Research of weak signal acquisition algorithms for high sensitivity GPS receivers

Weak signal acquisition has been a limiting factor for high sensitivity GPS receiver. This paper presents GPS signal acquisition algorithms: coherent integration (COH), noncoherent integration (NCOH), and differential coherent integration (DFC) with detailed analysis. Numerical simulations demonstrate that DFC is a superior approach than NCOH in weak GPS signal detection. DFC improves acquisition sensitivity by approximate 1.9 dB, 0.8 dB than its counterpart NCOH without and with 100 Hz carrier Doppler shift as the probability of false alarm is fixed to 0.1% and the probability of detection setting to 90%. In addition, DFC decreases mean acquisition time by about three times than NCOH under the same simulation conditions.