Assessment of the GPS L2C Code Structure for Efficient Signal Acquisition

L2C is the second Global Positioning System (GPS) civilian signal to become available over the full constellation. Because of the unusually-long ranging codes used in L2C signal, the search space and the computational complexity for signal acquisition become huge. The time-multiplexed nature of L2C code can, however, be exploited to design smarter replica codes that expedite the signal search and reduce the computational complexity. In this paper, various designs of L2C replica code are assessed for efficient signal acquisition, and the search capabilities and potential application scenarios for each of the assessed designs are identified. The nonreturn-to-zero civil moderate (NRZ CM) replica code design is exploited to develop a chipwise (CW) correlation strategy. In this strategy, the received L2C code samples are accumulated across each chip period, and the correlation is then performed at the L2C code chipping rate, reducing both the code search space and the computational complexity significantly. The detection performance of CW strategy is assessed as equivalent to that of the full-rate correlation, irrespective of the phase of the received L2C code.