It seems that almost everyone has heard of GPS (Global Positioning System) in one form or another. The most well known GPS device is the car navigation system that shows and tells the driver through voice commands how to get to their desired pre-programmed destination. But if you’re wondering how these little technological wonders work then you’ve come to the right place.
A GPS receiver is an electronic device that uses the Global Positioning System to determine its exact location on earth with pin-point accuracy. This system is made up of the three parts; 27 satellites that send out continuous positioning signals, ground stations around the world that help synchronize the satellites, and various types of GPS receivers.
In this article we’re going to concentrate on how a GPS receiver works within this system since it’s the piece of the GPS puzzle that keeps you from getting lost. Its main function is to calculate its position on the earth using the signals that it receives from the satellite system.
To do this the receiver needs to lock onto the signals of at least 3 satellites. Once 3 or more satellites have been detected it then needs to determine the distance between the satellites and the distance between itself and each satellite. It then uses the basic math principles of triangulation or trilateration to compute its location on the earth’s surface.
The signals a GPS receiver uses to figure its location are radio signals transmitted by the satellites. These radio signals have three bits of information embedded in them; ephemeris data, almanac data, and a pseudorandom code. Using this information the GPS unit is able to triangulate its position and report that back to its user.
Accuracy is another question many first time users wonder about. The good news is GPS receivers are very accurate with the ability to pin-point your location to within a radius of 20 meters. There are ways to increase accuracy through the use of DGPS (Differential GPS) and WAAS (Wide Are Augmentation System) which can get within 3 meters of accuracy. Units with these two features normally cost more but the increase in accuracy can be well worth the cost.
There are many factors that can and do affect how accurately a GPS unit reports its position. These include:
1. The number of visible satellites
2. Signal delays caused as they pass through the earths atmosphere
3. Signals bouncing off of objects
4. Inaccurate clock in the GPS unit
5. Ephemeris errors
6. Satellites in poor positions
7. Satellite signals that are blocked because of terrain or manmade features
GPS is a great technology that has found its way into many everyday applications. Depending on your needs for keeping track of where you are there is sure to be a GPS receiver that fits the bill.
By: Andrew Bicknell
Posts Tagged ‘Gps Unit’
Garmin Rino 520 Handheld GPS – Review
March 20th, 2010
Have any of these things every happened to you?
* You are on a hike trip and you have lost a friend. Storm clouds are looming and they are nowhere to be found.
* You have taken your family on an outing at an amusement park. It is closing time but you can’t find one person.
* You are on the boat and you want to make sure you are going in the right direction, whether its north, south, east or west.
Garmin’s RINO 520 portable GPS navigator can solve all of those problems. These two-way radio systems are equipped with a GPS navigator that can help you find your way and lead your group as well. The patented GPS receiver allows other members of your party to tell you where they are as well as showing them your location.
One of the best features on the RINO 520 is its display. With bold colors, it is easy to see and interpret. You will never need to look at a large map from an atlas again after using the RINO 520. Garmin’s Rino 520 handheld GPS units not only have built-in base maps of North and South America, but you can choose optional City Select software. These can be adapted to almost any trip, hike or boating excursion you plan to take. This GPS navigator unit allows you to customize your route, complete with turn-by-turn directions and alert tones. No more getting lost on the trails or at sea. If you are just on a sight-seeing trip, the RINO 520 makes finding a hotel or restaurant that his nearby easy. This GPS navigator unit can map points of interest along your route
If the sea is your passion, this portable GPS unit can be customized with Garmin’s exclusive optional cartography that includes the fishing hot spots on recreational lakes in the United States. The built-in calendar can show you the best fishing times. If you like to hunt, this portable GPS unit can also tell you the best hunting times for snaring your prey.
What are some of the other outstanding features of the RINO 520? The RINO 520 unit has 56 megabytes of internal memory so that you can quickly download personalized maps for your use onto your portable GPS. The two-way radio has five watts of power, allowing you to contact help from as far away as 14 miles. The portable GPS unit has a WAAS enabled, 12 parallel GPS receiver. It has a bright color display and a rechargeable battery that can last up to 16 hours. Priced at about $482, Garmin’s RINO 520 is one of the best buys of portable GPS systems on the market.
By: Catherine Tower
GPS Buyer’s Guide
March 19th, 2010
For drivers in North America who are tired of staring at maps and pulling into gas stations to get directions the new technology of GPS may be the answer. GPS or Global Positioning Systems are an inexpensive and reliable way of finding your exact position on the globe at any given time. For the driver this can mean never having to look a road map again. This is a brief introduction to the major brands of GPS units and some information about each.
Garmin offers two different types of GPS units and many models for each type. The larger of the two the Streetpilot is meant to be mounted in your car and provides street to street directions map and much more useful information during you trip. Some of the more recent models of the Streetpilot offer voicecapabilities and will vocally give a driver directions. The Quest offer many of the same features as the Streetpilot but it comes in a smaller handheld size and is battery powered. The Quest may be a better option if you often find your self leaving the car behind and need directions on foot.
Magellan is one of the oldest consumer level GPS manufacturers and they are still one of the finest. The Roadmates line of GPS units have been around for a while and the newest models are still in competition for the highest in quality. The newest models of Roadmates provide turn by turn directions to your destination with its internal speaker. This line of GPS units are powered by the cars cigarette lighter and mounts easily to most automobiles. The Roadmate 800 provides color 3-D maps on its 3” screen.
The newest brand of GPS unit comes from Tom-Tom. The Tom-Tom Go700 provides directions on it’s 3.5” screen which gives its display in 3-D. The Go700 can give vocal directions in dozens of languages. The most interesting feature about this unit is it’s Bluetooth capability allowing it to connect to cell phones to give weather, traffic and road conditions for your trip.
By: David Stone
