GPS in Competitions

All competitions now use 3D GPS tracks for flight verification so if you want to enter a comp you have to have one and you better know how to use it. 3D means the GPS records height data in the track log. Make sure yours does.

You should know how to:

  • Add a waypoint by hand.

  • Define a route and activate it

  • Clear the track log and change track log settings.

  • Change the track sample rate

  • Change the interface mode.

  • Change the batteries (in flight if necessary)

  • Modify the track display

  • Mark a waypoint

  • Turn track recording off and on.

  • Change the display contrast

  • Set the coordinate system.


At registration for the comp (or on line before the comp if they are well organised) you will get your GPS loaded with the waypoints to be used in the comp. These will usually be prefixed by S (for start), T ( for turn point) or G ( for goal), and then a number to identify it and sometimes a short name. An additional waypoint is usually loaded containing your pilot registration number. If you get an unofficial download from another competitor you could will end up with their number on your flight. May not be a big problem for you but better to point it out to the scorers when you submit the flight.

If you wish to keep the waypoints you have stored in your GPS then download and save them to a computer and clear out you waypoint list before the comp. There are a number of reasons for this:

  • The scoring software has to read through all of the waypoints to find the one containing your pilot number. That slows things down.

  • You run the risk of having one of your waypoints overwritten by the comp ones (or vice versa).

  • When defining the task you have to scroll through a long list of irrelevant points to find the right ones. Not only slower but there is a great possibility of selecting the wrong one.

The Task

The task for the day will be given as a route with a start point, possibly one or more turn points and a goal. You will have to enter these as a route in your GPS by selecting the points from the list provided. The start time is often only 15 mins after the briefing so the less time you spend putting in the route the more time you have to think about how you are going to get around it. Always check that you get the same total distance for the task as shown on the task board.

The launch window will define the earliest and latest times you can takeoff to fly the task. If you take off outside those times your flight won't count in the comp.

The start can be from takeoff, or on entry to or departure from a defined cylinder after a defined time (think of a beer can sitting on the waypoint, you have to be in it).

Each turnpoint will also have a cylinder radius defined on the task board. You have to record at least one track point within this distance of the waypoint before going on to the next one. By setting a route the GPS will tell you how far and in which direction the next one is. If you are lucky the organisers will also have told you some landmark for the turnpoint as well. If your track points are recorded at 15 sec intervals then you had better make sure you are inside the cylinder for at least 15 secs to be sure of getting a point recorded. If your GPS doesn't tell you when you have entered the cylinder then you can set the rings on your map page to the same radius and zoom in when you are getting close to the waypoint to make sure you get the track point in there. A faster sample rate as on the bigger garmins or the competino/compeo is an advantage because you can spend less time in the cylinder.

Garmins have a bad habit of skipping waypoints on a route in tasks that zig-zag. So if the task requires you to fly to T 1 then T2 then back to T1 again before going to T3 the garmin will assume you have already made T1 the first time and will point you straight to T3. In zig-zag tasks rather than setting a route you can select the waypoints manually while flying and use the GOTO function to avoid accidentally skipping any.


Goal (Yipee!)

Goal can be either a line or a cylinder. If you get to goal ( lucky you) fly over the line or in to the cylinder and lose height away from the goal line before you find a safe landing place. If possible turn off your GPS or track recording to prevent overwriting any of your flight. AND DON'T USE TRACK/SAVE ON A GARMIN. If you have to turn your GPS on again for retrieve then turn off the track recording. Leave it set to wrap and remember to turn it on again before the next task.

Now make sure you report back by the deadline and sign out. Don't turn you GPS on until it is ready to be plugged in to the PC for download and do have your pilot number stuck on the GPS where the scorer can see it.

After the download, leave your track there until the next day, just in case there are any problems with it.


Overnight, charge your batteries.


Next day before you launch:

  • Clear the old track log

  • Make sure track recording is on

  • Clear the old route, enter the new one and activate it.

  • Switch on just before launch, and if you have to move launch sites then clear the track log again.

  • Write the route down where you can see it in flight.

Also read GPS in XC flying.


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