A Method of Extracting High-Accuracy Elevation Control Points from ICESat-2 Altimetry Data

2021 ◽  
Vol 87 (11) ◽  
pp. 821-830
Author(s):  
Binbin Li ◽  
Huan Xie ◽  
Shijie Liu ◽  
Xiaohua Tong ◽  
Hong Tang ◽  
...  
Keyword(s):  
Large Scale ◽  
Comprehensive Evaluation ◽  
Photon Counting ◽  
High Accuracy ◽  
Airborne Lidar ◽  
Altimeter Data ◽  
Control Points ◽  
Laser Altimeter ◽  
Terrain Elevation ◽  
Along Track

Due to its high ranging accuracy, spaceborne laser altimetry technology can improve the accuracy of satellite stereo mapping without ground control points. In the past, full-waveform ICE, CLOUD, and Land Elevation Satellite (ICESat) laser altimeter data have been used as one of the main data sources for global elevation control. As a second-generation satellite, ICESat-2 is equipped with an altimeter using photon counting mode. This can further improve the application capability for stereo mapping because of the six laser beams with high along-track repetition frequency, which can provide more detailed ground contour descriptions. Previous studies have addressed how to extract high-accuracy elevation control points from ICESat data. However, these methods cannot be directly applied to ICESat-2 data because of the different modes of the laser altimeters. Therefore, in this paper, we propose a method using comprehensive evaluation labels that can extract high-accuracy elevation control points that meet the different level elevation accuracy requirements for large scale mapping from the ICESat-2 land-vegetation along-track product. The method was verified using two airborne lidar data sets. In flat, hilly, and mountainous areas, by using our method to extract the terrain elevation, the root-mean-square error of elevation control points decrease from 1.249–2.094 m, 2.237–3.225 m, and 2.791–4.822 m to 0.262–0.429 m, 0.484–0.596 m, and 0.611–1.003 m, respectively. The results show that the extraction elevations meet the required accuracy for large scale mapping.

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 Alignment determination of the Hayabusa2 laser altimeter (LIDAR)

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Hirotomo Noda ◽  
Hiroki Senshu ◽  
Koji Matsumoto ◽  
Noriyuki Namiki ◽  
Takahide Mizuno ◽  
...  
Keyword(s):  
Altimeter Data ◽  
Gravity Assist ◽  
Laser Altimeter ◽  
Trajectory Error ◽  
Flight Data ◽  
Camera Image ◽  
Operation Period ◽  
The Cross ◽  
Along Track

AbstractIn this study, we determined the alignment of the laser altimeter aboard Hayabusa2 with respect to the spacecraft using in-flight data. Since the laser altimeter data were used to estimate the trajectory of the Hayabusa2 spacecraft, the pointing direction of the altimeter needed to be accurately determined. The boresight direction of the receiving telescope was estimated by comparing elevations of the laser altimeter data and camera images, and was confirmed by identifying prominent terrains of other datasets. The estimated boresight direction obtained by the laser link experiment in the winter of 2015, during the Earth’s gravity assist operation period, differed from the direction estimated in this study, which fell on another part of the candidate direction; this was not selected in a previous study. Assuming that the uncertainty of alignment determination of the laser altimeter boresight was 4.6 pixels in the camera image, the trajectory error of the spacecraft in the cross- and/or along-track directions was determined to be 0.4, 2.1, or 8.6 m for altitudes of 1, 5, or 20 km, respectively.

scholarly journals Performance Assessment of ICESat-2 Laser Altimeter Data for Water-Level Measurement over Lakes and Reservoirs in China

2020 ◽  
Vol 12 (5) ◽  
pp. 770 ◽  
Author(s):  
Cui Yuan ◽  
Peng Gong ◽  
Yuqi Bai
Keyword(s):  
Measurement Uncertainty ◽  
Large Scale ◽  
Temporal Frequency ◽  
Altimeter Data ◽  
Profile Measurement ◽  
Accuracy Evaluation ◽  
Radar Altimeter ◽  
Laser Altimeter ◽  
Ice Cloud ◽  
Lakes And Reservoirs

Although the Advanced Topographic Laser Altimeter System (ATLAS) onboard the Ice, Cloud, and Land Elevation Satellite-2 (ICESat-2) was primarily designed for glacier and sea-ice measurement, it can also be applied to monitor lake surface height (LSH). However, its performance in monitoring lakes/reservoirs has rarely been assessed. Here, we report an accuracy evaluation of the ICESat-2 laser altimetry data over 30 reservoirs in China using gauge data. To show its characteristics in large-scale lake monitoring, we also applied an advanced radar altimeter SARAL (Satellite for ARgos and ALtika) and the first laser altimeter ICESat (Ice, Cloud and land Elevation Satellite) to investigate all lakes and reservoirs (>10 km2) in China. We found that the ICESat-2 has a greatly improved altimetric capability, and the relative altimetric error was 0.06 m, while the relative altimetric error was 0.25 m for SARAL. Compared with SARAL and ICESat data, ICESat-2 data had the lowest measurement uncertainty (the standard deviation of along-track heights; 0.02 m vs. 0.17 m and 0.07 m), the greatest temporal frequency (3.43 vs. 1.35 and 1.48 times per year), and the second greatest lake coverage (636 vs. 814 and 311 lakes). The precise LSH profiles derived from the ICESat-2 data showed that most lakes (90% of 636 lakes) had a quasi-horizontal LSH profile (measurement uncertainty <0.05 m), and special methods are needed for mountainous lakes or shallow lakes to extract precise LSHs.

