GNSS Interoperability Parameters And Signal Analysis

With the development of the Global Navigation Satellite System (GNSS), GPS, GLONASS,Galileo and Beidou have composed the four satellite navigation system. The construction ofmulti-GNSS made interoperability as a key means to make GNSS stay harmoniously, improvethe user service quality, strengthen competitive power, and etc.The aim of GNSS interoperability is to improve navigation service quality, the prerequisiteis not increasing the cost of receiver to a great extent, and realization of interoperability needsthe sharing of GNSS resource. To achieve the goal of not increasing the cost of receiver, thedifferences among systems must be reduced and weakened. The differences among systemsmainly include: space-time references, navigation information, signal, and constellation. Thispaper focus on the research of interoperability parameters and signal performance, and the maincontent is as follows:1. GNSS interoperability parameters research(1) GNSS interoperability ephemeris parameter analysisSpace-time reference is the basis parameter for navigation positioning, as the reference ofeach system is different, so solve the difference of references in each system is the prerequisite tothe realization of interoperability. This paper analyzed the space-time references of each system,proposed that the time reference should normalized to UTC, the coordinate reference shouldnormalized to ITRF, and introduce the transformation parameters of system times. Besides,BURSA seven parameters model is a preferred method for the transform of GNSS coordinatereference. Besides, this paper analyzed the pseudo range equation, extracted parameters whichusers get from satellite broadcast ephemeris, researched the time delay of satellite equipment,clock offset, ionospheric error and their correction parameter.(2) GNSS interoperability ephemeris accuracy analysisUsers get positioning parameters from ephemeris, and different systems have differentephemeris parameters, so analysis of different system’s ephemeris accuracy has sifnificance forthe improving of user positioning accuracy. This paper proposed that take the error betweensystem broadcast ephemeris and IGS precise ephemeris as standard of GNSS interoperability,analyzed the ephemeris orbit accuracy and clock offset accuracy.(3) GNSS interoperability constellation GDOP value analysisBesides, this paper simulated the value of GDOP in multi-GNSS to monitor theimprovement of GNSS interoperability service and chose five site to analyze the changeregulation of GDOP value, contrast the GDOP value in multi GNSS and one system. The research provided a scaleplate for GNSS interoperability users, offered research method forsolving the differences among systems, has significant sense for improving user accuracy.2. GNSS interoperability signal research(1) GNSS interoperability signal performance analysisSignal is very important for the satellite navigation service, which determines the navigationaccuracy. GPS and Galileo have made the MBOC signal as the baseline of interoperability signal,more specialists work on the interoperability signal design and performance analysis in recentyears. As MBOC plays an important role in interoperability signal, the research of MBOCinteroperability performance is useable. This paper introduced the basic theory of MBOC signal,analyze the correlation characteristics, the tracking accuracy, and multipath error ofinteroperability signal TMBOC and CBOC(2) GNSS interoperability signal interference analysisGNSS interoperability will take more visible satellites and navigation signals for users. Therealization of GNSS interoperability is a process of multi-GNSS resource sharing, and union ofsignals from systems. So, monitoring the anti-interference and interference level of MBOC is animportant work for the choice of future interoperability signal. This paper analyzed the spectrumseparation coefficient, the code tracking interference coefficient, interference coefficient andequivalent carrier-to-noise ratio of TMBOC and CBOC signal. This paper also analyzes the Weilcode and Random code performance.