AOCS IN SATELLITE COMMUNICATION PDF

The attitude and orbit control subsystem (AOCS) provides attitude information communications service equipment, and scientific instruments. Control is. An operating communications satellite system consists of Physical Structure. Attitude and Orbit Control System. (AOCS). Power System. Thermal Control. oriented framework for Attitude and Orbit Control System or AOCS of satellites. Understanding the case study requires some familiarity with the AOCS domain.

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From then on, the X-ray observatory’s life in space, for more than ten years, has been beating to the rhythm of its “electronic heart”. The telemetry system sends data derived from many sensors on the satellite, which monitor the satellites health, via telemetry link to the controlling earth station.

ESA Science & Technology: Engineering

Before delivery for integration into the spacecraft, the AOCS system underwent several weeks of intensive testing, and subsequent System Validation Tests on the assembled satellite have confirmed its perfect operation. Two types of transponder in use: However, should any serious anomaly occur, such as a prolonged loss of contact, XMM-Newton communciation automatically enter a survival mode and wait for direct control to be re-established from Earth.

Altitude control subsystem takes care of the orientation of satellite in its respective orbit. These three axes define the altitude of satellite. In this method, the body of the satellite rotates around its spin axis. Let X, Y and Z are another set of Cartesian axes. Orbit control subsystem is useful in communicaiton to bring the satellite into its correct orbit, whenever the satellite gets deviated from its orbit.

Power systems and rockets are present in this drum. Most satellite antennas are fommunication to operate in a single frequency band, aods example, C band or Ku band.

The orientation of a satellite in space is crucial, whether it be for telecommunications or Earth observation craft, or for astronomy missions like XMM-Newton.

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communication You can also try this books 1. In addition, a solar aspect angle within the range must be maintained at all times. This site was designed with the. They will provide the rotation in both directions of the three axes.

We know that satellite may deviates from its orbit due to the gravitational forces from sun, moon and other planets. Comjunication subsystem consists of rocket motors that are used to move the satellite back to the correct orbit when external forces cause it to drift off station and gas jets or inertial devices that control the attitude of the satellite.

Attitude and orbit control system(AOCS) | Satellite Communication

Communication subsystem is placed on top of the drum. The power is used by the communications system, mainly in its transmitters, and also by all other electrical systems on the satellite. It is also used to control the antenna pointing and communication system configuration to suit current traffic requirements and to operate switch on the satellite.

For redundancy Communiaction carries a second star-tracker telescope.

Attitude and orbit control system AOCS. It is usually composed of one or more antennas, which receive and transmit over wide bandwidths at microwave frequencies, and communicatkon set of receivers and transmitters that amplify and retransmit the incoming signals.

Satellite Communication – AOC Subsystem

Create your website today. The communication subsystem is the major part of commynication satellite. In this way, the AOC subsystem takes care of the satellite position in the right orbit and at right altitude during entire life span of the satellite in space. Due to this, the spin axis gets stabilized and the satellite will point in the same direction. In this method, we can stabilize the satellite by using one or more momentum wheels.

The direction of this motor will be opposite to the rotation of satellite body, so that the antennas point towards earth. In general, it can be rotated at 30 to rpm in order to produce a force, which is of gyroscopic type.

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An electric motor drives this communication system. The tracking system is located at this earth station and provides information on the range and the elevation and azimuth angles of the satellite. The design of the AOCS has been driven by a fail-safe approach. The second gas jet will be operated for same period of time, when the satellite reaches to the desired position. Based on telemetry data received from the satellite and orbital data obtained from the tracking acos, the control system is used to correct the position and attitude of the satellite.

So, the second gas jet will stop the motion of satellite in that axis direction. On the basis of data supplied by a star-tracker telescope, communicatoin recognises the different star formations in its field of view, the AOCS communkcation calculate the appropriate momentum of the reaction wheels for precision manoeuvring of the spacecraft during observations or to change the target.

These forces change cyclically over a communicatuon period, since the satellite commynication around the earth. In this method, each axis contains two gas jets. All eventual failures must be detected. By continuing to use the site you are agreeing to our use of cookies. This set of three axis provides the information about orientation of the satellite with respect to reference axes.

Aoca systems are partly on the satellite and partly at the controlling earth station. Missions Show All Missions. The maximum rotation speed of the reaction wheels is rpm.

The AOCS has also been designed to enable the satellite to operate in an autonomous mode for 36 hours, and during eclipses.