The Simulation Of GNSS Blocking Jamming And The Research On Its Restrain Technology

The signal from the satellite to the devices can be easily disturbed in the process of the satellite navigation system. So, the satellite-ground communication link is the weak point of GNSS. The jamming on the links mainly aims at GNSS receivers. Technically, there are two kinds of jamming, the suppressing and the cheating. Between them, the suppressing jamming is more dangerous and more harmful to GNSS. So, we must study the suppressing jamming method. Analyze the effects of them and do further study on jamming detection and restrain.According to the requirements of863project "The study on the vulnerability of GNSS and the transmission environment of the signals". This dissertation fastens one’s attention upon the study of GNSS barrage jamming which belongs to the suppressing jamming and jamming detection and restrain. The main contributions are as follows:1. Analyze the mathematical model of GNSS receiver, the effect of jamming is studied from the point of view of BER. The BER expression of different type jamming signals is calculated. The best barrage jamming type is known by simulation.2. Analyze the principle of the barrage jamming. And give the design scheme for the jamming generation. Finally, output four kinds of barrage jamming through programming implementation on the forged satellite system.3. A new method to detect barrage jamming by AGC(Auto Gain Control) is presented. And the possibility of the method is verified. Combined Ublox receiver and interference signal theoretical analysis, establish the jamming detection threshold.4. Introduce the performance and characteristics of LDPC codes. Through the simulation circuit, analyze the effects using different parity check matrices. Bring up the best code length to provide reference for navigation message design from the point of view of BER and decode time. 4. Study the spatial filtering, temporal filtering, space-time filtering and other anti-jamming technology. And their advantages and disadvantages are compared through simulation.