What is GPS?

What is GPS?

How Does GPS Work?

GPS satellites orbit the planet twice a day in a very accurate orbit, transmitting signal data to the ground. GPS receivers utilize this information to compute the user's precise position via triangulation. In essence, the GPS receiver compares the time a satellite-delivered a signal to the time it was received. The GPS receiver uses the time difference to determine how far away the satellite is. The receiver can now identify the user's position using distance measurements from a few additional satellites and show it on the unit's electronic map.

The GPS Satellite System

The 24 satellites that make up the GPS space segment circle the planet at a distance of roughly 12,000 miles. They're continuously moving, clocking in at over 7,000 miles per hour and completing two circles in under 24 hours.

Solar energy is used to power GPS satellites. They're equipped with backup batteries to keep them functioning in the case of a solar eclipse when solar power is unavailable. Each satellite is equipped with little rocket boosters that keep it on course.

Here are some fascinating facts regarding GPS satellites (also known as NAVSTAR, the official name for GPS in the United States Department of Defense):

1. In 1978, the first GPS satellite was launched.

2. In 1994, a full constellation of 24 satellites was completed.

3. Each satellite is designed to survive around ten years. Replacements are manufactured and sent into orbit on a regular basis.

4. With the solar panels extended, a GPS satellite weighs around 2,000 pounds and measures about 17 feet across.

5. The transmitter's output power is limited to 50 watts or less.

What is WAAS?

You've probably heard of WAAS, seen it on GPS product packaging and advertisements, and maybe even know what it stands for Wide Area Augmentation System. So, what exactly is it, exactly? It's essentially a system of extra satellites and ground stations that give GPS signal adjustments, allowing you to get even more precise with your position. How much great can it get? Try improving your average by up to five times. 95% of the time, a WAAS-capable receiver will give you a location accuracy of fewer than three meters. Your GPS must be "WAAS-enabled" in order to benefit from this enhancement.

What are GPS Applications?

GPS offers a wide range of uses on land, at sea, and in the air. In general, GPS may be used anywhere except when receiving a signal is difficult, such as within most buildings, tunnels, and other underground places, and underwater. General aviation and commercial aircraft use the most popular airborne applications for navigation. Recreational boaters, commercial fishermen, and professional mariners all utilize GPS for navigation when at sea. The range of land-based applications is greater. GPS is used by scientists because of its accuracy time and location information.

Surveyors are increasingly relying on GPS for their work. By dramatically decreasing setup time at the survey location and offering amazing precision, GPS delivers significant cost savings. Basic survey equipment, which might cost thousands of dollars, can provide accuracies of one meter. There are more costly devices that can offer accuracies of up to a centimeter.

The number of recreational GPS applications is almost as large as the variety of leisure sports accessible. Hikers, hunters, snowmobilers, mountain bikers, and cross-country skiers, to mention a few, are all fans of GPS. The benefits of the global positioning system may be used by anybody who wants to keep track of where they are, find their way to a certain destination, or know what direction and speed they are traveling in.

Automobiles are increasingly equipped with GPS as well. Some rudimentary systems are in place, and at the touch of a button, they give emergency roadside help (by transmitting your current position to a dispatch center). There are even more advanced devices that display your location on a street map. Currently, these systems allow a driver to keep track of his or her location and recommend the best route to take to go to a specific place.