23.04.2016 / 1619
With the advent of new technologies for laying routes and orienting on the ground, the traditional paper map and compass are used less and less often, because they have been replaced by a high-precision electronic device - a navigator that allows you to determine your location with an accuracy of several meters. Anyone can use it - no special skills are required from the user, and it does not matter where the object is: in a metropolis, mountains or forest.
A GPS navigator is an electronic device equipped with a special module for receiving signals from satellites from the NAVSTAR global positioning system, with the help of which it determines its current position on Earth. There are two satellite navigation systems in the world: GPS (Global Positioning System), which is a development of the US Department of Defense and is under its control, and the Russian analogue of GLONASS. Depending on the purpose, GPS navigators are geodetic, marine, aviation, automobile, portable and have various technical designs.
GPS navigator device
The hardware part of the GPS navigator includes a plateau with a processor, antenna, display, memory, power supply. The software consists of an operating system, software shell, BIOS, navigation programs and additional applications.
Maps in GPS navigators
The basis of any navigator is maps, since with the help of satellites the system can only determine the coordinates of an object, but only with the help of maps a graphic version is recreated on the screen, which allows you to navigate the terrain. Maps in the GPS-navigator are loaded separately, and their choice is determined by the owner of the device. A variety of maps may include, in addition to the route to the destination, attractions along the route, gas stations, hotels, cafes, etc.
How the GPS navigator works
The navigator communicates with satellites, receives signals from them, with the help of which it determines the parameters of longitude, latitude and altitude, selects the corresponding map and determines the location of the object. The satellites must remain in sight, the quality of the signal is affected by the terrain and weather conditions. Binding radio signals are transmitted by more than 24 satellites located in 6 near-earth orbits. The satellites form an interconnected network operated by GPS stations located on tropical islands that are linked to a US-based focal point.
Each navigator has a receiver that communicates directly with the satellites. The radio signals arriving from satellites contain encoded information, including the number of the transmitting satellite, its technical condition, location in the Earth's orbit, and the current date and time. To determine the location of an object, the GPS-navigator calculates the time elapsed from the moment the signal was sent from the satellite until it was received on Earth. The resulting time difference, multiplied by the speed of the radio wave, allows the receiver to obtain distance data for a specific satellite. By collecting information from several satellites, the GPS navigator can calculate the coordinates of its location. Having signals from 3 satellites, the device can determine latitude and longitude - the so-called "two-dimensional fixation". If there are 4 or more satellites, then the navigator can determine the location of the object in 3-dimensional space, that is, indicate the longitude, latitude and altitude.
Scope of GPS navigators
This device can be useful everywhere, except in places where satellite signals are not available (under water, underground, etc.). GPS navigators have found application in the military, aviation, navigation, geodesy, road transport, tourism, hunting and fishing, rescue operations, scientific and research activities.
According to their purpose, navigators can be divided into professional and household ones. Professional devices are characterized by special software and navigation systems, high positioning accuracy and long battery life. Household GPS-navigators became widespread after 01.05. 2000, since before this date, the positioning accuracy was artificially lowered using a special error (SA), which was ± 50-100 m. At present, the maximum accuracy of a domestic navigator is ± 3-5 m, and of a professional one, up to several cm, subject to a corrective signal from a ground station.
Types of GPS navigators
Aviation navigators. These devices are installed on various aircraft and perform a number of special functions. They have special maps and databases.
Marine navigators. These devices contain special nautical charts reflecting a database of depths, dangers to navigation (shoals, reefs), names of islands, ports, bays. They are installed on all types of maritime transport and are often equipped with echo sounders.
Car navigators. These most popular and widespread household navigators will help you find the right address, lay the shortest path, and avoid traffic jams. They are practical and functional, simple and easy to use, equipped with sound interactive prompts and many additional functions.
Travel (portable) navigators. These compact devices are lightweight, and there are models with shock and water resistant casing. Their display is often black and white to save energy. The device displays the route, terrain features, heights. Some models may have additional functions: altimeter, compass, solar and lunar calendars, temperature sensor, etc.
