GPS

What GPSs are permissable?

We support all widely-used 'free flight' GPS and integrated instruments from major manufacturers which record 3D tracks, including:

- Aircotec
- Brauniger
- C-Pilot
- Digifly
- Garmin
- Flymaster
- Flytec
- MLR (Free flight version only)

Generally if it is supported by GPSDump it will be supported by our Check in program. If in doubt ask and we will check.

Must the primary GPS or flight recorder be capable of recording in 3D format - ie including altitude?

Yes, following airspace infringements we have decided to make this a requirement.

What is the procedure at Registration with respect to GPS's?

If you have a Garmin GPS, have it set to the following values: 1. UTC offset = +01:00 2. Map Datum = WGS84 3. Interface = Garmin/Garmin If you have an MLR have the serial port Active, make the Datum WGS84. The Coordinate system may be set to whatever you like . Note that you may need to change the GPS datum if you are given TP co-ordinates on the hill. Read this document for a full breakdown on using the Garmin 76 Series for comps. Delete all your waypoints in the GPSs. This is not essential, BUT if you subsequently have problems navigating the task due to conflicting waypoints or pilot numbers, you will have no comeback against the organisers. For Garmins prior to registration make sure you have no waypoints with negative signs before them. If you dont know how to do these things please ask someone else before getting in the queue to upload. Once you have your GPS correctly configured, go to the desk with the plumbers Mac PC on it. Tell the nice man behind the monitor your pilot number and get your GPS(s) uploaded with the turn points for that weekend. If you have a Garmin, the first waypoint on your GPS will now be a 3 digit negative number. This is your pilot number, eg -004, -058 -101 etc. If it is not 3 digits, change it or ask for help to do so.

Is there a predefined interval for recording track logs?

Not specifically, but it should not be more than 30 seconds. Depending on your GPS you may select the frequency that it records. The old Garmin GPS12s will record 1024 points, so at 1 every 20 seconds you can record a flight of just over five and half hours. Problem with this is that if you clip a turn point you may record a point just outside the radius, fly straight through and out the other side of the radius and then record another point. This would be interpreted as a missed turn point. To get round this you can either increase your record rate to say 10 seconds but limit your flight to less than 3 hours, or count to 20 once the GPS says youre less than 399 m away and then turn for the next waypoint. An MLR will start to record every second when inside a turn point radius. One of their good points!

I have a Garmin GPS. Does it matter whether I set the track log to 'Fill' or 'Wrap'?

It's better to set it to Fill and not Wrap With it set to 'Fill', it will stop recording when the memory is full and youd score from the start to the point it became full. If it was on Wrap, it records over the beginning of the log and so you loose the start and thus all your score. The last thing you should do before taking off is clear your tracklog. The more modern GPSs have much bigger memories and these problems are not that apparent. Check before you fly.

How do I enter a UK grid ref into the MLR?

The MLR supports British Grid format - but displays the 100K grid letters as numbers, and expects an accuracy of 1 metre when entering waypoints. A letter/ six digit Grid ref is of course only accurate to 100 metres. One way is to find someone with a Garmin who can enter a British Grid ref and then display it in UTM or Lat Long, or any format that you can enter directly into the MLR. The MLR will then do the conversion automatically when you set the display to British Grid. If you have an OS map, it will show the 100K numbers you need on the Eastings and Northings grid lines on the corners of the map. Eg for a map where the bottom left corner is SU 200 550, the map shows 420000 and 155000 as the grid line refs on the corner. The '4' and '1' are shown in very small text and represent the 100K square in numbers to which the point relates. To enter into the MLR you need to prefix a leading zero to the 100K number then suffix two zeroes to represent 10's of metres and single metres. For the point above, SU 200 500, the x becomes 04 200 00 and the y becomes 01 550 00. Providing the MLR is set to display in British Grid and the datum is ORD SURV GB 361 you can enter these numbers directly.