Bitwise Based Real-Time Gnss Software Receiver

The implementation of GNSS software defined receiver (SDR) platform has been receiving considerable attention in satellite navigation area. Due to the different work principle between hardware and software, it would not be possible to just copy the architecture of a hardware receiver to a software receiver. Types of SDRs have been introduced for different requirements. The general commercial GPS-CA receiver is often 2-bit quantized. In this paper, an innovative implementation of SDR based on bitwise method as well as varied sampling frequency in carrier phase is proposed. Optimization algorithms in signal acquisition, tracking and data storage are considered to reduce the computation load. Compare with traditional SDRs, this platform enjoys simple architecture, low computation demand and high expansibility. Real data are used to test the performance of the receiver and results show that fast acquisition is achieved and the maximum number of tracking channel simultaneously is highly enlarged. Finally, the computation complexity and expansibility of the platform are discussed.