Analysis Of The Distinguishability About Adjustment Model And The Regularity Of CPⅢ Horizontal Control Network

The regularity of railway track is a prerequisite for smooth running of high-speed train, and the survey datum of ballastless track is based on CPIII control network. The accuracy of CPIII control network directly affects the construction quality of ballastless track. In order to ensure the CPIII accuracy, total stations with high precision are required in specification. However, during the measurement, error is inevitable, and gross error must be found and removed before adjustment. Many methods of detecting gross error are based on the statistics of residual which is the result of least squares adjustment. However the conventional least-squares procedure tends to homogenize the gross errors into good observations, especially those corresponding weak observations. Therefore how to detect the gross errors totally on corresponding residual is a worthy issue.CPIII control network is the basis of ballastless track measurement. It needs to retest CPIII control network periodically, in order to ensure the reliability of the control network. How to evaluate the impact of updating CPIII coordinate on ballastless track regularity is worthy of discussion.In response to these problems above:the basic principle of simplex method based on LI norm estimation is stated. All variables are split into two nonnegative variables, according to the basic requirement of simplex method, and then translate the function model of indirection adjustment into the basic model of simplex method. The algorithm provides a robust basis for the calculation of the residuals, which divides observations into the actual discrepancies of observation and the unreliable observations. Subsequently, the test statistic result shows that the detection and isolation of gross errors will be greatly improved. It is still effective for the detection of multiple gross errors.Secondly, the judgement matrix is used to analyze the observations of CPIII control network. When using the method in combination of simplex method and the judgement matrix, there’s a positive correlation between gross error detection capability and the maximum absolute value of the corresponding column in judgement matrix. If there are at least two non-zero elements in one column the gross error in the homologous observation can be detected and identified. If the absolute value of non-zero element is far less than one, then only gross error is large enough can be found, which must be considered. The analysis results show that gross error of long line direction or distance observation can be detected and isolated easily, and that gross error of short-side direction observation is difficult to detect and cannot be correctly located.At last, the track irregularity indicator in high-speed railway is introduced to the evaluation system of CPⅢ data in order to better evaluate the impact on the irregularity of ballastless track of updated coordinates of CPDI points. The regularity model of CPⅢ is constructed and the model has been proved right. The threshold value of regularity of long wave is derived.