GPS Rental & Purchase

Some travellers prefer to rent a GPS. Please check out quality GPS rental options: Rent-a-GPS.

For possible purchase of cheap GPS units, we recommend you try Tiger GPS.

GPS Review

The Global Positioning System (GPS) is a fully functional Global Navigation Satellite System (GNSS) that utilizes more than two dozen GPS satellites in medium Earth orbit. The satellites transmit signals allowing GPS receivers to determine the receiver's location, speed and direction.

GPS System

Since the first experimental satellite was launched in 1978, GPS has become an indispensable aid to navigation around the world, and an important tool for map-making and land surveying. GPS also provides a precise time reference used in many applications including scientific study of earthquakes, and synchronization of telecommunications networks.

Since GPS signals at terrestrial receivers tend to be relatively weak, it is easy for other sources of electromagnetic radiation to overpower the receiver, making acquiring and tracking the satellite signals difficult or impossible.

Solar flares are one such naturally occurring emission with the potential to degrade GPS reception, and their impact can effect reception over the half of the Earth facing the sun. GPS signals can also be interfered with by naturally occurring geomagnetic storms, predominantly found at near the poles of the Earth's magnetic field.

Automobiles can be equipped with GPS receivers at the factory or as after-market equipment. Units often display moving maps and information about location, speed, direction, and nearby streets and landmarks. Popular brands include Garmin GPS and Magellan GPS.

Hikers, climbers, and even ordinary pedestrians in urban or rural environments can use handheld GPS to determine their position, with or without reference to separate maps. In isolated areas, the ability of portable GPS to provide a precise position can greatly enhance the chances of rescue when climbers or hikers are disabled or lost (if they have a means of communication with rescue workers).

Aircraft navigation systems usually display a "moving map" and are often connected to the autopilot for en-route navigation. Cockpit-mounted GPS receivers and glass cockpits are appearing in general aviation aircraft of all sizes, using technologies such as WAAS or LAAS to increase accuracy. Many of these systems may be certified for instrument flight rules navigation, and some can also be used for final approach and landing operations. Glider pilots use GNSS Flight Recorders to log GPS data verifying their arrival at turn points in gliding competitions. Flight computers installed in many gliders also use GPS to compute wind speed aloft, and glide paths to waypoints such as alternate airports or mountain passes, to aid en route decision making for cross-country soaring.

Boats and ships can use GPS to navigate all of the world's lakes, seas and oceans. Maritime GPS units include functions useful on water, such as “man overboard” (MOB) functions that allow instantly marking the location where a person has fallen overboard, which simplifies rescue efforts. GPS may be connected to the ships self-steering gear and Chartplotters using the NMEA 0183 interface. GPS can also improve the security of shipping traffic by enabling AIS.

Precise time reference — Many systems that must be accurately synchronized use GPS as a source of accurate time. GPS can be used as a reference clock for time code generators or NTP clocks. Sensors (for seismology or other monitoring application), can use GPS as a precise time source, so events may be timed accurately. TDMA communications networks often rely on this precise timing to synchronize RF generating equipment, network equipment, and multiplexers ().