Today, to ensure safety, mankind even uses outer space. 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 you to determine the coordinates of any object based on those signals that came from the satellite. And today, such navigation is used in rescue and geodetic operations, as well as to ensure the security of the state and citizens.
What are satellite systems? These are complex electronic and technical communications. Moreover, their implementation is possible only with the combined work of space and ground equipment. At the same time, satellite systems can determine the height and geographical coordinates, time and movement parameters of water, ground and air objects.
Classification
Satellite systems are divided into the following areas:
- security search, designed for cars;
- navigation, to protect offices, houses, personal territories and apartments;
- security for sites on the Internet and cell phones;
- search navigation (GPS).
Essential 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 receives and processes the information transmitted by them;
- client receiving equipment necessary for determining coordinates;
- beacons, which are a ground-based system that improves the accuracy of determining the location of an object;
- an information radio system transmitting corrections to coordinates to users.
Principle of operation
Satellite navigation systems measure the distance from an antenna located on an object to a satellite whose position in orbit is known with high accuracy. This uses a special table called the almanac. It should 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 If such a table is not outdated, then the location of an object in space is determined by instruments using simple geometric constructions.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 know the location of the object above the surface? To do this, you need a signal from the fourth satellite.
All information received is processed by the ground unit, which, with the help of a certain system of equations, displays the necessary coordinates. However, the data obtained will require some adjustment. This is due to the influence on the operation of the system of atmospheric pressure, air temperature and degree of humidity. Each of these factors introduces an error within 30 m, the total value of which sometimes reaches 100 m.
Differential GPS helps reduce inaccuracy. It transfers the necessary corrections to the user, which ensures the accuracy of object detection up to 1 cm. At the same time, satellite search systems 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 traveled by it, 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 air and on land. Let's consider these navigators in more detail.
The history of the American GPS satellite system began in 1973. This was the period of development of the DNSS program. Later it was renamed to Navstar-GPS, and then to GPS. The first of its satellites was put into orbit in 1974. And only in 1993 their number was brought up to 24, which made it possible to cover the entire earth's surface.
Initially, the GPS satellite system worked for the US military complex. And only in 2000 , the signature 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 territories where military operations take place, or create interference 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 forces 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 be increased 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 provides not only freight, but also passenger transportation. Here GLONASS is a satellite monitoring system, as well as a tool to optimize the traffic schedule. Such navigation is used in their work by the operational services of the Ministry of Emergencies, police and ambulance.
The principle of operation of the GLONASS system is based on the receipt of information from a tracking beacon via a GSM channel to a remote server. Here it is saved for further transmission to the user. Data collection time is in the range from 15 to 240 seconds. Next, a special computer program processes the information on the server and gives out the location of the object.
In Russia, the latest project, called ERA-GLONASS, is being developed. Such a system will allow special services to respond urgently in case of 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 dispatch service in the event of a serious accident, that is, when airbags are deployed in the car. After that, the operator will try to clarify all the details of the incident with the driver. In the absence of an answer or when confirming information at the specified coordinates, rescuers of the Ministry of Emergencies, doctors and traffic police will be sent. Thus, satellite transport systems will serve as a first aid for the driver in emergency situations.
Galileo
This satellite navigation system is designed for countries within the European Union. The project, whose cost is estimated at $ 2 billion, was named in honor of Galileo Galilei - a famous Italian astronomer. In its work, Galileo is independent of the Russian GLONASS satellite system and American GPS.
In addition to determining the location of an object whose coordinates can be found with an error of one meter, Galileo has a search and rescue function. There is no such project in any country in the world (in Russia it is only being developed).
Vehicle Security
Today, the attention of many motorists attracts a satellite anti-theft system. According to the reviews of numerous users, it is not only reliable, but also very convenient.
Such security navigation works on the principle of communication between an antenna installed on a car and several satellites. Information about the coordinates of the machine 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 transfers them to the control center or owner. If intruders who try to hack the system have entered the car salon, then immediately through the networks of the mobile operator or through channels specially designated for these purposes, a signal will be received that the owner’s mobile phone or control tower will receive. After that, a response group begins to work, which will determine the movement and further location of the machine.