Sports navigators. They are used by athletes in cyclic outdoor sports (running, skiing, cycling). These devices provide registration of the parameters of the athlete's body together with the parameters of movement (speed, trajectory, distance traveled). Devices are made in the form of a wristwatch or mounted on a bicycle handlebar, in a waterproof, shockproof case, with minimal dimensions and weight. Sports navigators are equipped with external sensors that record the heart rate, the number of revolutions of the bicycle pedals, the number of steps, etc., which transmit data over the radio channel to their own non-volatile memory.
Car GPS Navigators
Car navigators look like a small TV that is mounted on a bracket on the dashboard or suspended from the windshield. The device is powered from its own battery or cigarette lighter. Navigators have a powerful processor that allows you to quickly and without delays "redraw" the map and move the car on the display. The purpose of car GPS navigators is to automatically plan a route, taking into account its options and road infrastructure, accompanied by voice prompts.
The standard functions of the car GPS-navigator are route planning, address search, and voice assistance. Additional options include storing routes, notification of accidents, traffic jams and radars in the direction of travel, touchscreen display, video recorder, access to multimedia applications, playing MP3 files, FM transmitter, video player, Bluetooth, GSM / GPRS module, TV tuner ... Expansion of the functionality entails an increase in the cost of the device.
The most popular brands of car GPS navigators
Garmin
The products of the American company Garmin are of high quality, reliability and versatility. At the same time, the devices are not equipped with unnecessary functions, since, according to the developers, the navigator serves solely to plot the exact route. Garmin car navigators have an intuitive menu, built-in routing function, loaded with the largest maps of Russia, and the presence of an FM antenna will help track traffic jams and traffic lights located on the route. Some of the more popular models are the Garmin nuvi 2455, Garmin Nuvi 3597LMT and Garmin Nuvi 1410T.
Prestigio
The models of the Chinese company Prestigio are distinguished by a high degree of reliability, they look stylish, are easy to install, and fit well into the interior of the car cab. They are faithful driver assistants, comfortable and easy to use with software from Navitel. Prestigio car navigators are equipped with navigation software with stunning 3-dimensional visualization of buildings and landmarks, voice instructions, traffic alerts. The best models are Prestigio GeoVision 5056, Prestigio GeoVision 7777 and Prestigio GeoVision 5660GPRSHD.
TomTom
GPS-navigators of the TomTom brand are made in the Netherlands from high quality materials, equipped with comfortable mounts, a loud speaker, and are fully Russified. They have a simple interface, lightweight smart menus, proprietary software and maps, fastest route calculation, traffic information, voice commands, quick search for points of interest and free lifetime map updates. The most popular models are TomTom Start 60, TomTom GO 610 World, TomTom GO 6000, TomTom Urban Rider 5, TomTom VIA 135, etc.
Domestic manufacturers are represented by the most popular brands Lexand, Navitel, Explay, TM Shturmann, Prology, TeXet.
Lexand
Under the Lexand brand, inexpensive and functional navigators are sold, the only drawback of which is low anti-glare protection. Buyers appreciated them for the high capabilities of the built-in memory, good software, variety of functions and the presence of a DVR. The best models are Lexand D6HDR, LEXAND SA5 HD + and Lexand ST-5650 PROHD.
The Russian brand TeXet can be attributed to the budget segment, nevertheless, the devices are equipped with a video recorder, built-in memory of 4 GB, CityGuide and Navitel software. The best navigators are the TeXet TN-522HD DVR and TeXet TN-515DVR.
Explay
Explay navigators can be safely called reliable, convenient and high-quality equipment. The line includes both compact budget devices with a minimum set of functions necessary for navigation at an affordable price, as well as expensive multifunctional models with a camera, Bluetooth, TV tuner, GSM / GPRS module and a rich selection of multimedia applications. All devices are equipped with a large widescreen display and a large speaker. The best models are Explay Patriot, Explay ND-41, Explay ND-52B, Explay PN-965 and Explay PN-955.
Navitel
Navitel navigators have already loaded maps covering Russia and 11 more countries. Some models provide the ability to receive information about traffic jams. It is the Russian company Navitel that is the developer of the Navitel Navigator software, which is distinguished by the accuracy of maps and the relevance of information about the traffic situation, radars and cameras. The best navigators are Navitel A730, Navitel A501.
