地空数据链通信差分解调算法研究

Research on Differential Demodulation Algorithm for Air-ground Datalink Communication

地空数据链通信具有传输速率快、抗干扰能力强、数据通信量大等优点,在民航领域得到了广泛的应用。VDL A模式报文信号以ARINC—618协议为依据,采用MSK编码方式。差分解调技术因其较强的抗干扰能力而在MSK中广泛使用。然而,传统的差分解调需要低通滤波器,算法无法满足实际要求。因此,设计了无低通滤波器的简化差分算法,采用Ts邻域实现了抽样判决,确保解调算法的稳定性。仿真实验证明了算法的有效性和实时性。

Air-ground datalink communication has been widely applied in civil aviation because of its fast trans- mission, strong anti-jamming feature and large data traffic. The signal of VDL A is based on ARINC--618 proto- col, and encoded into the MSK form. The differential demodulation technology was widely used in MSK because of its strong anti-interference ability. However, the traditional differential demodulation requires low-pass filters, and the algorithm can not meet the actual requirements. Therefore, a simplified differential algorithm without low-pass filters is designed. The algorithm makes a sampling decision by using Ts neighboring region to ensure the stability of the demodulation algorithm. The simulation results verify the validity and the real-time performance of the algo-rithm.