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NAVIGATION SATELLITE

SECOR - TRANSIT - NNSS - NAVSTAR GPS - CYCLONE, PARUS, CYCLE - GLONASS - OTHER NAVIGATION SYSTEMS

NAVIGATION SATELLITE

SECOR, TRANSIT, NOVA

The launch of the first artificial satellite Sputnik has launched research into the development of the satellite navigation system. The first American satellite navigation system was SECOR (Sequential Collation of Range) - Thirteen satellites were launched from 1963. to 1969. The mass of the satellite was 17 to 20 kg.

The beginnings of modern navigation satellites are found in US Navy programs that culminated in the project at the end of the 1950s Transit. Its purpose was to allow ships off the mainland at all times to find the exact position. Using navigation satellites is in some way an extension of old navigation techniques that have increased the Old World.

Skilful European seafarers colonize the Earth's ball only after the chronometer's discovery. The time read from the exact track and the angle information between the horizons and some stars allow the navigator to determine the position of the ship. As the stars are not always visible, they can use the radio signal from the known location, say the satellite, for the same purpose. In that case, the wavelength of the signal will decrease in moments as the aircraft approaches the ship, or increases at the time of departure. The so-called. Doppler effect It serves to measure the relative velocity of the satellite towards the observer. Since radio waves reach the Earth's surface in all weather conditions, satellite navigation is potentially the simplest and most efficient way of determining position on our planet. In practice, this is not quite so because some unknowns, or at best uncertain values, make budgeting difficult. To calculate the position of an object, it is most important to know the navigational satellite path. But homogeneous cosmic bodies are virtually unavailable, and the exception is not Earth. Due to certain gravitational irregularities, the path of all satellites is slowly changing. The navigator's bridge may not be as accurate as it is thought (the differences measured in seconds are quite unacceptable), the pressure of solar radiation shifted the aircraft from the theoretical position, and the earth's atmosphere curves the path of the radio signal, and the apparent position of the satellite is not the same as the actual one. All these difficulties have been established and partially solved in the Transit program. The first aircraft from that series flew on Thor-Able The rocket is still 1960. years. Already 1963. The project is no longer publicly mentioned because it wants to hide it from curious ears and eyes.

During 1964. he became the first operational Naval Satellite Navigation System NNSS (Navy Navigation Satellite System), in consisted of 5 navigation satellite Transit in polar orbit, which defined the position by measuring the Doppler effect and the imputation of the known parameters tracks satellites and accuracy was ensured at 160 meters. Transit satellite, whose production is being downloaded RCA, Have different shapes, but mostly it is a sphere with a diameter 90 cm, weight 100 kg, set in orbit heights between the 220 and 1300 km, tends to 28 90 degrees to the equator. The system is designed to support naval vessels, particularly nuclear submarines Polaris but it proved to be good enough for use in many civil and commercial projects. Information on Transit aircraft reaches several thousand receivers, not only in military ownership, but also on merchant ships, submarine communications cables, and oil exploration platforms. All navigational satellites in use are located in a polar path, about 1100 km above Earth. Second generation transit vehicle, named Nova, Are designed to fulfill all the tasks the US Navy by the end of the eighties. As satellites last series, produced by a company RCA Astro-Electronics. Mass of 167 kg, housing New is in the shape of an octagonal diameter of 52 cm with 27 cm high with position control equipment. Total, the satellite is long 116 cm. Electricity is generated on four panels with photovoltaic cells, and at the ends of the long pole there are two masses for gravitational stabilization; this technique has enabled the long-haul aircraft to be continually driven to the center of the Earth.

By means of the Transit and the New American Navy, besides serving the positioning of ships and submarines, planes flying low over the enemy area should receive information for the continuation of the flight, intercontinental ballistic missiles change the course, cruise missiles receive notices of new goals, and units on the front and in the background to avoid the opponent. Due to the complex and difficult calculation, a system development was developed that would determine the position of the receiver faster and easier. The TRANSIT system worked all the way to 1996. and now the US Navy uses it to control the ionosphere. In the US, many new satellite navigation technologies have tested satellites timationAnd the first such satellite was launched 1972. years. Timation was the first satellite to crystalline quartz oscillator, atomic clock and GPS technology demonstrator. There is a possibility to improve the navigation system, with benefits to all four roles of US armed forces.

Global Positioning System - GPS

The research carried out through the Defense Navigation Satellite Program (Defense Navigation Satellite Development Program) Is born 1974. Navstar world positioning system (Global Positioning System, GPS). Using 18 satellites positioned in three equally spaced 63 inclination degrees at the equator, the position will be found in all three axes with an error smaller than 16 meters. In addition, the system will also enable speed measurement with accuracy of 0,2 km / h. Every Navstar satellite, and it makes them Rockwell International, it has three oddly pointed rubies of atomic clocks to measure time. A one-second error occurs only with 36 thousands of years ago.

