Difference Between GPS and A-GPS – Explanation with Examples!

A-GPS and GPS are different navigation aids where both use satellite information to determine their exact location on Earth.

Difference Between GPS and A-GPS - Explanation with Examples

GPS stands for Global Positioning System. A GPS device communicates with four or more satellites to determine their exact location coordinates in latitude and longitude anywhere on Earth through triangulation. It works in any weather, since the handset has a clear line of sight for the satellites.

A-GPS stands for Assisted Global Positioning System (Assisted Global Positioning System). While it works with the same principles as GPS, the difference here is that it obtains information from satellites using the network capabilities of its towers telephone service provider. Let’s understand these systems a little deeper.

How do GPS satellites work?

GPS satellites surround the earth twice a day in an orbit. These satellites continuously send information to Earth via radio waves. Messages transmitted by satellites include: (a) the time the message was transmitted, (b) information about the orbit and (c) the orbits of all satellites, as well as the “health” and quality of each satellite. GPS receivers use these signals, calculating the time the signals were sent by the satellites and the time they were received on Earth. Once the GPS receiver knows the position of at least four satellites and the transmission time of each, it is able to recognize its own location. This method of computation is called triangulation.

It can take from 3 seconds to a few minutes to get the signal depending on the location and amount of interference. Interference may be due to terrain or number of buildings, foliage, atmospheric inconsistencies, etc. This would result in reflecting signals and having several possible paths to follow.

The difference from A-GPS device to normal GPS

In the case of an A-GPS device, they use existing servers, such as a mobile network tower (cell phone antennas) and bases (servers) to obtain information from satellites constantly. Since these servers are continuously sending and receiving information from satellites, there is no delay in delaying knowing the orbit and the exact location of the satellites. In other words, the time to receive the data is much faster than a normal GPS, since the data is already stored on the servers.

These servers have good computing power so they can analyze the fragmented signals received from the GPS receiver and those received directly from the satellite to correct errors. Much of the computation and computation is then done before the data reaches your receiving device with A-GPS. Your device then only has to do some triangulation calculations with existing mobile network antennas that have the GPS satellite data stored and then it gives you its exact or approximate position also connecting to existing satellites.

Already a “pure” GPS device will take a little longer to “lock” its position, it will have to have a larger physical size to store more space for a battery and will have to have a greater computational capacity than an A-GPS device, since he will have to do all the calculations himself. There are already devices with both systems, but an A-GPS will usually require you to have a mobile data plan with some cellular carrier. There are even devices with the so-called S-GPS, which enables an instrument to receive both data, voice and information from GPS satellites at the same time, increasing sensitivity and improving the meeting of your exact location.

Performance and cost

A-GPS is faster at finding the GPS location and gives a more accurate location information. While there is no additional cost involved in the use of GPS devices, A-GPS has an additional cost involved as it utilizes the services and features of a mobile carrier. Some A-GPS models have the ability to connect to GPS satellites directly in case the service server is unavailable or outside the cellular network coverage area, but GPS devices can not connect to a cellular network .

Here’s a gadget that can work both ways, since it’s not all the places in the world that will have access to a cellular network, nor is it necessary to stay connected to the data network constantly. It is worth saying that unique GPS devices have much more precision than A-GPS, but are also more expensive.

For cost-effective and battery-saving, all currently manufactured smartphones use some form of assistance with the antennas, servers, and towers of mobile phone networks. The GPS that these devices have got very good calculations, but are dependent on the mobile network and do not work alone.

Examples of use

I understand both systems, you know that the A-GPS was made for devices such  as phones and tablets . Already for cars, airplanes, boats, ships, extreme sportsmen, the GPS is much more reliable and usable, because besides the precision, it can be used at any moment.

What about GLONASS?

You may have come across the term GLONASS for some devices, especially SAMSUNG models. GLONASS, for those who do not know, is basically the Russian GPS. It’s an investment from our cold-land friends to become less dependent on the North American GPS system. China also has a similar system in place, as do some other countries, including Brazil in this list. The connectivity continues in the same way: assisted, using data from the mobile networks, or independent, with all the calculations made by the device that accesses the satellites.

Final considerations

We need to say that you can not rely solely on the GPS of your mobile device for more adventurous deeds, such as a walk in the forest. But it serves very well for the day to day, and the speed with which it connects to the network makes it a great utility to help us find our way right when we use the appropriate programs. Plus, you’re saving money and a lot of battery power with the help of the antennas and servers in your mobile network. For this, you will pay a certain amount for the data network, but that generates an economy in the final value of your device, which would be much more expensive if you had an independent GPS, besides that it would be a big problem.

Some devices today can operate independently of mobile network access. However, you will realize that it takes longer to find the location and will spend more of the battery for it. If you want to use the type of GPS of your device as a criterion for the purchase of a cell phone, it is worth researching in websites with the technical data of the complete device, especially on Wikipedia, to know if the system meets you. Reviews and user reviews are also great ways to evaluate the GPS of some devices.

We know this was a long article. We hope to have solved all the doubts of our readers here. If you have any further questions, please use the comment space below to ask. We are here to help!