Global positioning system or GPS initially referred to a radio-navigation system of the U.S. government that used satellites and has come to mean any group of satellites that broadcast at L1, L2, and L5 carrier frequencies and apply trilateration to calculate distances accurately. This article goes through the meaning and functionality of GPS, its key types, and applications with examples.
Global positioning system or GPS initially referred to a radio navigation system owned by the U.S. government that used satellites and has come to mean any group of satellites that broadcast at L1, L2, and L5 carrier frequencies and apply trilateration to calculate distances accurately.
GPS has become a general term used in the navigation and mapping sector. When people mention GPS, what comes to mind is the ability to track the location of objects or determine the direction of a place, which is very accurate.
GPS or global positioning system is a radio-navigation setup based on satellite systems that provide positioning, navigation and timing information to users through sending impulses to an earthbound receiver. GPS was initially known as NAVSTAR and is a constellation of satellites owned by the United States. It is operated by the U.S. space force and was originally reserved for military use but has now been made available for commercial and civilian use.
The global positioning system operates based on satellites orbiting the earth. It consists of 31 well-placed satellites that allow users with sensors and receivers to pinpoint the exact location when they are within the line of sight of at least three of those orbiting satellites.
What does GPS stand for?
GPS stands for global positioning system. It is a subcategory of global navigation satellite systems (GNSS). It is the pioneering technology among other navigation satellite systems being used today.
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How Does GPS Work?
GPS works by communication between its different components, similar to GLONASS, BeiDou, and Galileo satellites. The global positioning system (GPS) has three parts or elements. These components work together to make sure that the navigation, timing, and positioning information sent across are consistently accurate. The parts are the space segment, control segment, and receivers.
1. Space segment
This GPS component is made from a constellation of 31 satellites that revolve in a specific orbit around the earth. They are located at the height of 20,000 kilometers above the planet, and each of them continuously sends out microwave signals sensed by the preset receivers. Each satellite has inbuilt atomic clocks – exact and accurate clocks – that keep the satellites in sync and synchronized with earthbound clocks.
2. Control segment
The control segment is also known as the ground segment. This global positioning system component is very similar to a tower station. The control segment is responsible for managing and ensuring the proper functionality of the satellites.
The control segment comprises a master control station, a backup master control station, several command antennas, control antennas, and monitoring sites. The critical functions of the ground segments include tracking satellite movements, performing analysis, monitoring satellite transmissions, and communicating with the satellite to make sure that the information transmitted from the satellites to the receivers is as accurate as possible.
3. Receivers or user segment
Receivers are the third and most common component of the GPS. They are found embedded in virtually all smartphones and trackers in day-to-day devices. Their application cuts across several industries, from transport and aviation to military, automobile, and IoT. GPS receivers consist of an antenna and a processor.
The antenna is tuned to pick up the frequency of wave signals being transmitted from satellites. At the same time, the processor uses a method known as trilateration to decode and interpret the information. Receivers also have a clock that records the time a signal was detected. Receivers come in various sizes and can be as minute as those found in mobile phones.
How do receivers work in GPS?
A GPS receiver can only work when it is in the line of sight of at least three satellites. This is why GPS devices are less accurate when used indoors. Each satellite sends a signal encrypted with the satellite’s location at the time of transmission and when it sent the signal. A receiver uses the site from three satellites sending signals to the same receiver and the time difference from the time of signal transmission to when it was received.
It then uses a mathematical equation to determine the distance of the satellites from it and each other, therefore deducing its location via latitude and longitude coordinates. Using the fourth satellite, the receiver can verify the accuracy of the information it gives and, therefore, avoid the need for an atomic clock.
Types of GPS
The global positioning system has a widely varied application. It has also undergone several modifications giving rise to the different types of GPS. While they all work using the same fundamental principle, each class specializes in meeting specific demands. The types of GPS systems include:
Assisted GPS (A-GPS) is a type of GPS that allows receivers to get information from local network sources, which helps in the location of satellites. Assisted GPS is usually used in areas where satellite signals cannot easily reach, probably due to trees or tall buildings. However, there must be cellular networks for A-GPS to work.
