| With the rapid development of Internet of things technology,Unmanned Aerial Vehicles(UAV)have expanded their application fields to the military,agriculture,logistics,photography,mapping and disaster relief industries due to their advantages of low cost,convenient operation,strong mobility,and ease of production.In order to adapt to the increasingly complex application scenarios of UAV,UAV Communication system is facing many challenges.In this thesis,the concurrent multipath transmission technology for UAV is studied,and a concurrent multipath transmission system with the advantages of fast data transmission rate,long communication distance,strong anti-interference performance and high data accuracy is designed and implemented.The main work of this thesis is as follows:1.According to the functional requirements of concurrent multipath transmission for UAV,the overall scheme is designed.The system is composed of two parts: remote control and UAV,both of which include control unit and radio frequency unit.There is a one-to-one correspondence between the radio frequency unit on the remote control side and the UAV side,forming multiple relatively independent data transmission channels.The concurrent multipath transmission for UAV can process data and transmit data through multiple data transmission channels.2.The hardware platform of the system is designed and implemented.In this thesis,a lowpower,high-performance and micro size hardware platform is built.The selected microcontroller is STM32L072 CBT,which simultaneously controls multiple SX1276 RF communication chips.The SKY13330-397 LF chip is used as the antenna switch.STM32 Cube MX software was used for pin configuration and clock configuration.Finally,a system engineering file with initial configuration of the bottom layer was generated.3.The software platform of the system is designed and implemented.The software platform can split and package the data at the sending end and send them through multiple data transmission channels,and then upload the data to the application layer after analyzing and integrating the data packets at the receiving end.The system can use Lora and FSK to transmit data and adaptively switch communication technologies according to received signal strength indication(RSSI).In this thesis,the data scheduling algorithm is optimized,and the data packets are allocated to each data transmission channel reasonably by estimating the throughput of each transmission channel.The software platform adds the cyclic redundancy check to the data package,and ensures the data accuracy of the system through the retransmission mechanism.4.The thesis build a test system to complete the function and performance test of concurrent multipath transmission for UAV.The test results show that the system can achieve wireless communication,error control,adaptive switching communication technologies,data scheduling and retransmission functions,and meet the design requirements.The system can improve the data transmission rate,ensure the stability of data transmission,adapt to the transmission scenarios of various distances,and has a good application prospect. |
