Research On Interference Evaluation And Suppression Method To GNSS Signal

The initial object of the satellite navigation system is provide the precise positionmessage in real time to the dynamic user, but the problem that the receiver is working inthe all kinds of electromagnetism environment has not been considered. Since theself-characteristic of the navigation signal, there is a common shortage to the GNSSsignal: the satellite navigation signal is vulnerable to various interferences and thus leadsto losses in performance of received signal. Now the satellite navigation positioningtechnology has been having an extensive application in modern military and civil fields,the environment becomes more and more complicated, the anti-jamming ability of thereceiver has been a key question which decide if the receiver can working normally. Soanalyzing the receiving performance of the GNSS signal and researching onanti-interference technology of satellite navigation receivers are of significant importancefor improving operating performance of satellite navigation system in complicatedelectromagnetic environment and enhancing its fitness for use in various environments.Aiming to the limited anti-jamming capability of the satellite navigation system, inthis paper, the method about how to evaluate the performance of GNSS signal in theinterference environment is researched and the interference suppression method arediscussed.The first content is how to evaluate the performance of GNSS signal in theinterference environments. By analyzing the frequency domain performance, acquisitionperformance and tracking performance of the receiver signal, the capability of the signalcan been reflected. Then aiming to problem of the GNSS intrasystem interference, a newmethod which can evaluate the intrasystem interference directly is proposed for the firsttime. The interference genek~jamis considered as the parameter it can evaluate theintrasystem interference, and the is getting bigger, the interference is more great. Inaddition, the performance of the receiver in the AWGN condition, narrowbandinterference condition, wideband interference condition are respectively researched andanalyzed.The second working content of this paper is the research on interference suppressingmethod. To the familiar narrowband interference, the LMS linear rejection algorithm iseffectual. But to the wideband interference, the suppressing methods in the time-domainor frequency-domain are not useful. So the interference suppression method to the wideband interference is an emphases in the paper. The LFM and SFM widebandinterference are studied primarily, different suppressing methods are proposed, and theimplementation way and the applied condition are given respectively.Lastly, in order to prove the feasibility and validity of the interference suppressionmethod proposed by this paper, an experiment flat and a portable GNSS signal acquisitionsystem is designed and the principle and system structure are given. At the same time, bystackingd with different of interference to the measured BD1navigation satellite signal,the performance of the interference suppression method is given and compared. Thisexperiment flat can offer an associated tache between the theory and practice.