GPS Receiver
The job of the GPS receiver is to determine your precise spot as the satellite determines your longitude and latitude. Other devices can even include your altitude. Knowing the accuracy of your location varies from unit to unit. Additionally, you may expect the device to be highly accurate in an area where you can get a clear view of the sky. Heavy trees and tall buildings affect the accuracy of the navigation GPS. The unit will possibly not manage to have a lock on sufficient satellites if there are extreme obstructions. It makes the unit less accurate.
Physical Attributes
Ranging from 2.5 to 7 inches, navigation GPS are available in various sizes. The smaller size is for portability while the larger size is to make the screen easier to read. These GPS systems can be mounted in a variety of ways into a car. Some can be screwed to a dashboard or console with a support bracket or with the use of a suction cup. Some units use a beanbag-type base which is attached to the dashboard by friction.
Accuracy of Directions
The most important purpose of navigation GPS for cars is to provide driving directions. Nearly all navigation GPS systems are offering voice feature that delivers turn-by-turn directions. The routes that are calculated by the GPS devices are normally precise though they may be not spot on at all times. GPS systems may fail occasionally in providing directions. It is helpful to know though that conditions such as these rarely happen.
Maps
The maps of GPS for cars are very detailed and substantially accurate. The map database stores a great deal of data of roads and highways. Information on speed limits of specific roads, road numbers and names of streets, details of expressway ramps, one-way streets and other specific information are incorporated in the maps. The maps in GPS are kept in either a secure SD memory card or a compact flash card. Majority of navigation GPS devices have enough memory that stores maps of several states or a large city.
Points of Interest (POIs)
Points of Interests are restaurants, hotels, parks, ATM machines, gas stations, and other establishments which are stored in the database of GPS device. A unit may store millions of these POIs which often come with phone numbers. Some establishments possibly will discontinue engaging in business or may transfer to another location so there are times when the navigation GPS may go wrong in locating POIs. Keep your navigation GPS updated frequently to minimize receiving inaccurate information about the Points of Interests.
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