Geometric calibration of satellite laser altimeters based on waveform matching

2021 ◽  
Author(s):  
Shaoning Li ◽  
Chaokui Li ◽  
Guo Zhang ◽  
Yanan Wang
Keyword(s):  
Geometric Calibration ◽  
Laser Altimeters

Thematic maps in the scientific studies of the moon

2019 ◽  
Vol 943 (1) ◽  
pp. 68-75
Author(s):  
S.G. Pugacheva ◽  
E.A. Feoktistova ◽  
V.V. Shevchenko
Keyword(s):  
Natural Resources ◽  
Thermal Inertia ◽  
High Growth ◽  
Lunar Soil ◽  
Nature Management ◽  
The Moon ◽  
Surface Cooling ◽  
Laser Altimeters ◽  
Space Infrastructure ◽  
The Impact

The article presents the results of astrophysical studies of the Moon’s reflected and intrinsic radiation. We studied the intensity of the Moon’s infrared radiation and, thus, carried out a detailed research of the brightness temperature of the Moon’s visible disc, estimated the thermal inertia of the coating substance by the rate of its surface cooling, and the degree of the lunar soil fragmentation. Polarimetric, colorimetric and spectrophotometric measurements of the reflected radiation intensity were carried out at different wavelengths. In the article, we present maps prepared based on our measurement results. We conducted theresearch of the unique South Pole – Aitken basin (SPA). The altitude profiles of the Apollo-11 and Zond-8 spacecrafts and the data of laser altimeters of the Apollo-16 and Apollo-15 spacecrafts were used as the main material. Basing upon this data we prepared a hypsometric map of SPA-basing global relief structure. A surface topography map of the Moon’s Southern Hemisphere is given in the article. The topography model of the SPA topography surface shows displacement centers of the altitude topographic rims from the central rim. Basing upon the detailed study of the basin’s topography as well as its “depth-diameter” ratio we suggest that the basin originated from the impact of a giant cometary body from the Orta Cloud. In our works, we consider the Moon as a part of the Earth’s space infrastructure. High growth rates of the Earth’s population, irrational nature management will cause deterioration of scarce natural resources in the near future. In our article, we present maps of the natural resources on the Moon pointing out the most promising regions of thorium, iron, and titanium. Probably in 20 or 40 years a critical mining level of gold, diamonds, zinc, platinum and other vital rocks and metals will be missing on the Earth.

scholarly journals A New Combined Adjustment Model for Geolocation Accuracy Improvement of Multiple Sources Optical and SAR Imagery

2021 ◽  
Vol 13 (3) ◽  
pp. 491
Author(s):  
Niangang Jiao ◽  
Feng Wang ◽  
Hongjian You
Keyword(s):  
Remote Sensing Data ◽  
Observation Data ◽  
Multiple Sources ◽  
Accuracy Improvement ◽  
Geometric Calibration ◽  
Proposed Model ◽  
Calibration Methods ◽  
Earth Observation Data ◽  
Sar Imagery ◽  
Geolocation Accuracy

Numerous earth observation data obtained from different platforms have been widely used in various fields, and geometric calibration is a fundamental step for these applications. Traditional calibration methods are developed based on the rational function model (RFM), which is produced by image vendors as a substitution of the rigorous sensor model (RSM). Generally, the fitting accuracy of the RFM is much higher than 1 pixel, whereas the result decreases to several pixels in mountainous areas, especially for Synthetic Aperture Radar (SAR) imagery. Therefore, this paper proposes a new combined adjustment for geolocation accuracy improvement of multiple sources satellite SAR and optical imagery. Tie points are extracted based on a robust image matching algorithm, and relationships between the parameters of the range-doppler (RD) model and the RFM are developed by transformed into the same Geodetic Coordinate systems. At the same time, a heterogeneous weight strategy is designed for better convergence. Experimental results indicate that our proposed model can achieve much higher geolocation accuracy with approximately 2.60 pixels in the X direction and 3.50 pixels in the Y direction. Compared with traditional methods developed based on RFM, our proposed model provides a new way for synergistic use of multiple sources remote sensing data.

