TECNOLOGY GPS (Global Positioning System) & REPAIR

 

In March 1994, the NAVSTAR GPS satellites 24 units and 3 units have been in orbit operating reserve for the development of navigation technologies which can be used for materials research, Sport, Agriculture, Military, Pilot, Surveyor, Mountain Climber, driver, captain, cruise, and much more usefulness of this tool. GPS is a satellite-based navigation system, consisting of a network of 27 satellites (24 operational, 3 spare) that were placed in Earth orbit by the U.S. Department of Defense (U.S. DoD). GPS was originally intended for military purposes (NAVSTAR, the name given the U.S. DoD for GPS).This GPS system development cost of approximately $ 12 milliard is specifically made for the U.S. Military with the transmission line band "L.2". (1227.60 MHz). Further around the year 1983-1984, the U.S. government to allow the system developed for the first time used by civilians. GPS can work in all weather, anywhere in the world, 24 hours a day 7 days a week, without paying any subscription fees or setup for general use.

GPS Satellite System

 NAVSTAR GPS satellites Production of Rockwell International USA has a weight range of ± 1900 Lbs with 5.66 meter solar panel, the maximum radiated power of 50 Watt. Each satellite is made with a service life of 7.5 years. Twenty-four (24) that form a network of satellites that orbit as high as 17 120 km. Constantly in motion, orbiting around the Earth twice per day (Orbit Period setiap12 Jam) at ± 8500 km per hour.The orbits of satellites are designed such that it anytime, anywhere on earth, the GPS Receiver will be able to access at least 4 satellites. Electrical power to the GPS satellite dimemakai solar energy with solar panel, battery backup is available in addition to the satellite can keep working while a solar eclipse, or when solar energy is not available.Serves as a small rocket booster to ensure the correct trajectory and satellites orbiting the earth properly. In addition to SystemGPS in orbit with 24 satellites and three reserves are also required supporting surface of the earth station that is used to monitor the condition of the satellite and the satellite's orbit to match.Navstar GPS system is controlled by a master ground station 5 that specifically monitors the GPS satellites in space satellites are located: Hawaii, Ascension Island, Diego Garcia, Kwajalein, and Colorado SpringGPS satellites circle the earth twice a day in a very precise orbit while emitting a signal to Earth. GPS receiver (receiver we call it) receives this information using a triangulation method to calculate exactly where the location of the receiver. Basically, the receiver compares the micro-second timing pulses in the time of the signal transmitted by a satellite with a timing pulse time, received at the receiver by transmitting a pseudo random code. The time difference is what will tell the receiver how far away the satellite is and the direction of it. Once the distance is measured by a number of other GPS satellites, the receiver can be. determine its position in latitude and longitude degrees. Receiver must be locked at least three satellites to calculate the two-dimensional position (latitude and longitude) and track movement. With 4 or more satellites that can acess, the receiver can determine the three dimensional position (+ height). Once the position of the user can be determined, the GPS receiver can also determine other information such as speed, trajectory that has been passed, which had taken the trip distance, distance to destination, sunrise and sunset times, and so forth.TriangulasiDengan method using 3 Satelite Navstar GPS system and a method of triangulation to determine the position of the GPS receiver on the surface of the earth is very accurate. For the first time three Navstar satellite unit determines the distance between the satellite and the GPS receiver on the surface of the earth with a mathematical calculation. A Navstar Satellite is able to capture and calculate the direction and distance of signals from the GPS receiver as far as 11 000 miles or 17 600 km.Satellite to the two determines the direction and distance of approximately 12,000 Miles (19.200km), from two satellites that determine the distance and direction of the GPS Receiver is there a meeting point in the earth's surface, but for more accurate then the task into three Navstar satellites to determine the direction and distance GPS Receiver as far as 13,000 miles (20.800km) and each satellite in orbit and always have ID signal is transmitted to more complex computations performed by the GPS receiver.Calculating the Atomic Clock Atomic clock is running does not use atomic energy, but it's just name the figure of the oscillations of a particular atom under the name "Metronome" and can work accurately as "Clock", until now the technology is still being developed.Trilangulasi in a rather complicated three-dimensional space is described. Let's start with a simple explanation of two-dimensional triangulation. Imagine you are somewhere in America, and you really get lost: (you meet a local resident and asked "Where am I now? '. He said" you're 625 miles from the city of Boise, Idaho ". Information good, but still it has not been beneficial to you. you could be in any point covering 625 miles from Boise city.Then you are asked again to others, where are you located, and he said "you're 690 miles from the city of Minneapolis, Minnesota". If you combine this information with the information the city of Boise. You get two intersecting circles. Now that you know for sure you are in the intersection of two circles.Then, if there is a third person to tell that you are 615 miles from the city of Tucson, Arizona; you can throw one of the two points above possibilities, because the third circle will intersect in one point. Well now you know exactly where you are - in the city of Denver, Colorado.This triangulation method is used to determine the point of the GPS satellite receiver location. To supportcalculation of triangulation, the receiver should know two things:
    A. The location of at least three satellites will be accessible
    2. The distance between you and the satellites.GPS signals

