Navigation today is a simple, necessary and incredibly popular service. Not only are navigators almost the most popular product on the mobile market (only ubiquitous phones overtake them), but many smartphones have acquired their own GPS and A-GPS chips over the past couple of years - and users are so used to it that “smartphones without navigation ”is now at least surprising to them. All this, of course, is very encouraging (progress! Civilization!), But there is only one problem: manufacturers are trying so hard to sell their goods that they often wishful thinking, enticing buyers not with the specifications of their products, but with loud words on the boxes. In this article, we will tell you what these words mean and what navigation actually is.
Technology: how does it work?
Today, there are, in fact, only two technologies that allow users of mobile technology not to get lost in the stone jungle: satellite and cellular navigation. The first is GPS itself, a global satellite positioning system, invented by American scientists for the American military, and then donated to the rest of the world for Thanksgiving. The second is AGPS (not to be confused with A-GPS), a cellular technology that allows you to determine your approximate location (with an accuracy of 500 meters) if you are in a cellular network coverage area.
GPS is good first of all because it is accurate (determines your position with an accuracy of five meters) and absolutely free (good Americans allow everyone to use their satellites). Of course, you will have to pay for specific navigation programs and maps - but this fee will be a one-time fee, and no subscription to GPS services exists in nature. The bad thing about GPS is that it works only outdoors, and mainly in clear weather - if the sky is cloudy, it is quite difficult to find the number of satellites required for work. In order to fight the clouds, a special A-GPS (Assisted GPS) technology was invented: using this technology, instead of sending signals to the heavens, the navigator simply connected to a server, where it downloaded information about the location of satellites, and, using these coordinates, I found them much faster. Today A-GPS is an indispensable companion of any GPS-receiver in a car navigator. The most popular maps that work with the GPS service: iGo, Avtosputnik, Navitel, Be-On-Road.
The cellular AGPS (Alternative Global Position System) system, of course, gives a much less accurate determination of the position of an object on the map, but it does not depend at all on the weather and the degree of depth into the building. The main thing is that your smartphone can catch the network, your number has the GPRS service activated, and you still have money on your account. The principle of operation of AGPS is similar to the principle of operation of a satellite navigation system: a smartphone receives signals from several (at least three) base stations and, based on the signal strength of each of them and taking into account their location, calculates your coordinates. Cheap and cheerful: of course, you won't be able to get anywhere with AGPS, but on the other hand, you will definitely not get lost on the map. The most popular maps that work with the AGPS service are Google Maps, Yandex.Maps.
Devices: what happens?
The simplest of all existing GPS navigation devices in nature is an external GPS receiver. By itself, he only communicates with satellites, and, in fact, does not provide any navigation. But you can connect it to almost any device - laptop, pocket computer, phone or smartphone - and then, with the right software, you can navigate in space and plot routes to your destination. The receivers are especially useful for tourists who prefer narrow mountain or forest paths to beaten roads: the receivers, unlike most other devices, are not tied to a map, and if they so desire, they can guide you even along scanned graph paper with a navigation grid superimposed on it. If you, of course, find one for the region you need.
The most popular navigation device today is the car GPS navigator. It is essentially a small touchscreen computer that runs on a closed operating system. The manufacturer has already installed a navigation program in the navigator, which usually cannot be changed without violating the licenses. In addition to navigation itself, car navigators often know how to do a lot more: play music, show movies, work with e-books and pictures, and even connect to the Internet.
Recently, a new class of devices has appeared on the market - smartphones with a built-in GPS receiver. On the one hand, these devices are extremely convenient: they can call, they will prompt the way, and they can do a lot of other things. On the other hand, the software component of such devices is still very weak: mainly “online solutions” like Nokia Maps or Google Maps are used as navigation programs, for which you need a constant connection to the Internet (although some smartphones can be equipped with a real navigation software). Yes, and such smartphones are more suitable for pedestrian than for car navigation - they have a small screen, the map is poorly visible, and with the maps of our vast homeland everything is, to put it mildly, bad. You can only drive around the city.