According to user reviews, the car’s satellite security system is quite reliable. It is much more difficult to neutralize it than a simple alarm with a siren.
Some satellite search engine models provide remote engine blocking. Thanks to this function, the criminal will not be able to drive even one meter on your car. Sometimes attackers use jammers. These are silencing devices that do not “trigger” the signal. This was taken into account when developing the latest security systems. Their design uses special modules that do not allow jammers to work.
Echelon
This satellite car security system has been operating in our country since September 2003. It is a regular GPS-GSM alarm system, only its processor unit is programmed in a special way. When an attempt is made to steal a vehicle, an alarm is triggered, and when the criminal uses a jammer or if there is no connection with the dispatcher’s console, the engine is blocked. Such is the algorithm of actions by 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 case of:
- exceeding a certain speed value;
- travel outside the boundaries of the designated area;
- longitudinal and lateral acceleration of the vehicle.
Moreover, this work algorithm can be changed even remotely. To do this, it is enough to send the desired program of work via the GSM channel.
"Arkan"
The bulk of the car’s satellite security systems works on the principle of delivering the “Alarm” signal to the control panel. However, such protection is ineffective in the absence or intentional suppression of the GPS channel.
An alternative is the Arkan satellite system. It transmits information through the eponymous special navigation network. Due to the constant radio signal, constantly changing the frequency, the attackers are not able to disable the system.
At the moment, such navigation is the most advanced technological solution, which allows you to easily locate the machine without much difficulty.
In addition, the Arkan satellite system:
- can transmit the coordinates of the machine when you press the panic button, as well as when trying to unauthorized access to the cabin;
- switches to low power mode when the battery is low;
- controls the operation of the Arkan channel using continuous supply of test signals.
Satellite connection
There are various types of similar systems.
Among them:
1. Trunk communication. Its development was dictated by the ever-increasing needs 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, trunk satellite communications systems are being supplanted by fiber optic networks.
2. VSAT systems. They are a terminal with a minimum volume of 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 communications. A feature of such systems is the small size of the antenna, which causes difficulty in receiving a signal. In order to increase the power of radio waves, satellites are placed in a geostationary orbit, providing them with a strong transmitter. Such systems provide communications to ships and individual regional operators. To enhance the radio signal, a large number of satellites are placed in polar and inclined orbits. Transmit information and numerous mobile operators.
4. Satellite internet. Such communication systems have their own characteristics. It separates outgoing and incoming traffic, and also uses certain technologies for their further combination. 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 to all clients simultaneously.
Satellite television
Since the middle of the last century, mankind has been increasingly using outer space to achieve its goals. And today, the Earth’s 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 satellite specially designed for these purposes. It is she who receives a television signal, which is then sent to Earth and received by special transponders-transmitters. Those areas where you can catch such radio waves are called the coverage area.
An antenna that receives signals from satellites has the shape of a dish. Such a surface allows the radio waves to be reflected, and then focus at one point, where the convector is installed. This device receives signals, which are then sent to the receiver via a special cable. It is also a receiver, but converts the radio waves and transmits them in the form of pictures on the TV screen.
Satellite television systems provide high quality sound and image. This is made possible by the receipt 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. When watching such programs, children and adults can find a virtual interlocutor for themselves, as well as check and significantly replenish their knowledge. Numerous thematic channels of satellite television attract the attention of the viewer. Children can choose cartoons for themselves, and adults can plunge into the world of travel or music.
Providing your home with satellite TV will not only broaden 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 satellite equipment will forever remain in the ownership of its owner.
It is worth mentioning that, according to the reviews of residents of small settlements, such television often helps them out. Indeed, sometimes in small towns there are no cable operators, and the quality of signal transmission through a conventional television antenna leaves much to be desired.
By the way, in many small towns due to problems with the reception of television signals, installing dishes is perhaps the only way to enjoy watching TV in good quality.