Combining L1 Signals for Improved Sensitivity

Global Navigation Satellite System (GNSS) receiver developers have long sought to achieve higher sensitivity. This is beneficial for both civilian and military users. Improved sensitivity increases availability in urban and indoor environments and provides greater robustness against radio frequency interference (RFI). With the coming of GPS III, users will have new features that can be used to improve sensitivity. GPS III will provide multiple signals on multiple frequencies. These signals can be processed together to improve sensitivity. At GPS L1, a civilian user will have access to L1 C/A as well as L1C pilot and data. Additionally, military user will also have L1 P(Y) and M code. This paper examines combining different L1 signals to improve sensitivity and how to use the combination with other techniques such as extended averaging. The paper demonstrates results using on air data from the Japanese Quasi-Zenith Satellite System (QZSS).