Embodiments of the present invention pertain generally to methods and systems of processing a global positioning satellite (GPS) signal. More particularly, embodiments of the present invention provide an improved discriminator function that utilizes the early, prompt, and late correlator values. For example, the improved discriminator function may be normalized based on all three of the early, prompt, and late correlator values. The improved discriminator function behaves linearly across a prescribed region whose width depends on the separation between correlators.