2004 Vol. 29, No. 7
The concept, main composition and key technologies of the deep space network(DSN) are introduced. The DSN's meaning and application to radio astronomy and space detection are summarized. Last, the prospect of DSN is discussed.
This paper focuses on bridging the imaging architecture of OpenGL and photogrammetry analytic theory. Firstly, the imaging mechanism of OpenGL has been analysed in the light of projective geometry, and the relationship between exterior and interior parameters in photogrammetry and image matrix in OpenGL has been summarized. Then, the transition equations of two imaging processes are inferred, and a set of equations that conform the perspective imaging matrix are built. By the experiment of simulation of real camera imaging process in OpenGL, the consistency of collinear equation in photogrammetry and perspective imaging mechanism in OpenGL is validated, which will pave the way for the usage of OpenGL. In this experiment, a CCD camera has been used. Firstly, several images of a industry part have been taken by this camera. Then the exterior and interior parameters of these images have been calibrated and these parameters have been input into our OpenGL program to produce corresponding imaging matrix. The experimental results show the reliability and correctness of derivation.
This paper discusses the prediction methods of gross arable land based on grey-markov model. The advantages and disadvantages of grey GM(1,1) prediction and Markov prediction model have been analyzed. A new method, which is called grey Markov model, is presented based on analyzing current methods for arable land prediction. This prediction model is identified by taking prediction of arable land in Hubei province.
This paper proposes to make a spatial database that have an excellent expansibility for the road bureau of Yunnan province. The proposal is discussed in five aspects: the defined data-layer of the road data, the design of the relation of the road entity, the expansion of the managed subject, the expansion of the road graphic attribute and the graphic dynamic update by dynamic segmentation. Last, some useful advice are given about the system of management and the process of data collection.
After studying on the shape change in a group of spatio temporal data for land use, the authors concludes that there are only four basic types of shape change and the time slices for each case of shape change can be interpolated by curve interpolation and shape interpolation. Thus, a powerful interpolation algorithm for shape interpolation is needed in order to realize the visualization of shape change. The algorithm is able to interpolate for both curve and polygon. The commonly used interpolation algorithm can not achieve this, because it is a local interpolation algorithm. After investigating into the interpolation algorithm deeply, the authors concludes that a global interpolation algorithm based on potential field theory can be used for shape interpolation in the visualization of spatio-temporal data for land use.
On the basis of the description of time and its relationship in cadastral information system, this paper brings forward a way of ground state modification according to the changing frequency to deal with historical data, and expounds the spatio-temporal data model based on event semantics.
Conventional reservoir evaluation method and its existing problems are analyzed through studying commercial GIS. The spatial database of oil-gas reservoir evaluation is established. All kinds of multidisciplinary oilfield graphic information and its correlating attribute data relating to reservoir are integrated. By means of integrating reservoir evaluation model with GIS, oil-gas reservoir evaluation problem is figured out. Thus the spatial analysis function of GIS is extended. An instance of a western oilfield in our country is cited to prove that the new method makes the evaluation more accurate and reliable.
This paper studies and analyses the function and influence of parameter α,β,ρ in the three models of ant algorithm theoretically, taking TSP as an example. The computational results of oliver 30 city shows that the analysis on the three parameters is rational. Furthermore, we study the optimum configuration of the parameters. To improve the efficiency of the algorithm, we present to amend the strategy of choice used to decide the next city and propose a new method and a group of optimum parameters. Experimental results indicate that the change is practical and valuable.
Taking the geological exploration engineering as our research objects, we propose a QTPV (quasi tri-prism volume) model and make research about the model manipulation. In this paper, QTPV data structure is analyzed. 3D QTPV data model and data structures are designed. Model manipulation algorithms, such as modeling according borehole sample data, model cutting, model partition into tetrahedron, are proposed. The QTPV model features have been discussed by making a comparison among 3DFDS, TEN and QTPV. A system prototype is developed based on the proposed model and manipulations on QTPV by using VC ++ and OpenGL graphic library under Windows environment. A set of real borehole sample data, which come from Inner Mongolia China, is used to verify the model and algorithms implemented in the system prototype.
A view angle of landslide-monitoring data mining is proposed. With the view angle three, Baota landslide is taken as a case study to discover quantitative, qualitative and visualized knowledge from its monitoring databases. The results are satisfactory.
The abundance fractions of endmembers in an image pixel are estimated by unsupervised fully constrained least squares (UFCLS) based on the inversion of linear spectral mixture method. The results of the experiment show that the effects are good. Compared to CSMA method, UFCLS method is better in both the effects of classification and the consumption of computation time.
