-
An orbiting GPS satelliteGlobal positioning systems are based on the development of radiowave-based ground systems that were developed for use by the allies in World War II. The systems were used by allied warships seeking their destinations, while maintaining their cover. The U.S. Navy built the first satellite system in the late 1950s, using a network of five satellites in orbit. The system was limited, as it was only able to provide one location update per hour. The development of global positioning technology has continued and the current system is based on a group of 30 satellites in orbit. - GPS services were not made available to the public until 1983. President Ronald Reagan opened the network up to civilian use after the 1983 missile attack on a Korean Airlines plane. The plane was shot down by the Soviet Union after it had drifted into Russian airspace en route to Seoul, South Korea. The Soviets justified the attack by saying that they thought it was an American military jet. President Reagan chose to make the system available, when completed, so that civilian air flights would avoid flying into restricted airspace. The American GPS system was fully operational in 1989.
-
A GPS Chip with antennaNavigational systems, like those mounted in automobiles or equipped in planes, are synchronized with the satellite system and maintain continual contact to track the location of the device. The device's antenna is trained to look to a specific orbit to find a signal from anywhere between 1 to 12 different satellites at once. The GPS receiver uses information from those satellites to pinpoint its position. Because the device remains in continual contact and is constantly measuring where it is at that exact moment, the GPS receiver is able to track variables such as speed, latitude, longitude and the user's precise location. -
A GPS mounted in a Japanese taxiGPS devices have been on the consumer market since 1991. Garmin debuted its first receiver that year, charging 2,500 dollars each. The devices showed latitude, longitude and compass position. Garmin was the first company to market a GPS navigational device with integrated maps, introducing the StreetPilot in the early part of the century. Since then, companies like TomTom and Magellan have released similar devices. -
TomTom Navigator software in use on a Palm TreoWith the dearth of navigation systems for drivers, companies like Garmin, TomTom and Magellan have worked to separate themselves on the market. Garmin has partnered with Microsoft to integrate weather, traffic and updates from its MSN Direct service, using a Bluetooth connection to a cellphone. TomTom offers traffic services, through a separate antenna, and has software that will reprogram a route based on traffic conditions. Magellan works with the American Automobile Association (AAA) to offer tourist and city information on its mapping systems. - Like the Earth itself, GPS satellites move. The satellites are in constant motion, due to their orbits. As a result, GPS systems require regular calibration to consistently and quickly synchronize with orbiting satellites. This is usually accomplished through software updates offered by the GPS company.
