GPS has become a crucial part of our day-to-day activities. Everyone can vouch for the Global Positioning System’s usefulness, especially when you’re lost. But with GPS, navigation has never been more straightforward.
GPS can allow users to pinpoint their exact location accurately. They need a GPS receiver, which can now be found in boats, cars, laptops, planes, mobile phones, and numerous other applications. To appreciate the usefulness of the Global Positioning System, one has to understand its history and appreciate how technology has influenced the applications of GPS.
History of GPS
GPS was created by the US Department of Defense back in 1973 but was only introduced to the rest of the world in 1995. It uses trilateration to tell a device’s location and improves the accuracy through the help of atomic clocks and Differential GPS.
Originally dubbed NAVSTAR, GPS tracking was intended to be used solely for military purposes. In 1978, five years after its creation, the first four GPS satellites were launched into space. However, full coverage was only achieved in 1995 after the required 24 satellites finally orbited the earth.
Before the commercial release of GPS systems, the US military decided to develop two separate systems – SPS and PPS. SPS was set for commercial release, but PPS would be used only by the US military. SPS had a deliberate error that kept civilians from accurately pinpointing locations by using a technique they referred to as selective availability (SA). This was done because the military felt the need to protect the security of the US. They, therefore, deliberately deteriorated the accuracy of the NAVSTAR system by roughly 100m.
On May 1st, 2000, the continued advancement in technology forced the then President of the US, Bill Clinton, to end the use of SA. The accuracy of SPS increased fivefold (though SPS is still not as accurate as PPS), helping boost the commercial and scientific interests of many countries worldwide and the transportation safety of countless people.
The Global Positioning System has a lot of uses today, which vary from military missile guidance to personal navigation. The continued advancement in technology has caused the cost of GPS systems to decrease, leading to increased application of GPS in more exciting ways.
How GPS Works
GPS systems use vital features to display the location of a device accurately. Trilateration, measuring distance, atomic clocks, and critical errors using differential GPS. Here’s how technology is applied in the working of the GPS:
Trilateration
The GPS has 29 satellites that orbit the earth twice daily. Twenty-four of these satellites operate to pinpoint locations, while 5 are backup satellites. Trilateration uses the concept that four of these 24 satellites would be visible from any point on the earth’s surface. These four satellites calculate the positioning of an object on the earth’s surface.
Measuring Distances
The most essential task of the GPS is to accurately measure the distance between an inquiring device and the receiver: the satellites stream radio signals, which tell the satellite’s time and position. The inquiring device has receivers that receive the signal and decode it; then, they use the information acquired to calculate its distance from the satellite.
Atomic Clocks
The time taken by the signal to travel should be accurately measured to determine the distance between the satellite and the receiver. Atomic clocks, the most accurate clocks globally, are used to reduce the time difference and give precise measurements. However, atomic clocks are very expensive and are only used on satellites. More accurate clocks for receivers are still being developed to increase further the accuracy of the distance measured.
Differential GPS or DGPS
This is a technique that the GPS uses to increase the accuracy of your location. It was initially developed to diminish the errors caused by SA, but its use continued after SA ended. DGPS uses stationary receivers worldwide, and their locations are known. This allows for the calculation of the error between the location calculated by the GPS and the exact location of the receivers.
Conclusion
GPS is a good system with a massive variety of modern world applications. Advancements in technology have significantly increased the accuracy of GPS since its creation and have also caused increased application of the system.