How Does GPS(Global Positioning System) Work?

What is GPS?

It’s twelve o’clock … do you know where your kids are? Would you like to know? One way to track them would be to have a GPS receiver installed in the car! The GPS, or Global Positioning System, is one of the hottest technologies around, and no wonder.

In brief, The Global Positioning System (GPS) is a navigation system using satellites, a receiver, and algorithms to synchronize location, velocity, and time data for air, sea, and land travel. Generally, It provides location, velocity, and time synchronization. Further, GPS is everywhere. However, You can find GPS systems in your car, your smartphone, and your watch. Hence, GPS helps you get where you are going, from point A to point B.

GPS works in any weather conditions, anywhere in the world, 24 hours a day, with no subscription fees or setup charges. The U.S. Department of Defense (USDOD) originally put the satellites into orbit for military use, but they were made available for civilian use in the 1980s. However, The satellite system consists of a constellation of 24 satellites in six Earth-centered orbital planes, each with four satellites, orbiting at 13,000 miles (20,000 km) above Earth and traveling at a speed of 8,700 mph (14,000 km/h).

How Does it Works?

In Fact, GPS is the only system that can show your exact position on the Earth anytime, in any weather, no matter where you are! GPS answers five questions simultaneously:

  • “Where am I?”
  • “Where am I going?”
  • “When will I get there?”
  • “Where are you?”
  • “What’s the best way to get there?

Generally, GPS satellites circle the Earth twice a day in a precise orbit. In fact, Each satellite transmits a unique signal and orbital parameters that allow devices to decode and compute the precise location of the satellite. Moreover, Its receivers use this information and trilateration to calculate a user’s exact location. Generally, the GPS receiver measures the distance to the satellite by the amount of time it takes to receive a transmitted signal.

Generally, With distance measurements from a few more satellites, the receiver can determine a user’s position and display it electronically to measure your running route, map a golf course, adventure anywhere. While we only need three satellites to produce a location on the earth’s surface, a fourth satellite does validation of the information from the other three. The fourth satellite also moves us into the third dimension and allows us to calculate the altitude of a device.

To calculate your 2-D position and track movement, a GPS receiver must be locked on to the signal of at least 3 satellites. In fact, With 4 or more satellites in view, the receiver can determine your 3-D position (latitude, longitude, and altitude). Generally, a GPS receiver will track 8 or more satellites, but that depends on the time of day and where you are on the earth.

Once your position has been determined, the GPS unit can calculate other information, such as speed, Bearing, track, distance, sunrise and sunset time, and much more.

History of GPS

Humans have been practicing navigation for thousands of years using the sun, moon, stars, and later, the sextant. Generally, It was an advancement of the 20th century made possible by space-age technology. In fact, GPS technology has been used globally throughout history.

The launch of Russia’s Sputnik I satellite in 1957 ushered in the possibility of geolocation capabilities and soon after, the U.S. Department of Defense began using it for submarine navigation. In 1983, the U.S. government made it publicly available, but still kept control of the available data. It wasn’t until 2000 that companies and the general public gained full access to the use of GPS, eventually paving the way for greater GPS advancement.

Basic structure

GPS is made up of three different components, called segments, that work together to provide location information. It consists of the following three segments.

Space segment: In fact, The satellites circle the Earth, transmitting signals to users on geographical position and time of day. Generally, Several GPS satellites are deployed on six orbits around the earth at the altitude of approximately 20,000 km and move around the earth at 12-hour-intervals.

Ground segment(Control segment): Ground control stations play the roles of monitoring, controlling, and maintaining satellite orbit to make sure that the deviation of the satellites from the orbit as well as its timing are within the tolerance level. However, There are monitoring stations on almost every continent in the world, including North and South America, Africa, Europe, Asia, and Australia.

User segment: Its receivers and transmitters include items like watches, smartphones, and telematics devices.

How accurate is GPS?

Today’s GPS receivers are extremely accurate, thanks to their parallel multi-channel design. Our receivers are quick to lock onto satellites when first turned on. GPS device accuracy depends on many variables, such as the number of satellites available, the ionosphere, and more. Some factors are:

Physical obstructions: Arrival time measurements can be skewed by large masses like mountains, buildings, trees, and more.

Ephemeris: The orbital model within a satellite could be incorrect or out-of-date, although this is becoming increasingly rare.

Atmospheric effects: Ionospheric delays, heavy storm cover, and solar storms can all affect GPS devices.

Artificial interference: These include GPS jamming devices or spoofs.

Numerical miscalculations: This might be a factor when the device hardware is not designed to specifications.

