An unmanned aerial vehicle (UAV) has a toroidal fuselage and a rotor assembly having a pair of counter-rotating rotors secured in fixed coaxial combination with the toroidal fuselage to provide a vertical takeoff and landing (VTOL) capability for the UAV. One embodiment of the VTOL UAV is especially configured for ground surveillance missions by the inclusion of an externally mounted, remotely controllable stowable sensor subsystem that provides an azimuthal scanning capability and a predetermined elevation/depression scanning capability to accomplish the ground surveillance mission and a foldable landing gear subsystem to facilitate landing of the VTOL UAV at unprepared ground surveillance sites.