About GPS

What Can GPS Do For Me? 

GPS enabled systems are increasingly being used to by consumers and businesses to track persons, possessions and products. It can be used by a small business to see and dispatch the closest delivery or service vehicle saving time and money. It can be used by families to keep track on the vehicle location of loved ones. It can be used to monitor the location of patients who suffer from dementia or Alzheimer's. It can even help give seniors with an easy to operate means of communicating with a live person if they are lost or need emergency assistance.

In short, GPS enables systems and services are becoming the latest technological boom. GPS enabled cell phones, are already being mandated by the year 2006. Industry experts predict that by the year 2010, GPS products will account for a $20 billion dollars in retail sales. 

WHAT IS THE GLOBAL POSITIONING SYSTEM?

Our ancestors had to go to pretty extreme measures to keep from getting lost. They erected monumental landmarks, laboriously drafted detailed maps and learned to read the stars in the night sky.

Things are much, much easier today. For less than $300, you can get a pocket-sized gadget that will tell you exactly where you are on Earth at any moment. As long as you have a GPS receiver and a clear view of the sky, you'll never be lost again.

When people talk about "a GPS," they usually mean a GPS receiver. The Global Positioning System (GPS) is actually a constellation of 27 Earth-orbiting satellites (24 in operation and three extras in case one fails). The U.S. military developed and implemented this multi-billion dollar satellite network as a military navigation system, but soon opened it up to everybody else. 

A GPS receiver's job is to locate four or more of these satellites, figure out the distance to each, and use this information to deduce its own location.   

If you know you are 10 miles from satellite A in the sky, you could be anywhere on the surface of a huge, imaginary sphere with a 10-mile radius. If you also know you are 15 miles from satellite B, you can overlap the first sphere with another, larger sphere. The spheres intersect in a perfect circle. If you know the distance to a third satellite, you get a third sphere, which intersects with this circle at two points.

clayton communications, clayton communication, gps, global positioning system, global positioning systems, lifeguardian, life guardian, safeguardian, gps2000, gps 2000, safe guardian, gps phone, gps phones, gps cell phone, gps cell phones, gps watch, gps watches, fleet tracking, gps vehicle tracking, gps tracking, gps systems, gps units, gps receivers, auto gps, gps receiver, gps system, gps systems, car gps, gps navigation, gps devices, portable gps, gps tracking devices, gps for cars, gps cell phone, gps cell phones, gps navigation systems, automobile gps, gps tracker, gps tracking, gps tracking system, gps tracking systems, gps tracking device, automotive gps, automobile gps navigation systems, auto gps systems, car tracking devices, covert vehicle tracking, gps vehicle tracker, live gps tracking, gps vehicle tracking, automobile tracking, vehicle locator, automobile locator, gps locator, gps locators, gps locater, personal gps locator, personal gps, gps device, mobile gpsThe Earth itself can act as a fourth sphere -- only one of the two possible points will actually be on the surface of the planet, so you can eliminate the one in space. Receivers generally look to four or more satellites, however, to improve accuracy and provide precise altitude information.

In order to make this simple calculation, then, the GPS receiver has to know two things:

The GPS receiver figures both of these things out by analyzing high-frequency, low-power radio signals from the GPS satellites. Better units have multiple receivers, so they can pick up signals from several satellites simultaneously.

Radio waves are electromagnetic energy, which means they travel at the speed of light (about 186,000 miles per second, 300,000 km per second in a vacuum). The receiver can figure out how far the signal has traveled by timing how long it took the signal to arrive. In the next section, we'll see how the receiver and satellite work together to make this measurement.

Once the receiver makes this calculation, it can tell you the latitude, longitude and altitude (or some similar measurement) of its current position. To make the navigation more user-friendly, most receivers plug this raw data into map files stored inmemory.

You can use maps stored in the receiver's memory, connect the receiver to acomputer that can hold more detailed maps in its memory, or simply buy a detailed map of your area and find your way using the receiver's latitude and longitude readouts. Some receivers let you download detailed maps into memory or supply detailed maps with plug-in map cartridges.

clayton communications, clayton communication, gps, global positioning system, global positioning systems, lifeguardian, life guardian, safeguardian, gps2000, gps 2000, safe guardian, gps phone, gps phones, gps cell phone, gps cell phones, gps watch, gps watches, fleet tracking, gps vehicle tracking, gps tracking, gps systems, gps units, gps receivers, auto gps, gps receiver, gps system, gps systems, car gps, gps navigation, gps devices, portable gps, gps tracking devices, gps for cars, gps cell phone, gps cell phones, gps navigation systems, automobile gps, gps tracker, gps tracking, gps tracking system, gps tracking systems, gps tracking device, automotive gps, automobile gps navigation systems, auto gps systems, car tracking devices, covert vehicle tracking, gps vehicle tracker, live gps tracking, gps vehicle tracking, automobile tracking, vehicle locator, automobile locator, gps locator, gps locators, gps locater, personal gps locator, personal gps, gps device, mobile gpsA standard GPS receiver will not only place you on a map at any particular location, but will also trace your path across a map as you move. If you leave your receiver on, it can stay in constant communication with GPS satellites to see how your location is changing. With this information and its built-in clock, the receiver can give you several pieces of valuable information:

To obtain this last piece of information, you would have to have given the receiver the coordinates of your destination, which brings us to another GPS receiver capability: inputting location data. 

Each of these 3,000- to 4,000-pound solar-powered satellites circles the globe at about 12,000 miles (19,300 km), making two complete rotations every day. The orbits are arranged so that at any time, anywhere on Earth, there are at least four satellites "visible" in the sky.