Theoretical Research On UAV Secure Communication Link Based On Chaotic Modulation

UAVs are widely used in many fields such as information perception and intelligence reconnaissance because of their unique advantages such as small size,low cost,and flexible deployment.As the primary mean to obtain spatial data,UAV contains a large amount of high-value data,which makes it one of the targets of attacks.This can be proved from the public UAV security incidents in the past two decades,the most famous of which is the interception of U.S.UAV by Iran.In the UAV system,the security of the UAV data link is very important.As the communication link between the airborne and the ground control terminal of the UAV,which provides support for the operation of the UAV and the execution of various tasks.This paper focused on the UAV uplink and downlink respectively,with the goal of improving the security and reliability of the UAV data link,and launched the theoretical research of UAV security communication link based on chaotic modulation.The main research works are as follows:(1)Aiming at the problems of low security,low reliability and low anti-interference ability in the UAV uplink,a DS-FH UAV secure uplink scheme based on Chaotic Sequence Insertion(CSI)was proposed(CSI-DS-FH).The scheme is to insert redundant chaotic sequences into the transmitted data according to pre-set rules and complete the process of chaotic DS-FH.After receiving the chaotic spread spectrum signal,the receiver performes the process of chaotic despreading.And the redundant sequence and useful data can be selected to verify the reliability of the data and recover the original sent data respectively.The simulation results of the CSI-DS-FH scheme showed that the scheme can ensure the secure transmission of data,and the reliability of the data source can be further judged according to the redundant information in the despreading result,so as to prevent illegal signals from being received and improve the reliability of UAV uplink data transmission.(2)In order to solve the problem of data leakage caused by eavesdropping in the communication of UAV downlink,a UAV secure downlink scheme based on Chaotic Constellation Scrambling(CCS)was proposed.This scheme modifies the mapping rules of the initial constellation by using the chaotic sequence of quantized grouping,so as to construct chaotic constellation diagrams conforming to the Gray code,which are used in the constellation mapping and de-mapping process.The proposed CCS scheme was simulated and analyzed,and the results showed that the scheme ensures the security of data transmission without affecting the transmission performance of the UAV high-speed data link system.(3)Foucsing on the problem of unreliable data received on UAV downlink due to data tammpering,a UAV secure downlink scheme based on Chaotic Sub-carrier Modulation(CSCM)was proposed.In this scheme,the grouped quantized chaostic sequence is used to perform chaotic serial-to-parallel conversion and chaotic disturbance on the sent data.The receiver descrambles the received data through the same chaotic sequence,and filteres out redundant data and useful data,which can be used to judge the reliability of the data source and recover the original data.The simulation results of the CSCM scheme showed that the scheme can not only realize the encrypted transmission of UAV data,but also identify the reliability of the data source,so as to achieve the purpose of secure and reliable transmission of UAV data.