA's ICESat-2 mission. We selected the terrain-matching method to determine the position of laser altimeter profiles within a precisely knownn surface, represented by a DEM. We took this classical approach a step further, approx-imated the DEM by planar surfaces and calculated the optimal position of the laser profile by minimizing the square sum of the elevation differences between reference DEMs and ICESat-2 profiles. We found the highly accurate DEMs of the McMurdo Dry Valleys, Antarctica, ideal for this research because of their stable landscape and rugged topography. We computed the 3D shift parameters of 379 different laser altimeter profiles along two reference ground tracks collected within the first two years of the mission. Analyzing these results revealed a total geolocation error (mean + 1 sigma) of 4.93 m for release 3 and 4.66 m for release 4 data. These numbers are the averages of the six beams, expressed as mean + 1 sigma and lie well within the mission requirement of 6.5 m.

scholarly journals Combined Block Adjustment for Optical Satellite Stereo Imagery Assisted by Spaceborne SAR and Laser Altimetry Data

2021 ◽  
Vol 13 (16) ◽  
pp. 3062
Author(s):  
Guo Zhang ◽  
Boyang Jiang ◽  
Taoyang Wang ◽  
Yuanxin Ye ◽  
Xin Li
Keyword(s):  
Large Scale ◽  
Satellite Image ◽  
Field Measurements ◽  
High Elevation ◽  
Global Scale ◽  
Stereo Image ◽  
Image Process ◽  
Control Points ◽  
Altimetry Data ◽  
Laser Altimetry

To ensure the accuracy of large-scale optical stereo image bundle block adjustment, it is necessary to provide well-distributed ground control points (GCPs) with high accuracy. However, it is difficult to acquire control points through field measurements outside the country. Considering the high planimetric accuracy of spaceborne synthetic aperture radar (SAR) images and the high elevation accuracy of satellite-based laser altimetry data, this paper proposes an adjustment method that combines both as control sources, which can be independent from GCPs. Firstly, the SAR digital orthophoto map (DOM)-based planar control points (PCPs) acquisition is realized by multimodal matching, then the laser altimetry data are filtered to obtain laser altimetry points (LAPs), and finally the optical stereo images’ combined adjustment is conducted. The experimental results of Ziyuan-3 (ZY-3) images prove that this method can achieve an accuracy of 7 m in plane and 3 m in elevation after adjustment without relying on GCPs, which lays the technical foundation for a global-scale satellite image process.

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