Research On Signal Multiplexing In Modernized GNSS

Global Navigation Satellite Systems for the national and regional security andthe economy plays an important role. On the one hand, the suitable spectrumresources for the current satellite navigation system are limited, on the other hand,the satellite navigation system modernization for escalating the original signalsystem, adding new signals to meet new business needs. Multiplexing can combinethe traditional signal and modern signal, while enhancing the signal robustness.Therefore, this paper conducted research for multiplexing to provide a referencesignal for Beidou system.Firstly, studing navigation signal amplification principle, multiplexed signalis a constant envelope signal due to the nonlinear factors that affect the signal to bemultiplexed. Then study of the multiplexed input signal characteristics, especiallyin modern BOC signal, giving the BOC signal power spectral density functionexpression under four different conditions, the BOC signal that differs from thespectrum of the conventional BPSK signal is split, because of this feature makesBOC signal can be well compatible with other signals.Then, study the Interplex technology, majority voting technology, AltBOCtechnology and ACED (asymmetric constant envelope double-sideband) four kindsof multiplexing technology, from the particular to the general stepwise analysis ofthese four multiplexing principle. Interplex signal technology uses product termsto replace the original linear terms. The improved majority voting technologytaking advantage of Interplace reflects probability of by the signal power and usesgrouping method for implementing signal even large ones. Study the four-waysignal AltBOC constant envelope process technology. Study the characteristics ofACED.Analyzed the efficiency for each multiplexing technology. Find navigationsignal multiplexing can use the carrier phase multiplexing, can be divided intotime slots multiplexing, also select a different complex subcarrier multiplexing.Finally, achieve application of the multi-channel signal multiplexing, andgenerate a specific form of the multiplexed signal, the power spectrum of themultiplexed signal is similar to that of the multi-channel signal, note quadraturemultiplexing is the best way when combined two signals, three-way joint whenInterplex signal multiplexing technology is the best way when combined threesignals, AltBOC and ACED technology are best when combined four signals.