GPS has become a staple service that many Hong Kongns are utilising today. Many Hong Kongn drivers use GPS devices to guide them on the best routes to use to reach a designated destination. GPS systems are accessible via our smartphones and a variety of handheld GPS devices. Some cars also have come with built-in GPS systems for you to navigate your trips easily.
Despite being used almost every day, not many people know how the GPS works. Most people know that GPS, short for Global Position System, basically uses satellites to determine the position of your location and the destination you are heading to. Here is an in-depth insight into how the global positioning system (GPS) works:
Founding of the Global Positioning System
The Global Positioning System, also known as NavStar was built by the US military system and has been fully operational since 1995. The system was initially developed for military navigation but now anyone with a GPS device, be it a mobile phone or a handheld GPS unit, can receive the radio signals broadcasted by the satellites from outer space. The GPS system currently has 31 active satellites orbiting the Earth from 20,000 kilometres away, making two complete orbits a day. Not all are used though as some are spare satellites in case one malfunctions.
Concept Behind the GPS System
GPS uses a lot of complex technology to operate but the concept is relatively simple to understand. The satellites are arranged in such a way that no matter where you are on the planet, there will be at least four GPS satellites that are “visible” at any point of time. Each of these satellites will transmit information about its position and the current time at regular intervals. Your GPS receiver which will analyse and calculate the high-frequency radio signals emitted by the GPS satellites to determine the distance of the satellite based on how long it took for the messages to arrive. Once your device is able to calculate how far away at least three satellites are, it can pinpoint your location through a simple mathematical principle known as trilateration.
To understand trilateration, you need to imagine yourself standing somewhere on Earth with three satellites in the sky above you. If you are able to know the distance you are from one satellite, say Satellite A, then you will be able to build an imaginary circle with the distance you are from the satellite as the radius. By doing the same thing for satellite B and C, you can work out your location by defining a point where these three circles intersect. This is how your GPS receiver determines your location with the only difference is that it uses overlapping spheres instead of circles.
Although an approximate position can be determined with only three satellites but to improve accuracy and obtain precise altitude accuracy, having information from four or more satellites will be ideal. Planning to get yourself a GPS tracker? Brands like Garmin and OEM manufacture reliable GPS units that you can use to ensure that you reach your destination without any hassle.