Author: KALP SYSTEM (530)50
Modified on 17/01/2009
Much talk in the day to day GPS navigators. We took in the car or pocket, some even on a clock and not even know it. But what these acronyms mean? Where do they come? I will try to tell you the clearest possible way the origin, meaning, operation and types of GPS navigators that we find today. WHAT IS THE GPS The Global Position System (GPS) or Global Positioning System (its correct name is NAVSTAR-GPS1) is a Global Navigation Satellite System that enables us in the place we’re in the world (is worldwide, unlike the Russian system GLONASS) to determine our position or that of an object to within a few meters, but could be improved. This technology has its origin and development in the military. Specifically, is currently responsible for the Department of Defense of the USA. In the next version, GPS III, will be a branch that is not dependent on the military field. HOW IT WORKS Although one might think the GPS device is placed in the car, the reality is that this element is only one part, namely one third of the entire system. What we have between the hands is only the receiver. For this element we need to be of some satellites, 27 in total, which orbit the Earth. These teams have a lifespan of about 8 years, after which generally are replaced with more modern ones. Power is receiving solar cells. The satellites circle the Earth and their orbits are calculated so that at any time and from anywhere on Earth have at least six satellites are visible by our receiver. That everything happens as planned in charge of monitoring stations that synchronize the atomic clocks of the satellites and alter the trajectory and orbit. These data will be crucial if our receiver then know where we stand. Receivers to calculate their position, they need the following information: ? The exact location in space of at least three satellites. ? The exact distance between himself and each of those satellites. ? The exact time at which the satellite transmitted the information received. Briefly, because the entire process is complex and does not interest us, each of the satellites constantly transmit their exact position, its unique identifier, information from the satellite’s orbit, and very importantly, the exact time of which was sent transmission. With these data, the receiver can calculate the time it took to travel information and using triangulation to calculate its 3D position. With more satellites is achieved slightly higher accuracy. Basic is that the clocks of all the parts are very precise and are perfectly synchronized. The ideal is to have an atomic clock at the receiver, but its price is infeasible, so you place a normal quartz clock adjusts its time with the satellites. Moreover, theirs will be adjusted also by ground stations. As for timing, it is considered that the signal travels at the speed of light and necessary adjustments are made by small variations due to the atmosphere. ACCURACY OF GPS The accuracy of GPS systems can vary depending on many factors: weather, number of visible satellites, natural or artificial barriers? In general, captured more than 7 satellites, GPS accuracy is about 2.5 meters for 95% of the time, albeit with DGPS (Differential GPS) is available within 1 meter. Until 2001, this had to be added to the random error introduced due to U.S. military technology. However, since then there is no such fact was called Selective Availability. As for the DGPS correction is applied in the receiver with data from ground stations, they always have well defined coordinates. When receiving data from satellites, the station calculates its exact position to increase accuracy, as we have said may even be + / – 1 meter. Browser types Currently, a consumer may find the following basic types of browsers: ? Handheld GPS. ? Mobile phone with integrated GPS or agenda. ? GPS integrated into vehicles. ? GPS receivers for use with other equipment such as phones. For the ultimate in personal pleasure that I recommend Garmin for my use and knowledge is one of the best and affordable for the market.
