Most GPS receivers have a built in antenna. The two most popular types of antennas used in GPS receivers are "patch" and "quadrifilar helix" or "quad helix" for short.

The GPS antenna combines a planar antenna and a frequency converter, which translates the high-frequency phase-modulated spread spectrum signal of the GPS system to an intermediate frequency. In this way a standard coaxial can be used for the connection with the GPS clock and a distance of up to 300 meters or even 700 meters between receiver and antenna is possible without requiring an additional amplifier.

Like a cell phone, a GPS receiver relies on radio waves. But instead of using towers on the ground, it communicates with satellites that orbit the Earth. There are currently 27 GPS satellites in orbit - 24 are in active use and 3 act as a backup in case another satellite fails. In order to determine your location, a GPS receiver has to determine the locations of at least three satellites above you and where you are in relation to those satellites.

The receiver then uses trilateration to determine your exact location. Basically, it draws a sphere around each of three satellites it can locate. These three spheres intersect in two points -- one is in space, and one is on the ground. The point on the ground at which the three spheres intersect is your location.

A GPS receiver has to have a clear line of sight to the satellite to operate, so dense tree cover and buildings can keep it from getting a fix on your location.

To get a RFQ about Galtronics' GPS antennas please contact us.