Research And Design For High-Dynamic Anti-jamming Data Link

With the transformation of modern information-based warfare from platform centric warfare to network centric warfare,the effectiveness of tactical information becomes more and more prominent.High-dynamic anti-jamming data link can guarantee the security and reliability of the transmission of tactical information effectively,is the key factor of the outcome of the war.This thesis focuses on the synchronous acquisition technique of spread spectrum signal under not only the high-dynamic but under low SNR scenarios as well and the design of anti-jamming data link.The main research work and innovations of this thesis are as follows:1.This thesis proposes a PMF-FFT based Doppler shift change rate parallel compensation(PMF-FFT-DPC)acquisition scheme to acquire the spread spectrum signal with low strength and high Doppler shift change rate.In PMF-FFT-DPC,the output signal of PMF-FFT is accumulated non-coherently to improve the acquisition sensitivity of the weak signal firstly,and then Doppler shift variation rate is compensated in parallel so that the residual of it is negligibly small.Simulations results prove the acquisition performance of the PMF-FFT-DPC scheme,whose acquisition probability is 10%higher than the traditional acquisition scheme.2.In order to reduce the non-coherent accumulation length for the PMF-FFT-DPC acquisition scheme,a stepwise non-choherent accumulation(SNCA)strategy with dynamic non-coherent accumulation length capping(DNCALC)is proposed in this thesis.The theoretical minimum non-coherent accumulation length,being setting as the DNCAL of SNCA strategy,for a specific acquisition probability under constant false alarm rate is drived by in-depth theoretical analysis.Simulations results prove the effectiveness of this strategy,which can reduce the non-coherent accumulation length and calculation amount significantly compared with traditional accumulation strategies.3.This thesis adopts FH-DS hybrid spread spectrum technology to make the data link can resistant multiple types of jamming effectively.In the aspect of DSSS,for the disadvantage that the traditional soft spread spectrum sequences are not orthogonal with each other,an orthogonal soft spread spectrum based on the improved Walsh sequence is adopted.In the aspect of FH,a random shift replace(RSR)based adaptive wide gap FH sequence(RSR-AWGFHS)construction algorithm is proposed to combine the advantages of adaptive frequency hopping and wide gap hopping.In addition,an anti-jamming data link link-level simulation system is designed and built.Simulations results show that the BER performance of the improved orthogonal soft spread spectrum is 0.5dB higher than that of the traditional soft spread spectrum,and the performance of RSR-AWGFHS to resistant multiple types of jamming is improved by more than 0.5dB compared with the WGFHS produced by other schemes.