How GPS works- Read this Article to get the knowledge all about GPS
For years now, you have been using GPS technology on a daily basis: when you are in your car and set a route on your satnav , when you have to find a way in Google Maps or, more simply, when you place something on Facebook while keeping the geographical position active. But have you ever wondered how GPS works and how does it always detect (or almost) the right position of a person or an object? If the answer is yes and you are looking for more information on this extraordinary technology, know that you have come to the right place at the right time!
Following, in fact, I will lead you into the world of GPS, providing you with all the information you need to fully understand the operation of this system that now accompanies us every day in our work and play activities. I will then explain the meaning of the acronym GPS, I will mention the history of this technology and then I will go into the heart of the matter giving you some technical details on this technology and explaining how to use it on smartphones, tablets and computers.
Do not worry, you do not need to be an aerospace engineer or possess high-level computer skills to understand everything: you will just need a few minutes of free time (the necessary to read this in depth) and, I assure you, at the end of the reading will have everything very clear. That said, I can only wish you good reading and have fun!
What is GPS
Before entering into the matter and explaining how the GPS works , it is good to start by explaining what this term means: GPS is the acronym of Global Positioning System and it is a positioning system based on satellites in orbit, able to to provide the exact position and time to any device equipped with a dedicated receiver . It works at any time and regardless of weather conditions. To be more precise, the complete definition of this positioning system is NAVSTAR GPS , that is, Navigation Satellite Timing and Ranging Global Positioning System .
The GPS system, designed by the US Department of Defense, was established in 1973 as a successor to the Transit system to offer the possibility for military vehicles to navigate in space (and time) in any position and in any weather conditions. Only in 1991, however, the United States decided to open the use of GPS to civilians, but with some limitations (which did not concern military use): for security reasons, the signal sent by the satellites was “altered” on purpose by a particular mechanism , decreasing the order of precision of the detection of civilian receivers – the detection error could reach up to 950 meters compared to its original position.
In 2000, these limitations were abolished, making the detection for civil uses much more precise: the detection by GPS, to date, guarantees an accuracy of 10 or 20 meters compared to the real position, certainly a great leap forward compared to what happened in past.
Mainly, the whole GPS system consists of three “parts”, or segments , that work together to offer positioning in the ways I have indicated to you previously. Below I illustrate you all.
Spatial segment – this is the constellation of satellites arranged in the Earth orbit. In total, around the earth, orbit 31 artificial satellites (24 are active, while others become if necessary) arranged on 6 distinct levels, which continuously emit signal on two different channels: L1 for civil use ( SPS ) , and L2 ( PPS ) for military use.
Control segment – this is the combination of the 8 satellite monitoring stations (7 operational and a “reserve”), scattered in strategic points of the Earth, together with the 4 terrestrial antennas able to send to each satellite the necessary updates over time . The personnel inside the control stations take care of the complete management of the satellites, the signals and the services.
User segment – this segment is nothing more than the set of GPS receivers on our planet, both military and civil. Generally, a receiver consists of a small processor for processing operations, a GPS antenna and a time source, useful to perform the synchronization operation (I’ll talk about it soon).
The detection of the position via GPS is based on the trilateration principle : using the radio signals generated by three satellites and the distance of the Earth from each of them, the receiver, thanks to the 3 signal travel time, is able to calculate the point of the planet in which it is located, with a fairly high margin of precision, reproducing it when necessary on a digital map (as I explained before, the SPS localization has an error of less than 20 meters compared to the real position).
The watch on the receiver, however, is not as precise as what is on board the 3 satellites involved in the triangulation, so the receiver itself is not able to know immediately the exact moment in which the signal has left: for this, the signal sent by a fourth satellite is exploited, useful to “correct” the watch on the receiver and synchronize it with the satellite one. This is the reason why, at any point on earth, a GPS receiver can receive signals from at least 5 different satellites (4 operational and one “spare”).