scholarly journals Bering Glacier surge 2011: analysis of laser altimeter data

2013 ◽  
Vol 54 (63) ◽  
pp. 158-170 ◽  
Author(s):  
Ute C. Herzfeld ◽  
Brian McDonald ◽  
Maciej Stachura ◽  
Robert Griffin Hale ◽  
Phillip Chen ◽  
...  
Keyword(s):  
Large Scale ◽  
Altimeter Data ◽  
Small Scale ◽  
Rapid Progression ◽  
Laser Altimeter ◽  
Reservoir Area ◽  
Airborne Laser ◽  
Bering Glacier ◽  
Change Characteristics ◽  
Elevation Changes

AbstractThe Bering Glacier–Bagley Icefield system in Alaska is currently surging (2011). Large-scale elevation changes and small-scale elevation-change characteristics are investigated to understand surge progression, especially mass transport from the pre-surge reservoir area to the receiving area and propagation of the kinematic surge wave as manifested in heavy crevassing characteristic of rapid, brittle deformation. This analysis is based on airborne laser altimeter data collected over Bering Glacier in September 2011. Results include the following: (1) Maximal crevasse depth is 60 m, reached in a rift that separates two deformation domains, indicative of two different flow regimes. Otherwise surge crevasse depth reaches 20–30 m. (2) Characteristic parameters of structural provinces are derived by application of geostatistical classification. Parameters include significance and spacing of crevasses, surface roughness and crevasse-edge curvature (indicative of crevasse age). A classification based on these parameters serves to objectively discriminate structural provinces, indicative of surge progression down-glacier and up-glacier. (3) Elevation changes from 2011 and 2010 altimetry show 40–70 m surface lowering in the reservoir area in lower central Bering Glacier and 20–40m thickening near the front in Tashalich arm. Combining elevation changes with results of crevasse profilometry and pattern analysis, the rapid progression of the surge can be mathematically–physically reconstructed.

scholarly journals Estimation of the Effect of Eddies on Coastal El Niño Flows Using Along-Track Satellite Altimeter Data

2013 ◽  
Vol 43 (6) ◽  
pp. 1209-1224 ◽  
Author(s):  
Emma M. Giunipero ◽  
Allan J. Clarke
Keyword(s):  
Sea Level ◽  
El Niño ◽  
Time Scale ◽  
Large Scale ◽  
El Nino ◽  
Altimeter Data ◽  
Western Coast ◽  
Shelf Edge ◽  
Shelf Sea ◽  
Along Track

Abstract Previous work has shown that the El Niño sea level signal leaks through the gappy western equatorial Pacific to the coasts of western and southern Australia. South of about 22°S, in the region of the Leeuwin Current, the amplitude of this El Niño signal falls. Using coastal sea level measurements and along-track altimetry data from the Ocean Topography Experiment (TOPEX)/Poseidon, Jason-1, and OSTM/Jason-2 satellites, this study finds that the interannual divergence of the eddy momentum flux D′ is correlated with the southward along-shelf sea level amplitude decay, consistent with the eddies removing energy from the large-scale sea level signal. The quantity D′ is also correlated with the interannual flow with a surprisingly short dissipation time scale of only 2 days, much shorter than the interannual time scale. A similar analysis off the western coast of South America, site of the originally named “El Niño” current, was carried out. Interannual sea level decay along the shelf edge is observed, and the interannual southward flow along the shelf edge is found to be highly positively correlated with the along-shelf sea level decay with a dissipation time scale of a few days. Dynamics similar to the Australian case likely apply.

scholarly journals Research on the Control Point Extraction Method of Chinese Gaofen 7 Satellite Using Altimeter and Footprint Camera

2020 ◽  
Vol 237 ◽  
pp. 01016
Author(s):  
Binbin Li ◽  
Huan Xie ◽  
Xiaohua Tong ◽  
Yinqiao Cai ◽  
Zhijie Zhang
Keyword(s):  
Information Acquisition ◽  
Control Point ◽  
High Accuracy ◽  
Ground Control ◽  
Observation System ◽  
Control Points ◽  
Accuracy Control ◽  
Laser Altimeter ◽  
Intensity Information ◽  
Earth Observation System

Satellite laser altimetry is one of the most advanced information acquisition technologies in Earth observation system. It can provide high-accuracy elevation information, however, due to the lack of detail intensity information, its planimetric accuracy is usually worse than the elevation accuracy. Gaofen 7 (GF-7) satellite scheduled for launch in 2019 will be equipped with laser altimeter, footprint camera, stereo mapping camera, etc. The laser altimeter together with the footprint camera was designed to provide high accuracy ground control point of satellite mapping. The laser altimeter can provide the high-accuracy elevation information and the joint processing of footprint camera and stereo mapping camera can provide high-accuracy planimetric information. Therefore, this paper mainly studies the technology of extracting high-accuracy control points based on GF-7 satellite’s altimeter, footprint camera and stereo mapping camera using a simulated dataset extracted from Quickbird image and ICESat altimetric data.

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