Occasionally while watching the Dakar you will see cars driving around circles, or so it seems. What they are looking for are the navigation points set by the organizers to keep and verify that the competitors are on course.
For navigation purposes the Dakar Rally uses Waypoint Safety (WPS) and Waypoint Hidden (WPM) points which are defined by GPS coordinates. All competitors are required to use the same brand and type of GPS units. These are provided by the organizers, but the entrants are required to install all of the wiring and mounting equipment so that the Dakar organizers just have to plug in the units. Most competitors, at least in the car class, fit their vehicles with two of the GPS units, in case something happens to one unit during the rally. With the difficult conditions at Dakar this would seem like a good strategy.
Using these provided GPS units, the waypoint system works as shown on the sketch below.
Waypoint Operational Sketch
Note in the above sketch that DSS is the start of the special stage and ASS in the end of the special stage. Between these two points the Dakar rally uses a series of waypoints to ensure that the competitors are following the correct route and also to locate competitors who get very lost.
When the competitors are between two 2 WPM or WPS, the GPS units will only show the compass heading and the speed. Once the car has entered the 800 m radius around a WPM or 3 km radius around a WPS, the GPS will display all the usual functions of a GPS: COG (Cap over Ground), SOG (Speed over Ground), CTW (Cap to Way Point), DTW (Distance to Way Point), etc. This information will guide them to the “blue zone” or validation zone. Once the competitors get within the “blue zone” then the WPE (Waypoint Eclipse) is activated and the competitors head towards the next waypoint along the route.
Inside Carlos Sainz’ Peugeot
The picture above shows a portion of the inside of Carlos Sainz’s car. They have two GPS units installed and below each one of them, they have installed Easy Trip rally odometers.
The Dakar is a little different from most rallies, but that is one of the things that makes it interesting.