Assessment and analysis of radio frequency compatibility among several global navigation satellite systems

The increasing number of new global navigation satellite systems (GNSS) signals leads to more interference effects on existing and upcoming navigation signals in the same frequency band. GNSS radio frequency compatibility has become a matter of great concern for the system providers and user communities. This study describes a comprehensive methodology for radio frequency compatibility assessment, and analyses the intersystem interference among several GNSS systems. Firstly, the methodology is presented, considering the geometry-dependent and time-varying terms such as space constellation, signal modulation, emission power level, space loss, satellite antenna gain and user receiver characteristic. Then, the intersystem interference is computed for signals where GPS, Galileo, Compass and SBAS systems are sharing the same frequency band. The analysis results show that interference effects on GNSS user receiver from the above-mentioned systems are acceptable. The introduction of Compass system can provide a sound basis for compatibility with GPS and Galileo.