TM Shturmann
TM Shturmann navigators have a clear, fully Russified interface, the ability to work with multimedia applications, including getting information about traffic jams from the Yandex. The devices are loaded with maps and atlases, which are the company's own developments. Some of the most popular models are Shturmann Link 500 FM, Shturmann Link 700HD, SHTURMANN Mini 100.
Prology
The Russian company Prology manufactures its products in China, but the Prology GPS navigators, as well as, are of good quality and reliable assembly. The installed Navitel Navigator software does not require additional purchase of maps. There are models with a built-in DVR, FM modulator and Bluetooth. The most popular models are Prology iMap-5600 Black, Prology iMap-7300, Prology iMAP-4300, Prology iMap-580TR, Prology iMap-4020M.
Tourist GPS Navigators
Portable GPS navigators are designed to be taken with you on hiking, cycling, fishing, hunting, etc. These are compact, lightweight devices with a small screen, a large battery and a powerful receiver. Many devices are equipped with additional options, including a compass, barometer, altimeter, temperature sensor, etc. Ordinary batteries can be used as an alternative power source, which is very convenient when there is no access to electricity. Portable navigators are made in the form of small tablets or mobile phones, in convenient narrow formats that allow them to be fixed on the shoulder, wrist or handlebars of a bicycle, and in the format of a wristwatch. For extreme conditions, rugged navigators are produced in a rubberized shockproof, dustproof and waterproof case.
The most popular models of tourist GPS navigators
The undisputed leader in the travel navigator market is Garmin, which produces a number of popular series: eTrex, GPSMAP, Fenix, Monterra, Dakota, Montana and Oregon.
This series presents a navigator wristwatch equipped with an altimeter, barometer, compass, stopwatch, temperature sensor. This lightweight, compact, convenient and reliable device with stable satellite signal reception weighs only 82 g. Unfortunately, the map display on the small black and white screen leaves much to be desired. There is no Russian language, so all messages are received in English (French, German, Spanish, Italian). Fenix can exchange stored data using BlueTooth, Garmin ANT's wireless service, via USB with a computer.
Monterra
This Android based navigator uses 2 navigation systems: GPS and GLONASS and a pre-installed set of maps. The device is equipped with a large display with durable mineral glass, a built-in camera and a flashlight. The IPX7 waterproof housing guarantees the instrument operation at a depth of 1 m for 30 minutes.
Gpsmap 64
The device has a color screen, fast processor, Bluetooth, memory card slot, massive antenna. Gpsmap 64 uses 2 navigation systems: GPS and GLONASS and a pre-installed set of maps. The buttons are located on the front panel of the device, the case is firmly assembled, reliably protected from shock, dust, immersion in water and freezing temperatures.
Montana 650t
This navigator has 3GB memory, memory card slot, large anti-glare touchscreen and simple interface. The moisture-proof housing has increased durability. The built-in camera (5 Mpx) allows you to take photos with reference to the shooting coordinates. The device can be used as a car navigator. With the headphone jack, you can listen to voice prompts on the road.
How to choose a GPS navigator
The starting point when choosing a GPS navigator is its purpose and the range of tasks for which the device is supposed to be used. Once you have identified a list of suitable devices, you need to decide on an acceptable price range. Study the most popular models carefully and determine what the more expensive devices have and what the cheaper ones don't. Then decide if you need the extra features found in more expensive models, or if a cheap equivalent will suffice. When you first get to know your car navigator, pay attention to the display diagonal and picture quality, choose a navigation software. Once you've settled on 2 or 3 models, be sure to try each one, as the difference in usability can be quite large. One navigator will be clear and easy to use for you, while the other will be overly complicated.
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 Internet connection (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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What is GPS?
