Multiplex Techniques for GPS, Galileo and Compass

All the existing and developing Global Satellite Navigation Systems (GNSS) will provide more than two services in each transmission band. For example, GPS plans to transmit at least four signals: The old C/A Code and P(Y) Code, the modernized military M-Code and the new L1 Civil signal (L1C). Therefore, signal multiplexing technique is necessary in satellite navigation field. It is a common technique applied in modernized GPS and Galileo signal system design. Coherent Adaptive Sub-Carrier Modulation (CASM) and Interplex multiplexing techniques are used in GPS and Galileo system respectively, while Chinese Compass system has not such signal multiplexing design yet. This paper studies the characteristics of current and future multiplexing techniques for GNSS, such as CASM, Interplex and Majority Voting (MV). Meanwhile, it also designs multiplexing schemes for signals of GPS on L1 band, Galileo on E1 band and Compass on B1 band. Simulations for the schemes above mentioned are realized and proof that the availability of spectrum is increased efficiently and also solve the power losses of High Power Amplifier (HPA) effectively.