2013 Toyota Corolla Owners Manual - Page 680

6. NAVIGATION SYSTEM INFORMATION 1. LIMITATIONS OF THE NAVIGATION SYSTEM This navigation system calculates the current vehicle position using satellite signals, various vehicle signals, map data, etc. However, an accurate position may not be shown depending on satellite condition, road configuration, vehicle condition or other circumstances. The Global Positioning System (GPS) developed and operated by the U.S. Department of Defense provides an accurate current vehicle position, normally using 4 or more satellites, and in some case 3 satellites. The GPS system has a certain level of inaccuracy. While the navigation system will compensate for this most of the time, occasional positioning errors of up to 300 feet (100 m) can and should be expected. Generally, position errors will be corrected within a few seconds. Even when the navigation system is receiving clear GPS signals, the vehicle position may not be shown accurately or inappropriate route guidance may occur in some cases. NOTICE ● The installation of window tinting may obstruct the GPS signals. Most window tinting contains some metallic content that will interfere with GPS signal reception of the antenna. We advise against the use of window tinting on vehicles equipped with navigation systems. Accurate current vehicle position may not be shown in the following cases: • When driving on a small angled Yshaped road. • When driving on a winding road. • When driving on a slippery road such as in sand, gravel, snow, etc. • When driving on a long straight road. • When motorway and surface streets run in parallel. • After moving by ferry or vehicle carrier. • When a long route is searched during high speed driving. • When driving without setting the current position calibration correctly. • After repeating a change of direction by going forward and backward, or turning on a turntable in the parking lot. • When leaving a covered parking lot or parking garage. • When a roof carrier is installed. • When driving with tire chains installed. • When the tires are worn. • After replacing a tire or tires. • When using tires that are smaller or larger than the factory specifications. • When the tire pressure in any of the four tires is not correct. The GPS signal may be physically obstructed, leading to inaccurate vehicle position on the map display. Tunnels, tall buildings, trucks, or even the placement of objects on the instrument panel may obstruct the GPS signals. The GPS satellites may not send signals due to repairs or improvements being made to them. 66