Assisted GPS became necessary when GPS was introduced for commercial use. A-GPS is extensively used in smartphones where it makes the phone’s location information accessible by emergency call dispatch. The technology increases start-up time and allows cell phones to lock into the navigation system even when the signal is weak, or their phone is visible to only two satellites.
Simultaneous GPS (S-GPS) is a modification of GPS that allows both voice data and GPS signaling to be transmitted from a phone simultaneously. Both data types are sent simultaneously rather than alternating the SPS signal and the reception for the telephone call, and there is better sensitivity. This is particularly useful in emergencies to allow service providers such as ambulances, fire stations, etc., to locate the source of a call even as the call is ongoing.
Differential GPS (D-GPS) is a correction technique used to increase the accuracy of location data obtained from a traditional GPS receiver. D-GPS is an enhancement to GPS, providing a better sense of the actual location of an object or person.
The usual range of accuracy for GPS is, at best, 15 Meters. D-GPS can narrow the location error limit to 1 inch (2.5cm). It works using a network of fixed ground stations that broadcast the calculated difference between the known fixed locations and the satellite location. D-GPS is applied by the United States and the Canadian Coast Guards.
4. Non-differential GPS
Non-differential GPS, as opposed to differential GPS, uses direct satellite signals to deduce positioning. It is less accurate than D-GPS, but has a significantly more comprehensive range of use.
5. Mapping and non-mapping GPS
Mapping GPS is a type of GPS unit that comes with in-built maps. It is also possible to download maps to add to the mapping GPS. This is the type of GPS unit often found in mobile devices and other handheld devices. Non-mapping GPS is a type of GPs unit that comes without maps. It shows you your location and the direction to get to another point without seeing roads or landmarks. It uses breadcrumb-like trails to mark your progress and direction.
Examples of GPS
GPS solutions have been put across several use cases. Several companies have developed software that takes advantage of GPS technology for commercial and government purposes. Examples of the top GPS software are:
1. Google Maps Navigation
Google Maps is a commercial web mapping platform powered by the Google Cloud Platform and marketed as an application to people worldwide. As of 2020, it was recorded to be used by over one billion individuals every month. The original version of Google Maps, released in 2005, was a combination of web-based mapping software, geospatial data visualization, and real-time traffic analysis. Using a global positioning system, Google Maps provides many features such as:
- Navigation: It shows you the best possible route you can take to get from one location to another. It also calculates the travel time you should expect based on transportation or current speed.
- Street view: Google street view gives you an experience close to reality. With 360-degree panoramic images at street level, you can visualize several locations.
- Real-time traffic updates: by amassing information from several smartphones, Google maps can determine how congested a road ahead of you is and provide alternative routes.
- Landmarks and business listings: Through satellite positioning systems, businesses, companies, and hospitals can be identified along various routes, making it easy for users to access services.
2. NASA’s GIPSY OASIS
GIPSY OASIS is a navigation software used primarily for geophysical and global positioning system research. The whole meaning of GIPSY OASIS is GNSS-inferred positioning system and orbit analysis simulation software. It is owned by the National Aeronautics and Space Administration (NASA). It measures navigation, timing, and positioning using three geodetic techniques:
- The global navigation satellite systems (GNSS)
- Satellite laser ranging (SLR)
- Doppler orbitography and radio positioning integrated by satellite (DORIS)
GIPSY OASIS supports the combination of geophysical and geodetic parameters and uses them on actual or simulated data. It considers parameters like station coordinates, satellite orbits, earth orientation, etc.
3. Amazon Location Service
Amazon Location Service is an Amazon Web Services (AWS) product that allows developers to add location data and functionality to their applications. Amazon Location Services is further divided into different specific features, which are:
- Amazon Location Service Maps: This allows you to select your preferred map on your mobile or web application.
- Amazon Location Service Places: You can choose a data provider to search for places of interest.
- Amazon Location Service Routes: It allows you to discover different routes to particular locations. Using real-time traffic updates, it estimates the time it would take to arrive at your destination.
- Amazon Location Service Geofences: This allows you to map out an area and then get movement notifications in and out of that area.
