Field tests were made to evaluate the accuracy/resolution relationship of the NAVAID systems (Loran/Omega) for measuring the vertical profile of the wind. Specifically, these tests involve a series of flight comparisons between the AN/FPS-16 radar and the Omega and Loran equipments. These comparisons were performed using balloon-borne radiosondes with the receiving and processing equipment located on the ground. The specific Air Force requirements are for an accuracy of 3 knots with a 2000 ft sensing interval and a fall rate of 1000 ft/min or greater. The Loran equipments were found to be capable of a 1.4 knot accuracy for these conditions, while the Omega equipments provided an accuracy of 4.3 knots. (Author).