When antenna arrays are placed on platforms, antenna patterns and antenna characteristics change significantly. Calibration of antenna arrays becomes an inevitable and important task to correct the imperfections due to the antenna surroundings. In this paper, a time-gating method is proposed to calibrate the direction finding antenna array on a UH-60 helicopter on ground. The helicopter is placed above the ground plane whereas the source antenna is further away to account for the reflections from the helicopter appropriately. It is shown that the proposed approach can be used effectively to eliminate the ground reflections and obtain accurate calibration data. This technique is both effective and a cost cutting approach for array calibration.