4. Verizon Connect
Verizon Connect offers an exact GPS tracking solution to meet the needs of all fleet sizes, stimulating a nearly 360-degree view of the day-to-day operations of a fleet. It aims at improving driver safety and productivity and helps you stay abreast of any need for repairs and maintenance. They offer a variety of GPS solutions that you can choose from to track driver behavior, improve asset tracking and delivery, locate the best routes, and ensure customer satisfaction.
5. NAVSTAR GPS
The United States Global Navigation Satellite System is more commonly known as NAVSTAR GPS. It is utilized by the U.S. Department of defense for military tracking, carrying out specialized operations, etc.
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Top 9 Applications of GPS
GPS technology, once developed, spread across the globe and has become an essential part of global infrastructure, finding applications in every field. GPS services’ low cost and global availability have spurred global positioning system technology applications in several industries.
In addition, receivers have been well developed, such that it is both affordable and compact enough for varying use. Applications of GPS technology range from the internet of things, banking, communication network, mapping, military, agriculture, etc. Some of these include:
1. Road transportation
GPS has proven to be a crucial part of road transportation and automobiles today. Road transport applications have shown to be one of the largest markets for GPS receivers. They are used in fleet management, public transport monitoring, taxi services, dispatch services, logistics and delivery services, private car users, etc. Most cars now come with built-in GPS navigation or placeholders for phones with GPS tracking applications.
2. Quick access to emergency roadside services
The global positioning system is applicable even in emergencies. Whether you are personally involved in such an event or come across the victims of an accident, etc., you can place a phone call across an emergency hotline.
The service providers automatically track your precise location using GPS technology, immediately dispatching trained workers to you. So even if you do not know the exact location details, GPS does this for you.
3. Applications in the aviation industry
The global positioning system is also applied in the aviation industry. Almost all aircraft now rely on GPS technology to direct and navigate their course during a flight. It also helps in air traffic control by sending the locations of one plane to others within an area. Even more effective is the use of GPS in unmanned aerial vehicles or drones. These vehicles can launch into the air without a driver, following a particular route and performing the specified task. This is just another way GPS is and will be applied in the Internet of Things (IoT).
4. Law enforcement
Police and law enforcement also use GPS technology in performing their duties. By installing GPS-enabled tracking devices on suspects’ vehicles, they can gain a clearer insight into a particular crime and even prevent loss of life and property in time. Other special forces also use GPS trackers to locate troops, missiles, etc., in real-time.
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5. Banking and finance
The global positioning system also offers accurate timing services, which one can use to schedule, monitor and trace local and international money transfers. In the case of financial crimes, law enforcement agencies can use them to provide an audit trail. Financial service providers use the atomic clocks on GPS satellites to mark dates and time stamps for e-money transfers.
6. Car theft prevention and security
Most cars are now fitted with GPS tracking devices in hidden locations. This makes it the best anti-theft protection hardware you can install on your vehicle or other valuables. Once a car is missing, you can track the car’s present location from another device and, with the help of security operatives, reclaim your stolen vehicle in little time.
7. Health and fitness trackers
By including GPS tracking technology, healthcare wearables worn by patients and those working out can easily send a patient’s location to their primary health care physician or caregiver in times of emergency. With GPS, geofencing has also become a better reality, mapping out areas and keeping track of movement within the boundary. This can be used for pets, enforcing curfews and other security purposes.
8. Applications in agriculture
GPS has profound application in the agricultural sector. From soil sampling to plotting yield maps to monitoring tractors and other machinery, it contributed to better yield and higher productivity.
9. Child monitoring
Children are vulnerable when not in the immediate sight of their caregivers and may be at risk of crimes such as kidnapping, or they might just wander away. By adding GPS trackers to wristwatches and other wearables, parents can find it very easy to locate a child. Therefore reassuring the parent while giving the child some degree of freedom. Such wearables can also be fitted with alarms to send out warnings in case of danger.
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The accuracy of the geographic location provided by your GPS server ranges from 10 meters to 100 meters. With high-grade receivers such as those in military-issued devices, the location accuracy can get as close to one meter. Currently, GPS-enabled devices and the technology it works on are used across several industries and markets.
Indeed, GPS sensors and receivers are now so affordable that almost anybody can get access to one. This widespread use has made GPS a driving force in IoT device management. Smart devices work better because of their ability to monitor and send information about their location.
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