When purchasing a smartphone or tablet, you can find GPS and A-GPS support in its characteristics. What is this technology with the letter A, and how does it differ from the satellite navigation system that has long been familiar to everyone?
Is there a difference between GPS and A-GPS?
GPS (from the English Global Positioning System – global positioning system) – satellite navigation system. It allows you to determine the current location of your gadget on the globe by picking up a signal from a satellite.
And what is A-GPS? In fact, this is not some kind of separate technology, but an add-on to the global navigation system. It adds to it a very important function – triple positioning.
What is triple positioning?
When you turn on navigation on your phone, it needs to contact the satellite to determine your current location – the so-called “cold start”. Depending on the location of the device, it can take a decent amount of time: from 10-15 seconds to a couple of minutes.
When using the new technology, the phone receives coordinates not only from space during a cold start. The data can be taken from your carrier’s base station or, more commonly, over the internet, mobile or Wi-Fi.
In a word, what you connect to first, from there you will get your location. If cellular operator towers are used, at first there may be inaccuracies in the positioning of the device. They are corrected when the gadget “calls” to the satellite.
What does it give?
One head is good, but three is already a dragon! Positioning from three different sources allows not only to speed up the acquisition of coordinates, but also to compare them with each other in order to determine the location with an accuracy of several meters.Another important advantage of the technology is the ability to receive a signal in the so-called “dead zones” – tunnels, lowlands, dense forests. One of the three signal sources will one way or another “finish” to the “dead zone”, and the phone will receive the coordinates.
Annoying little things
Despite the obvious advantages, the technology has several disadvantages:
- Some receivers of this type require the radio module to work. If, for example, your tablet does not have a SIM card, that is, the radio module (GSM) is disabled, then you will not be able to use A-GPS.
- Outside the coverage of the cellular network and without access to the Internet, the function simply does not work.
- When using technology, a phone or tablet transmits some information over the Internet. Its volume is small – only a few kilobytes. But if you are in roaming, a significant amount can be deducted from your account even for them.
Otherwise, geolocation with the letter A is a handy thing. No wonder three-source location is used in children’s watches and dog collars! It is much faster and more accurate than conventional geopositioning, and also works where the satellite “does not finish off” – for example, inside reinforced concrete buildings or in the subway.
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Photo: Pixabay, Dissolve