 GPS satellites send two signals to the transmission of radio waves emission "Code-Phase" and "Carrier-Phase" to calculate the distance and GPS Satellite Receiver to be more accurate, with the L1 frequency (1.57542 GHz) GPS Signal transmission is intended civilian users and L, 2. (1227.60 MHz) U.S. GPS signal transmission for military purposes to the specifications and Error Correction accuracy is better. Navstar GPS satellite signals radiating surface of the Earth highlight the very character of the band microwave signal of about 1.2-1.5 GHZ, through clouds, glass and plastic but will not be able to penetrate solid objects / hardware such as buildings or mountains.GPS signal contains three pieces of information that is pseudorandom code, ephemeris data and almanac data. Transmission signal from a GPS satellite signal when the satellite is transmitting the identification information of the GPS receiver. GPS receivers calculate the subsequent timing of the wave propagation time Navstar satellites to calculate the pulse timing difference between the "pseudo random code" from the GPS receiver to generate an identical signal from Navstar GPS satellites. Freqwensi width (bandwidth) required to transmit the pseudo random code around 1 MHz, so that the transmission of GPS signals are transmitted in waves of 20 cm or about 1.2 -1.5 GHz.Calculation of pseudo-random code signal• ephemeris data is data that has always sent a satellite, contains important information about the status of the satellite, data and time of the latest atomic clocks in GPS satellites, this is a very important part in determining the position.• almanac data tells the receiver where each satellite orbit should be at any time throughout the day.Factors that lead to error on the receiver so that the lower the accuracy of information include:o Delay in the ionosphere and troposphere: uninterrupted satellite signal as it passes through Earth's atmosphere is contained in the surface layer of the earth at an altitude of 50-500 km. The ionized particles in this layer makes the effect on GPS signals, resulting in one of the highest causes of error in the determination of distance and location of the GPS receiver. Sedangangkan layers of the troposphere is a height of 50 km down to the earth's surface temperature is always changing pressure of the clouds, dust, only relatively few as the interfering signals from the GPS satellite transmission is the cause of an error or miscalculation of the GPS receiver.o Signal multipath: occurs when the GPS signal is reflected by tall buildings or dense surfaces such as the mountains before the signal reaches the receiver. This case adds to a long signal travel time (timing), because it causes the error in the calculation of the GPS receiver.o Error on the clock at the receiver. Built-in clock in the receiver is not as accurate as the atomic clock in GPS satellites. Therefore, it would be easy in case of error in the determination of the time.o orbital (ephemeris) error, this happens due to inaccuracies in reporting the location, number of satellites visible satelit.: The more satellites that can be the Access by the receiver, the more accurate the information obtained. Building, the contours of the earth, electronic equipment interference or even dense foliage can interfere with reception of signals that cause the error position. Receivers usually can not work indoors, underwater or underground.o Satellite Geometry: This refers to the relative position of satellites at any given time. Ideal satellite geometry occurs when the satellite is at wide angles relative to the other satellites. Geometry bad happens when the satellite is a single line or a distance that is too close to others resulting in slipping of GPS receiver calculations performedGPS technology in Europe has been the trend since the year 2000, all types of vehicles have been equipped with a GPS Receiver for Automatic Navigator tool. GPS also has involved the development of the Russian state, which these days akhitr reached an agreement with the American GPS system for the synergy that has been fully operational since 1994.In addition to the two satellite systems are also planning a European Union with the name of the Galileo Navigation System. The first launch carried out late 2006, launch of Galileo consists of 30 satellites orbiting the earth and is expected to be operational in 2012, Galileo GPS System is a refinement of previous technology with the ability to operate in excess of the slits storey building and also in the room though.