Papers by Keyword: Accuracy Analysis

Abstract: As aviation technology continues to evolve, the function and safety of a large maneuvering have been required highly. As a large maneuvering system is becoming more and more complex , the trajectory design and simulation of a large maneuvering have become an important mean to ensure the mobile flight safety and design. The main focus of this research is to analyze the accuracy of the strapdown navigation algorithm and its impact in large motorized sport state by the large maneuvering trajectory design and its inertial system simulation. The authors build the model of the maneuvering trajectory by the Matlab program which is based on the design principle of the maneuvering flight path. Then, by using some coordinate system and the classical strapdown algorithm, specially attitude updating algorithm, the location update algorithm and the velocity update algorithm, the designed maneuvering trajectory model has been simulated and the simulation results are analyzed.

Abstract: Combined with the experimental tunnel actual environment to select the appropriate control points as the logo, layout tunnel three dimensional modeling control network. using high-precision total station TM30 to control, measure and acquire image control points coordinate. in the following field collection imaging principle, the actual target of image acquisition, 3D modeling of tunnel based on the software platform of Lensphoto, the research results show that, the tunnel homonymous control point coordinates measured by Lensphoto three-dimensional model and using high-precision total station TM30 observations are of basic agreement, the error in the centimeter level, verified the feasibility of using digital close range photogrammetry in actual measurement of tunnel engineering,has the long-term guiding significance to the tunnel three-dimensional digital information collection and safety production.

Abstract: The accuracy of broadcast ephemeris is an important index of a satellite navigation system. The theory and method of precise ephemeris assessing broadcast ephemeris are introduced. The accuracy of GPS satellite broadcast ephemeris is assessed with the precise ones provided by IGS. The orbital coordinates of GPS broadcast ephemeris from 18th to 24th October 2013 are calculated. The analysis shows that during this time the GPS satellite broadcast ephemeris is reliable, accurate and safe as the whole, meanwhile the broadcast ephemeris accuracy is about 1 meter, better than nominal accuracy of 5 meters.

Abstract: Remote sensing image radiation correction is a key technique for quantitative remote sensing data processing is essential, especially in the surface undulating mountains, surface radiation affected by topography, the radiation correction of remote sensing inversion error can reduce the surface information, so as to maximize the accuracy of remote sensing investigation of mountain area. In this paper, the ETM image in mountain area of Western Beijing as an example, application of cosine correction model and Sandmeier correction model of image are topographic radiation correction, and then proposed an improved Sandmeier correction model, and carries on the precision analysis from the visual effect and quantitative parameters. Experiments show that, the improved Sandmeier correction model eliminates the influence of topography, greatly improving the accuracy of remote sensing image Topographic Radiation correction.

Abstract: According to the problems of island air defense, an air defense autonomous weapon system carried by a floating platform on the water is proposed. Compared with the traditional land-based air defense weapons, this weapon system has higher security and mobility. On the other hand, the waves would have a greater impact on the stability of weapons platforms. In order to demonstrate the feasibility of the weapon system in a variety of error conditions, the combat system model facing with the whole process from the sensors finding the target to the air defense weapons capturing the target. At the same time, the model of the chain of system accuracy is proposed by adding the various error sources generated by the waves and the system itself to the model. The quantitative assessment of the impact on accuracy system by each source of error is implemented with the system simulation method. Finally, the feasibility of using the weapons on the actual combat is demonstrated with the results of the accuracy analysis .

Abstract: In this study, three years of the zenith tropospheric delay (ZTD) data observed from 46 International GNSS system (IGS) sites distributed in Asian area used to assess the effectiveness and accuracy of ZTD calculated from EGNOS model, and the application of the EGNOS model are also analyzed in Asian area. Relative to IGS observed ZTD, the bias and root mean square (RMS) for ZTD calculated from EGNOS model presents an obvious variation in temporal and spatial. These results provide a reference for the study of the tropospheric delay correction model, the real-time GNSS navigation and positioning.

Abstract: In order to solve the problem of the linear measurement of arch ring for the detection of bridge,a new method is presented that measures the arch ring using a reflectorless total station on the side of the arch bridge and the detail operations are given. Taking account of weakness of edge suveying using a reflectorless total station,some formulas on the 3d coordinates calculation of the above and down edge of the arch ring based on the arch ring points are deduced.According to the law of error propagation, the accuracy of the X and Z axial coordinates are analysed.It is helpful for calculating lateral and vertical deformation and biridges elevation map that the transformation from free-station coordianates to the birdge axis coordinate by programming using EXCEL software is achieved.The method is used for bridges arch ring axial measurement in Qingcheng town,Yuzhong county,Gansu province,and its deformation is consistent with the measured results of the dial indicator,which satisfies the requirement of bridge detecton accuracy.So it is showed that the method is a good way of linear measuring of bridges arch ring.

Abstract: Continuous wave (CW) radar and global positioning system (GPS) is the main equipment of trajectory measurement in range. Based on range test background, propose a method to fuse GPS pseudo-range and CW radar range to provide complete trajectory positioning parameters, effectively reduce the impact of the systematic error of the measuring element to improve positioning precision of aircraft orbit solving. Through research on the measurement principle and the practice calculated data is given in this paper. Finally, several famous practical examples and simulation results are presented to illustrate our method efficiently.

Abstract: Single precision can only achieve 6-7 decimal places, which does not satisfy accuracy demand in many calculations. Double precision can get 13-14 decimal places, but the resource cost is high. In this paper, effects of data bit-width on digital logic design are studied. The accuracy of different bit-width is determined. Then, addition operation, multiplication operation and matrix multiplication with different bit-width are tested on FPGA platform. The results show bit width and circuit design platform have obvious effect on resource cost and circuit efficiency. Finally, a bit-width based circuit design optimization method is proposed.

Abstract: For the analysis of plane charged conductors by the method-of-moments (MoM), the basic idea and a simple derivation of the formulas is presented in this paper. Veneer conductor capacitor and dual-board conductor capacitor are respectively solved by the method-of-moments, with piecewise function as the basis function and δ function as the weight function. The comparison of the accurate solution illustrates the method-of-moments with good accuracy.