Research On Gnss Multi-frequency Signal Compatibility

The construction of American Global Positioning System(GPS) has been bringgreat changes to the navigation,positioning and timing technology of the wholeworld.Russia,Europe and China also begin to independently develope the L-bandGNSSs of their own.Compared with the L-band GNSS signal, the C-band GNSSsignals have the advantages of anti-ionosphere interference and anti-multipath, andthis can provide the important sectors and industries such as aerospace, finance andpower that requring a very high quality of the signal a more secure serviceperformance,at the same time,the development and construction of the S-band GNSSis attracting a lot of investment of more countries duo to the advantages of beingeasier to combing with other mobile services and wireless service in the same band.Inthe future, multiple navigation satellite system signal to coexist in C, S-band shouldnot be ignored, and the radio signal interference will be inevitable, therefore to carryout multi-band GNSS signals compatibility analysis technology research is significantfor L,C,S-band satellite navigation system construction and development.In this paper,based on the support of the research the863project and special project, acomprehensive theoretical analysis and simulation for the L, C, S-band compatibilityof GNSS signals are conducted;RF signal compatibility techniques between GNSSsignals and other adjacent bands signals are complemented; GNSS signal modulationand spreading codes design are thoroughly researched;The effect of the modulation onthe signals compatibility is analyzed; A new spreading codes design method andspreading codes compatibility analysis concept are proposed.The research contents are divided into four areas:(1) A comprehensive analysis of GNSS signals compatibility assessment modelsand methods are completed; Based on Spectral Sepration Coefficient(SSC) and CodeTracking Spctral Sensitivity Coefficient(CT_SSC),compatibility assessment modelsare respectively constructed, and effective carrier to noise ratio degradation is adoptedas L, C, S-band GNSS signals compatibility assessment method; After thecompatibility assessment, the simulation results are analyzed.(2) Analysis of interference characteristics between L,C,S-band GNSS signalsand the RF signals adjacent to them are finished; The interference assessment modelsand methods are determined and interference assessment are conducted, includingL-band GNSS signals to Radio Astronomy(RA), C-band GNSS signals to RA and Micowave Landing System(MLS), S-band GNSS signals with the Globalstarsystem,Fixed Service(FS) and Worldwide Interoperability for MicrowaveAccess(WiMAX).(3) Analyzing GNSS signal waveforms modulation; the application ofMSK-BCS modulation waveform in C-band and GBOC modulation waveform inS-band will improve the compatibility compared with the traditional navigation signalmodulation waveform.(4) Based on Weil sequence, a class of spreading codes whose autocorrelationand crosscorrelation performance in odd and even case are comparable with the GPSL1C signal spreading codes of length10230are generated; Based on a new proposedspreading codes generation method, a set of100length4092spreading codes withexcellent performance are successfully obtained after a novel optimizationprocedure.As the GNSS signals center frequency overlap seriously, GNSS signalspreading codes compatibility assessment concept is proposed based on thecharacteristics of spreading codes correlation performance; Evaluation parameters aregiven, and the spreading codes compatibility evaluation of GNSS signals areconducted with the establishment of the mathematical model and receiver model ofspreading codes compatibility analysis.In this paper, the innovations reflect in the following areas:(1) Using the general evaluation methods, the intrasystem and intersystemcompatibility evaluation of L,C,S-band GNSS signals are finished; The interferenceassessment between L,C,S-band GNSS signals and all the RF signals adjacent to themare completed.(2) Compatibility assessment of the new GNSS signals modulation waveformMSK-BCS and GBOC in C,S-band are respectively completed and the results showthat the compatibility have greatly improved.(3) A new spreading codes generation method is proposed; A group of100length4092spreading codes are acquired using the fast optimization algorithm;Autocorrelation performance of new spreading codes is significantly better thanGalileo EIOS signal spreading codes with the same length, and cross-correlationproperty is comparable with the latter;The concept of spreading codes compatibilityassessment is proposed and the GNSS signal spreading codes compatibilityassessment is conducted.