Rapid zero-knowledge GPS signal acquisition

A GPS acquisition system which achieves extremely short search times is presented. The system requires no prior knowledge of position or time. Using a 50 MHz clock frequency, 25 satellites can be searched in parallel. The acquisition system has been implemented in 0.35 um CMOS process. Under nominal signal conditions, 2 second total search times have been demonstrated. The acquisition unit performance has been verified both with live satellites as well as with a GPS simulator. The acquisition threshold with a RF noise figure of 4 dB was found to be −134 dBm. The paper reviews the design and used algorithms.