Eads Astrium Sas

Astrium Sas

Matra Marconi Space France

Eads Astrum Sas

Ange Defendini

Kristen Lagadec

Mehdi Ghezal

Philippe Faucheux

Pascal Guay

Julien Morand

A method of controlling the attitude of a satellite () including two gyrodynes () and a third main actuator () which delivers torques at least along the Z axis. The method includes: fixing the gimbal axes, Aand A, of the gyrodynes () parallel to Z; setting a non-zero bias (&#x3b1;) between the angular momentum vectors (Formula I) of the gyrodynes; using the measurements provided by the sensors on board the satellite to estimate the kinematic and dynamic variables necessary in order to control the attitude of the satellite (); calculating set variables in order to the objectives assigned to the satellite () attitude control system; and using the deviations between the estimated variables and the set variables to calculate control orders and to send same to the main actuators ().

Method of controlling the attitude of satellites, particularly agile satellites with a reduced number of gyrodynes

A control moment gyro comprising a wheel support structure which is mounted on a base by a motor, which is used to rotate the support around a first axis and bearing a wheel arrangement for driving the wheel spinner at a high speed around a second axis perpendicuIar to the first. The support structure includes a tubular part which rotates on the base and a flange which is disposed on only one side of the wheel and which is fixed both to the wheel and the tubular part. The diameter of the wheel and the point at which the wheel is fixed to the flange are proportioned such that the wheel penetrates the tubular part.

Control moment gyro for attitude control of a spacecraft

In order to control the attitude of a satellite having at least four gyroscopic actuators with respective spinners mounted on gimbals steerable about axes parallel to one or the other of only two different directions that are fixed relative to the satellite, the attitude of the satellite is measured using sensors on board the satellite, the control torque required to perform an attitude-changing maneuver is calculated, local linearization calculation is performed based on pseudo-inversion of the Jacobean matrix of the function associating the orientations of the actuator gimbals with the total angular momentum of the cluster in order to determine a new gimbal orientation, and precession speeds of at least one of the gimbals of the actuators are controlled to deliver the control torque for reaching the desired configuration.

Method and device for controlling satellite attitude and steering using a gyrodyne cluster

For controlling the attitude of a satellite placed on a low earth orbit, components of a vector Bm of the earth's magnetic field along three measurement axes of a frame of reference bound with the satellite (typically by means of a three-axis magnetometer) are measured. The orientation of the earth's magnetic field in the frame of reference is computed and a derivative {dot over (B)}m of the vector is also computed. Magneto-couplers carried by the satellite are energized to create a torque for spinning the satellite at an angular frequency &ohgr;c about a determined spin axis of the satellite, where &ohgr;c is greater than an orbital angular frequency 2&ohgr; of the satellite.

Method of controlling the attitude and stabilization of a satellite in low orbit

A method is disclosed for controlling the attitude of a satellite by controlling the speed of the gimbals of CMGs in a cluster of CMGs, the CMG having respective wheels mounted on gimbals that are mounted on a satellite platform to rotate about different orientation axes. From starting conditions and end conditions relating to attitude and angular speed and time, a cluster configuration is determined that is remote from any singular configuration such that exchanging angular momentum between the cluster of CMGs and the satellite during a given length of time will give rise to the desired attitude maneuver. The orientation of each gimbal is changed in simultaneous and independent manner into its reference orientation by using an angular position reference, applied in an open loop in the local servo-control of the angular positions of the gimbals.

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Montjoire, France

Ange Defendini