GPS - General Positioning System - consists of 24 satellites that move in orbits around the earth. Each satellite is powered by solar panels and has a lifespan of about 10 years. All satellites are united into a single network and are absolutely free when used by civilians. Anywhere in the world, the user of a GPS navigator will be able to determine his location in a matter of seconds. To determine the coordinates, the GPS-receiver needs to “see” at least two satellites. This method of determination is called "two-dimensional fixation", while on the screen of the receiver you can see the latitude and longitude, but if there are more than four satellites in the navigator's field of view, then the determined information becomes more. Parameters such as the speed of movement of the object and its height above sea level are added (by the object we mean a GPS navigator). Of course, GPS navigators are presented on the market not by one device, but by a fairly large number of them, ranging from GPS modules integrated into pocket computers and ending with specialized system devices created exclusively for orientation on the ground. Since the beginning of the 21st century, GPS has exploded into the automotive industry. As a consequence of this, an additional option appeared in the right cars (BMW, Audi, Mercedes) - a satellite navigator.
We will talk about all GPS navigation devices in this article.
Types of GPS receivers.
Let's not hide the fact that GPS technology is exclusively of military origin. Modern military operations imply pinpoint strikes against enemy forces, and precise knowledge of the coordinates is required to target the shells.
Needless to say, in earlier times, military and civilian navigators had colossal differences. For example, the positioning accuracy of the civilian navigator was "shifted" by 150 (!) Meters in the radius, while the military navigator allowed himself to make errors of no more than 1-5 meters. The difference, especially in the mountains, is quite decent. But the Chinese brothers absolutely do not care what their American friends think about positioning accuracy. For this reason, the market was flooded with streams of various microchips for the manufacture of GPS-receivers with an error of up to one meter, and the result was not long in coming. The first type of navigators appeared - a symbiosis of a pocket computer and a GPS-receiver installed in a Compact Flash slot. It went on sale already in 2002.
Prior to this event, sagacious techies connected the Garmin receivers existing up to that moment to the COM port of handheld computers, of which there were also not very many at that time. While writing these lines, one involuntarily thinks about the insane speed of technical progress: it would seem that in 2002 all this was just beginning, and just four years later, GPS navigation performs so many different functions that you are amazed.
Specialized devices on the market were constantly present, another question is that consumers did not really like the strange box with a monochrome display, standing like a good 19-inch monitor (remember that this happened in 2002-2003). Nevertheless, the boxes were sold and enjoyed a well-deserved reputation among tourists and outdoor enthusiasts.
As we mentioned above, such a device was the Garmin navigators. The company is the undisputed leader in the production of specialized GPS-receivers, however, despite its superiority, it is very weakly represented on the Runet. A feature of these navigators is the need to use only "native" maps and software. However, we will talk about this later.
At the same time, the Bluetooth wireless communication standard received its development, which brought a lot of new things to the mobile phone industry and not only. Soon, the first Bluetooth GPS-adapters appeared, which were connected to a pocket computer via a wireless connection - in fact, a hardware COM-port was emulated for the software to work, and no one noticed the substitution.
In 2003-2004, the idea of universal miniaturization was developed, which brought many strange products to the market. For example, companies have stopped producing pocket computers with a Compact Flash port interface. Instead, there is only one slot left on the top of the PDA - SDIO MMC. And the presence of the CF-port automatically designated the PDA as an advanced and serious model. SDIO devices could also emulate a COM port, so SD GPS receivers soon appeared on the market (around the end of 2004). It should be noted that the size of these devices has been greatly reduced, and this, in turn, has led to a decrease in power consumption. microchips have also been affected by progress. And finally, the last step in the integration of GPS-navigation was made by Mitac, having arranged the delivery of a PDA with an integrated GPS-module. The PDA worked on its own, and the GPS could be used at any time.
Maps and software.
A set of maps is required for any navigator, otherwise the use of the device becomes impossible. Maps are most often supplied in maximum detailed magnification and allow you to navigate literally "home". For a PDA, one of the best examples of such a map is the Pocket GPS PRO program operating in Moscow. There is also a Palm GIS program on the market, but this system is unknown to most users. Perhaps the most powerful program for compiling and editing maps and routes is Ozi Explorer, which works with raster maps. This program has just a colossal number of different cards. The author of this text has a DVD, on which more than 4 GB of cards have been collected by the careful hands of our head of the test lab. And, most importantly, these cards are created by enthusiasts, are completely free and can help out a lot in a critical situation. One thing is bad - Ozi Explorer is not cheap, but this does not stop our colleagues, you just need to think a little, and the problem will be solved.
Auto.
Now is the time to deal with the most interesting representative of GPS devices - the car navigator.
