The Lunar Vitrual Reality Structure Basing On CE-1 Laser Altimeter Data

Authorized by Nation Astronomical Observatory, China University ofGeosciences has the right to use CE-1 remote sensing data. The thesis forms with thepriority project named"Application and Research to the Scientific Data of LunarOrbiter Project"(863 Program) as the base, extracting remote sensing information,constructing virtual reality of the full lunar for scientific research.The altimetry data of 400-circle CE-1 laser altimeter (2B) is a scientific data,which is founded upon the lunar area coordinate. It comes into being through altitudecalculation basing on satellite trajectory data, via altitude and geometrical orientation,and the research is done based upon it. The high resolution lunar DEM is producedvia leading modified altitude data to ERDAS, using ERDAS software and datainterpolation method.Based on the high resolution lunar DEM model, the next work for this thesis areextracting and dealing with further information, constructing virtual reality of the fulllunar. First, build the three-dimensional model of the lunar surface, importthree-dimensional camera image, and then use Super3Deditor platform drawing thelunar surface true three-dimensional virtual reality scenes. The virtual reality of thefull lunar provides a new means of technology for lunar science research, that is uponthe technology of virtual reality of the full lunar, a further work of informationextraction and processing can develop, such as arbitrary roaming, measurement,annotation, screen shots and so on. The virtual reality of the full lunar technology hasbecome a high-grade technical means for information extraction and processing. Themajor achievements and innovation of this paper can be summarized as follows:1. Building high-resolution DEM model on the basis of the CE-1 satellite laseraltimeter data.Extract and process laser altimeter data to get the 400-circle laser altimeter data,then do elevation conversion and dispose singular data in order to get the textelevation file. Import the file into ERDAS for data processing and interpolationoperations to acquire full lunar DEM (digital elevation model) image. Spatialresolution: latitude, longitude, 607m, longitude direction (along the weft) 303m, andput the full lunar DEM model out.2. Constructing the full lunar of true three-dimensional virtual realityConstruction of the virtual reality of full lunar is based on full lunar DEM model. Generating lunar three-dimensional model is an artificial or automatic geometricmodeling process, which describes shape and texture. Lunar DEM defines the shapeof lunar model, and lunar image defines the texture of it. The construction ofgeometric model shape (polygon, triangle, tiptop and spline) and texture areconditional, so the process of generating lunar three-dimensional model is a continualcourse of resample and slicing, extracting images. The number of files depends on theslicing lumps numbers of three-dimensional model in every level. When browsinglunar three-dimensional model, model import is changing from one level to another.The lunar true three-dimensional virtual reality generates by using 1082-circle dataproduction (CCD 2C data), which comes out via radiation, geometric and photometricadjustments to the data captured by the CCD piranha color in CE-1.The virtual realityof the full lunar becomes a new technique for the extraction of lunar surfaceinformation.3. Using the virtual reality of the full lunar to abstract information on the lunarsurfaceThe full lunar virtual reality operating system which equipped withSuper3Deditor as the platform can support any roaming, height measuring, grounddistance measurement, the straight line distance measurement, area measurement, theslope measurements, screenshots, marking and so on. In the thesis, important pointson the lunar surface in the virtual scene have been marked, and a part of the virtualscene images have been intercepted. Measured the diameter of 50 craters which wereselected arbitrarily on the lunar surface in order to verify polynomialrelations d = k_dD~n,d stands for the crater depth, D is the crater diameter, finally getthat n = 1.9. The result of length measurement fof Plato Wolgye and Alpine Canyon isselected.4. Making use of the full lunar virtual reality to display and analyze singular datain order to look for new areas of researchIn the thesis, there is theoretical analysis to the cause of accidental error in thelaser altimeter 2B data, which reveals that the greater the slope of the lunar surface is,the more the singular data is, that is to say, frequent changes in the slope of the lunarsurface would produce great amount of singular data. The virtual reality of the fulllunar appears to be good technology for displaying singular data, and singularelevation data are displayed in the virtual reality of the full lunar which can be analyzed in further. Singular data latitudes are mainly located at low latitudes (30°N→-30°S) and high latitudes (70°N and S→90°N, -70°→-90°S). A peak (20°W orso) appears at 0°→30°W through longitude analysis. The fault peak data in themid-latitude regions in the south of the equator around 20°W coincides with theradiation pattern of the Tycho crater, and it is found that in virtual reality research, theradiation pattern exists with deep depth and complex structure. Singular data to acertain extent reflects the complexity of the topography of the lunar surface, thesurface topography of underground tectonic situation is highly subject to singularanalysis of the data interpretation of the lunar geological structures, which is a newarea for research.5. Finding a serious error of Google MoonVisiting the Web site http://earth.google.com/moon/ of Google Moon, it is foundthat the moon is marked with 23°26'on the Tropic of Cancer and Tropic of Capricorn,the same with those of Earth, which is a serious error, inconsistent with the facts. Onthe Moon, Tropic of Cancer is 1°32'N, while Tropic of Capricorn 1°32'S, which is thelatitude range of direct sunlight spot moving on the moon in a year.