Once upon a time, maps were used to find or locate the place where we are. The patterns are drawn in the map by noticing the unique turns and crosses. But, there was a way in a war, a technique to take advantage by locating the enemy from very high altitude places like mountains or some artificial towers. And by finding paths using the stars in the night sky.
Invention:
The technology in the late 70s focused on a particular purpose: tracing something or someone. It starts with the military involvement, which is why it did not come to the market. The US government undertook the project and came out as a military invention.
The GPS stands for the global positioning system. At the time of its invention, they named it “navstar”. In order to trace or find something in the whole world, it has to be in orbit. So, the invented machine is carried through a rocket into space to orbit the earth. This satellite is named navstar (Navigation system timing and ranging). Though the technology was built in 1978, it was introduced in 1995. This is because it requires more and more satellites for accuracy. Also, the backups have to be constructed and activated whenever needed.
Satellites:
About 32 satellites are working for this purpose. Out of this, eight are used as a backup if any other satellites didn’t work. A typical GPS satellite orbits around the earth at nearly 14,000 km per hour.
The technology behind GPS:
The GPS requires a satellite, a ground station and a receiver. The ground stations work by connecting with the satellite in space. In an effort to find the location, the satellite has to be in a certain location at a particular time. Apart from this, the ground station uses radar to confirm the satellite’s location where it is supposed to be. The last one, the receiver (which may be a watch or a car), follows the satellite’s signal, and the receiver calculates how far it is from satellites. When a receiver connects like this with four or more satellites in space, it can determine the receiver’s location with higher accuracy.
Did you know?
- The GPS technology does not require wifi or internet connectivity to work, but it will be much more effective with these.
- On average, it costs the US Government $2 million every day to run, but it is free for public use.
Principle:
The principle behind the positioning system is called trilateration which is of two types: 2 dimensional and three-dimensional trilateration. It is a complex mathematical process, but here is an example to know the principle effortlessly.
You were travelling in a rural area and ended up near an unnamed lake. Near the lake, a post indicating the signs showing three cities and how far it is from here in kilometres.. The first sign tells you that you are 500 km from a city. Let’s say it is called “city A“. you cannot locate yourself from that city A’s distance because this may be anywhere from the city like a radius. Then went on to the second sign, which shows that the city B is 600 kilometres from the place where you are. Using these two pieces of information, we can draw two radii in a map, producing an intersection. But this alone gives a location with less accuracy. The third sign also tells you that you’re 1,100 km from city C. By extracting all this information, we can narrow it down and find the location with greater accuracy. This is how 2-dimensional trilateration works. The 3d trilateration used spheres instead of circles to find the place. Four or more satellites are connected with the receiver to get high accuracy because the four circles will be enough to narrow it down.
You may wonder how google maps or other navigating applications were used to find the distance between a receiver and an exact city or place we are searching. The GPS satellites use radio signals that travel at the speed of light, making it possible to find how far it will take to get received by a receiver. Moreover, GPS tracking and navigation is not affected by climatic conditions like heavy rain or shine.
Other applications:
- The mapping can be precisely drawn with the help of GPS.
- Apart from locating and navigating through GPS, the tracking can be done for the suspected one or personal movement in legal ways.
- The timing can be precisely calculated all over the world with the help of an atomic clock which is used in GPS satellites.
- One of the main applications is to locate ships and boats in the marine bodies, which will be very helpful to navigate to the coasts.
- Nowadays, GPS trackers are available in tiny sizes and can be integrated with many things like in shoes of children and aged people with Alzheimer’s disease in case they get lost.
- In our developing years, civilians are already able to use GPS. However, the high-quality satellites, i.e. with more accuracy than usual.