Study of the GNSS Jamming in Real Environment

GNSS systems are susceptible to radio interferencedespite then operating in a spread spectrum. The commercejammers power up to 2 watts that can block the receiver functionat a distance of up to 15 kilometers in free space.Two original methods for GNSS receiver testing were developed.The first method is based on the usage of a GNSS simulatorfor generation of the satellite signals and a vector signal RFgenerator for generating different types of interference signals.The second software radio method is based on a software GNSSsimulator and a signal processing in Matlab. The receivers weretested for narrowband CW interference, FM modulated signaland chirp jamming signals, and scenarios. The signal to noiseratio usually drops down to 27 dBc-Hz while the jamming tosignal ratio is different for different types of interference. Thechirp signal is very effective.The jammer signal is well propagated in free space while inthe real mobile urban and suburban environment it is usuallystrongly attenuated