Key Technology Research And Verification Of Link 16 Data Link Transmission Waveform

As one of the most representative data links of the US military.Link 16 has the characteristics of efficient transmission,high confidentiality,and strong anti-jamming ability.It has equipped the US Air Force,Navy,and Army air defense units.Based on the existing research on the Link 16,we have mainly done the following work for its transmission waveforms in the thesis:The first part is research and modeling of Link 16 data link.In this part,we search a large amount of related data,especially the physical layer message format and signal processing flow,then we introduce the functions of each module roughly and establish a preliminary physical layer transmission model by simulink.The second part is research about the key technologies for transmission waveform.This part mainly includes MSK modulation&demodulation and time synchronization: Considering the simulation results and engineering implementation at the same time,the MSK signal is generated using the orthogonal structure,and demodulated using the differential method.Compared with the ideal coherent demodulation,the performance of this demodulation method only lost about 2.5dB,what's more,the differential method is not sensitive to carrier frequency offset;by combining the existing time synchronization algorithm with the signal characteristic of Link 16,which is composed of equal-interval pulses.A time synchronization scheme based on cross-correlation and counting is proposed.The third part is FPGA implementation of the transmission waveform.Based on the model and key technology research,we implemente the transmission waveform of the Link 16 standard dual-pulse format on the FPGA,Firstly,the chip platform and the clock relationship are introduced.Then the function and internal processing flow of each module are analyzed in detail from the top-level to the specific module;finally,the resource consumption and timing performance are optimized.The trade-off between area,speed and development workload is taken into account in the implementation.Finally,test and verification of transmission waveforms are performed to verify the implemented waveform in the chip loopback and RF-connected situaition.The test results show that the Link 16 standard dual-pulse format implemented in this paper can realize the communication function.Time synchronization,bit error rate performance and anti frequency-offset capability are corresponding to simulation.The Link 16 transmission waveform realized in this paper has certain reference significance for the research and development of the data link;on the other hand,it can be used to simulate the electromagnetic environment of the foreign military data link to test the performance of our interference and navigation equipment.