无人机高速DS/FH混合扩频通信系统关键模块设计

针对UAV(Unmanned Aerial Vehicle,无人机)测控链路高抗干扰需求,给出了实现跳频速率20 000次/s的扩跳混合无人机测控数据链系统实现方案.系统采用跳频频率并行捕获模式.跳频源设计采用直接频率合成、DDS(Direct Digital Synthesis,直接数字频率合成)和PLL (Phase-Locked Loop,锁相环)相结合的混合频率合成技术.利用相位响应滤波器,通过正交调制技术完成MSK(Minimum Shift Keying,最小频移键控)、GMSK (GaussianMinimum Shift Keying,高斯最小频移键控)调制.通过推导得出2 bit差分解调输出与载波频率选择有关,且为四分之数据率的整数倍关系.然后通过实例分析给出了跳频频率间隔选取方法,即跳频间隔应当将临近跳频的主瓣分开,同时跳频载波频率应当设在其他跳频频谱的零点处.最后总结了高速扩跳频系统参数设计一般步骤.

Design of Key Blocks of a High Speed DS/FH Communication System for UAVs

A design solution is given for a Direct Sequence/Frequency Hopping (DS/FH) communication system with 20 000 h/s hopping rate to meet anti jamming requirements of Unmanned Aerial Vehicle (UAV) telemetry and command link.The hopping frequencies are captured in parallel.The hopping frequency source is constructed by direct frequency synthesizer, Direct Digital Synthesis (DDS) and Phase Locked Loop (PLL).Phase response filter is adopted in orthogonal modulation to realize Minimum Shift Keying/Gaussian Minimum Shift Keying (MSK/GMSK) modulation.The performance of 2 bits differentiated demodulation is correlative with carrier frequency, that is, the carrier frequency must be integral times of a quarter of data frequency.The hopping frequency spacing should separate adjacent main lobes while the hopping frequency should set at zero point in other hopping frequency spectrum at the same time.Finally, approaches are summarized for DS/FH parameter choice