What is WAAS and do I need it?
A lot of new GPS devices incorporate WAAS into their design – this is marketed as a tool that makes your location readings much more accurate. But what is WAAS – and do you really need it?
Actually there are various names for the system – WAAS is the American version, EGNOS is the European version. The idea behind WAAS is that base-stations at known locations can derive the current inaccuracy in the system – and therefore this information can then be used by others to adjust their readings.
Ie. A simplistic example would be that base-station A is known to be at N53 53.123 W01 07.888, but the GPS is reporting N53 53.125 W01 07.888. Therefore we can see that the Northings reading is off by .002. So this is then transmitted via the GPS network to all the WAAS receivers – and they then know to adjust by .002 any readings they have.
Simple eh? (Well not quite – WAAS costs $50 million (£25 million) to provide yearly!).
WAAS should improve the accuracy of your GPS so you are accurate to 1 – 2 metres.
I’ve been using WAAS for sometime on a Garmin GPSMAP 76 – and it works very well – but it only seems to work now-and-then.
Note: Some devices still need you to manually activate WAAS – keep this in mind!!
