Simplifying the Performance Analysis of the SPRT for GPS Acquisition

A new approximation for the distribution of the probability ratio in a sequential probability ratio test (SPRT) using noncoherent integration across a full code period is presented. The new approximation is valid for the carrier-to-noise power ratios (C/N0) typically encountered in GPS acquisition (20 dB-Hz ≤ C/N0 ≤ 50 dB-Hz), and it allows accurate theoretical performance analysis of the SPRT to be carriedout for signals in this C/N0 range, eliminating the need for lengthy simulations for each scenario underinvestigation. Thus, the SPRT performance can be readily compared to that of other acquisition strategiesfor receiver design. Previous approximations in the literature are not valid in the range 20 dB-Hz ≤ C/N0 ≤ 50 dB-Hz