Research On GPS Deception Jamming In UAV Navigation System

Based on the national defense pre-research project needs to solve the problem of interference with UAV GPS/INS integrated navigation system,this paper puts forward a method that combines GPS deception jamming and navigation system control.According to the features of GPS pseudorange positioning,by changing each satellite signal propagation delay,a scheme of GPS repeater deception jamming system is designed.The detailed simulation and software design is carried out,as well as the network test with the other modules involved with the project.The key modules of GPS signal acquisition and tracking in this system are designed and tested by FPGA.The following is the primary work.(1)The features of GPS signal are studied and the generating principle of pseudo random code and navigation message are analyzed.Besides,the data code is produced through the RINEX format navigation message.The simulation of GPS intermediate frequency signal is completed.(2)With the demonstration need of GPS deception jamming for UAV,the design principle of GPS receiver is studied.Different acquisition algorithms are analyzed and compared.It is proved that the parallel code phase search algorithm has both good acquisition performance and small computational complexity.The realization principles of PLL and DLL are studied,which help design a complete tracking module including carrier tracking loop and code tracking loop.The least square method is adopted to complete the positioning calculation by the principle of pseudorange positioning.The feasibility of GPS software receiver is proved by the actual GPS intermediate frequency signal.(3)According to the control features of UAV GPS/INS integrated navigation system,the location deception is completed by changing the delay of each satellite signal.The limitations of direct repeater jamming are analyzed.An innovation detection rule for the navigation system state estimation is designed.Methods of direct track deception and track fusion are adopted to realize the intrusive control of UAV navigation system.The normalized innovation squared results under two control modes are given through theoretical derivation and simulation analysis.The results show that the method of track fusion not only can realize the cheating trajectory,but also not easy to be checked.(4)With the large scale FPGA chip as the hardware platform,the verifications of key modules such as acquisition and tracking in UAV navigation deception jamming system are completed.