The challenge of sensing relative motion between vehicles is an important subject in the engineering field in recent years. The associated applications range from spacecraft rendezvous and docking to autonomous ground vehicle operations. The focus of this thesis is to develop the simulation tools to examine this problem in the laboratory environment. More specifically, the goal is to create a virtual unmanned ground vehicle that operates in the same manner as an actual vehicle. This simulated vehicle allows for safely testing other software or hardware components before application to the actual vehicle. In addition, the simulated vehicle, in contrast to the real vehicle, is able to operate on different surfaces or even different planets, with different gravitational accelerations. To accomplish this goal, the equations of motion of a two-wheel driven unmanned vehicle are developed analytically. To study the spacecraft application, the equations of motion for a spacecraft cluster are also developed. These two simulations are implemented in a modular form using the UMBRA framework. In addition, an interface between these two simulations is created for the unmanned vehicle to mimic the translational motion of a spacecraft's relative orbit. Finally, some of the limitations and future improvements of the existing simulations are presented.