Designed And Implementation Of UAVs Relay Data Link System

Small UAV,which is widely applied in aerial photograph, detection and reconnaissance, has great scientific and practical value. It has become a hot topic of study around the world. As an important part of the small UAV flight control system, the data link system is the communication bridge between ground station and helicopter. It is responsible for the transmission of control command and flight status of aircraft. Due to the cost and hardware limitations, the traditional small UAV data link system can not work beyond eyesight, which greatly limits the application of it. Therefore, how to design a common security and reliable relay data link system that can break communication hardware limitations to communicate over the horizon has become an important issue need to be resolved.This paper references several kinds of typical data link system, and deeply researched related theory, including theory communication distance, data congestion control and multiple access, about the small UAV data link system. A relay data link system that suited for small UAV’s characteristics is designed. First, according to the GCS agreement, the uplink and downlink data messages standard is defined and a Linux-based base station subsystem is designed, which is used to integrates the multiplexed data from the ground station and remote controller and codes them into particular format guided by the protocol specification. Secondly, the communication node of data link system is extended by use the multipoint communication function of wireless data transmission module Xtend and key problems of multi-UAV communication is solved. Finally, use the small UAV as an aerial mobile relay platform to accomplish the design of relay data link system. Considering small UAV probably lose contact with the ground system, a small UAV automatic return function is designed to enhance the safety performance of the system. After the design of point to point system and relay system, conducted a great deal of practical flight experiment and verify the reasonable and practical of system design.