| Today's tactical data link has become a standard communication method in the field of military communications.The Link series tactical data link is a typical representative.Among them,Link-11 adopts mesh communication technology and standard information format,and completes data transmission in real time through half-duplex working mode.It is one of the most widely used and longest-serving data links and the basis for subsequent Link-16 and Link-22 development.Therefore,it has always been one of the key research objects in the field of military communication confrontation.The existing research work mainly focuses on signal simulation,parameter estimation and type identification.However,there are not many studies on the system to discriminate and decipher Link-11.This paper mainly considers designing a fast and accurate Link-11 data link signal identification decoding scheme.First,the four major components and five working modes of the Link-11 data link are described in detail.This paper introduces two waveform systems of link-11 data chain,different data transmission structures and encoding modulation modes corresponding to different waveform systems.Secondly,the identification method of Link-11 data link is introduced.In order to improve the response time of the identification system,the signal to be identified in this paper uses the undersampling method to move the high frequency signal to the baseband for processing,which eliminates the influence of the useless high frequency carrier on the identification time.Aiming at the single feature of SLEW signal characteristics,the method of synchronous sequence waveform matching is used for fast identification.The method uses the synchronization sequence unique SLEW transmission structure unit as a template for waveform matching,and verifies the type of the received signal by performing waveform matching with the received signal.For CLEW signals with multiple feature quantities,a hybrid identification method is adopted.Firstly,the bandwidth characteristics and spectral characteristics of the CLEW signal are used,and the non-CLEW signal is eliminated by the fuzzy recognition method.Then,the preamble code of the CLEW is used as the template of the waveform matching,and matched with the signal to be identified,thereby determining whether the signal to-be-identified is a CLEW signal.Finally,the Link-11 signal is demodulated and decoded according to the data format and encoding mode of the Link-11 signal.The simulation results show that the recognition method used in this paper can identify the data type and parameter characteristics of Link-11 signal in real time,and the demodulation of Link-11 signal can be completed well. |
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