Correlation properties of Multiplexed Binary Offset Carrier (MBOC) modulation

Recently, a Multiplexed Binary Offset Carrier (MBOC) modulation has been recommended by the GPS-Galileo Working Group on Interoperability and Compatibility in order to increase the tracking abilities of Galileo Open Service signals and of GPS L1 civil signal. MBOC modulation also ensures a better spectral separation with C/A codes. The purpose of this paper is to analyze the MBOC properties in time and frequency domain and to present a unitary theoretical model of MBOC waveforms. First, several spectral properties of MBOC signals are presented, namely: spectral separation coefficients with GPS signals, root-mean-square bandwidth and maximum value of the spectrum. Second, two implementations of MBOC signals are discussed and a generic baseband model for them is introduced. Third, a unified theoretical formula for the autocorrelation function of MBOC-modulated pseudorandom codes is derived. Finally, the advantage of a theoretical framework for the MBOC correlation properties is emphasized via an example of tracking multipath performance in multipath channels. The theoretical findings are also validated via simulations.