2008 Mazda RX-8 Owner's Manual - Page 426

GPS Before Use Getting started GPS is a position detecting system utilizing the signals from GPS satellites deployed by the U.S. Department of Defense. The Mobile Navigation System uses input from three or more satellites and calculates the vehicle position based on the principle of triangulation. The positioning accuracy of the system corresponds to the error display of the GPS which is from about 30 to 200 meters. lIf you are using the system for the first time, or if you have not used it for some time, it takes about 5 minutes (or about 2 minutes in open areas) to calculate your vehicle's position. n GPS 52 Routing Address Book Voice Recognition signal reception is poor in the following places If necessary In tunnels Among high-rise buildings Under elevated roads In wooded areas lThe GPS satellites are controlled by the U.S. Defense Department, which may intentionally lower positioning accuracy. In such cases, there may be vehicle position deviations. lThere may be vehicle position deviations for some time until GPS signals are received after turning on the ignition. Map Matching This function compares your vehicle's tracking data with the road data on the map disc, applies dead reckoning to determine the road you are driving on, and displays your vehicle on that road on the map. lIntelligent map matching addresses the following problems to achieve high accuracy in vehicle positioning. Position Correction for Elevated Roads Position accuracy is improved by detecting if the vehicle is running on or under an elevated road. Position Correction for Parking Garages Position accuracy is improved by detecting if the vehicle is driving in an elevated or underground parking garage. High-precision Gyrosensor A gyro detects turns with an accuracy of 0.05° per second. Combined with a speed sensor, it enables the system to display the current vehicle position even where GPS signals may be blocked. lUsing a spare tire in place of the regular one may cause vehicle position deviations. lAny difference between the direction which your vehicle actually travels and that shown on the map is automatically eliminated by azimuth correction.