GPS Tracking and Navigation

Since the government launched its Global Positioning System satellites, locating just about anything on the planet has become significantly easier. From locating stolen vehicles and finding lost pets to keeping airliners and cruises ships on course, GPS has simplified navigation and tracking. And while use of the satellites' signals are free, one must purchase a GPS device to make use of the signals. The cost of a GPS device will depend on what the user plans to accomplish.

Initially GPS was developed to aid the government locate numerous types of assets around the world. GPS is now available to the public with locating and navigational services for private vehicles. There is a cost to utilize these services. However, it can be invaluable in recovering stolen vehicles and finding missing persons. Emergency services can locate a person with a GPS-enabled cell phone.

A handheld GPS device can help someone determine exactly where they are on the planet. With this information, it greatly simplifies navigation to another known location. Using signals beamed by the approximately 36 satellites equally spaced around the Earth, private companies can provide turn-by-turn direction service from one location to a destination.

How GPS Operates

Managed by the U.S. Air Force, satellites beaming microwave signals orbit 11 nautical miles above the earth. GPS devices require signals from three or more orbiting satellites to fix a position on Earth using trilateration. Trilateration measures the angles at which the signals intersect.

More Satellites Provide Better Location Services

GPS satellite signal reception requires line-of-sight positioning. When personal GPS devices became available, there were only about 24 satellites in orbit to send signals. At that time most devices could receive only 4 to 6 signals depending on where they were located on the planet.

As more satellites have been launched the number of available signals has increased. Today it is not unusual to have a personal GPS unit able to receive up to 18 or 20 different signals.

The more satellite signals a unit receives, the greater the accuracy of the locating. For example, receiving four signals can place the user within a few hundred yards of their position. A GPS device utilizing  20 signals can pinpoint the location to within a few inches.

The most common uses for GPS navigation is for aircraft as they navigate through clouds or fog. Relying on radar to place their location can be uncertain. With the use of GPS systems, the airplane's exact position in the sky can be pinpointed. This enables air traffic controllers as well as other aircraft in avoiding mid-air collisions, providing for the public safety.