A DYNAMIC PERFORMANCE EVALUATION METHOD FOR DGPS RECEIVERS UNDER LINEAR PARALLEL-TRACKING APPLICATIONS
GPS (Global Positioning System) receivers have been widely used as position sensors in precision agriculture. Many GPS manufacturers report GPS accuracy using stationary test data. However, most agricultural applications, such as tillage, planting, spraying, and harvesting, in which GPS receivers are used under dynamic conditions, are mobile operations. In this study, we developed a method to evaluate the GPS dynamic position accuracy under linear parallel-tracking applications. It is proposed that the pass-to-pass accuracy is the most important criterion in evaluating a receiver's dynamic performance for those applications. Eight commercially available DGPS receivers were tested during the spring of 2002 under different dates, times of the day, and travel speeds. As examples of using the proposed method, the dynamic performance of these receivers was evaluated. It was found that the dynamic performance of a receiver was extremely variable from test to test. The cumulative frequency distribution of the pass-to-pass average error provided a good statistical measure of the GPS dynamic accuracy.