A Theoretical Approach to Determining the 95% Probability of TTFF for the P(Y) Code Utilizing Active Code Acquisition
Jack K. Holmes, Neil Morgan, Philip A. Dafesh · 24th AIAA International Communications Satellite Systems Conference · 2006
This paper deals with the problem of mathematically describing the probability specification of the time to first fix (TTFF) for a navigational receiver such as GPS, as a function of the receiver search time and the initial conditions. Commonly many analyses are based on computing the mean TTFF; however, in contrast, many navigational specifications are for the 95% probability TTFF. For the GPS P(Y) code, results are provided for both the mean TTFF and the 95% probability of TTFF, and the two times are compared. The approach is approximate, but is believed to be quite accurate.