Research and design on the software-based integrated receivers of GPS/Galileo

GPS is already fully operational by America in orbit about the Earth, while the Galileo is not yet operational by E.U.. But the user receiver equipment should be able to take advantage of both systems to increase accuracy, integrity, and overall performance with as little impact on each other as possible. This paper presents the research and design on a hybrid software-based GPS/Galileo receiver, together with the signal acquisition and tracking processing using a GPS/Galileo software intermediate frequency (IF) architecture. And the software-based integrated receiver architecture eliminates the traditional baseband ASIC and performs all digital signal processing in software. This approach completely separates the analog signal conditioning (in hardware) and the digital signal processing (in software), resulting in significant gain. So it will become increasingly important as new signals from modernized GPS satellites become available and as the Galileo or China's BeiDou system starts operation.