Acquisition Algorithms for the GPS L5 Signal

his paper describes acquisition algorithms for the new civil GPS L5 signal and evaluates their performance. In particular, two classes of acquisition techniques are described: (1) correlation with the I5 and Q5 signal components using 1-ms coherent integration, (2) correlation with Q5-only using longer coherent integration. It is expected that, as for the L1 C/A-code, 1-ms coherent integration with further non-coherent integration will be the most common approach for cold L5 acquisition since this method provides good performance for a preponderance of applications, and minimizes the number of frequency bins that need to be searched for a rapid time-to-first-fix. Some applications that need to acquire or re-acquire in very low signal-to-noise conditions can benefit tremendously from the dataless component of L5. Using a simple approach described in this paper, correlation of the receiver's replica code with the Q5 component of L5 can be based on very long coherent integrations (limited only by line-of-sight acceleration and the quality of the receiver's oscillator).