Geometric calibration for a next-generation digital breast tomosynthesis system

2017 ◽  
Author(s):  
William S. Ferris ◽  
Trevor L. Vent ◽  
Tristan D. Maidment ◽  
Raymond J. Acciavatti ◽  
David E. Wurtele ◽  
...  
Keyword(s):  
Digital Breast Tomosynthesis ◽  
Next Generation ◽  
Breast Tomosynthesis ◽  
Geometric Calibration

Geometric Calibration of Digital Cameras for 3D Cumulus Cloud Measurements

2009 ◽  
Vol 26 (2) ◽  
pp. 200-214 ◽  
Author(s):  
Jiuxiang Hu ◽  
Anshuman Razdan ◽  
Joseph A. Zehnder
Keyword(s):  
Field Measurements ◽  
Geometric Error ◽  
Digital Cameras ◽  
Cumulus Clouds ◽  
Geometric Calibration ◽  
Earth Observing System ◽  
Stereo Photogrammetry ◽  
Camera Parameters ◽  
The Right ◽  
Coarse To Fine

Abstract A technique for calibrating digital cameras for stereo photogrammetry of cumulus clouds is presented. It has been applied to characterize the formation of summer thunderstorms observed during the Cumulus Photogrammetric, In Situ, and Doppler Observations (CuPIDO) project. Starting from gross measurements of locations, orientations of cameras, and landmark surveys, accurate locations and orientations of the cameras are obtained by minimizing a geometric error (GE). Once accurate camera parameters are obtained, 3D positions of cloud-feature points are computed by triangulation. The main contributions of this paper are as follows. First, it is proven that the GE has only one minimum in the neighborhood of the real parameters of a camera. In other words, searching the minimum of the GE enables the authors to find the right camera parameters even if there are significant differences between the initial measurements and their true values. Second, a new coarse-to-fine iterative algorithm is developed that minimizes the GE and finds the camera parameters. Numerical experiments show that the coarse-to-fine algorithm is efficient and effective. Third, a new landmark survey based on a geographic information system (GIS) rather than field measurements is presented. The GIS landmark survey is an effective and efficient way to obtain landmark world coordinates for camera calibrations in these experiments. Validation of this technique is achieved by the data collected by a NASA/Earth Observing System satellite and an instrumented aircraft. This paper builds on previous research and details the calibration and 3D reconstructions.

HIGH-PRECISION IN-FLIGHT CALIBRATION USING UNKNOWN LANDMARKS

2021 ◽  
Vol 4 ◽  
pp. 117-124
Author(s):  
Alexander Tkachenko ◽  
Keyword(s):  
Good Accuracy ◽  
Star Tracker ◽  
Coordinate Frame ◽  
Geometric Calibration ◽  
The Earth ◽  
Imaging Camera ◽  
Calibration Accuracy ◽  
Combined Algorithm ◽  
Fuzzy State ◽  
Fuzzy State Observer

An in-flight geometric calibration (further — calibration) is interpreted here as a procedure of making more preceise mutual attitude parameters of the onboard imaging camera and the star tracker. The problem of calibration is solved with using of observations of the landmarks from the orbit. In this work, the landmarks are considered as unknown in the sense that they may be identified on the several snapshots, they may be associated with synchronous data of the star tracker and GPS, but their location in the Earth coordinate frame is unknown. While unknown markers are used, it is more complicated to provide high accuracy of calibration than when geo-referenced markers are observed. In such a situation, improvement of the onboard devices and gauges and increasing of their accuracy strenghtens advisability of agreement of attainable accuracy of calculations while in-flight geometric calibration with accessible measurings accuracy. It concerns properly calibration so as geo-referencing of space snaps using results of calibration. In particular, it is important to consider how accuracy of calibration depends on the accuracy of specific measurings and initial data. Actuality of the considered problem is indisputable. Without its solution, attraction of high-accurate measurings is senseless. A main means of investigation is computer simulanion and analysis of its results. The combined algorithm is proposed for the processing of the calibration measuring equations. It consists of two independent parts. The first one belongs to author of this work and is based on photogrammetric condition of collinearity The second part belongs to D.V. Lebedev and is based on photogrammetric condition of coplanarity. The method of state estimation with high convergence characteristics — fuzzy state observer — is used for resolving of measuring equations. The results of above-mentioned calibration are fully fit for the geo-referencing of the unknown ground objects with acceptable accuracy. Computer simulation had demonsrated good accuracy of the proposed method of the in-flight geometric calibration using unknown landmarks in a combination with high-precise characteristics of used technical means. The simulation had shown the calibration accuracy on the level of 5 arc sec and accuracy of the geo-referencing on the level of 10–20 m. It is fully comparable with accuracy when geo-referenced markers are observated.

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