Positioning Improvement by Combining GPS and GLONASS Based on Kalman Filter and Its Application in GPS Spoofing Situations

摘要

After renewed GLObal NAvigation Satellite System (GLONASS) was completed and it became world wide as its U.S. counterpart, Global Positioning System (GPS), the best way for increasing the number of satellites in the user's view is combining these two systems. On the other hand, as it is possible for GPS satellites to be spoofed or blocked, combining becomes more efficacious. In this paper, GPS and GLONASS are used for positioning using Kalman filter. Kalman filter is utilized here because it is one of the cheapest and applicable tools for implementing on cheap processors. In addition, in this paper, we proposed a method against GPS signal spoofing based on combination of GPS and GLONASS regarding to pseudorange behavior in spoofing situations. The proposed method is not only easy to implement, but also low cost and high precision. This method without any need for expensive receiver has ability for real-time recognition of spoofing attacks and eliminating its effects. The recorded data was collected using an implemented GPS, and GLONASS RF front-end in stationary mode and in order to show spoofing effects on positioning an artificial spoofing was applied on GPS satellite signals in different scenarios. The simulation results showed a big improvement in Root Mean Square (RMS) error in comparison with GPS-only positioning in all spoofed scenarios.