The last type of navigation device is cellular navigation smartphones (AGPS). They don't have a built-in GPS chip. They are suitable only for those who do not want to carry a paper map with them - they do not provide guidance on the route, or even an exact determination of your location. On the other hand, they are excellent help to navigate in space during a long trip or to find some particularly inconspicuous alley that none of the passers-by you interviewed have heard of.
Unfortunately, there is no perfect map in nature (if only simply because everyone has their own ideas about the ideal), so first you have to understand why you basically need a navigator and what you will do with it: one type is suitable for hiking trips devices and maps, for car navigation - another, for pedestrian navigation - a third. In addition, you need to pay attention to the cartographic base itself: the most attractive-looking program may suddenly not have a map of your city, and the most "urban" of the maps will show you white spots immediately behind the ring road. In general, whatever one may say, but you still have to devote some time to the selection process. You can read about how to choose a map for a navigator in the article "What kind of navigational maps are there?"
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A-GPS (English Assisted GPS) - a technology that allows you to speed up the so-called "cold start" of the GPS receiver. The provision of the required location information is accelerated through the use of other communication channels. This system is often used in smartphones and cell phones that have a built-in GPS receiver chip.
Modern smartphones have large displays that allow you to display any graphical information, in particular geographic maps, in excellent quality. This allows the user to easily solve both business problems and receive information for personal needs or see information of an entertainment nature.
In Europe, GPS users often confuse it with the LBS service. LBS is a range of entertainment and information services that are based on the location of a subscriber in a cellular network. The use of GPS or A-GPS technology is not required to provide these services. The location of the subscriber is calculated with an accuracy of 50 - 100 meters by measuring the signal level from the GSM plus base stations by means of signals from access points to the Internet using Wi-Fi technology, to which the subscriber's gadget is connected.
How A-GPS works:
For the A-GPS system to function, it is necessary to have an additional communication channel through which information from a remote server can quickly get to the receiver input. Mobile devices (smartphones, telephones) most often use cellular communication channels for this. If the phone is within the range of a cellular network and has access to the Internet, the A-GPS system is activated automatically.
Approximate location:
To speed up the processing of location data, the system A-GPS limits the search area for satellite signals by first determining the approximate location. Mobile phones allow it to be calculated by the base stations of the GSM operator. The accuracy of the calculations depends on how many signals from different base stations the phone picks up. The highest density of base stations is usually found in city centers. In these places, the position measurement accuracy reaches 200 - 500 meters. On the outskirts of cities and in sparsely populated areas, the measurement accuracy is only 1500 - 2000 meters.
GPS technology is used not only by motorists and taxi drivers. It is also popular with nature hikers, fishermen and people with an active lifestyle who constantly walk / drive back and forth. If someone needs to find out where he is, where the location he needs is located, how fast he is moving and how soon he will reach the goal, GPS will come to the rescue.
The reason for the widespread popularity of this technology lies in the following:
- the coverage area covers the entire globe;
- the technology is used not only in expensive secure GPS trackers, but also in relatively cheap GPS navigators for cars and even smartphones;
- there is no need to pay for using GPS.
More about what is GPS
GPS is an abbreviation for the English concept of Global Positioning System, which is translated into Russian as "global positioning system". This project was conceived and implemented by the US military for military purposes only, but later became widely used for civilian needs.
The GPS system is based on 24 NAVSTAR navigation satellites that make up a single network and are located in the Earth's orbit in such a way that at least 4 satellites can be accessed from anywhere in the world.
The operability of the global positioning system is monitored from Earth by observation stations located in the Hawaiian Islands, in the city of Colorado Springs (Colorado), in the Kwajalein Atoll and on the Ascension and Diego Garcia Islands. All information collected by these stations is recorded and then transmitted to the command post, which is located at the US Air Force base "Shriver" (Colorado). Here navigation information and satellite orbits are adjusted.
The calculation of the coordinates of the GPS tracker is carried out according to the following principle. A radio signal passes from each navigation satellite to a receiver within their reach. The propagation delay of this signal is measured and the distance to each satellite is calculated from these measurements. The location of the receiver is calculated on the basis of measuring the distance from it to all available satellites (in geodesy, this method is called triangulation), the coordinates of which are known and are contained in the signals they transmit.
