How does it work?All the units work by receiving signals from a number of satellites in earth orbit. As long as there are 4 or more of these satellites in range (5 preferably) then a reasonably accurate position can be calculated (normally accurate to less than 5 meters). Once the position is known then the Golf GPS systems can compute the distance to the various hazards and green positions which are stored in the database for each club. Think of the Golf GPS systems as SatNav for the golf course. Is it legal?Rule 14-3/0.5 of the R&A states: Q. May a Committee, by Local Rule, permit the use of distance-measuring devices? A. Yes. A Committee may establish a Local Rule allowing players to use devices that measure distance only. However, the use of devices that gauge or measure other conditions that might affect a player’s play (e.g., wind or gradient) is not permitted. In the absence of such a Local Rule, the use of a distance-measuring device would be contrary to Rule 14-3. (New) How a course is mapped?The golf courses are mapped by either of one of two ways: First from aerial photography. Typically 1 meter accuracy images have been used, though a lot of the new imagery has an accuracy of 12.5 centimetres. This allows us to extract highly accurate positions for each of the hazards and green locations. However sometimes either the imagery for a course does not exist (for a course that has just been built for instance) or if a course has just under gone an extensive renovation. When this happens then an engineer is required to go on site to the club and manually do a GPS survey. The engineer uses a high accuracy survey grade GPS receiver which gives positional accuracy of less than 2 centimetres. How accurate is it?When considering accuracy you have to take into account the accuracy of the Golf GPS system and the accuracy of the points in the database. As shown in the previous topic, all professionally mapped courses have an accuracy between 2 centimetres and 1 meter. The Golf GPS systems have an accuracy of less than 5 meters in normal conditions (more about how the accuracy is affected below). What affects the accuracy of the Golf GPS systems?There are a number of factors that effect GPS accuracy. However the most important factor is the number and position of the GPS satellites in range. Ideally you want 5 or more satellites spread around in different directions. The more satellites visible; the higher the accuracy of the fix What causes poor positional accuracy?The most likely cause of poor positional accuracy is either a low number of satellites in range or a situation where the satellites are all in the same segment of sky rather than being nicely spread out. Another cause of poor accuracy is either an out-of-date or missing almanac. This is information that lets GPS receivers know the position of each of the satellites in the sky (this is vital for computing the location). This almanac is downloaded from the GPS satellites when the unit is switched on. However this can take 4 minutes (sometimes longer) to download the first time. Fortunately subsquent downloads are a lot quicker but for peace of mind it's good to expose your Golf GPS to the sky for a good 5 minutes before you move to the first tee. How accurate are Player Mapped courses?Player Mapped courses have the same positional accuracy as the Golf GPS units themselves; Typically less than 5 meters. How many courses can be stored on the unit at one time?The Caddy, Caddy Lite and Sureshot can all hold 10 courses in their memory at one time. These courses can be changed as often as you like. How much does annual subscription cost?Caddy and Caddy Lite subscriptions: Click here for Golf Plus Subscriptions |
