The modern hardware-based standard GPS receiver can provide accurate position and navigation data to user. However, the standard GPS receiver consists of hardware framework, its architecture and parameters are very difficult to modify for different environments. Recent advancement in digital signal processing and analog-to-digital conversion techniques has
motivated the development of software defined radio. In comparison with
the standard approach, major advantage of the software defined receiver is
the programmable algorithm. With the programmable algorithm, it is easy
to change the parameters of the algorithm for whatever purposes. The
software defined radio is more flexible than the traditional approaches.
This paper will study the GPS signals of different strength received by
a GPS receiver under different environments. The parameters of tracking
loop are compensated according to signals of different strength. This
paper uses NordNav R30 software receiver to collect the GPS signals under
different environments and store the real intermediate frequency data for
after process. According to the different strength of signals, the purpose of signal tracking can be reached by changing the tracking architecture and parameters.