Today, humanity even uses outer space to ensure security. For this, satellite search engines were created. It is believed that the beginning of such navigation was laid on October 4, 1957. It was then that the first artificial Earth satellite was launched for the first time. By the end of the 70s, the first radio navigation system appeared. It allowed to determine the coordinates of any object based on the signals that came from the satellite. And today, such navigation is used in rescue and geodetic work, as well as to ensure the security of the state and citizens.
What are satellite systems? These are complex electronic-technical communications. Moreover, their implementation is possible only with the combined operation of space and ground equipment. At the same time, satellite systems make it possible to determine the height and geographical coordinates, time and parameters of the movement of water, land and airobjects.
Classification
Satellite systems are divided into the following areas:
- security search engines designed for cars;
- navigational, to protect offices, homes, personal territories and apartments;
- security search engines for Internet sites and cell phones; - search navigation (GPS).
Basic elements
Satellite systems include:
- orbital constellations of several satellites (from 2 to 30) that emit special radio signals;
- a ground-based monitoring and control system that establishes the current position of the satellites, as well as receiving and processing information transmitted by them;
- client receiving equipment required to determine coordinates;
- radio beacons, which are a ground-based system that increases the accuracy of establishing the location of an object;- an information radio system that transmits corrections to users to coordinates.
Working principle
Satellite navigation systems measure the distance from an antenna on an object to a satellite whose orbital position is known with high accuracy. In this case, a special table called the almanac is used. It must be stored in the memory of the receiving device and indicate the position of all satellites. If such a table is not outdated, then the location of an object in space is determined by devices using simple geometric constructions. To correctly calculate the width and longitude, the receiver must receive signals from at least three satellites. Well, if you need to knowthe location of the object above the surface? This will require a signal from the fourth satellite.
All the information received is processed by the ground unit, which, using a certain system of equations, displays the desired coordinates. However, the data obtained will require some adjustment. This is due to the influence of atmospheric pressure, air temperature and degree of humidity on the operation of the system. Each of these factors introduces an error within 30 m, the total value of which sometimes reaches 100 m.
Differential GPS mode helps reduce inaccuracy. It transmits the necessary corrections to the user, which ensures the accuracy of determining the object up to 1 cm. At the same time, satellite search engines are able to accumulate and then process data received over a certain period of time. Thanks to such processes, the user has an idea of the speed of the object, the path it has traveled, etc.
GPS
Today, several navigation systems are actively working at once. These are American GPS, Russian GLONASS and European Galileo. All of them will allow you to determine the current location of the object, as well as its time and date, speed and trajectory of movement on land, in the air and on the ground. Let's take a closer look at these navigators.
The history of the American GPS satellite system began in 1973. This was the period of the development of the DNSS program. Later it was renamed to Navstar-GPS, and then to GPS. The first of her companionslaunched into orbit in 1974. And only in 1993 their number was increased to 24, which made it possible to cover the entire earth's surface.
Initially, the GPS satellite system worked for the purpose of the US military complex. And only since 2000 the secrecy stamp was removed from the system. GPS began to serve the needs of civilian consumers. However, at present, the Pentagon can either turn off satellite signals over the territories where hostilities are taking place, or interfere with them. In addition, US intelligence agencies reserve the right to install local "jammers" covering the conflict zone. At the same time, such electronic warfare will not interfere with NATO troops operating on a coded signal.
GLONASS
This Russian navigation system has been operating since the 90s of the last century. To date, the composition of its orbital constellation has more than twenty satellites in orbit. In the near future, their number is planned to increase to thirty.
Since 2007, the GLONASS satellite system has been used for civilian purposes. Today it covers the entire territory of Russia and finds its application in different directions. It is successfully used in transport, which carries out not only freight, but also passenger transportation. Here GLONASS is a satellite monitoring system, as well as a tool that allows you to optimize the traffic schedule. Similar navigation is used in their work by the operational services of the Ministry of Emergency Situations, the police and ambulance.
The principle of operation of the GLONASS system is based onreceipt of information from the tracking beacon via GSM-channel to a remote server. Here it is stored for further transmission to the user. The acquisition time is in the range from 15 to 240 seconds. Further, a special computer program processes the information on the server and gives the location of the object.
In Russia, the latest project is also being developed, called ERA-GLONASS. Such a system will allow special services to respond urgently in case of road accidents and accidents. It is planned that by 2020, all vehicles will be equipped with navigation and communication terminals that automatically transmit signals to the duty and dispatch service in the event of serious accidents, that is, when airbags deploy in the car. After that, the operator will try to clarify all the details of the incident with the driver. If there is no answer or if the information is confirmed, rescuers of the Ministry of Emergency Situations, doctors and traffic police will be sent to the specified coordinates. Thus, satellite transport systems will serve as the driver's first assistant in case of emergencies.
Galileo
This satellite navigation system is designed for countries within the European Union. The $2 billion project is named after Galileo Galilei, the famous Italian astronomer. In its work, Galileo does not depend on the satellite control system of Russia GLONASS and American GPS.
In addition to determining the location of an object whose coordinates can be known with an error of onemeter, Galileo has a search and rescue function. There is no such project in any country of the world (it is only being developed in Russia).
Vehicle security
Today, the attention of many motorists is attracted by a satellite anti-theft system. According to numerous users, it is not only reliable, but also very convenient.
