Natural satellite is a celestial object is not man-made orbiting a planet or other object that is larger than themselves, such as the moon is a natural satellite of Earth. Actually, this terminology also applies to planets around a star, or even a star around the galactic center, but it is rarely used. Earth itself is actually a natural satellite of the sun.
Artificial satellite transmission medium which is the main function receives the signal from the ground station and continue to another earth station.
Several explanations satellite understanding both natural and artificial satellites satellites.
Discussion.
Artificial satellites are man-made objects that orbit around other objects such Palapa that surrounds the Earth.If the station in the heading is located opposite to the location used as a relay satellite, the satellite will emit a signal to other satellites that are not located opposite to the destination station
Satellites orbiting at an altitude of 36000 km above the earth have orbital angular velocity equal to the Earth's orbital velocity.
History.
The first man-made satellite was Sputnik 1, was launched by the Soviet Union on October 4, 1957, and start the Russian Sputnik program, Sergei Korolev with as head of design and Kerim Kerimov as his asistent. This triggers the launch of space race (space race) between the Soviet and American.Sputnik 1 helped to identify the density of the upper atmosphere by measuring the change in orbit and provide data on the distribution of the radio signal in the ionosphere layer. Because the satellite body is filled with high-pressure nitrogen, Sputnik 1 also provided the first opportunity in the detection of meteorites, because the pressure loss caused by the penetration of meteroid can be seen through the data sent to the earth's temperature.
Sputnik 2 was launched on November 3, 1957 and carried a crew of the first living creature into orbit, a dog named Laika.
In May, 1946, the Project Rand issued a Preliminary design for experimental spacecraft to encircle the world, stating that, "a satellite vehicle that contains the appropriate instrumentation can be expected to be a powerful tool for the science of the twentieth century". Americans are already thinking to launch orbiting satellites since 1946 under the Office of the US Navy Aeronotis (Bureau of Aeronautics of the United States Navy). Project RAND US Air Force finally issued the above report, but did not believe that the satellite was a potential military weapon; However, they regard it as a tool for science, politics, and propaganda. In 1954, the US Defense Sekertari stated, "I am not aware of any single American satellite program."
On July 29, 1955, the White House announced that the United States would be willing to launch a satellite in the spring of 1958. It was then known as Project Vanguard. On 31 July, the Soviets announced that they will launch a satellite in autumn 1957.
Following pressure from the American Rocket Society (Rocket America), the National Science Foundation (national Science Foundation), and the International Geophysical Year, increased interest of the armed forces and in early 1955 the US Air Force and Navy work on Project Orbiter, which uses vehicle Jupiter C to launch a satellite. This project was a success, and Explorer 1 became the first American satellite on January 31, 1958.
In June 1961, three and a half years after the launch of Sputnik 1, the US Air Force to use various facilities of Space Eye Network of America (the United States Space Surveillance Network) to catalog number 115 satellites orbiting the earth.
The largest man-made satellite currently orbiting the Earth is Interasional Space Station (International Space Station).
Working Principle Satellite.
Satellite is a relay station that hung in the sky. Called a relay station for the main function is to relay satellite signals originating from the earth. The signals received from the earth shifted first new frequency is then transmitted back to earth. So basically the satellite contains a frequency translator circuit, ie a circuit which consists of the receiver, and transmitter frequency slider.
Signals sent from Earth to reach the satellite will go through the path (path) so much space so that the signal will suffer attenuation (free space path loss) is very large. This attenuation due to the nature of the electromagnetic wave radiation radiating in all directions (such as an expanding ball) so that the signal strength will weaken proportional to the square of the distance which he passes. In addition, the distance it would seem more distant to the signal wavelength shorter.
This attenuation is very large so that the signals received at the satellite is very weak. So that's a very weak signal can be transmitted back to earth with sufficient transmit power, it takes a series of terraced amplifier. At the first level of the signal is amplified by the gain of the receiving antenna. The output of the antenna, which is still very weak and then amplified again with LNA (Low Noise Amplifier). Once the level is sufficient, this signal is then fed into the mixer circuit-1 to be shifted in frequency to the frequency of the L-Band.
Shift to lower frequency signal level, so that the signal must be amplified again at this stage. After a sufficient level, a signal is fed back to the mixer-mixer for frequency is shifted again to the operating frequency (frequency down link). At this stage, the signal is amplified again by the driver amplifier and then amplified by the HPA (High Power Amplifier) so obtained are quite large emittance. In the final stage, the signal is then amplified again by the transmitter antenna to produce what is referred to as EIRP (Equivalent Isotropic Radiated Power). The amount of EIRP is then by satellite beamed back to earth.
Frequency shift frequency translation did not alter the value of the information contained in the signal. So even though in the satellite signal frequency in the shear twice, but the information contained in it is still intact (not changed). Therefore, it becomes clear that the satellite function in this case is only relaying signals from the earth and then transmitted back to earth again.
