Research On Signal Design And Reception Technology Of Communication And Navigation Integration

Satellite navigation systems can provide global coverage,low-cost,and highprecision navigation,positioning,and timing services through broadcasting navigation messages.Since the advent of the global positioning system(GPS),satellite navigation has become the foundation and core of international spatiotemporal information services.However,various existing navigation systems also have inherent defects such as low landing level and slow information rate.Taking satellite navigation systems as the core,supplemented by other means,to provide services with greater signal strength,higher positioning accuracy,more types of services,and higher information rates is currently an urgent demand of the international community.Communication and navigation integration technology is one of the important methods.Low Earth orbit satellite signals have the advantages of low orbit height,high communication rate,and it is complementary with navigation signals.Relying on low Earth orbit satellite communication networks to supplement and enhance satellite navigation systems,the two can exhibit significant synergy advantages.With the rapid development of large-scale low Earth orbit satellite systems such as Starlink,and the completion of China’s Beidou-3satellite navigation system,there is an urgent need to study communication and navigation integration technologies compatible with GNSS and low Earth orbit satellite systems.According to different design requirements,this thesis studies the design of communication signals and navigation signals with integration of communication and navigation based on low-earth orbit satellites,and initially establishes the physical layer process and framework of the integrated signal.The performance of the designed signal is analyzed.In order to enable communication signals and navigation signals to be broadcast on a low-earth orbit satellite at a single frequency,while allowing the satellite amplifier to operate in a linear saturation region,a constant envelope multiplexing method suitable for the designed signal is studied in this thesis.Based on the four valued characteristics of CBOC signals,methods such as QPSM、POCET、and CSPOCET for eliminating intermodulation signals containing non independent signal pairs have been studied.Through the analysis of the analytical expression of the multiplexed signal,it is found that some intermodulation components of the CSPOCET method can generate gains on the values of some signal components.Based on this characteristic,the similarities between the CSPOCET method and the QPSM method are explained,the general process and method for converting QPSM method to CSPOCET method are given.Finally,this thesis combs out the design of the integrated signal reception process.Using the method of non matching reception during acquisition can reduce the sampling bandwidth of the signal,and the PMF-FFT method achieves time-frequency twodimensional parallel acquisition.In order to eliminate the ambiguity problem of CBOC signals in the pseudo code tracking stage,based on the PUDLL method,this thesis designs two local chip vectors to correlate with the input signal,linearly combines the correlation results,and provides an analytical expression of the combined pseudo correlation function.The obtained pseudo correlation function eliminates the side peaks,making the discrimination curve of code tracking no longer have the ambiguity problem.