The GPS receiver is able not only to determine its location, but also to calculate the speed of movement, the time it takes to reach the designated place, and show the direction. But this already refers not so much to the capabilities of the GPS system itself as to the navigator software.
About the history of GPS and navigation satellites
The Americans came up with the idea of creating a satellite navigation system in the distant 1950s, when the first artificial Earth satellite was launched in the USSR. In 1973, the DNSS program was launched, which was later renamed Navstar-GPS, and then simply GPS. The first satellite (test) was launched into orbit in 1974.
After the first Soviet navigation satellite GLONASS (Global Navigation Satellite System) was launched into orbit in 1982, the US Congress allocated funds to the American military to speed up work. The first working GPS satellite was launched in February 1978, and the system began to function at full capacity at the end of 1993, when all 24 satellites took their places in Earth's orbit.
Each navigation satellite weighs about 900-1000 kg, and reaches 5 meters in length with open solar panels. The average service life of a satellite is 10 years. After this period has expired, a new satellite is displayed to replace the exhausted satellite.
About GPS receivers
The speed of calculating coordinates when the receiver is turned on, its sensitivity and positioning accuracy are determined by the chipset with which it is equipped. Chipsets for GPS devices are made by several manufacturers, but the most common is SiRFstarIII from SiRf Technology.
Receivers with the SiRfstarIII chipset have a short cold start time (a few seconds) and can simultaneously receive signals from 20 satellites. They are very sensitive and allow you to determine coordinates with high accuracy.
What is the Difference Between GPS and A-GPS
The list of characteristics of some smartphones indicates the presence of a GPS module, others - A-GPS. What is the difference between these modules?
A device with a conventional GPS receiver during a cold start (when the navigation system has not been used for a long time) can search for satellites for a long time - the waiting time sometimes reaches 10 minutes or more. This is because the GPS receiver searches for satellites without knowing their location.
When using A-GPS, the device immediately receives part of the necessary information using the GPRS / 3G network (traffic no more than 10 KB). Thus, A-GPS is a software add-on over the GPS-receiver, which significantly reduces the satellite search time during a cold start. In addition, this add-on allows you to increase the accuracy of positioning in areas with a weak signal from satellites.
There is, however, one small drawback to A-GPS. Unlike GPS, which is absolutely free to use, A-GPS has to be paid according to the tariff set by your provider, since it consumes Internet traffic (albeit insignificant).
Smartphones have long ceased to be simple "dialers". They have opened up a lot of new opportunities for their owners.
In the first place is full-fledged high-speed Internet access and communication in social networks and instant messengers. But no less in demand is GPS positioning, which we will now discuss in detail.
What is GPS?
GPS is a navigation system that determines the location of the smartphone, builds routes and allows you to find the desired object on the map.
Almost every modern gadget has a built-in GPS module. This is an antenna tuned to the GPS satellite signal. It was originally developed in the United States for military purposes, but later its signal became available to everyone. The gadget's GPS module is a receiving antenna with an amplifier, but it cannot transmit a signal. Receiving a signal from satellites, the smartphone determines the coordinates of its location.
Almost every modern person has at least once used GPS navigation on a smartphone or tablet. The need for it can arise at any time for people of different professions and different occupations. It is necessary for drivers, couriers, hunters, fishermen and even ordinary pedestrians who find themselves in an unfamiliar city. Thanks to such navigation, you can determine your location, find the desired object on the map, build a route, and if you have Internet access, bypass traffic jams.
Offline maps for GPS
Google has developed a special geolocation application for its Android operating system - Google Maps. It quickly finds satellites, develops routes to facilities and suggests alternatives. Unfortunately, in the absence of a cellular network coverage area, Google Maps does not work, since geographic maps are loaded here via the Internet.
For offline navigation, the best solution is to download apps that support offline maps, such as Maps.me, Navitel and 2GIS. You can also install the Maps: Transport and Navigation application for Google Maps.
