What is GPS and how does GPS work? A practical guide to the navigation system

What is a GPS system?

The GPS (Global Positioning System) is a global satellite navigation system that allows precise location anywhere in the world. The system was developed on behalf of the US government and is available for both military and civilian purposes. GPS is part of our daily lives, and its technology is used in a wide range of applications, from car navigation to cell phone applications.

24 Satellites will allow you to determine your position

The GPS system consists of at least 24 satellites, which are located in orbits around the earth. These satellites follow precise routes to ensure that the entire globe is covered by the signal. With GPS, we can determine our location, speed and also the exact time. It operates around the clock, regardless of weather conditions, with no subscription fees, making it a very versatile and practical navigation tool. GPS is part of the broader category of global navigation satellite systems (GNSS), which also includes other systems such as GLONASS, GALILEO, BeiDou and QZSS. The cooperation of these systems, known as GPS systems, increases the accuracy and reliability of navigation.

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The emergence of GPS in the 1980s.

GPS was originally designed and implemented by the U.S. Department of Defense for military purposes, but in the 1980s its services were also made available for civilian use. Since then, GPS has gained immense popularity, and today it is widely used by individual users as well as by companies and institutions around the world.

History and development of the GPS system

The GPS system derives from lessons learned from the development and use of earlier satellite navigation systems, such as the TRANSIT system, developed by the US Navy. Work on the GPS system began in the 1970s, and the first Block I satellite, known as SVN 1, was launched on February 22, 1978. The system was designed to meet several important requirements, such as the ability to determine location in real time and independence from the conditions under which it is used. GPS satellites play a key role in providing precise navigation data.

The origins of the GPS system

Initially, GPS was mainly used in the military. Over time, its functions were expanded, leading to widespread implementation in various areas of civilian life. In the 1990s, GPS was made available for widespread use, revolutionizing the way people move, communicate and plan travel.

Principles of GPS system operation

The basis of the system's operation is the precise measurement of time and the positioning of satellites in orbit. Each GPS satellite is equipped with an atomic clock, which is extremely accurate and is used to send signals to receivers on Earth. Accurate satellite coordinates are crucial for determining a receiver's position in three-dimensional space. The satellites emit signals on two carrier frequencies: f1 = 1575.42 MHz and f2 = 1227.6 MHz.

In-car GPS receivers:

A GPS receiver, such as a cell phone or car navigator, receives these signals and calculates its position based on the time elapsed between sending the signal and receiving it. The signal contains various types of information, such as almanac and ephemeris, which are crucial to the accuracy of the receivers' calculation of geographic position. To accurately determine position, a receiver needs signals from at least four satellites. This makes it possible to calculate geographic coordinates and altitude above sea level.

System components

The GPS satellite system consists of three main segments: the space segment, the control segment and the user segment. The space segment includes satellites that orbit the Earth and transmit navigation signals. The control segment is a network of ground stations that monitor and manage the satellites. The user segment is the receivers that receive signals from the satellites and calculate the user's position. The key component of the system is the signal receivers, which identify signals from the satellites and affect the precise determination of the user's position.

GPS accuracy

Satellite navigation depends on many factors. Under ideal conditions, when the satellite signal is not disturbed, the system can provide a location accuracy of 5 meters. However, in practice, this accuracy can vary depending on factors such as :

• number of satellites available,
• atmospheric interference,
• signal reflections from buildings and
• GPS receiver quality

To use the services of the system, the user must have a suitable receiver, which is manufactured by independent commercial companies.

To improve accuracy, various assistive technologies have been developed, such as DGPS (differential GPS) and SBAS (Satellite-Based Augmentation System) systems. They allow accuracy of up to several tens of centimeters. Such technologies are often used in surveying, precision agriculture and other fields where very high precision is required.

What is the Global Positioning System?

The Global Positioning System is an advanced satellite navigation system that was developed by the United States Department of Defense. It consists of a network of satellites that orbit the Earth, sending signals to GPS receivers on the surface. With this system, it is possible to pinpoint your location anywhere in the world. Today, it is an invaluable tool in satellite navigation, making it possible not only to determine location, but also speed and time. The system is widely used for both civilian and military purposes, making it extremely versatile.

History and development of GPS

The history of the system dates back to the 1970s, when work on its development began. The first GPS satellite, known as SVN 1, was launched on February 22, 1978. Initially, the system was designed exclusively for military purposes, but in the 1980s its services were also made available for civilian use. Since then, the system has undergone many improvements, which have greatly increased its accuracy and reliability. Today it is an integral part of our daily lives, used in car navigation, cell phones and even sports watches.

Principles of GPS system operation

The system works on the principle of precise measurement of time and distance between satellites and the GPS receiver. Each GPS satellite is equipped with an atomic clock that sends out a signal containing information about its location and time. A receiver, such as a smartphone or car navigation system, receives these signals and calculates the distance to each satellite. Based on this data, the GPS receiver can determine your exact location. To obtain precise coordinates, the receiver must receive signals from at least four satellites. This allows it to accurately determine your position in three-dimensional space.

System components

The GPS system consists of three main segments: the space segment, the ground segment and the user segment. The space segment includes a network of satellites that orbit the Earth in precisely defined orbits. The ground segment consists of a series of ground stations that monitor and control the satellites. Thus providing them with new parameters for satellite orbits and time synchronization. The user segment consists of GPS receivers that receive signals from satellites and calculate the user's location. Each of these segments plays a key role in ensuring the accuracy and reliability of the system.

Accuracy of the system

The accuracy of the system depends on many factors, including the number of GPS satellites visible from a given location and the quality of the receiver. Under ideal conditions, when the GPS signal is not disturbed, the system can determine the user's location to within a few meters. However, in practice, this accuracy can be lower due to signal interference, signal reflections from buildings and other atmospheric factors. To improve accuracy, various augmentation technologies are used, such as DGPS (differential GPS) and SBAS (Satellite-Based Augmentation System) systems, which can increase location accuracy up to tens of centimeters.