Working Principle of GPS


GPS is the abbreviation for Global Positioning System. GPS is nothing but a satellite navigation system that is used to provide us with information about the current location and the current time. The satellite navigation system used by a GPS includes approximately 24-33 satellites. The first fully functional global positioning system was launched by the United States in the year 1995. One of the major advantages of using a GPS system for various applications is that it does not necessarily need an active internet connection for proper operation; however, the availability of an internet connection significantly improves the efficiency of the system. The accuracy with which the location or position of an object is determined with the help of a global positioning system is considerably high. GPS applications remain unaffected by the bad weather conditions and produce results with the same accuracy irrespective of the physical conditions of the environment such as temperature, pressure, humidity, etc. One of the biggest disadvantages of using a GPS is the inability to perfectly locate places in remote areas. Sometimes the inaccuracy of the global positioning system leads to miscommunication and extreme discomfort to the user. Initially, a GPS system was designed to support military applications such as operating missile launch controls, locating enemy vehicles and target devices, etc. The first civilian application of GPS technology was observed in the year 1996. GPS system finds its prime application in tracking devices, transport navigation, banking systems, etc. A number of gadgets such as mobile phones, laptops, smartwatches, etc. also make use of a GPS. There are certain shoe soles available in the market that are equipped with GPS chips and can be used to track the movement and location of the wearer. Such devices serve to be quite helpful for young children and people suffering from Alzheimer’s, memory loss, and other severe health issues.

Working Principle of a Global Positioning System

A global positioning system used for the purpose of navigation and detection of objects and places typically works on the basic principle of exchange of radio waves between the ground stations, satellites, and the receivers. This transmission and reception of data prefer a trilateration mechanism of operation. The trilateral mechanism states that to estimate the precise location of an object or device, it must be in the range of at least four satellites. The number of satellites that transmit and receive data to and from the object is directly proportional to the accuracy of the information processed by the GPS. This means that if you increase the number of satellites that are able to communicate with the device, the accuracy to estimate the location of the device improves proportionally. The trilateration mechanism can be verified in both 2-dimensional and 3-dimensional views. The two-dimensional trilateration mechanism makes use of longitudes and latitudes to determine the location of a particular place. On the other hand, a three-dimensional trilateration mechanism makes use of longitudes, latitudes, and altitude values.

Working Principle of a Global Positioning System

Parts of a Global Positioning System

Typically, the working of a global positioning system can be divided into three main parts, namely a ground station, a network of satellites, and a receiver.

1. Ground Stations

The ground stations of a global positioning system typically make use of multiple RADARs to monitor the position and the condition of the satellites present in outer space. The satellites tend to move in a fixed circular path around the earth and are susceptible to frequent wear and tear. The ground stations help to keep a check on the health of the satellites. The working of a global positioning system to detect the location of a particular object or place primarily depends on the position of the satellites, which is why the information regarding the position, distance, location, and health of a satellite is required to be processed and maintained by the RADARs available at the ground stations at every instant of time.

2. Satellites

A global positioning system typically comprises a network of 32 satellites orbiting the earth. 24 out of the 32 satellites are the core satellites; whereas, the remaining 8 are known as the emergency satellites. The emergency satellites are reserved to be used in case a malfunction or failure occurs in any of the core satellites. The average life span of a satellite is about 10 years. The satellites receive the signal broadcasted by the ground stations and transmit it back to the earth after processing.

3. Receiver

The receiver element of a global positioning system is nothing but the GPS chip that is present within the gadgets that we use in our daily life. This means that the mobile phones that we use, the smartwatches that we wear, and the navigation system installed in our vehicles serve to be the receiver and an integral part of the global positioning system. The receiver devices continuously receive signals from the satellites and help calculate the distance between the receiver devices and the network of satellites. The distance estimated with the help of four or more satellites present in outer space helps locate the exact position of an object, a device, or a person.

Parts of a Global Positioning System

Working of a Global Positioning System

The working of a global positioning system involves simple steps. The first step involves the continuous transmission of the signal from the satellite to the GPS receiver. This transmission signal contains information regarding the current position of the satellite and the current time. The position of the satellite can be determined easily as the satellites tend to move in a fixed orbit. The signal that is received by the receiver devices is then processed and analysed. The main objective is to estimate the location of at least three satellites present in outer space and the distance of the receiver device from those satellites. Since the speed with which the signal travels between the satellite and the receiver is equal to the speed of light and the time taken by the signal to travel from space to earth and vice versa is noted with the help of a timing circuit, the calculation of distance can be done easily with the help of the speed and distance formula. The timing circuits used by some of the global positioning systems make use of atomic clocks; however, they can not be used for each and every GPS application due to the high cost. One of the prime concerns of using the satellites present in outer space to estimate the location of the objects present on the surface of the earth and to determine the current time is the relative nature of time. The relativity of time means that time tends to move faster for the objects that are present in outer space with respect to the objects that are present in the earth’s atmosphere. This problem can be resolved easily by fetching signals from more than three satellites and processing the information extracted from the data received by all of them. This helps reduce the chances of miscalculation and misinterpretation of data by the receiver devices.

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  1. Aruwa Daniel Onuche

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