In this case, you will not have to spend Internet traffic to download maps - they will always be in your device, regardless of location. This is especially true when you are abroad, since the cost of roaming for Internet access is very high.
How to enable GPS on Android?
The GPS module can be activated in the Android operating system in two ways:
- Upper curtain. Swipe down on the display and in the menu that opens, click the button "Location", "Geolocation" or "Geodata" (depending on the version of Android).
- In the Android settings, find the item similar items, move the checkbox to the "Enabled" position.
During the active operation of the smartphone's navigation system, its battery charge begins to be consumed quite actively, so you should take care of additional power sources. For example, when driving, you need to use a car charger, and when traveling by bike or on foot -.
It is also worth remembering that reliable reception of a satellite signal is possible in an open area, so when you are in a room or a tunnel, geolocation becomes impossible. Cloudy weather also affects - because of the clouds, the device searches for satellites longer and less accurately determines its coordinates.
Not so long ago, GPS was the only geolocation system, so in earlier versions of Android only it was mentioned, and the button for activating the service was called that. Since 2010, the Russian one has fully earned, and since 2012 -.
To begin with, GPS or Global Positioning System is a global positioning system. Quite simply, this system is a virtual map with which the user can determine his location. It should be noted that the above-mentioned system has nothing to do with GPRS (General Packet Radio Service), since the latter is a so-called GSM add-on for packet data for accessing the mobile Internet.
If, nevertheless, to return to GPS technology, then it is used not only by motorists, as many people think. The scope of the GPS system is much wider. For example, it is very popular among travelers, hunters, fishermen and other people who prefer active pastime and who from time to time need information about their own location or the location of a particular location. In addition, if you need information on the speed of the vehicle and the estimated time of arrival at the destination, GPS can become an indispensable tool.
Note that GPS receivers differ in the speed with which they can calculate coordinates from the moment they are turned on, as well as in sensitivity and positioning accuracy. All of these parameters depend on the chipset that the GPS receiver is equipped with. There are chipsets for GPS devices from a number of manufacturers on the market, however, the most popular are SiRfstarIII chipsets, which are manufactured by SiRf Technology. Receivers equipped with the SiRfstarIII chipset demonstrate a short so-called cold start time, when the navigation system has not been used for a long time, it amounts to a couple of seconds. In addition, these chipsets provide the ability to receive signals from 20 satellites at once. Moreover, GPS receivers with SiRfstarIII chipsets are considered the most sensitive and have high-precision positioning ability.
What is the difference between GPS and A-GPS?
To begin with, it is worth mentioning that the technical specifications of smartphones contain information about different modules. While some are talking about a GPS module, others are about A-GPS. What is the difference between them? If the device is equipped with a conventional GPS receiver, then during a cold start (what it is - read above), the search can be delayed because the navigator cannot quickly find the satellite, and this can take more than one minute. The reason for the long search for a satellite by a GPS navigator is simple - the lack of information about the actual location of the satellite.
If the device uses the A-GPS technology, then the necessary information is promptly received using the GPRS, 3G or LTE (4G) network (traffic does not exceed 12 Kb). At its core, A-GPS is a software add-on for a GPS receiver, with the help of which the satellite search time during a cold start can be significantly reduced. As already noted, the acceleration is achieved mainly due to alternative communication channels. By and large, for the A-GPS technology to function, a communication channel with a remote server is required, from which the information necessary for a GPS receiver is received. If we return to mobile devices, then in their case it is an Internet connection of cellular communication or using Wi-Fi.
Note that the A-GPS add-on has both advantages and disadvantages. If you start with the advantages, then it is worth noting the very quick determination of coordinates immediately after switching on. In addition, the technology increases the sensitivity of receiving a weak signal in the so-called dead zones - tunnels, indoors, in valleys, etc. However, a significant disadvantage in A-GPS is the inability to work where there is no cellular network coverage. In addition, the use of A-GPS cannot be completely free, like, for example, GPS. This is due to the consumption of Internet traffic by the A-GPS add-on, which must be paid depending on the tariffication of a particular Internet provider.
