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 ‘Exact Location’
Marine GPS Maintains Boater Safety
March 7th, 2010
It’s never a good feeling when you are lost on your boat in an unfamiliar lake, yet on occasion even experienced boaters have had that unnerving feeling of losing their navigational way. However, if your boat is equipped with a Marine GPS unit, your chances of returning safely to shore increases exponentially.
It does not matter whether you use a standalone Marine GPS unit, or a handheld unit or have a GPS capable personal data (PDA) finding your bearings can be made much easier. Additionally, God forbid there is an emergency, you can use your marine GPS unit to give rescuers an exact location which would make you safe return to shore pretty much guaranteed and you will also get a quicker response.
When utilizing a handheld Marine GPS unit, it is best to first check the location when you are on the shore and market that down in your unit, in the event you get lost while you are out on the water. You can get to your destination in a quicker, safer, simpler manner by knowing where you are and where you need to go. Particularly if you are in water that you are not familiar with or a quick storm makes visibility nearly impossible. A Marine GPS unit can help you find yourself into a safe harbor in the event that you travel too far away from shore and loose any of your directional bearings that you were hoping you had if you maintained a line of sight.
Marking and Recalling Locations of Successful Fishing Spots
When on the water and your fishing and you come upon a suitable location that gives great results, you cannot put a ‘X’ on the water, but by utilizing a Marine GPS, you can do the next best thing. You can go back to the precise spot the next time you are looking for a place to catch fish, by marking the location that is revealed by the unit. There will be no judging location by a reference point on the shore and there will be no guessing involved because your Marine GPS unit has the data within it marked.
When boaters sometimes wander away from the territory that they are familiar with they need to send for help. Whether there was a malfunction on their boat or they lost their bearings on the lake and they have a need to guide the rescue craft to their location it becomes more crucial as time goes by. A Marine GPS unit on board can make your imminent rescue easier and faster if you can provide them with the exact location to give to a rescue craft.
In a more severe accident on the water, such as your boat sinking, then a quick rescue is in order. By utilizing a Marine GPS, particularly if equipped with a GPS locator, you can assist rescuers to find you near your last reported location. Having a starting point for a rescue operation can be a life-saving and critical piece of knowledge.
By: Korbin Newlyn
