136Present location display errorIn order to find the exact position of the present location, this device uses compiled datafrom the GPS satellite, vehicle speed sensor and vibration gyro sensor. Because each ofthese contains a margin of error, the present location indicated may not coincide with youractual positioning.If the indication is different from the actual positioning, the present location displayed canbe corrected. Park the vehicle in a safe place first before proceeding.Error due to having changed a tireThe device calculates the distance traveled by the vehicle using a speed sensor (inproportion to the tire rotation). The following situations would result in a significant error thatmay render proper present location positioning impossible.•When using a sub-standard tire•When driving on a snow covered, gravel road or any slippery road•When the tire air pressure is incorrect•When using new tires (the distance correction coefficient setting can be changed andadjusted)Correcting the map matching vehicle position sensorMap matching is a system that compares present location positioning data from the GPSand other sources with information concerning all the roads driven on until now in order tocorrect the present location onto the most appropriate road. This device corrects thepresent location data compiled from a combination of independent navigation and satellitenavigation and matches it with the shape of the road.However, there may be instances when the present location error cannot be avoided andthe position indicated on the map does not coincide with your actual positioning even after acorrection using map matching.Also, driving along a road whose actual shape differs from the map data may result in avehicle position mark misalignment.3. Accuracy and errorHelpful tips
