GPS - Global Positioning System

In a number of movies or real-life incidents, we hear that a person's position was tracked by the police. Also, in our smartphones, there is a feature named G.P.S., which many applications often ask to keep open while using. G.P.S. doesn't end up here; G.P.S. systems are everywhere as you can find them there in your car, your wristwatch. Why is so? What is a G.P.S.? How does it work? In this discussion, we are going to get all these answers.

What is a G.P.S.?

The G.P.S. abbreviation of Global Positioning System is a satellite-based navigation system created with the help of at least 24 satellites which is expanded into six earth-centred orbits, four satellites in each orbit. No matter where you are or what weather it is, a global positioning system works 24 hours a day without any subscription or purchase, and there is no money charged for G.P.S. service.

G.P.S. helps us know where we are going or the velocity or time. Whereas we only need three satellites to know the location, the fourth satellite is used to know the location of all those three satellites and the 4^th satellite automatically moves when the previous three satellites move but in 3-dimensions so that we can calculate the exact altitude of the device in which G.P.S. is used.

The United States government is the original owner of the global Positioning Systems. The G.P.S. Service does not ask for any data or need any data transactions; it works over simple internet or only by telephonic connections. G.PS also provides timely information to the users. Sometimes the areas like mountains or hills may have weak G.P.S. services as only geological positions can be identified here.

A little history about the GPS

The U.S. Department of Defense firstly created the G.P.S. to help the Army in 1973. But in 1980, they permit civilians to use this service after, in 1983 a huge mistake in identifying the position was made up by Korean Airways. It caused a huge accident in which nearby 269 passengers was killed, including Larry MC Donald, a United States representative.

But in 1990, the service of the Global Positioning System was weakened by the U.S. president, as converting it into "selective Ability", but later in 2000, then-President Bill Clinton signed a bill which discontinued this.

In 1999, the Indian Army faced a huge Kargil war in which having position access to the enemy locations was proven as a con. So after that, different nations started working to provide their own positioning systems. There are many G.P.S. services in different countries such as the Russian Global Navigation system (now added in G.P.S.), China's BeiDou Navigation System, European Galileo positioning system, India's NavIC and Japan's Quasi-Zenith Satellite System (QZSS) etc.

How G.P.S. works?

The Global Positioning System is circling the earth twice a day in a fixed orbit daily. There are different satellites in which every satellite creates an exclusive signal that permits the global positioning system devices so that they can decode the signal and tell the accurate locations of that satellite.

That's how the receiver of the G.P.S. gets an idea. Then by calculating the time taken by the satellite to receive a signal, it measures the same from different satellites to find the exact location of the user. Later it displays it to electronic devices as we live in a three-dimensional world, so the signal generated by each satellite is a sphere, not a circle. This is how it helps us measure our daily routines, get the map, help us find ways or find a home also helps us for adventures.

To calculate our location in 2 dimensions, A GPS takes the help of 2 or 4 satellites. If you want to know your locations in 3 dimensions, eight or more satellites are used. But depending on device, place of location and time, a G.P.S. can even work from your wrist watch (electronic G.P.S. supporting wrist bands). After knowing your location, A GPS device may also track the following things:

• Speed
• Roadway
• Trip Distance
• Time required
• Distance left for the decided destination
• Time left for the sunrise or a sunset
• Blood pressure
• Heart rates of the user
• Steps walked by the user
• And many more things

What are the three main elements of G.P.S.?

G.P.S. is built with the help of three main elements, which are as follows;

i) Space

Some satellites are spinning the earth, broadcasting signals to users on geographical positions and times of the day.

ii) Control stations or segments

To control the activities done by the G.P.S. satellites, it is important to track and manage the operating of the satellites in space and monitor them. While creating the control segment, the earth-based monitor stations, master control stations and ground antenna are included. These monitoring stations are almost everywhere on the earth; continents like North and South America, Africa, Europe, Asia and Australia.

iii) User tools

Global Positioning System receivers and transmitters are some equipment, which receives the signals and displays them. These are electronic devices or gadgets such as mobile phones, P.C.s, smartwatches (wrist bands) or telemetric devices.

What are the main uses of the Global Positioning System?

The global positioning system is a really useful and reliable tool for all the business and organizations in several different departments. When we talk about the people who use G.P.S. in daily life, some are inspectors (surveyors), scientists, pilots, boat captions, first responders, and people working in the mines and agricultures. These people use G.P.S. for the correct surveys or the maps, taking complete management of time, taking situations or positions and for the right navigations of the way.

The best thing about the G.P.S. is that it works in all weathers and even whatever the time is or the month or day. However, these are some main uses of the Global Positioning System.

