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Study On The Compatibility And Interoperability Of Global Navigation Satellite Systems

Posted on:2012-09-22Degree:DoctorType:Dissertation
Country:ChinaCandidate:W LiuFull Text:PDF
GTID:1480303389990939Subject:Navigation, guidance and control
Abstract/Summary:PDF Full Text Request
Global Navigation Satellite System (GNSS) has become one of the most challenging and promising issues in modern information technology. Nowadays, many countries and regions are currently developing their own navigation satellite systems and China also plans to complete its own satellite navigation system by 2020. Since new systems use signal sturctures similar to existing GNSS systems and share frequencies close to or overlapping those of existing systems. The GNSS radio frequency compatibility (RFC) and interoperability have become a matter of great concern for the system providers and user communities. On the basis of the preliminary research of the National High Technology (863) project, the main purpose of this thesis is to study the technology of GNSS compatibility and interoperability, provide a comprehensive methodology for GNSS compatibility and interoperability assessment, and propose some new results for the navigation constellation and signal structure design.This thesis penetrates into GNSS RFC assessment techonlogy and its application, RFC assessment model improvement and RFC thresholds determination method, constellation and signal interoperability technology, and navigation signal structure design. The primary research contributions and results are presented here:(1) A comprehensive methodology for GNSS RFC assessment is presented, considering the criterion, model, method, and formula. Based on the comprehensive methodology, a simulation system for GNSS RFC assessment is built. The results show that the comprehensive methodology is more realistic, the maximum interference of GPS L1 C/A code and GPS L1C signal is smaller than those of Galileo E1OS and COMPASS B1C signals, and analytical approach may not provide the same level of accuracy as computer simulation, but it can be easy to implement and save computer time.(2) Based on the theoretical framework of signal model, analytical expressions are derived for the Spectral Separation Coefficient (SSC) and Code Tracking Spectral Sensitivity Coefficient (CT_SSC) between any two signals. The SSCs and CT_SSCs of between any two GNSS signals are assessed under ideal and realistic signal conditions. Moreover, the simplified calculation criterion is proposed which allows fast calculation of SSCs and CT_SSCs for realistic signal conditions. Finally, an analytical model for GNSS receiver losses is introduced, numerous practical scenarios are studied, and some important results are displayed.(3) For determination of the required acceptability thresholds for the RFC assessment, all recevier processing phases, including the acquistion, code and carrier tracking and data demodulation phased must be considered. Based on the performance requirements of the receiver characteristics, the method for assessing the required acceptability threshold is proposed. The results show that all civil signals are compatibility based on the specific receiver configuration.(4) A methodology for GNSS interoperability assessment and an algorithm of quantitative approach for interoperability analysis is presented. Based on this methodology, an example of interoperability among GNSS signals in L1 band are analyzed and some new analysis results are displayed. Moreover, a systematic approach for global interoperable constellation design is introduced. Two optimal GNSS constellations which are Walker 27/3/1 and Walker 27/3/0 are proposed. In addition, the limited standard for growth interoperable signal and satellite is studied based on the interoperable performance. For realistic application, the optimal intersection of the increase in the noise floor and interoperable performance may lie in the range of about 75 satellites.(5) Some classes of particularly attractive modulations called MSK-BCS, GBOC and MSK-MBOC modulations are proposed, and their essential characteristics and performance for GNSS are demonstrated. A new set of spreading code is proposed based on the main figures of merit for PRN codes, namely the auto and crosscorrelation. The results show the proposed spreading code has better performance than the random code of Galileo E1 OS signal. Moreover, a complete overview of all the multiplexing schemes of navigation sytems is provided, and the multiplexing schemes of COMPASS signals are investigated.The key technologies and innovations in the research focus on the following points:(1) Traditional RFC assessment model is improved, and a simplified calculation criterion is proposed allows fast calculation of SSCs and CT_SSCs for realistic signal conditions. For the sake of realistic, an analytical model for GNSS receiver losses is presented and some important results are displayed. Moreover, the method for assessing the required acceptability threshold is proposed. The simulation system and analysis results make contributuions to the system design and GNSS RFC coordination.(2) A methodology for GNSS interoperability assessment is presented. Two optimal GNSS constellations which are Walker 27/3/1 and Walker 27/3/0 are proposed. In addition, the limited standard for growth interoperable signal and satellite is presented based on the interoperable performance.(3) Some classes of particularly attractive modulations and spreading codes are proposed, and the multiplexing schemes for COMPASS signals are also presented. The results of this work can be considered as a significant contribution to the signal structure design.
Keywords/Search Tags:GNSS, compatibility, interoperability, GPS, Galileo, GLONASS, COMPASS, signal structure
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