Twice the frequency shift is intended to obtain a very high gain. For amplifying the signal at the working frequency will cause the amplifier is oscillating (signal output back into the input). To avoid this from happening, the signal must be amplified at a frequency different work. In the picture (3) is shown an example that the total gain of the satellite is about 170 dB. The gain of this magnitude would be extremely difficult to obtain when the amplifier works on a working frequency. Therefore the signal amplification is done in 3 different frequencies. The first signal is amplified at the Rx frequency (using LNA). Then the frequency is shifted to the L-Band and strengthening both performed at this frequency. Furthermore, the frequency of the signal on the slide again to the Tx frequency and amplified again (by HPA) to achieve the desired transmit power. In this way it will obtain a very high total gain.
Strengthening the signal from the receiver antenna, LNA, the HPA to the antenna transmitter called Gain Satellite. The amount of gain satellites have been designed such that the signals received from the earth capable of producing maximum transmit power according to the capacity installed in the satellite HPA. Power output of the HPA further reinforced by the antenna in order to obtain a high EIRP. Because the signal emitted by the satellite to the Earth will experience a very large damping. Just picture eg down link frequency used is 4 GHz = 4,000 MHz, then the amount of damping in the direction of Down Link is:
L-down = 32.4 + 20 + 20 log log 36,000 4,000 = 32.4 + 91.1 + 72.0 = 195.5 dB
Down-link attenuation is very large, so that the signals received on Earth is also very weak. That is why it takes a pretty big gains in the receiving station on Earth so that the information contained in the signal can be detected back. If the quality of the received signal is not in accordance with the requirements, then the transmit power on the sending side needs to be enlarged. In this way it will automatically power emitted by the satellite is also enlarged. The increase in satellite transmission power is a linear function of the increase in the sender's transmission power. For instance, if the transmit power on the sending side is increased 3 dB, then the transmit power satellites will also rise 3 dB. If increased again 10 dB, the transmit power at the satellite will also rise 10 dB. And so on until at a point where the increase in satellite transmission power is no longer linear. At this point the satellite transmit power has exceeded the linear limit. Therefore, the addition of power on the sending side should not be arbitrary. There are certain limits that should not be exceeded. This is what is referred to as Power Limitted, meaning that the satellite has a limited transmit power.
If the transmit power on the sending side can no longer be raised, while the received signal is still not in accordance with the requirements, then the only way is to increase the diameter of the receiving antenna. The larger the diameter of the receiving antenna, the better, because the system will be more sensitive receiver, it means more capable of receiving weak signals. However, the greater the diameter of the antenna will require a larger area, large size is clearly not practical and the price is also definitely more expensive. Therefore the calculation of the transmit power on the sending side and the magnitude of the diameter of the antenna at the receiver side should be calculated correctly. For that there is some parameter that needs to be known. Satellite parameters such as G / T, Saturated Field Density (SFD) and EIRP and contour maps or foot print is generally provided by the operator / owner of the satellite to its customers, so that each customer can count themselves anything they need. If the transmit power on the sending side can no longer be raised, while the received signal is still not in accordance with the requirements, then the only way is to increase the diameter of the receiving antenna
Satellite type.
Astronomy satellite.
Satellites are used to observe planets, galaxies, and other outer space objects.
Satellite communications.
Is an artificial satellite mounted in space with the goal of using radio telecommunications at microwave frequencies. Most communications satellites use geosynchronous orbit or geostationary orbit, although some new type using low Earth orbiting satellites.
Earth observation satellites.
Satellite is designed specifically to observe the Earth from orbit, such as reconnaissance satellites but intended for non-military uses such as environmental monitoring, meteorology, map making, etc.
Satellite navigation.
Are satellites which use radio time signals transmitted to the receiver on the ground to determine the location of a point on the surface of the earth. One of the very popular satellite navigation is the GPS of the United States but it is also the Russian Glonass. When the line of sight between the satellite and the receiver on the ground there is no interference, then with a satellite signal receiver (GPS receiver), can be obtained position data in a place with a few meters of accuracy in real time.
Spy satellites.
Are Earth observation satellite or communications satellite deployed for military or spy.
Solar power satellites.
Is a proposed satellite made in high Earth orbit that use microwave power transmission to beam solar power to very large antenna on Earth where it can be used to replace conventional energy sources.
Space station.
Is a man-made structures that are designed for human habitation in space. The space station is distinguished by other spacecraft by the absence of the main spacecraft propulsion or landing facilities, and other vehicles are used as transport to and from the station. Space stations are designed for medium-term living in orbit, for a period of weeks, months, or even years.
Weather satellites.
Satellites are primarily used to observe the Earth's weather and climate.
Miniature satellites are lightweight and small satellites. The new classification is made to categorize these satellites: mini satellites (500-200 kg), micro satellite (under 200 kg), nano satellite (under 10 kg).
Type of orbit.
Many categorized on altitude orbit satellites, although a satellite can orbit at any altitude.
Low Orbit (LEO Low Earth Orbit): 300-1500 kilometers above the Earth's surface.
Orbit Medium (Medium Earth Orbit, MEO): 1500-36000 km.
