| With the fast development of the computer technology, there has been continual presence of change both in terms of the capability of hardware and the technology. This leads to a result that much original software can't follow the technical development in the new environment. Abandoning the current software will be a large waste of money and labour, even some matural software accomplishments. Software migration is right an effective method to solve this problem. Meanwhile, there is also vital significance in developing the new software under the new environment.The satellite orbit determination has great significance for national defense development, national economy development as well as scientific research. GEO satellite precise orbit determination is one of the key technologies to satellite navigation system, which directly affects the positioning accuracy of satellite navigation system. Therefore, the precise orbit determination software of GEO satellite holds an important position in the application of technique. The original method of determination of satellite orbit by transfer, which was invented by NTSC (National Time Service Center, Chinese Academy of Sciences), and has been successfully applied to the project of Chinese Area Positioning System (CAPS) for satellite orbit determination. The accuracy for range is about centimeter and the orbit determination is up to meter level. At present, the satellite precise orbit determination software which has been used and run in CAPS,is based on UNIX system, the practice application of many years has show that it is a very successful software, and has quite a lot of advantages. However, it has also some disadvantages, which have restricted the development and application of the satellite orbit determination software, the dependence of the satellite orbit determination software on the UNIX platform and the UNIX platform's command-style operation and so on for example, at the same time, it costs too much to run and maintain this software which is running on the SUN workstation. For above reasons, the main research works of this thesis are as follows:Firstly, analyzing and discussing the time and coordinate system, the principle of orbit determination, the mechanical mode used in the analysis process and measurement model, reference system, the satellite precise orbit determination software's establishment,constitution and algorithm characteristic and flow and so on in CAPS system.Secondly, based on the elementary theory of software's transplant, We propose to adopt the graphical user interface development tools is Microsoft Visual Studio 2005 Integrated Intel(R) Visual Fortran Compiler Professional 11.0, and transplant the high accuracy satellite orbit determination software in CAPS system from UNIX to Windows Platform successfully,that has perfected the software system and improved the speed to solve satellite orbit by optimizing and improving some program. It has been shown the accuracy, reliability and fidelity of transplanting work by comparing the results of Windows Platform and UNIX Platform.Thirdly, based on the foundation of high accuracy satellite orbit determination software's transplanting successfully, we propose to and complete the development and study of visual software of GEO satellite orbit determination using Microsoft Visual Studio 2005 as software platform and Visual Basic.NET as designing language. This visual software can pre-process observation data,compute the high accuracy GEO satellite orbit, analyze and plot the results of calculating the satellite orbit and so on. At the same time, it improves the work efficiency of GEO satellite orbit determination greatly with its friendly user interface, high operability, time saving convenience, studying and using easily. Its successful development has simplified the operating steps of satellite orbit determination software, shorten the time of computing, reduced the mistake caused by human factors and improved the intuition of computing result. Fourthly, proposing a method by generating normal points with the least squares way to reduce observation data. Owing to the rich observation in CAPS(each station implements continuous sampling in each second), which leads to take quite a long time to compute the satellite orbit, and affects the work of the navigation system in real time and so on . We apply the method to compute the satellite orbit and reduce the observation data for determination of satellite orbit without distortion, which has been enhanced the calculating speed for satellite orbit determination. It has been shown that our method not only reduces the time of computing satellite orbit greatly, but also the orbit using the normal point is nearly as same as the orbit with all of the observation data, the difference of two orbits are in a few millimeters. This approach of reducing the observation improves the computational efficiency of the satellite orbit and meets the requirements of navigation system in real time.
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