多旋翼无人机搭载同频直放站的技术实现

Technical implementation of co⁃frequency repeater in multi⁃rotor drone

搭载无线通信设备的多旋翼无人机作为天线架高平台得到越来越广泛的应用,但鲜见搭载同频直放站,最主要的原因是同频直放站存在收发天线耦合问题。多旋翼无人机机体小,天线安装位置受限致使收发天线间的隔离度较小,且由于多旋翼无人机的气动要求,一些地面常用的隔离措施无法采用,因此更容易产生自激现象。为了避免多旋翼无人机搭载的同频直放站自激,文中将具有同一工作频率的远端覆盖天线与对地回传天线的方向图零点或低增益方向互为对准,且两个天线之间有无人机壳体、螺旋桨等有效物理隔离,使天线之间的隔离度大大提高。另外,还采用自激抵消算法进一步提高了隔离度。通过以上技术使多旋翼无人机搭载同频直放站不仅具有开通撤收方便、地面支持设施少、频率规划简单等特点,还可支持跳频系统的无线中继转发,具有非常广阔的应用场景。

Multi⁃rotor drones equipped with wireless communication equipment are becoming increasingly widely used as antenna elevation platforms.However,it is very rare for them to be equipped with co⁃frequency repeaters.The main reason is that the coupling problem between Tx and Rx antennas occurs to co⁃frequency repeaters.The small size of the multi⁃rotor drone and the limited installation position of its antenna result in low isolation between the Tx and Rx antennas.Moreover,due to the aerodynamic requirements of the multi⁃rotor drone,some commonly⁃used methods to increase isolation on the ground cannot be adopted,making it more prone to self⁃excitation.In order to avoid self⁃excitation of the co⁃frequency repeater on multi⁃rotor drone,the zero points or low gain direction of remote⁃coverage antenna and ground⁃backhaul antenna with the same operating frequency are aligned with each other,and there are shell and propellers between the two antennas.All of these greatly improve the physical isolation between the antennas.In addition,the ICS(interference cancellation system)algorithm is adopted,which improves the isolation degree more effectively.By the above technologies,the multi⁃rotor drone equipped with co⁃frequency repeater not only has the characteristics of convenient activating and retraction,fewer ground support facilities and simple frequency planning,but also supports wireless relay of frequency hopping systems,which has a very broad application scenario.