Abstract: In order to meet the requirements of deep space exploration, effectively utilize the TTC resource, and improve the link calculation accuracy, statistical analysis method of the link was studied and the characteristics of probability density functions of three link parameters recommended by the Consultative Committee for Space Data System (CCSDS) were analyzed. A method was put forward when the link parameters can not meet the Lyapunov condition that uses the saddle point approximation to estimate the tail probability function to determine the derived parameter probabilities. The result shows that the parameters derived of this method are similar to that of the real function. This method can further improve the statistical calculation method of the link analysis and make it more universal.

Key words: link statistical analysis, derived parameter, probability density function, saddle point approximation, tail probability function