So, what is interesting about the car navigator. Firstly, it integrates directly into the car and, importantly, allows the use of certain functions of a modern car to facilitate its operation. For example, with a small amount of fuel in the gas tank, the system gives a voice that it would be necessary to refuel, and the nearest gas station is such and such a number of kilometers, so we may not get there, so turn back, master, otherwise we will stand here in the middle of the Kalmyk steppe. Secondly, the correct car GPS-navigator allows you to edit routes in every possible way, leaving various marks on the map, for example - there is a diner here, but here were my comrades in blue-gray uniforms and took me for 180 km / h ... pit, and here - tire fitting. Thirdly, GPS navigation in cars has another useful advantage - it can be silenced at any time by pressing one button, which is not always possible when using the symbiosis of a PDA and a navigator module. This quality is especially noticeable in the latest BMW models of the fifth and seventh series - the car is able to drive anyone to a frenzy, he is very sociable.
However, this is not all. GPS navigation in cars is extremely popular with companies specializing in protecting vehicles from theft. We will talk about this in the next part of the article.
Anti-theft protection with GPS and mobile phone.
We do not believe that it is necessary to somehow compromise the providers providing tracking services for your car, but we consider it necessary to warn that absolutely any car is hijacked, absolutely regardless of what and how is installed on it. No one has yet escaped from a tow truck, a muffler and a shielded concrete box outside the city.
How it works? A set of equipment is installed on the car, consisting of a GPS receiver for determining coordinates and a device for organizing a communication channel between the car and the dispatching console. The latter is a conventional device that essentially works as a cell phone. The device connects to the system via a COM port and allows two-way signal transmission. Thus, you can give commands to the car - start / stop the engine, close / open the doors, or instantly determine the location of the vehicle. Plus, if the GPS signal does not pass, and the mobile device “sees” the towers of the cellular operator (most often GSM), then the coordinates can also be determined by the position of the phone. Similar services are provided by all GSM-operators in the Moscow region (by the way, it was this decision that saved the BMW X5 of one of my acquaintances - author's note).
In the event of a pre-agreed "contingency" situation, the alarm signal is transmitted to the dispatching control panel and, upon confirmation of the problem, to the traffic police station ... Then everything works only at the behest of the police officers. Of course, if the hijackers are professionals in their field, the car will simply disappear from the monitors at one point, and the only thing left to do is to hope for the best anti-theft - car theft insurance. At the moment, only such protection can guarantee a relatively restful sleep of the owner of an "interesting" car.
However, satellite signaling in most cases allows a fairly high level of control over the car and, at least, will save if inexperienced hooligans are interested in it. Another thing is that, as a rule, after the intervention of such "pioneers" the car is very distorted. The larvae of the door locks are turned out, the blocker and the ignition lock are broken. The pleasure is very expensive. So the garage, security ... and more money.
What to choose?
An absolutely uncertain situation is emerging, since the choice of GPS devices is extremely large and interesting. However, we have tried to classify the most popular GPS receivers on our market. Regarding the built-in navigation systems in cars, we can note that there are practically no official maps for our country, and those that exist cost about a thousand euros. By the way, it was also necessary that for a long time civil GPS was outlawed, and this greatly impeded the development of such solutions on the territory of our country.
And if there is no extra money, then the good old PDA and Compact Flash GPS-adapter will help you solve the problems with navigation. Believe me - just try it once and you will never part with GPS!
Gps- the initial letters of the name of the global coordinate system - Global Positioning System.
What is this system?
This is a system that allows you to determine the location of an object with an accuracy of at least 100 m, i.e. determine its latitude, longitude and height above sea level, as well as the direction and speed of its movement. In addition, using GPS, you can determine the time with an accuracy of 1 nanosecond.
What is GPS made of?
GPS consists of a set of a certain number of artificial earth satellites (satellite system NAVSTAR) and ground tracking stations, united into a common network. The subscriber equipment is individual GPS receivers capable of receiving signals from satellites and calculating their position based on the received information.
What is the NAVSTAR satellite system?
