Vol 7, No 4 (2016)

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.

Regularizing properties of stabilizing factors are studied to improve the accuracy of the Fourier series summation by spherical functions, used to describe the Earth’s gravitational field. The efficiency of the tested methods is estimated using the nonregularized global gravity field model ITSG-Grace2014s available on the ICGEM website [8].

The paper focuses on the problem of synthesis of path following control for a robot with omni wheels. Control is synthesized using differential geometry methods through nonlinear transformation of the initial dynamic model. The main results are presented in the form of nonlinear control algorithm and experimental data.