Before moving on, I feel obliged to provide you with another important piece of information: GPS is the most used positioning system in the world, but it is not the only one. Some nations and continents, for a number of reasons (including the fact that the GPS space and GPS segment are owned by the USA, a nation that could theoretically prohibit its use at any time), have created positioning systems alternatives: GLONASS (Russia), BeiDou / Compass (Asia), IRNSS (India) and Galileo (Europe).
What is GPS for?
If you have carefully read what I have told you so far, you have certainly understood the ultimate purpose of GPS: this system is able to locate any object with a receiver, anywhere on the Earth and at any time , regardless of weather conditions .
As I have already explained to you, a GPS receiver is nothing more than a “chip” equipped with an antenna , a tiny processor and a kind of clock able to pick up the satellite signal and to detect, with the rules that I explained to you a little while ago, the terrestrial coordinates of his position, possibly returning them to a map thanks to special systems, programs or apps.
The first devices equipped with GPS chips were simple detectors equipped with a small display on which the terrestrial coordinates were shown. With the passage of time and the evolution of technology, it has become possible to use many categories of devices to take advantage of this technology: here are some of them.
Navigators for automobiles – these are devices generally designed for navigation only using GPS technology. They are equipped with a screen, a processor, a RAM memory and a GPS chip (as well as optional components such as Bluetooth, battery, WiFi, etc.), and can show entire customizable travel itineraries, as well as the current position, exploiting maps of nations or entire continents , which can be downloaded as needed. If you need a navigator, I suggest you refer to my dedicated purchase guide .
GPS trackers – they are real “locators”, equipped with a GPS chip, able to determine the position of the object to which they are connected or the person who wears them, interfacing with appropriate programs for computers or apps for smartphones and Tablet. Some trackers are equipped with additional chips such as WiFi and Bluetooth, while others are so small as to be almost invisible: you can find a wide selection by consulting my guide to the best GPS Tracker .
Smartphones, tablets and computers – for a long time, these devices are commonly used with a GPS chip that can be activated or deactivated as needed and used, through programs or dedicated apps, for multiple purposes ( “transform” the devices in satellite navigators or to locate them when they are lost or stolen , just to mention two common scenarios). To be precise, not all computers are equipped with GPS chips, however it is possible to exploit the localization services using the Internet connection , by combining the IP address obtained from the machine to the nearest server, belonging to the operator to which it is connected. .
GPS for Garmin Device: GPS is also the important feature of Garmin devices to update the maps for route, Sport station for better navigation.
How to use GPS
Now that you’ve learned the basics of how GPS works , it’s time to move to practice and activate location systems on your smartphone, tablet or computer. Below, I’ll explain how to activate and use GPS on devices Android, on iPhone and iPad and on the computer.
Before continuing, however, I want to clarify that the location services can be used by the programs and apps that request it, only if you give them permission to access the GPS – by touching or clicking on Allow or OK inside of the dialogs that will be proposed to you.
Do you have a terminal equipped with the Android operating system ? Do not worry, activating the GPS is very, very simple and you can do it either using the notification area or the appropriate panel within the settings.
So, to activate the GPS almost immediately on Android, call the notification area on your smartphone or tablet, swiping from the top of the screen to the bottom, and touches the GPS icon (or Location , depends on operating system) present in the panel that opens: when this lights up, the GPS is active and available for the apps and services that wish to use them.
Can not find the GPS icon in the Android notification area? Do not worry, you can also do the same through the system menu: first, touch the Settings icon located in the app screen installed on your device, then scroll down to find the Personal section and touch the Geolocation . At this point, move the switch located on the upper right of the proposed panel to ON and you’re done.
In some customized versions of Android, for example, the MIUI of Xiaomi , the process may change slightly: in this case you must open the Settings Android, to bring in the section & Device System and, from there, tap entries Additional Settings , Privacy and Geolocation , then move on on the switch at the voice access to my location .
From the same panel, you can also activate high-precision localization services (I’ll discuss it in a moment) or check the apps that have recently accessed the location services. It was not difficult, was it?
Do you have an iPhone or an iPad ? Do not worry, enabling or disabling GPS is very simple! First, tap the Resident Settings icon on your device’s home screen and select the Privacy and Localization items from the menu that opens.
