The paper investigates the modeling and controller design of ground simulation system of scaled spacecraft orbital motion based on a four-wheel vehicle. The use of mean anomaly and eccentric anomaly of a general ellipse orbit facilitates the real-time generation of reference trajectories and their high-order derivatives. By eliminating the lateral degree of freedom of the studied vehicle and guaranteeing the consistent positiveness of longitudinal linear velocity, we derive a differential-like kinematic model for the vehicle. A composite architecture consisting of an exponentially convergent observer and a velocity controller is proposed to steer the vehicle position tracking errors approaching to zero asymptotically without attitude angle information. Simulations and experiments are subsequently conducted to verify the validity of the overall ground simulation system.