Simplified yaw steering method for satellite antenna beam control
AssigneeHughes Electronics Corporation
InventorHarold A. Rosen
Life of this patent
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Abstract
For an antenna on a satellite in an inclined orbit about the Earth, cross-track motion resulting from the rotation of the Earth can be reduced in antenna coordinates by yawing the antenna (preferably by yawing the entire satellite, for example, by using a reaction wheel system) by an appropriate angle, which varies throughout the orbit.
Claims13
A method of steering a satellite antenna mounted to a satellite having a pitch axis, a roll axis, and a yaw axis, the satellite traveling in an orbit around a rotating object, the orbit having an inclination and an ascending node, the method comprising the steps of:
- determining the inclination of the orbit;
- determining the time in the orbit from the ascending node;
- determining the period of the orbit;
- determining the period of the rotation of the object;
- and
- steering the antenna about the yaw axis by an angle, φ, wherein φ is a function of the inclination of the orbit, the time in the orbit from the ascending node, the period of the orbit, and the period of the rotation of the object.
A method for steering a satellite antenna mounted to a satellite having a pitch axis, a roll axis, and a yaw axis, the satellite traveling in an orbit around the Earth, the orbit having an inclination and an ascending node, the method comprising the steps of:
- determining the inclination of the orbit;
- determining the time in the orbit from the ascending node;
- determining the period of the orbit;
- and
- steering the antenna about the yaw axis by an angle, φ, wherein φ is a function of the inclination of the orbit, the time in the orbit from the ascending node, the period of the orbit, and the period of the rotation of the Earth.
A method for reducing pointing errors while steering a satellite antenna mounted to a satellite having a pitch axis, a roll axis, and a yaw axis, the satellite traveling in an orbit around a rotating object, the orbit having an inclination and an ascending node and the antenna pointed generally at a target area on the object, the method comprising the steps of:
- determining the inclination of the orbit;
- determining the time in the orbit from the ascending node;
- determining the period of the orbit;
- determining the period of the rotation of the object;
- and
- steering the antenna about the yaw axis by an angle, φ, wherein φ is a function of the inclination of the orbit, the time in the orbit from the ascending node, the period of the orbit, and the period of the rotation of the object.
A satellite having a pitch axis, a roll axis, and a yaw axis, the satellite traveling in an orbit around a rotating object, the orbit having an inclination and an ascending node and the antenna pointed generally at a target area on the object, the satellite comprising:
- a satellite antenna mounted to the satellite;
- and
- means for reducing pointing errors while steering the satellite antenna by steering the antenna about the yaw axis by an angle, φ, wherein φ is a function of the inclination of the orbit, the time in the orbit from the ascending node, the period of the orbit, and the period of the rotation of the object.
Dependencies are inferred from the claim text.