How does GPS work ?

Each region on the earth's surface is covered by at least 3-4 satellites. In practice, each new GPS can receive up to 12 satellite channels at once. Clear sky conditions and free from obstruction to make the GPS can easily capture the signal sent by satellite. More satellites are received by the GPS, the accuracy provided will also be higher.

How it works GPS logically there are 5 steps:

1. Use calculation of "triangulation" from satellites.
2. For to calculation of "triangulation", a GPS measure distance using the travel time of radio signals.
3. For to measuring the travel time, GPS needs require a high time accuracy.
4. For to distance calculation, we must know with certainty the position and the level of a satellite in orbit.
5. Corrects final delay time signal must travel in the atmosphere until it is received receiver.

GPS satellites revolve around the earth for 12 hours in a precise orbit and transmit signal her information into the earth. GPS receiver mengambl that information and by using the calculation "triangulation" to calculate precisely the location of the user. GPS receiver compares the time signal transmitted with time signals received.From the information that can be known how many satellite distance. By calculating the distance range of GPS receiver can perform calculations and determine the position of the user and display the electronic map.

A GPS receiver must lock the signals from at least three satellites to calculate the 2D position (latitude and longitude) and track movement. If the GPS receiver can receive four or more satellites, it can calculate the 3D position (latitude, longitude and altitude). If it can determine the position of the user, then the GPS can calculate other information, such as speed, direction of the destination, route, destination travel, destination distance, sunrise and sunset and many more. GPS satellites transmit information in time so precession because the satellite, which is using an atomic clock. Existing atomic clocks on satellites jalam with atomic particles in isolation, so as to produce an accurate clock than the usual hour.

Various kinds of GPS Satellite Signal

There are 3 kinds of signals which is owned by GPS :
Carriers
GPS satellites send signals on two frequencies. L1 1575.42 MHz by bringing the two status messages and pseudo-random code for the purpose of calculating the time. 1227.60 MHz L2 brings with menggunakaan precession more accurate due to military purposes. Power radio signals emitted only ranged from 20-50 Watts. This is classified as very low considering the distance between the GPS and satellite to 12,000 miles. The signal emitted by line of sight (LOS), can pass through clouds, glass but can not be solid objects like buildings, mountains.

Pseudo-Random Codes
GPS is used for the public to monitor the frequency of L1 on the UHF (Ultra High Frequency) 1575.42 MHz. L1 signal that is sent will have the patterns of a particular digital code known as pseudorandom. Transmit signal consists of two parts: the code Protected (P) and the Coarse / Acquisition (C / A). Code that was sent was also unique among the satellites, allowing each receiver to distinguish signals sent by one satellite with another satellite. Some code Protected (P) also exists a randomized, so as not to be accepted by ordinary GPS. The random signal is known as the Anti-spoofing, which is commonly used by GPS specifically for certain purposes such as military.

Navigation Message
There is a weak power frequency signal added to the L1 codes that gives information about satellite orbits, clock corectionnya and other system status.

GPS Functionality

GPS or Global Positioning System, is a device or system that can be used to information the user where he is here on satellite-based earth's surface. To be able to identify where a person is given the tools it needs a GPS receiver which receives signals sent from GPS satellites. The position on the change becomes a point known as waypoint. Waypoint in the form of points of latitude and longitude coordinates of the position of a person or a location is then displayed on the screen on an electronic map. Data sent from the satellite in the form of radio signals with digital data. Wherever you are, then the GPS can help indicate the direction, as long as you see the sky. GPS service is available free of charge, did not even need to pay anything except buy a GPS receiver. GPS receiver module shaped and generate NMEA data containing position data. GPS receiver itself contains several integrated circuit (IC) technology is so cheap and easy to use by everyone. Examples of GPS receivers currently on the market is the Garmin 10x. GPS receiver module has the characteristics of the data can only provide information on the position but were unable to send data over long distances. Therefore, we need technology to transmit data remotely through the Internet. The technology is GPRS (General Packet Radio Service).




At present GPS is implemented on many people's lives. For example, use on aircraft, ships, cargo car. In addition, GPS can also be used for the benefit of individuals (personnal tracking systems), for example, used as vehicle tracking.
In general, the use of GPS, among others:

1. Supports the application of GIS (Geographic Information System) includes monitoring (monitoring), tracking (tracking), pemandauan (guidance).
2. GPS as a means of digitizing the earth.
3. GPS function to correlate the data.
4. GPS is an auxiliary device analysis, because the GPS uses information as a key position to analyze, make inferences, or decided.

After experiencing growth, the GPS currently widely used to meet human needs such as:

1. Navigation system in ITS (Intelligent Transport System). This system can be implemented on a police patrol car, train, ambulance, taxi, car delivery (Courrier).
2. As an ocean transportation navigation systems.
3. In the world of the military, GPS is widely used in tracking the troops and equipment. In addition, GPS is widely used in the enemy's reconnaissance forces.
4. GPS is also used in monitoring forest fires.

Garmin 10X