GPS Watch Guide

When people talk about “a GPS,” they usually mean a GPS receiver. Its job is to locate four or more of the system’s 24 satellites, figure out the distance to each, and use the information to deduce its location. This operation is based on a simple mathematical formula called trilateration. Trilateration is a method of determining the relative positions of objects using the geometry of triangles in a similar fashion as triangulation. As long as you have a GPS receiver and a clear view of the sky, you will never be lost again.

GPS satellites send out radio signals that a GPS receiver can detect. But how does the signal let the receiver know how far away the satellite is? The simple answer is: A GPS receiver measures how long it takes a signal to travel from the satellite to the receiver. Since we know how fast radio signals travel — they are electromagnetic waves and so (in a vacuum) travel at the speed of light, about 186,000 miles per second — we can figure out how far they’ve traveled by figuring out how long it took for them to arrive.

GPS receivers come in one of two main types- non-mapping and mapping. Non-mapping GPS receivers show a numeric display of a location and route according to latitude and longitude, but the display does not overlay a map or other geographical information. Non-mapping GPS receivers are generally less expensive and less user-friendly than mapping GPS receivers. Mapping GPS receivers are by far the most common type because they show location and route graphically over some sort of map (geographical and/or road). This makes the mapping GPS receiver much easier to read, understand and navigate with.

GPS receivers are available in a wide range of sizes and types including handheld units, marine units, aviation units, and automotive units. They are sometimes incorporated into other electronic products such as cell phones, laptops, and more. And like many electronic devices, GPS receivers are growing more and more popular as the price and size has decreased while memory and functionality (and user-friendliness) has increased. GPS receivers are used across the country and on a daily basis for hiking, geocaching (finding and hiding ‘treasures’ for others to find with a series of clues placed by other ‘geocachers’), driving, flying, boating, and countless other activities that involve any sort of navigation, mapping, position, or timing.

This entry was posted on Wednesday, January 5th, 2005 at 12:00 pm and is filed under Uncategorized. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.