The NAVSTAR satellite system includes 24 satellites located in 6 different circular orbits, which are located at an angle of 60 degrees to each other. The orbital period of one satellite is 12 hours. Each satellite weighs about 787 kg and is over 5 m in size, including solar panels. Each satellite is equipped with an atomic clock providing an accuracy of 10-9 seconds, a computational encoder and a 50 W transmitter, emitting at a frequency of 1575.42 MHz.
The birth of NAVSTAR can be considered February 1978, when the first satellite of the system was launched into orbit. The average service life of one satellite is approximately 10 years, therefore the program includes continuous production and launching of new satellites into orbit, replacing those that have used up their resource. The cost of building and launching 24 satellites is $ 12 billion.
What information do satellites transmit to Earth?
Every millisecond the satellites transmit to Earth:
Your status (message about serviceability or malfunction);
the current date;
current time;
almanac data;
the exact time when the entire set of messages was sent.
What is an almanac?
This is information about where in the celestial sphere each satellite should be located at any time during the day, i.e. orbital data of all satellites.
How are coordinates determined?
Based on the information received from the satellites, the GPS receiver determines the distance to each satellite, their relative position and calculates its coordinates according to the laws of geometry. At the same time, to determine 2 coordinates (latitude and longitude), it is enough to receive signals from three satellites, and to determine the height above sea level - from four.
How does a GPS receiver determine the distance to satellites?
Since the propagation speed of radio signals is constant and equal to the speed of light, the distance to the satellites is determined by the delay in the time the GPS receiver receives a message relative to the time the message is sent from the satellite. Of course, in order to accurately determine this delay, the clocks on the satellites and the clocks in the GPS receiver must be synchronized, which is ensured by synchronizing the clocks of the receiver according to the information contained, as indicated above, in the satellite signals.
What are the sources of location bias?
The main source was the presence of the so-called "limited access" regime. In this mode, the US Department of Defense a priori introduced an error into the satellite signals, which made it possible to determine the location with an accuracy of 30 - 100 m, although in principle the accuracy of the GPS system can reach several centimeters. On May 1, 2000, the "limited access" mode was disabled.
Other sources of error are the unfortunate geometry of the relative position of satellites, multipath propagation of radio signals (the effect of multipath radio waves on the receiver), ionospheric and atmospheric signal delays, etc.
What is a GPS receiver?
The GPS system allows you to determine the location anywhere on land, at sea and in near-earth space. Depending on the field of application, the range of which is quite wide, as well as on the cost, which can range from hundreds to several thousand dollars, the performance of GPS receivers is also very diverse. In general, the entire range of models can be divided into four large groups:
Personal GPS receivers for individual use.
These models are distinguished by their small dimensions and a wide range of service functions: from basic navigation, including the ability to form and calculate routes to follow, to the function of receiving and transmitting e-mail.
Car GPS Receivers, which are intended for installation in any ground vehicle and have the ability to connect external transmitting and receiving equipment for automatic transmission of traffic parameters to dispatch points.
Marine GPS Receivers equipped with an ultrasonic echo sounder, as well as additional replaceable cartridges with cartographic and hydrographic information for specific coastal areas.
Aviation GPS Receivers used for piloting aircraft, including commercial aircraft.
Are there other positioning systems?
Yes. The domestic military space industry has created an alternative satellite system GLONASS. However, despite the higher positioning accuracy, its reliability and consumer characteristics are significantly lower than that of NAVSTAR, and today this system has not received widespread adoption.
GPS navigation is one of the most requested features on a smartphone. When exploring the city by car or bike, it is imperative to follow the optimal path. Navigators will help you optimize the auto and get to the desired coordinates faster.
We compared the popular top-end mobile navigators. Main criteria: ease of use, functionality and price (free of charge) of the navigator. At the end of the review, let's summarize: which navigator is the best.
Participants:
Over time, the review will be updated with new gps-programs. If, in your opinion, there are more interesting navigators for Android, leave your comments at the end of the article, through the contact form. Thanks!
Google Maps for Android - standard android navigator
Looking at Google Maps a year ago, we noted that some of the navigator's functions are not finalized, not optimized. By 2019, things have improved markedly - especially in terms of user experience. However, we note some of the rough edges of Google Maps.
