SystemC Model of an Interoperative GPS/Galileo Code Correlator Channel

Global navigational satellite systems (GNSS) are on the threshold of a new era. American global positioning system (GPS) gets a new rival from Europe as Galileo system is developing rapidly. For the best availability and navigation performance, users should be able to use satellites from both systems. There are two common operational frequency bands between GPS and Galileo, L1/E1 and LS/E5a. For a cheap, single frequency mass market receiver, L1/E1 centered at 1575.42 MHz will be a better choice because it has smaller ionospheric error and less complex spreading codes. Binary offset carrier (BOC(1,1)) modulation used in Galileo E1 signal makes it impossible to use traditional early-late code correlator architecture in combined GPS/Galileo receiver. Very early-very late (VE-VL) code correlator architecture is capable for tracking both GPS and Galileo codes. System level model of VE-VL code correlator channel is built with the SystemC hardware description language. Functionality of VE-VL code correlator model is verified with simulations and the results are presented. Simulation results show that VE-VL architecture works with GPS and BOC (1,1) modulated Galileo codes. SystemC proves to provide a very fast way to describe functionality at system level