Patent ID: 6024655
Filing Date: 2000-02-15
Classification: A63B,G01C,G01S

Abstract:
A method for obtaining accurate measurements of distance of a golf cart equipped with a computerized dead reckoning navigation (DRN) system from features of interest on a hole of a golf course including tee boxes, cups, water hazards, sand traps, rough areas adjacent fairway, and cart path, to assist golfers in playing the hole, wherein the golf course has been surveyed so that fixed positions of at least some of said features including the cart path are known and are part of a map of the course stored in the data base of the computerized DRN system, the DRN system having a capability to detect and indicate the position of said golf cart on the course map but undergoing a gradual increase in error of indicated position of the golf cart as the cart is driven about the course during play, thereby introducing error buildup into each said measurement of distance of the cart to said features, said method comprising the steps of:examining by means of the DRN system whether the golf cart is on or off the cart path during at least part of the time that said cart is in use in play of each hole; andat a point in time when the cart is determined to be on the cart path during said play, calibrating the DRN system, including Kalman filter processing information derived in said DRN system from driving said cart, to substantially eliminate the built up error and thereby restore accuracy of measurements performed by the DRN system at that point in time by substantially reducing the discrepancy between (a) a point on the cart path determined to be the actual approximate position of the golf cart and (b) the indicated position of the golf cart removed from said point on the cart path.