Interference Analysis of Interplex Modulation in GALILEO E1 Band

Numerous signals have to be located in a same frequency band because of limited spectrum resource and increased signal number of GNSS (Global Navigation Satellite System). Therefore a bandwidth-efficient modulation is needed to combine several signals to share the frequency resource. The Interplex modulation emerges to meet the need of transmitting several signals in a composite form and still keeping constant envelope. However it will induce an IM (intermodulation) term which will cause interference to useful signals. This paper aims to analyze the interference of Interplex modulation in GALILEO E1 band. The analytic expression of Interplex modulation will be presented, considering GALILEO E1 OS (Open Service) signal with the final modulation of MBOC (Multiplex Binary Offset Carrier) and GALILEO E1 PRS (Public Regulated Service) signal with modulation of cosinephased BOC (Binary Offset Carrier). Applying the most widely used interference assessing means, new conclusions about IM term' effect on all GALILEO and GPS signals in E1 band will be obtained. Recommendations about the design of Interplex modulation for GNSS will be made at the end of this paper.