Garmin GPS receivers are typically accurate to within 10 meters. Accuracy is even better on the water. However, WAAS improved the accuracy of some Garmin GPS. In fact, The US Coast Guard operates the most common DGPS correction service, consisting of a network of towers that receive signals and transmit a corrected signal by beacon transmitters. To get the corrected signal, users must have a differential beacon receiver and beacon antenna in addition to their GPS.

Accuracy tends to be higher in open areas with no adjacent tall buildings that can block signals. This effect is an urban canyon. However, many critical issues facing GPS technology have been identified and are nearing resolution. High-quality receivers provide better than 2.2-meter horizontal accuracy in 95% of cases and better than 3-meter accuracy in 99% of cases.

What are the uses of GPS?

Emergency Response:

During an emergency or natural disaster, first responders use GPS for mapping, following and predicting weather, and keeping track of emergency personnel. In the EU and Russia, the eCall regulation relies on GLONASS technology and telematics to send data to emergency services in the case of a vehicle crash, reducing response time.

Health and fitness: 

Smartwatches and wearable technology can track fitness activity (such as running distance) and benchmark it against a similar demographic.

Entertainment: 

GPS can be incorporated into games and activities like Pokémon Go and Geocaching.

Construction, mining and off-road trucking: 

In fact, From locating equipment to measuring and improving asset allocation, GPS enables companies to increase return on their assets. Generally, Check out our posts on construction vehicle tracking and off-road equipment tracking.

Transportation: 

Generally, Logistics companies implement telematics systems to improve driver productivity and safety. However, A truck tracker supports route optimization, fuel efficiency, driver safety, and compliance.

Other GPS Systems

There are other similar systems to this in the world, which are all classified as the Global Navigation Satellite System (GNSS). However, Russia built a satellite constellation system named GLONASS. The European Space Agency is creating Galileo, while China is creating BeiDou. Most Garmin receivers track both GLONASS and GPS and some even track BeiDou. You can expect a more reliable solution when you track more satellites. In fact, You could be tracking nearly 20 with newer Garmin products.

What’s the signal?

GPS satellites transmit at least 2 low-power radio signals. The signals travel by line of sight, meaning they will pass through clouds, glass, and plastic but will not go through most solid objects, such as buildings and mountains. However, modern receivers are more sensitive and can usually track through houses. Generally, Pseudorandom code is an I.D. code that identifies which satellite is transmitting the information.

However, You can see which satellites you are getting signals from on your device’s satellite page. However, Almanac data tells the GPS receiver where each GPS satellite should be at any time throughout the day and shows the orbital information for that satellite and every other satellite in the system. Moreover, Ephemeris data is needed to determine a satellite’s position and gives important information about the health of a satellite, current date, and time.

Errors Sources:

Ionosphere and troposphere delays: 

Generally, Satellite signals slow as they pass through the atmosphere. Generally, The GPS system uses a built-in model to partially correct this type of error.

Receiver clock errors: 

A receiver’s built-in clock may have slight timing errors because it is less accurate than the atomic clocks on GPS satellites.

Signal multipath: 

The GPS signal may reflect off objects such as tall buildings or large rock surfaces before it reaches the receiver, which will increase the travel time of the signal and cause errors.

The number of satellites visible:

When a signal is blocked, you may get position errors or possibly no position reading at all. GPS units typically will not work underwater or underground, but new high-sensitivity receivers are able to track some signals when inside buildings or under tree cover.

Selective availability: 

The U.S. Department of Defense once applied Selective Availability (SA) to satellites, making signals less accurate in order to keep ‘enemies’ from using highly accurate GPS signals. In fact, The government turned off SA in May of 2000, which improved the accuracy of civilian GPS receivers.

Satellite geometry/shading: 

Satellite signals are more effective when satellites are located at wide angles relative to each other, rather than in a line or tight grouping.

Short Summary of article:

GPS is a system of 30+ navigation satellites circling Earth. We know where they are because they constantly send out signals. In fact, A GPS receiver in your phone listens for these signals. Once the receiver calculates its distance from four or more GPS satellites, it can figure out where you are.  However, Over 30 navigation satellites are zipping around high above Earth. Generally, These satellites can tell us exactly where we are.

The future of GPS

So, World continues to build and make improvements to its GPS systems. However, worldwide all are trying to increase accuracy and improve reliability and capabilities. For example, Scientists are finding new ways to use this technology in natural disaster prevention, volcanic eruption, sinkhole, or avalanche.

For the COVID-19 pandemic, researchers are looking at using cellphone location data to assist with contact tracing in order to slow down the spread of the virus. So, The next generation will include better signal protection, decreased susceptibility to signal to jam, and more maneuverability to cover dead zones. The future of GPS tracking will likely be far more accurate and effective for both personal and business use.

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