In this paper, the problem of autonomous orbit control is addressed, for a spacecraft driven by an electric propulsion system composed of a Hall effect thruster and a resistojet. The considered reference mission is a low Earth orbit typical for observation satellites. An extended Kalman filter processes the measurements coming from GPS, gyro and star-tracker sensors, in order to estimate the spacecraft position and velocity. A hybrid continuous/impulsive control scheme is implemented to track the desired reference signals. The effectiveness of the proposed system is analyzed via numerical simulations.