Research Of GPS Satellite Clock Error Integrity Monitoring And Algorithm Implementation

The difference between GPS satellite clock time and GPS standard time caused by Satellite clock frequency drift is knew as satellite clock error. Satellite clock error plays an important role in precision positioning,high-precision GPS measurements is essential high-precision time measurements. The IGS Service Centers can provide the ex post clocks error which precision accuracy is close to 0.01ns currently. The ex post high-precision satellite clock estimation is no longer a problem, which can meet precision positioning requirements. However,satellite clocks may occur irregular Clock Jump beacuse the clocks are very sensitive and highly vulnerable to the impact of the external environment, which would lead to failure of navigation and positioning when serious Jumping occurred. The systerm can detect the gross errors form the satellite signals and timely warning to the user from the considerations of the security of using the signals by users, The role and significance goes without saying.From the view of safety using of navigation satellite signals, Its get the concept of GPS satellite clock error integrity monitoring. GPS Satellite Clock Error Integrity Monitoring, that is, to find outliers containing the satellite clock error and remove them ,along with warning to the users timely, to provide "clean", high-quality, and free clock error signals, thus ensuring the users' Security.This paper focuses on GPS Satellite Clock Error Integrity Monitoring and related algorithm implementation, mainly to study the following aspects:1. Estimating the satellite clock relative error and the accuracy by using values of combination ionosphere free carrier smoothed pseudorange in the SAN(small area network). In this paper, Its make ground stations and space as the base station respectively to estimate satellite clock error, the conclusions are consistent by two ways.2. According to the estimated satellite clock error residuals, It makes linear transformation by parity QR method, and make clustering analysis by the Indicators of Euclidean distance and the correlation coefficient, the final classes are clustered into two groups: a group containing the gross clock error satellites and another do not. According to the error satellites, It gives the users a tip to achieve the function of Integrity Monitoring Alarm.3. The author has designed GPS Satellite Clock Error Integrity Monitoring Software by using VC++ and Fortran mixed languages and used it to process Hebei Province CORS network data. The software removed the poor quality of the clock error satellites to "decontaminate" GPS raw data and achieved good results. The software has the based ability in engineering application.