Such security navigation works on the principle of communication between the antenna installed on the car and several satellites. Information about the coordinates of the car constantly comes to the receiving device and allows the user to determine the location of the vehicle with an error of several meters.
Unlike conventional navigation, the satellite anti-theft system not only receives signals from orbit, but also transmits them to the control room or owner. If intruders who are trying to hack the system have entered the car interior, then immediately a signal will go through the networks of the cellular operator or through channels specially allocated for this purpose, which will be received by the owner’s mobile phone or the dispatch console. After that, a response group begins to work, which will determine the movement and further location of the car.
According to user reviews, the car's satellite security system is quite reliable. Neutralizing it is much more difficult than a simple alarm with a siren.
Some models of the satellite search system provide remote engine blocking. Thanks to this feature, the criminal will not be able to drive even one meter on your car. Sometimes intrudersuse jammers. These are silencers that do not "let" the signal. This was taken into account when developing the latest security systems. Their design uses special modules that prevent jammers from working.
Echelon
This satellite car security system has been operating in our country since September 2003. It is a conventional GPS-GSM alarm system, only its processor unit is programmed in a special way. When attempting to steal a vehicle, an alarm is triggered, and when a criminal uses a jammer or if there is no connection with the dispatcher's console, the engine is blocked. This is the algorithm of actions according to which the Echelon satellite system operates.
A significant advantage of this navigation is its ability to prevent theft even in the absence of communication with the owner. According to user reviews, the undoubted advantage of the system is a number of additional features. So, the Echelon satellite system can be programmed to block the engine in the event of:
- exceeding a certain speed;
- leaving the designated area; - longitudinal and lateral acceleration of the vehicle.
Moreover, this operation algorithm can be changed even remotely. To do this, just send the desired program of work via the GSM channel.
Arkan
The bulk of the car's satellite security systems work on the principle of delivering an "Alarm" signal to the dispatcher's console. However, such protection is ineffective in the absence or deliberate suppression of the GPS channel.
The Arkan satellite system serves as an alternative. It transmits information on the special navigation network of the same name. Thanks to a constant radio signal that constantly changes frequency, attackers cannot disable the system. Now such navigation is the most modern technological solution that allows you to easily determine the location of the car.
In addition, the Arkan satellite system:
- can transmit the coordinates of the car when the panic button is pressed, as well as when unauthorized access to the salon is attempted;
- switches to low power mode when battery discharge;- controls the operation of the Arkan channel by continuously supplying test signals.
Satellite communications
There are different types of such systems.
Among them:
1. Trunk connection. Its development was dictated by the ever-increasing need for the transfer of large amounts of information. The first of these systems was Intelsat, and then the regional organizations Arabsat, Eutelsat and many others appeared. Today, backbone satellite communication systems are being replaced by fiber-optic networks.
2. VSAT systems. They represent a terminal with minimal equipment. Such systems are designed to provide satellite communications to small organizations that do not need high bandwidth. In addition, the VSAT system can provide channels on demand.
3. Mobile satellite communication. A feature of such systems is the small size of the antenna, which makes it difficult to receive the signal. In order to increase the power of radio waves, satellites are placed in geostationary orbit, providing them with a strong transmitter. Such systems provide communication to maritime vessels and individual regional operators. To amplify the radio signal, a large number of satellites are placed in polar and inclined orbits. Numerous mobile operators also transmit information.
4. Satellite Internet. Such communication systems have their own characteristics. Here, outgoing and incoming traffic is separated, and certain technologies are used to further combine them. That is why such satellite communication systems are called asymmetric. A feature of the Internet is that one channel can be used by several users at once. The fact is that data is transmitted through space orbit for all clients at the same time.
Satellite TV
Since the middle of the last century, humanity has been increasingly using outer space to achieve its goals. And today, the near-Earth orbit is literally surrounded by a satellite "necklace", which allows not only to serve as navigation systems, transmit information, but also … watch TV. How does this happen? A powerful antenna is installed on each of the satellites specially designed for this purpose. It is she who receives the television signal, which is then sent to Earth and received by special transponders-transmitters. Those areas whereyou can catch such radio waves, called the coverage area.
An antenna that receives signals from satellites has the shape of a dish. Such a surface allows radio waves to be reflected and then focused at one point, where the convector is installed. This device receives signals that are then sent to the receiver via a special cable. It is also a receiver, but it converts radio waves and transmits them as a picture to a TV screen.
Satellite TV systems allow you to get high quality sound and picture. This is made possible by the influx of information in digital form. In addition, satellite TV allows you to watch programs from different countries and continents. This opportunity is especially important for those who study a foreign language. Children and adults, when watching such programs, can find a virtual interlocutor for themselves, as well as check and significantly replenish their knowledge. Attract the viewer's attention and numerous thematic channels of satellite television. Children can choose to watch cartoons, while adults can plunge into the world of travel or music.
Providing your home with satellite TV will not only expand your horizons and get a lot of positive emotions from watching interesting programs, but also save money. You will have to pay only once for equipment for satellite communications. In the future, the consumer remains independent of the constantly changing tariff plans of cable operators, because satellitethe equipment remains forever the property of its owner.
It is also worth mentioning that, according to the opinions of residents of small towns, such television often helps them out. Indeed, sometimes in small towns there are no cable operators, and the quality of signal transmission through an ordinary television antenna leaves much to be desired.
By the way, in many small towns, due to problems with TV reception, installing dishes is perhaps the only way to enjoy watching TV in good quality.
