gps global positioning system
Global Positioning System (GPS) is the only satellite navigation system is functioning properly. This system uses 24 satellites that transmit microwave signals to Earth. This signal is received by a receiver on the surface, and is used to determine position, velocity, direction and time. Similar to the GPS system that among other things the Russian GLONASS, Galileo European Union, India IRNSS.
This system was developed by the United States Department of Defense, with his full name is NAVSTAR GPS (common mistake is that the NAVSTAR is an acronym, this is wrong, NAVSTAR is the name given by John Walsh, an important policy makers in the GPS program). This collection of satellites maintained by the 50th Space Wing United States Air Force. This system maintenance costs of about U.S. $ 750 million per year, including the replacement of old satellites, as well as research and development.
GPS Tracker or often called a GPS Tracking is a technology AVL (Automated Vehicle Locater) that allows users to track the position of the vehicle, or fleet car in the state of Real-Time. GPS Tracking utilizing a combination of GSM and GPS technology to determine the coordinates of an object, and then translate it in the form of digital maps.
How It Works
This system uses a number of satellites in earth orbit, which transmits its signal to Earth and was captured by a receiver.There are three important parts of these systems, namely the control, the spacecraft, and parts of the user.
Section Controls
As the name implies, this section to control. Each satellite can be a bit beyond the orbit, so that this part of the satellite orbit track, location, altitude, and speed. Extract the satellite signals received by the control section, corrected, and sent back to the satellite. Correction precise location data from the satellite ephemeris data is called, which will send it to our navigation equipment.
Aerospace Parts
This section is comprised of a collection of satellites in Earth orbit, about 12,000 miles above the earth’s surface.Collection of satellites is arranged so that the navigation tool at any time can receive signals from at least four satellites. These satellite signals can pass through clouds, glass, or plastic, but it can not pass through buildings or mountains. Satellites have atomic clocks, and will also transmit information ‘time per hour’ this. This data is transmitted with a code of ‘pseudo-random. ” Each satellite has its own code. This code number will usually be displayed on the navigation tool, then we can make the identification of the satellite signal is being received by the apparatus. This data is useful for navigation tools to measure the distance between the satellite navigation equipment, which will be used to measure the coordinates of the location. Satellite signal strength will also help in calculating tools. Signal strength is more influenced by the location of the satellite, a device will receive stronger signal from the satellite was directly above it (think satellite locations such as the position of the sun when the hours of 12 pm) compared with satellite which was in the horizon (think satellite locations such as the sunset position. There are two types of waves currently used for satellite-based navigation tools in general, the first better known as L1 at 1575.42 MHz. L1 signal is received by the navigation tool. Satellites also issued a wave at a frequency of 1227.6 MHz L2. Waves L2 is used for military purposes and not for the public.
User Section
This section consists of navigation appliance that is used. Satellites will transmit an almanac and ephemeris data to be received by the navigation equipment on a regular basis. Almanac data contains the approximate location (approximate location) satellites continuously emitted by the satellite. Ephemeris data transmitted by satellites, and is valid for approximately 4-6 hours.To show the coordinates of a point (two dimensions), navigation tools require at least three pieces of the satellite signal. To demonstrate the elevation data of a point (three dimensional), required additional satellite signals from a fruit anymore.
From the signals emitted by a collection of satellites, navigation devices will perform calculations, and the end result is the coordinate position of the tool. More and more the number of satellite signals received by an appliance, will make the tool calculates the coordinates of his position with more precision.
Because of this navigation tool relies fully on the satellite, the satellite signals are very important.This satellite-based navigation devices can not work a maximum when there is interference with satellite signals. There are many things that can reduce the strength of satellite signals:
The geographic conditions, as explained above. As long as we still can see the sky is wide enough, this tool can still be functioning. Increasingly thick forest, then petered out a signal that can be accepted. Not only when inside the building, located between two tall buildings will also cause such effects are in the valley.
Signals that bounce, ie when positioned between the tall buildings, can disrupt the navigation tools so that the calculation of the navigation device can show the wrong position or not accurate.
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