The offline map download feature is relatively new. It allows you to plan routes and navigate the map without an Internet connection. Due to the fact that offline maps are not yet a fully tested function, not everything is so smooth with it. However, like other Android navigators.
The disadvantage is that you cannot download maps for large regions of Ukraine, Russia, Belarus and other CIS countries. Only selected offline maps of major cities or regions are available. When driving outside the city limits, it is difficult for a motorist to do without online synchronization.
Disadvantages of Google Maps
1) The choice of locations and attractions in Google Maps is rather scarce: to get complete information about the hotels, restaurants, shops, schools and other things available nearby, you have to use third-party applets (Foursquare, TripAdvisor, Yandex.Gorod).
2) No data on road accidents; you cannot add points with car accidents yourself, which would be quite useful for alerting other drivers.
3) In comparison with Yandex Navigator, there is no warning about speed control, there are no alternative voice assistants.
Benefits of Google Maps
However, Google Maps has many positive aspects.
Yandex Navigator: a navigator with voice control
The interface of the mobile version of Yandex Navigator is well structured and clear. When driving a car along a laid route, it displays information about the approximate time remaining to the destination and the distance to the end point. If on the way you need to call at a service station, gas station or car wash, you can specify an additional point on the Yandex Navigator map - and the route will be optimally recalculated taking into account the intermediate point. You can turn on and off the layer with the display of traffic jams and directions by pressing a single button with a yellow traffic light.
One of the exclusive features of the navigator is the night gps mode for Android, where the map is displayed in dark colors, without distracting the driver's attention while driving at a later time and does not let the eyes get tired when looking at objects. By the way, the range of searchable POIs is really impressive. Along with the already familiar restaurants, ATMs and cinemas, you can use layers to display nearby points of contact, post offices, salons and many other interesting places.
Another nice feature is from the phone. Similar to Google Maps, you can search for the desired objects on the map, request addresses on the map.
As for the work of the program in offline mode, you can download gps-maps for Android for large settlements in Ukraine, Russia and Belarus. By turning on Yandex Navigator offline, you can view them, however, planning routes, searching for local attractions on the map is possible only if you have a connection to the network.
Thus, Yandex Navigator for Android leaves the most pleasant impression of itself. The product claims to be the best free gps navigator for Android in 2018.
Navitel: well-designed gps navigator for Android
Navitel Navigator is a gps software from a leading developer in the field of navigation and digital maps creation. To purchase the cards themselves, you will have to fork out for a small amount, but if you wish, you can also download them for free on torrents or file sharing services (for example, on the pda forum).
Strengths of Navitel Navigator
1) Map display options: switch between 2D and 3D modes, which in some situations will be especially useful.
2) Convenient interface. The lion's share of branded chips is available in the top line for quick access. Choose between night and day skin
4) Switching between satellites: in any weather conditions, a map with POI is always available.
Note. Not so long ago we did it for Android, where we listed in detail all the advantages and individual "features".
Navitel Navigator: GPS routes on the screen
5) Convenient management. When navigating along a route, managing the map is quite intuitive and simple: there is a zoom function, map rotation according to movement, the ability to switch between preset profiles for any type of transport.
6) Information content. The movement is visually accompanied by information about the speed of the object, the remaining time to reach the destination, the distance of the next turn and audio support. In general, the navigation is well thought out and intuitive.
A well thought-out functional part and high-quality design make the Navitel mobile application the main candidate for the "Best GPS Navigator for Android" nomination.
Waze - informative gps-navigator for Android
Waze (Free) is a free navigator for Android with opensource code.
Benefits of Waze
1) Social features integrated into Waze greatly improve driving experience. Waze users report problems on the road - be it repairs, accidents, traffic jams, traffic police posts, cameras and other “troubles”. Accordingly, other drivers are already aware of the changes. In addition to reviews, the application collects information from its own database on the server.
2) Map with routes - informative. Waze uses proven OSM maps. They are highly detailed and accurate.
3) Waze will automatically re-route if your phone crashes, an app crashes, or something else that could interrupt your navigation. Standard Google Maps doesn't. Likewise, Waze makes it easy to see your route or map when needed and always returns to Automotive mode.
OsmAnd: offline navigation for Android
Let's list the strengths of the OsmAnd navigator.