Four satellites are required to determine the position, and as the receiver works passively, user information can not be detected. The automatic device selects four most conveniently located Navstar aircraft and calculates the approximate distance from them. This gives the data needed for four equations: three spatial and one temporal. The user's microcomputer solves the system of equations and determines the time, position and speed of movement.

The satellite antenna emits a signal that covers the entire side of the planet facing it. Electricity comes from two sets of photovoltaic cells, which are continually facing the Sun. The aircraft also features a rocket engine with solid fuel to move in the desired trajectory as well as 18 hydraulic nozzles to maintain track position. In the initial elliptical trajectory Navstar starts on Atlas F carrier. Its mass at start of flight is 759 kg, and after engine ignition and entering the almost orbital 20200 km over Earth, it falls to 455 kg.

The first Navstar launched 22. February 1978, and four more fired in the next two years. 1985. 10 satellite was launched Block I, The entire system was in a pilot, partially operative phase. In one of the experiments, GPS satellites were used to indicate a deserted infantry boat to the beach foreseen for disembarkation. Without any sound or light signals, Navstar brought the unit 25 m from the ideal point. In the second experiment, a hired plane met with Lockheed C-141 who played the role of a tanker, also without any signal. Two paratroopers dropped from the cargo plane dropped off only 20 m from the goal. The moment of ejection was, of course, determined by Navstar. In a more complex simulation of combat tasks, GPS receivers on large B-52 bombers are used for "bombing" without radar control objectives; Two F-16 hunts are approaching the repetitious aircraft, and Grumman's A-6 aircraft leaps on the aircraft carrier, using only Navstar satellites in the Earth's path. In all of the above-mentioned examples, the ability to locate the correct position without signaling is an excellent display of the new generation of navigational aircraft. It is also the first project to take full advantage of the transition from one-time missile to the Space Shuttle.

The US constituency began to build 1989. Year launch of the 8 satellite GPS Block II was followed by the setting in the orbit of yet 15 slightly improved satellites Block IIA. In 1995. is a constellation of satellites GPS has become fully operational. GPS satellites are designed for transmission of navigation data to civil, and military sectors. GPS extremely reliably transmit data on the geographic location (latitude, longitude and altitude), velocity and forward time, which is precisely to 1 300000 seconds every year. Data are provided in all weather conditions in real time, supports an unlimited number of users and covers the whole world. GPS satellites, according to some reports, they have on-board detector for detecting nuclear explosions.

GPS satellites emit two distinct signals, the first being for military users, and the other for the civilian sector. Civilian signals have the accuracy of 100 to 15 meters, the deviation is deliberate, which is intended to prevent misuse of the correct signal for terrorist attacks or use in favor of repatriated states. Due to many of the intentional malfunctions, 2006. the civilian signal will be exactly the same as the military. Military signals are coded and are more resistant to interference, and have accuracy up to 1 meters. In addition to navigating all armies of the military, the satellite signal GPS is used to run maneuvering and ballistic missiles, guided bombs (JDAM, JSOW), and artillery grenades. The GPS receiver became a necessary part of the military equipment after successfully implementing such navigation in the 1991 Gulf War. years. GPS receivers have been developed for all types of transport equipment and have reached the size of the pocket calculator, which is why the use of GPS receiver greatly increased in wide everyday use.

GPS satellites are placed in 6 circular orbits at 20200 km, have a tour time of 12 hours so that 6 satellites are available at any time. For the normal operation of the system, 24 satellites are needed, with several additional reserves being placed in the orbit, while the spacecraft is launched with the launch rocket Delta II. Inclination satellites is 55 °, transmit two signals at different frequencies. Lifetime GPS satellite block IIR is 7,5 years. Constellation of the GPS of the GPS and monitored from the main control station GPS (MCS - Master Control Station), Which is controlled by the Space Command, the US Air Force. Terrestrial part of the GPS system makes 5 4 control stations and antennas positioned in different parts of the world, that the MCS sent to different information.

Satellite GPS is made by different manufacturers; so the Block I / II / IIA satellites were made by the company Rockwell - Boeing North American, Block II / R Lockheed Martin, a Block II / F constructs Boeing. Block II / IIA servers are replaced by improved versions of Block 2R, which has the ability to determine their own position with performing interlayer ranking and can reprogram themselves based on the detected errors and correct the error during flight. The Blocks 2R are more autonomous than their predecessors, and to maintain normal constellation work, they need less contact with the Earth observation station. Satellite Block 2Rs are also better protected from radiation effects, and have the ability to mount faster in the desired orbit than their predecessors, and the life span of the satellite is 10 years. company ITT Industries year 2001. has begun with the modernization of 12 satellite Block 2R, will be added another civilian signal and two more military signals, will improve their accuracy and resistance to interference. With these improvements, it will approach Boeing's Block 2F model. Enhanced models will be placed in orbit up to 2006. years.

