About navigation’s map matching

Current location marking via map matching

This product displays the current location calculated by integrating the sensor information on vehicle speed and direction and the GPS location data. Since errors exist in the location information calculated in this way, map matching is used to provide more accurate location information on the digital map roads.

	Actual vehicle path on the road
	Location mark on the map without using map matching
	Location mark corrected by using map matching

Inaccurate map matching

Sometimes, the location can be calculated inaccurately even using map matching due to the road or GPS conditions. GPS data can have errors of up to 15m. Especially in following cases, the actual location and the displayed location may differ. However, this is not a product failure.

Inaccurate calculation due to GPS failure

Signals weakened or interrupted around buildings or in tunnels or underground passes.
Failure of signal transmission from satellites. (The tracking control center in the US may stop signal transmission for maintenance.)
Satellite signals are blocked by objects placed on the GPS antennas. (Especially, when a metallic object or mobile phone is placed near the GPS antennas.) When the sunspot activity is intense.

Location tracking failure due to surrounding terrains

Driving near a parallel road.
Driving on a grid road.
Driving on a steep uphill road with frequent curves.
Driving on a narrow-angled Y-shaped road.
Turning around a roundabout.
Driving on a circle or P-shaed road with a short radius of rotation.
Vehicle is started in an underground parking lot or other places that cannot receive GPS signals and enters a road. (Failure lasts for a while.)
Driving slowly under an overpass or in other areas receiving GPS signals intermittently.
Driving in an urban area where GPS signals are excessively distorted due to presence of buildings and other obstacles.

,Reference

GPS may be affected by the type of dashcam installed in the vehicle.