1. Locations
   It helps in determining the position or location of a person.
2. Navigations
   It helps in directing from one place to another.
3. Tracking
   It helps in monitoring things or personal actions.
4. Mapping
   It helps in creating maps of the world or a particular place.
5. Timing
   With the help of G.P.S., we can find out the correct time.
6. Emergency Response
   Sometimes when situations of emergency or natural disasters occur, the G.P.S. works as the support in predicting the weather and keeping the time management and tracking the things. In counties like the E.U. and Russia, the E-call regulations rely on GLONASS technologies, which is an alternative to the G.P.S. services. It helps to send the emergency services in the situation of transport crash, thus reduces the time taken to respond.
7. Entertainment
   G.P.S. helps in different ways of entertainment. Many games like Pok�mon Go and Geocaching, Pubg etc., use G.P.S. for the services; also, many entertainment-related apps use G.P.S. for better services.
8. Health and fitness
   Many apps like a wristwatch and other related wearable technologies help track the user's health and they may also help in tracking your footsteps and heartbeats. It tracks the counting and exercise timings.
9. Construction, mining and off-road trucking
   The G.P.S. helped measure and improve asset positions. The G.P.S. also helps reduce downtime; helps find the stolen equipment and reduce accidents, controlling the fuel use and costs. In many counties, the G.P.S. service is used in construction, tracking the uses of equipment, properly maintained devices, and tracking the theft devices.
10. Transportation
    G.P.S. works as a supportive gadget in many ways in a tracking system for security and efficiency. It tracks fuel competencies, route optimizations, driver security and fulfilment.

The global positioning system is very helpful in all fields of agriculture and industries.

What is the use of G.P.S. in future?

As from years countries and science are continuously working in the field of the G.P.S. and bought needed changes and updates time to time, the G.P.S. services are becoming an important part of the latest technologies, and in the future, these are some main changes which they are trying to create or increase in the field of the Global positioning service.

• They are trying to make GNSS service become smaller, much accurate and well-organized. And GNSS technologies are supposed to be much price efficient.
• Scientists and other technologies departments are trying to add the "Natural Disaster Prevention" feature to analyze the earthquake, volcano, etc.
• In covid19 situations, scientists are trying to add a feature that helps in tracking whether the spread of the virus is slowing down or increasing.
• They are trying to launch new satellites which will help in G.P.S. exactness or improve the navigation systems and time taking components till 2023.
• They are trying to make new G.P.S. satellites stronger and less signal overcrowding and cover the dead signal zones.
• NASA (National Aeronautics and Space Administration) is trying to make it more time-efficient and helpful for prospective astronauts on their long journey.
  NASA and other scientists are working hard to make it more exact and efficient for all personal and professional uses.

What is the difference between G.P.S. and GNSS services?

G.P.S. is just a subset of GNSS, but the major difference between G.P.S. and GNSS is in the receivers. The receiver of the G.P.S. system is only free to use or read the signals from the G.P.S. satellites only, but the GNSS receivers can use both G.P.S. and GLONASS or even more than two systems at the same time.

Another difference between both is of the satellites, as a GNSS system has 60 satellites. However, only three satellites are enough to enable the tracking, so GNSS gives many options to the receiver, which makes this service more secure and clear, but the G.P.S. service only has 12 satellites till now.

A GNSS service is more accurate than the G.P.S. Service but the GNSS services are more expensive whereas G.P.S. is easily provided and very pocket friendly. A GNSS is far more power-consuming in comparison to the G.P.S. services.

How accurate is the G.P.S. system?

The Accuracy of the Global Positioning System isn't fixed. It depends on lots of variables like the environment, physical barriers etc. Some factors that can change or affect the G.P.S. accuracy are listed below;

• Physical barriers
  Some areas full of mountains, buildings, and trees can be working as physical barriers, which slowdowns the G.P.S. services.
• Atmospheric effects
  Heavy storms or windy seasons, or any natural disasters can affect G.P.S. satellites and slower the tracking.
• Ephemeris
  This happens rarely, but sometimes the orbit model can be old or up to date.
• Numerical miscalculations
  Sometimes a device can be miscalculated or wrongly designed or have some issues in hardware designing
• Artificial interference
  There are some jamming devices that are specially designed to stop G.P.S. from tracking the locations or stop working of the Global Positioning System.
• Selective availability
  The U.S. Department of defence, due to the security of their forces, applied a feature of selective availability so that the enemy can't get the location of the Army, but this decreased the accuracy of the G.P.S. Still, later the government stopped this feature in 2000, which helped the accuracy of the device for the public.
• Satellite shading
  Sometimes, the satellites don't work well because of lined or tightened groups; it works better when situated in wider locations.
• Signal multipath
  Sometimes the signal faces issues due to hurdles like mountains or rocks, signals change their paths, which may create the inaccuracy of the Global Positioning System.

Sometimes some areas with higher buildings and crowded areas can also block signals or may face issues in capturing the networks, which can cause low performance or less accuracy.

• Some important definitions related to this topic
  What is a GNSS service?
  When a G.P.S. satellite starts working with global coverage, it is known as GNSS (Global Navigation Satellite System). In the GNSS system, many G.P.S. systems are working together globally.
  What is the G.P.S. signal?
  The G.P.S. satellites work with the help of at least two short power radio signals. These signals travel through the line of sight, which means they can pass through the cloud, trees and other objects. But these signals face issues while travelling through solid objects like mountains or tall houses, buildings etc. however, nowadays, the transmitted signals are more sensitive, which can cross the houses easily.