The development of GPS satellites: Block I, Block IA, Block II, Block IIA

We are currently developing more advanced satellites Block IIF, Which should have more military and civilian signals, and above all to be better resistant to electronic jamming, the lifespan of satellites will be 15 years and will be able to launch with a variety of mounting missiles. The development is also a completely new generation of navigation satellites Block 3, where the cost of production would be considerably lower than the present, would have a longer life span, and would also be the other system functions and would meet the most varied needs. Usage should be 2009. years.

PARUS, GLONASS

The Soviet Union has begun to develop a satellite navigation system at the end of the 50 era. First navigation satellite Ciklon 1967 was launched. And was an experimental satellite, which calculated its position on the principle of dopler's effect. Initially, the navigation system had numerous program constraints, the site calculated with deviations up to 3 km. Clearing all the mistakes made it possible to set up the first operational military navigation system Parus or Cyclone-B. The first satellite of Cyclone-B was launched by 1974. year, and the entire constellation of 6 satellites reached the 1976 operation. years. The Parus system is still in operational use and neatly maintained, making it the 10 satellite in two constellations and designed for naval navigation needs of the Russian navy and strategic ballistic missiles. Based on the Parus system, for almost a year, 70 has developed an almost identical civil navigational system Cicada, composed of 4 satellites. Some Cikada satellite systems are from 1982. equipped with an international search and rescue system (COSPAS / SARSAT). The system is largely used by the USSR and Russian navy navy. In May, 2001. was launched Kosmos 2378, As a replacement Kosmosu 2279 which was a continuously operating 7 year.

SERIES
SATELLITE NAME
DATE OF LANSING
PARUS
Kosmos 2336
20. December 1996.
Kosmos 2341
17. April 1997.
Kosmos 2346
23. September 1997.
Kosmos 2361
24. December 1998.
Kosmos 2366
26. August 1999.
Kosmos 2378
8. June 2001.

An overview of Russian operational navigation satellites (data from July 2001)

The Soviet Union has developed a navigation system similar to American GPS, named GLONASS (GlObalnaja of the Sputnikova System of the Vigilance, global navigation satellite system). The full constellation of GLONASS satellites would have to include 24 satellites, 21 operating and 3 backups, at 19100 km in three different orbits with incidence of 64,8 °, in each orbit of 8 satellites. The satellite time is 11 hours and 15 minutes. The satellites transmit the same signal at different frequencies. The accuracy of the GLONASS satellite is similar to GPS satellites but does not have a selective signal for civilian users. GLONASS is operative of 1983. year, and due to Russia's economic difficulties, the full constellation of the 24 satellite reached December 1995. but the launch of new satellites did not reach the speed of placing outbound satellites out of use, so in January it was 2002. Only 9 satellites were active yet. The last launch of the GLONASS satellite was in December 2001. year, when they set 3 satellite type Uragan, of which one belongs to the new generation of satellites Hurricane-M, which has a lot of improvement and lifespan increased to 8 years instead of the previous 3 year.

OTHER NAVIGATION SYSTEMS

Several manufacturers of navigation equipment, trying to make a receiver that received the data from the American and the Russian navigation system, which would still increase the accuracy of the positioning. The main problem in the development causes different coordinate system both navigation systems. The European Space Agency is developing a civil satellite navigation system Galileo, which will be compatible with GPS and GLONASS systems, so that the user can receive data from all three navigation systems. The system should start running 2008. the constellation will be made by the 30 satellite that will circulate in the middle Earth's orbit at the height of 24000 kilometers and several satellites will circulate in the geostationary circle. The system will monitor 14 earth observation stations, set up in different parts of the world. The interest in participating in the Galileo system has been demonstrated by Russia and Japan, while the armed forces of the European states have been reluctant to do so. Different interests and bureaucratic constraints have not yet led to agreement on setting up the system.

China is developing its own satellite navigation system BNTS-1 (Beidou Navigation Test Satellite-1). Satellites BNTS-1 and BNTS-1B "Beidou" were launched in October and December 2000. missiles Changzheng-3 (Long march 3A) in a geostationary orbit with a cosmodrome Xichang Satellite Launching Center (XSLC) in the southwestern Sichuan Province, making China secure the coverage of its entire country. A new generation of satellites is also being developed, with larger possibilities to cover larger areas.

Secor
Transit
timation
Timation - launch 31.05.1967. Rocket Thor-Agena
Timation - Earth station
timation
timation
Navstar
Navstar
Navstar
Navstar
Navstar
Navstar
Navstar
Navstar
Parus-Cyclone
Cicada
Glonass
Uragan
Uragan
Hurricane-M
Galileo
Galileo
Galileo

Night launch of BNTS-1 with CZ-3A rocket