Weak GPS Signal Acquisition Method Using Variable Threshold

Coherent integration and non-coherent accumulation have been developed to acquire weak Global position system (GPS) signals. The threshold of acquisition algorithm is fixed, and is determined by the weakest signal. Strong signals and weak signals always coexist in the physical environment. A new method is presented for weak GPS signal acquisition using variable threshold. Through adjusting the thresholds with different noncoherent accumulation times, this method is applicable to all kinds of signals. It has wonderful acquisition efficiency through theory analysis and real signal verification, especially when strong signals and weak signals coexist, it can greatly reduce acquisition time.