The ground effect impacts rotorcraft performance in cases such as takeoff, landing, and hovering in proximity of a rigid surface. This paper investigates the performance of a quadrotor tracking a continuous trajectory during vertical takeoff and landing. The baseline controller is a cascaded P-PI controller which is then augmented with a disturbance observer. The addition of a disturbance observer improves rejection of the ground effect compared to the baseline controller. A Simcenter 3D and Simulink co-simulation environment is used to obtain simulation results. The proposed controller correlates well in simulation and experiment. The proposed controller shows better performance in landing compared to the baseline controller in both simulation and experimental results.