Pros of OsmAnd
1) Autonomy. OsmAnd is, first of all, not bad. Suitable for those who prefer to download maps to a gadget once and no longer connect to the Network while offline.
2) Maps. For navigation in OsmAnd, raster and vector Open Street Maps are used, compiled by users of the service. They allow you to filter POIs (attractions, museums, theaters, pharmacies, etc.), select a profile for the corresponding vehicle. The travel route can be optimized taking into account the shortest distance, avoiding toll, dirt roads, ferries, highways.
OsmAnd is one of the best navigators for Android
3) Customizable maps. You can add objects yourself, create or edit maps. Thanks to the support of plugins, the functionality of OsmAnd is significantly expanded: for example, you can activate the OsMo live monitoring system tracking other gadgets using the service; add to groups; download nautical and ski maps; calculate the optimal distances between the specified points using GPX; overlay contour lines and layers of relief, which will surely be appreciated by tourists and athletes).
4) Additional functions. All the standard features for gps-navigators are also present: voice control, assistant, screen reorientation, profile switching.
Maps.me
Maps.me is a gps navigator popular in Russia, USA and Germany. It is characterized by high accuracy and autonomy of maps.
Strengths of Maps.me
1) Accuracy and detail of maps is almost the most important, regardless of the type of transport. This navigator will be of interest to travelers and pedestrians, since the smallest details are displayed on the map - paths, benches, names of objects.
2) Additional layers. Maps.me displays vector maps, traffic jams and a subway map can also be displayed through layers.
3) Lots of settings. In the settings of maps.me, you can change the units of measurement, scaling, see the history of movement, and more. There are navigation settings, in particular, you can set up auto zoom, voice instructions, enable the display of speed cameras.
4) Switching navigation modes. You can choose from a car, a pedestrian, public transport, a taxi and a bicycle.
5) Autonomy. Offline maps downloaded to a mobile device take up little space, while they work fully, as if the Internet were present. It is clear that realtime functions will not be available, but information about traffic jams is not as important for a pedestrian or cyclist as it is for motorists.
Disadvantages of Maps.me
1) Limited navigation for motorists. It is difficult to call Maps.me a perfect car navigator. At a minimum, travel routes are not always built correctly, not to mention the fact that the navigator does not offer alternative options.
2) There are errors. Since the maps are developed by the community, the data is not always relevant, especially for remote places, villages.
3) A rather inconvenient mode of displaying maps. The maps look very dry and the scaling may not work.
Which navigator is the best as of 2019
Each of the android navigators, in some aspects (functions, maps), is better than its competitors and is good in its own way. Which navigator is right for you depends on your preferences and beliefs. We hope we helped you choose the right application and it will remain on your phone.
| Navigator app | Developer | Price | Offline maps support | Traffic jams | Voice acting | Russian language |
| Google maps | Google Inc. | is free | + | + | + | + |
| Yandex Navigator | Yandex. | is free | + | + | + | + |
| Navitel Navigator | Navitel | from 1000 rub. | + | + | + | + |
| Waze | Waze navigation | is free | + | + | + | + |
| OsmAnd for Android | OsmAnd | from 6.75 $ | + | + | + | + |
Yandex Navigator absolutely free and has excellent functionality. It wins in the nomination "Best Android Navigator with Yandex Maps Support".
Navitel Navigator created and supported by the most famous company, so the quality of products and technical support are at their best - both for Android OS and other mobile devices.
Navigation application Waze- certainly attracts with its openness and free cards. However, like any evolving product, this navigator is not perfect. We hope the growing community will have a positive impact on the quality of the app. For 2018, alas, Waze maps are inferior in informational content to the same Navitel or Google Maps.
Concerning OsmAnd, then this offline navigator for Android will perfectly serve in conditions of impossibility to connect a mobile device to the network and works using open technologies.
Google maps- navigator with voice control function. The good thing is that it is available out of the box (that is, it is initially included in Android). Google Maps is suitable for inexperienced travelers and drivers; they can be called one of the best offline navigators.
Maps.me will appeal to avid travelers and pedestrians. The navigator will delight you with detailed maps adapted for walking. For motorists, we would recommend alternatives - Google Maps or Yandex Navigator.
