GPS Receivers - How Do These Essential Gadgets Work?

GPS receivers take information and use the triangulation method to calculate a user's exact location. Essentially, the GPS receiver compares the time a signal was first transmitted by a satellite with the time it was then received. GPS receivers provide highly accurate time fixes anywhere worldwide. GPS system time is a worldwide standard atomic time which is exactly related to Coordinated Universal Time (UTC or "Greenwich time"). GPS receivers have largely replaced radionavigation services for the aviation and maritime industries and are being increasingly employed for land-based transportation (an industry which has not traditionally used any form of radionavigation). For example, combining GPS with broadcast information about traffic and road conditions can improve the safety and efficiency of vehicle transport.

GPS receivers typically allow waypoints to be saved in a specific sequence as a route, and when we follow that route-or its inverse-as we reach each waypoint, the display automatically brings up the next one on our route. Some units even record temporary waypoints automatically, allowing you to follow the same route home without the necessity of you saving waypoints at all. GPS receivers often provide a 1 pulse per second (pps) timing output, as well as standard output frequencies such as 5 and 10 MHz. If properly designed and used, a GPS receiver can provide traceability to the NIST frequency standard. GPS receivers receive this information and are capable of calculating their own location and position with utmost precision.

The GPS receiver must find the frequency of the signal before it can lock on. Knowledge of each satellite's position and velocity from an Assisted GPS server effectively reduces the number of frequencies to be searched because there's less guesswork involved, speeding TTFF up by (potentially) tens of seconds. The GPS data collected at these stations allow GPS users to determine more accurate positions through computation after the data are collected. Numerous federal, state, and local government agencies, as well as universities and commercial organizations, also operate CORS stations.

Positioning via GPS is possible just about anywhere in the world. To get your position, you need to be in line-of-sight of at least three of the orbiting satellites, which is possible all around the world. Position the receiver up on your dashboard and yet your PDA can be kept right next to you - or your passenger, or even someone sitting in the backseat of the vehicle. It is smaller than the regular Bluetooth receiver shown above, but it performs just as equally well. Positioning began from 1950s and improved in 1970s. In 1980s, GPS became an operational positioning system.