Navigon MobileNavigator 5 User Manual - Glossary

User's manual MobileNavigator | 5 

Glossary 

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Glossary 

COM-port 

A COM port is a connector to a communications interface, usually 

the serial port. The ports are numbered by a number behind 

"COM". A communications interface is designed to connect 

hardware like a mouse or a GPS receiver. 

GMT 

GMT (Greenwich Mean Time) is the mean solar time at the Royal 

Greenwich Observatory in Greenwich near London, England, 

which by convention is at 0 degrees geographic longitude. 

Theoretically, noon Greenwich Mean Time is the moment when 

the Sun crosses the Greenwich meridian (and reaches its highest 

point in the sky in Greenwich). Up to 1972, GMT was the global 

time standard. Because of the Earth's uneven speed in its elliptic 

orbit, GMT has been replaced by UTC (Universal Time 

Coordinated) which is an ultra stable time standard based on 

atomic clocks. 

GPS 

The GPS (Global Positioning System) is based on 24 satellites 

which are in orbit round the earth. They are permanently 

emitting the time and their current position. The GPS receiver 

receives this information and calculates the longitude and the 

latitude of its own current position. 

The signals of at least three satellites are needed to determine 

the longitude and the latitude. With the signals of at least four 

satellites the elevation may be calculated, too. The determination 

has an accuracy of about 3 yards.  

HDOP 

The Horizontal Dilution of Precision (HDOP) indicates the quality 

of position determination. Theoretically any value from 0 to 50 is 

possible. The smaller the value is, the more accurate is the 

position determination (value 0 = no deviation from the actual 

position). Values up to 8 are convenient for street navigation.  

POI 

Point of Interest (POI). See 

Î

Special destination. 

RDS 

Radio Data Signal (RDS) is a service offered by broadcasting 

stations. TMC information is broadcasted via RDS.  

Special destination 

Special destinations, also called POI (Points of Interest), are 

covered by the map and may be displayed on it. Harbours, 

airports, restaurants, hotels, petrol stations, public buildings, and 

others belong to the special destinations. You may determine 

special destinations as itinerary points for navigation purposes.  

TMC 

Traffic Message Channel (TMC) supplies your navigation system 

with the latest traffic information. A TMC module which is 

available as accessory receives the signals which are broadcasted 

by radio stations.