This paper presents an experimental investigation of the ERS-1/2 SAR tandem data in 1996 on DEM generation of the Grove mountains core area, compares the DEM with the actual topographic form and analyzes the feasibility of InSAR applied to Antarctic Mapping. In the relatively stable and with good coherence area, the RMS is about 5.4m. It is confirmed that InSAR can be used to produce more products to complement the dangerous field surveying. And for Antarctic investigation, InSAR is also an effective tool in studing ice sheet flow, ice sheet kinematic characteristics, and mass balance by adopting more pairs of radar image data.
This paper presents the principle of cosine backscatter model. The model has two unknown numbers: azimuth angle and range angle. For flat area, we assume the azimuth angle is zero, so we can get range angle. Then we can get DEM by integration. Based on this model, we introduce a new algorithm that does not omit azimuth angle and can get DEM in mountainous area. Using this model, we assessed the DEM of Zhangbei of Hebei province.
This paper presents a bi-graph image decomposition based on quincunx sampling lifting scheme, which decomposes an original image to a lower-resolution one and a different one between the original image and the lower-resolution image. The proposed scheme is of low-complexity and need not allocate additional memory.This paper introduces some simple examples, such as linear mean-lifting, nonlinear max-lifting and min-lifting. Mean-lifting is good at erasing redundant data, and max-lifting or min-lifting can effectively preserve important geometric information.
Digital watermarking is a key technique for protecting intellectual property of digital media. A lot of watermarking schemes in DCT domain have been presented. In this paper a new algorithm in DCT domain is discussed. Watermark detecting using this algorithm need not the original image. The experimental results demonstrat that the watermark is robust to general image processing and geometric distortions.
In order to solve the boundary value problem with chaos or complicated boundary dates, such as singularity etc., it is necessary to establish the model of stochastic partial differential equation for the gravity field. This paper first constructs the conception of stochastic Sobolev spaces H22(Ω), then gives the stochastic Poisson integral as a generalized stochastic functional, and compares the relationships between stochastic model and determined model of Poisson integral, and indicates that determined model is just one of the special situations of stochastic Poisson integral.
Mutuo of Tibet is located at the belt sewing Europe-Asia block and Indian Ocean block. The conditions of landform, relief, geology and weather in the area are very complicated. As Mutuo is the blank area of base information in China, it is difficult to survey it by traditional methods. The refining local 1'×1' quasi-geoid has been built by using the earth's gravity field model, the local gravity anomalies and relief rectification. The results show that the relative accuracy of this engineering quasi-geoid has reached 0.025m. It can substitute direct leveling and satisfy the need of the local engineering construction.
In this paper, a single epoch GPS ambiguity resolution is proposed. Then based on it and using the INS indirect error model, a new method, using Kalman filtering to process the new combination of GPS double-difference carrier phase and Doppler/INS integrated data, is presented. The exterior orientation elements of airborne three-line-scanner can be accurately calculated directly based this method. The experiment used simulated data proved that the precision of attitude is higher than 10 arc second and the precision of position is higher than 10cm.
A low-orbit satellite with precise and complete dynamic model and 500-km altitude is simulated. The precise coordinates of 27 GPS satellites in the same time span are calculated by using Chebyschev polynomial interpolation method. Based on simulated low earth satellite orbit and GPS precise ephemeris, P-code observations with different magnitude errors are simulated. By means of least square patch processing method, the biases of initial state parameters are calculated using double-frequency P-code ionospheric-free combinations of GPS simulated measurements. Last, double-frequency P-code observations with random error (standard error σ=2.7m) and GPS clock error (maximum bias=5m) in a motion period (95min) are simulated. By using ionospheric-free combination measurements, the short-arc orbit determination in a period is fulfilled. The results reveals that 6~9 GPS satellites can be traced at the same time using 5° cut-off angle and the biases between estimators of coordinate parameters and simulated true values are at centimeter level and those of velocity are at mm/s level.
There are two crucial steps in resolving semi-parametric model. One is to choose the regularizer, and the other is to determine the smoothing parameter. The emphasis of this paper is on the determination of the smoothing parameter. A new method for determining smoothing parameter, L-curve method, is investigated. On the basis of analyzing the basic theorem of L-curve, the authors realize its algorithm and apply it to the mitigation of systematic errors.Furthermore, we combine the L-curve with different methods to resolve the semi-parametric model and compare their results.
This paper considers the semiparametric regression model yi= X iTβ+s(ti)+ei(for i=1,2,...,n). Where si=s(ti) denotes the nonparametric signal of the observation and yi a number relating to the observation at ti, X i∈Rp(n > p), β=(β1,...,βp)T is parameter vector with p denoting the number of parameters, ei denotes the noise and is assumed to be independently N(0,σi2) distributed.