The satellite body frame is defined as [O.sub.b] - [X.su.b][Y.sub.b][Z.sub.b], originating at the mass center of the satellite and three axes aligned with the principal axes of the satellite.
Assuming that the 3-2-1 Euler angle of the satellite body frame with respect to the inertial frame is ([psi], [theta], [phi]), the coordinate of the object in the satellite body frame is given as follows:
where [R.sub.321] is the attitude matrix of the satellite body frame with respect to the inertial frame and [R.sub.X]([theta]), [R.sub.Y]([theta]), and [R.sub.Z]([theta]) are the coordinate transformation matrices after a rotation around the x-axis, y-axis, and z-axis, respectively, with the angle [theta]:
Assuming that the camera is fixed on the satellite and the 3-2-1 Euler angle of the camera frame with respect to the satellite body frame is ([[alpha].sub.0], [[beta].sub.0], [[gamma].sub.0]), which is constantly determined by the design of the satellite structure, then the attitude matrix of the camera frame with respect to the satellite body frame [R.sub.0] can be derived.
Avariant--"different lay-up, slightly different resin system"--also forms the basis of its AstroHinge system, to enable the deployment of a succession of large panels out from a satellite body
. In this case, the material acts like a spring, to separate the panels from each other and lock them into position, obviating any need for electric motors.
In the negative tether mode, the H-bridge connects the negative output of the converter to the tether and the positive output is connected to the satellite body. In this case the positive ions are being gathered by the tether and electrons are being absorbed by the satellite body that is connected to the main ground connections of the satellite.
It has been estimated that in the plasma conditions of the orbital altitude the rate at which the satellite body is able to attract electrons from the local plasma environment would be sufficient to compensate for the rate at which the tether attracts positive ions.
In addition, the size of the CubeSat is very small, so the reflections of the navigation signals from the satellite body
have only minimal impact on the position precision.
In its simplest form, the states of the UKF include the satellite quaternion and angular rates (both in satellite body
frame) [28, 29]:
Number of Malfunctions by Commercial GEO Satellite Body Type (1995 to April 2002)
The chart shows the number of malfunctions that occur in different commercial GEO satellite body types, such as the Spacebus or BS702 models.