Geosynchronous orbit (Geosynchronous Orbit, GSO): approximately 36 000 km above the Earth's surface.
Geostationary Orbit (geostationary orbit, GEO): 35 790 km above the Earth's surface.
Orbit (High Earth Orbit, HEO): over 36000 miles.
The following orbits are special orbits that are also used to categorize satellites:
Molniya orbit, the satellite's orbit with a period of 12-hour orbit and inclination of about 63 °.
Sunsynchronous orbit, the satellite's orbit with an inclination and a certain height that always crossed the equator at the same local clock.
Polar orbit, the satellite orbit that crosses the polar
Satellite Made in Indonesia :
Satellite Lapan-A1 / Lapan-TUBSAT.
- Orbiting on January 10, 2007.
- Launched in India
- The first satellite made in Indonesia. Was estimated to be 10 years.
- Produced by 18 engineering Indonesia in Berlin, Germany and led the team from the Technical University of Berlin (TU-Berlin)
- Can be controlled from the ground.
- Function: earth observation satellite (earth observation), mastery of technology, and monitoring (surveillance).
- Record performance: monitoring the longest bridge construction, monitoring the progress of Mount Merapi, Mount Bromo and Mount Cisadane. Photographing major cities and airports of space.
Satellite Lapan-A2 / Lapan-Orari.
- Plan in fielding two months.
- Contrived in Indonesia by Indonesian experts
- Launched in India in collaboration with the Indian space agency (ISRO), because Indonesia does not have a satellite rocket launcher.
mission:
a. Support disaster management
b. Digital cameras are attached can be directed photographing the moon and space environment
c. Traffic monitoring shipping and ship navigation through the data AIS (Automatic Identification System)
d. Observation (surveillance) earth with PAL video camera coverage of 80 km.
Satellite Lapan-A3 / Lapan-IPB.
- Plan in fielding in 2013.
- Most likely still be launched in India.
- Artificial experts in Indonesia
- Mission:
a. Improvement of the quality of disaster mitigation satellite Lapan-A2
b. Provide medium resolution satellite data 17 meter multispectral 3 bands on the affected area.
c. Being a communication tool orari wider, and replace the damage potential of mobile telecommunications since the brunt of the disaster.
Satellite Lapan-B1
- Plan in fielding in 2015
- Designed to support agriculture and food security programs.
- Being able to predict the season rice crop production, growth fields, irrigation, growth of plantations, as well as monitoring the increase and decrease in water reservoirs.
Satellite Satellite Tele-Education
- Unclear orbital plan.
- Used to support distance learning
- The incorporation of quality education from urban to rural.
- Including the distribution of health-related data, cleanliness, from urban to rural.
5 largest natural satellites ever invented by man are: Ganymede (Jupiter), Titan (Saturn), Callisto (Jupiter), Io (Jupiter), and Moon (Earth).
Satellite Applications.
Satellite Imagery.
This image was taken at infrared wave band and describe the relative temperature / warm or cold objects observed by weather satellites. Low clouds generally warmer temperatures and is relatively close to the earth's surface and the deep blue s / d light green, while the clouds into cooler are generally higher peak orange clouds s / d pink light. This infrared image is very useful to detect the clouds in both the time of day or night.
This image was taken at wavelength bands that are sensitive to water vapor content in the atmosphere. The bright white color illustrates the moisture content (moist air), blue indicates areas with high humidity and / or ice crystals in clouds. While the brown color indicates low air humidity / moisture content of water. No water vapor imagery is very important to determine the areas where the air content of wet steam / water high and detect mass flow circulation / air in the atmosphere.
Potential rainfall (rainfall Qualitative estimate).
Observation time in UTC / GMT (GMT = UTC + 7)
Animation Image 6 Last Hour
The following animation shows the growth and movement of clouds. In this image, the clouds shown is a cloud with a smaller peak temperature of zero degrees Celsius. Peak temperature gets colder clouds (indicated by color more white), the higher the potential for rain.
From the above explanation we get the conclusion that the satellite is divided into two natural satellites and artificial satellites. Where, some of which are natural satellites Ganymede (Jupiter), Titan (Saturn), Callisto (Jupiter), Io (Jupiter), and Moon (Earth). And also discusses artificial satellites including satellite Lapan-A1 / Lapan-TUBSAT, satellite Lapan-A2 / Lapan-Orari.
A description of the working principle of the satellite we can also understand that serves to relay satellite signals originating from the earth. The signals received from the earth shifted first new frequency is then transmitted back to earth. So basically the satellite contains a frequency translator circuit, ie a circuit which consists of the receiver, and transmitter frequency slider. Thank you for reading this article. Written and posted by Bambang Sunarno. sunarnobambang86@gmail.com
author:
http://schema.org/Personal.
https://plus.google.com/105319704331231770941.
name: Bambang Sunarno.
http://www.primadonablog.blogspot.com/2014/12/about-satellite.html
DatePublished: December 2, 2014 at 18:33
Tag : About Satellite.
Code : 7MHPNPADAEFW