Now, to “turn on” the GPS, activate the switch located at the top right, in correspondence of the Localization item and you’re done! From the same panel, you can activate or deactivate location sharing via system apps, or revoke permission to access apps installed on your device.
So far I’ve talked to you about how to activate GPS on smartphones and tablets. What if I told you that these services can also be activated from desktops and laptops? Yes it can be done. Before explaining how, however, I must make an important clarification: not all computers are equipped with GPS chips, so it can happen that the location is also obtained by taking advantage of any Bluetooth devices, the WiFi connection or possibly the connection via cellular modem (for eg using the ” 4G Internet keys “).
Without this premise, it is time to take action: if you use Windows 10 and you want to activate the GPS on your PC, click on the icon in the shape of speech bubble placed at the bottom right of the screen, next to the clock, and click Position icon . If you do not see the icon in question, click on the item Expand all and you should see it appear.
If you have a Mac , activate the localization in this way: click on the System Preferences icon located on the Dock , then on the Security and Privacy icon and on the Privacy section , located at the top right.
At this point, unlock the changes by clicking on the button in the form of a padlock at the bottom left, enter your password, press the Unblock button and check the Enable “Location Services” checkbox . Through the same screen, you can view all the programs that requested and obtained access to the position.
Once the service is activated, you can grant programs and / or Web sites permission to use GPS (or localization via WiFi / Bluetooth / modem) by clicking on the Allow button that appears in the confirmation windows proposed by the operating system, or information panels located immediately below the address bar of the Safari browser .
Even browsers such as Google Chrome have a function to allow the detection of the geographical location by the sites and Web services used: to proceed, open the browser of “big G”, presses the button ⋮ located at the top right, select the Settings item , scroll to the bottom of the page and click on the Advanced item .
After loading the next section of the page, click on the item Content Settings , then position , and moves on On the placed Switch up (the voice will change from Locked to Ask before accessing ). From this moment on, when a site wants to access the location, a small information panel is shown at the top left: to grant access, it is necessary to click on the Allow button .
How to improve GPS signal reception
I have mentioned several times, in this study, how the location by GPS signal is possible anywhere on the Earth, at any time and regardless of weather conditions. However, because GPS receivers rely on a satellite signal, reception is not always optimal, and in some cases it may take longer to get an acceptable result.
Do you find yourself exactly in this case? Do not despair, all is not lost: there are small “tips” to follow to improve the reception of the GPS signal , especially on smartphones and tablets. Below I’ll show you the most useful ones.
Eliminating obstacles – to receive the signal from the satellites better, it is good that there are no “obstacles” between the “source” (the sky) and the receiver. Consequently, I suggest you use the GPS pointing the device straight to the sky , better if outdoors and in the absence of elements such as ceilings, partitions or other.
High-precision location services – if GPS alone can not provide you with a very precise location, you can take advantage of the “high-precision” location, which also uses information received from WiFi, cellular connection and Bluetooth. To activate it on Android, go to Settings> Geolocation , tap on the Mode item and set the check mark on the item High precision . This step is not necessary on iOS, where “high precision” services are active by default.
Use an app – in the stores of Android and iOS, there are some apps that verify both how many satellites you can receive information, from the current location, both the quality of the signal received, so you can find the optimal position to reach your target. In this regard, I point out the GPS Test app for Android and GPS Status for iOS.
Use an external antenna – if you need to use GPS in a rough place, and your device just can not catch the signal, you could use an external GPS antenna. There are different types and with different connection modes, depending on the device to which they are dedicated (satellite navigation, smartphone / tablet, computer, etc.).
Now that you know all the information you need on GPS, you can finally take advantage of this technology with the knowledge of how this works. Before concluding, however, I want to give you some advice: do not think that the GPS is only for “navigation”, because this small chip can be useful even if your device is lost or stolen: if the GPS is active, there is the possibility to locate the device before it is turned off or to know its last position. I told you in detail about this in my guides on how to locate GPS and how to track a stolen phone : I suggest you read them carefully.