Research On Delay Model Of UAV Ground Air Data Link And Its Verfication System

With the characteristics of small, flexible, low cost, good environmental adaptability,the UAV(Unmanned Aerial Vehicle) become a research focus in the field of military equipment. The UAV communicate with the UAV Ground operators through the ground-air data link. The ground-air data link is the key to transmit tactical information bewteen the weapons unit, the control unit and the sensor unit. So the real-time transmission of information is a key requirement for data link. Especially in the modern network centric warfare, the real-time requirement of information transmission is higher. The communication delay may affect the war decision-making and command, and even affect the war results. Therefore, it's very important to reduce the delay as far as possible in order to ensure the performance of the UAV in the design of UAV data link.At first, the composition of the UAV system and the operation mechanism of the UAV data link are discussed. And the related factors causing the delay of the UAV ground-air data link are analyzed. Also the software and hardware and network protocol carried out by the UAV ground-air data link are analyzed. Then a TDMA(time division multiple access)network protocol is determined as the main research emphasis. Based on a thorough study of the operating principle of TDMA network protocol and the existing modeling methods, a delay model of the UAV ground-air data link is put forward with the method of queuing theory combining with theoretical analysis.The overall plan of the UAV Ground-air data link delay model verification system is designed. The time delay verification system uses the Android operating system for operating easily. The core unit of controlling board uses a 32-bit high speed embedded micro processor of the STM32 family as the main control processor. The instruction cycle of the high speed embedded micro processor is below 10 ns, which is good for reducing the influence of non-deterministic delay caused by processor for data and signal processing on measuring precision. Using color sensors, displacement sensors, and adopting the idea ofmodular design, the uplink, downlink, image transmission, and instruction callback delay measurement modules are designed. Finally, the hardware-in-the-loop simulation platform is set up to test and verify the delay model and delay measurement system. A comparative analysis on delay model shows that the UAV data link delay model can accurately describe the data link delay characteristics. The analysis of time delay test system shows that the delay measurement system can accurately measure the ground air communication delay link.