Two-Axis Payload Pointing Around a Virtual Focal Pivot
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Solution Overview
Problem
Conventional antenna pointing mechanisms experience signal degradation due to defocussing and depointing when the reflector is steered relative to a fixed signal source, as the focal point moves away from the source.
Innovation Solution
A two-axis pointing system with three struts connected to the payload by spherical bearings, controlled by two actuators, allowing the payload to rotate around a virtual pivot point close to its focal point, minimizing focal point movement relative to the source.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the reflector is steered relative to a fixed signal source using conventional pointing mechanisms, then the reflector can be positioned to point at the source, but the focal point moves away from the source causing signal degradation
Solution Approach 1:
The patent introduces a virtual pivot point in three-dimensional space that is distinct from the reflector's physical center. By defining the pivot point at the intersection of strut axes extrapolations and positioning it at the reflector's focal point, the system adds a spatial dimension to the rotation mechanism. This allows the reflector to rotate while maintaining its focal point stationary relative to the signal source, thereby preserving signal quality while achieving accurate pointing.
2Ease of operation
If the pivot point is positioned at the reflector's center, then the reflector can rotate easily, but the focal point moves away from the signal source causing defocussing
Solution Approach 1:
The patent introduces three struts as intermediary elements between the reflector and the base. These struts are positioned at different locations on the reflector's back surface and connect to a common base structure. The struts act as mediators that constrain the reflector's movement, ensuring that rotation occurs around the virtual pivot point (focal point) rather than the reflector's physical center, thereby maintaining focal point positioning precision while enabling rotation.
3Measurement precision
If conventional pointing mechanisms are used to steer the reflector, then the reflector can be positioned accurately, but mobile harnesses and hold-down release mechanisms are required increasing system complexity
Solution Approach 1:
The patent extracts and eliminates the need for mobile harnesses and hold-down release mechanisms by using a static base structure with three struts. Instead of requiring complex mobile support systems, the invention uses the triangular strut configuration to provide stable, passive support and positioning. The struts naturally constrain the reflector's movement and maintain its orientation without requiring additional active control mechanisms, thereby reducing system complexity while maintaining pointing accuracy.
Data Source
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AI summary
Provided herein is a two-axis pointing system and methods for pointing a payload, including a first actuator connected to the payload by at least a first connecting rod, wherein the first actuator controls movement of the payload along a first actuator axis by moving the first connecting rod, a second actuator connected to the payload by a second connecting rod, wherein the second actuator controls movement of the payload along a second actuator axis by moving the second connecting rod, and a first strut, a second strut, and a third strut, wherein each strut is movably connected to the payload at a first end and movably connected to a base at a second end, wherein the first strut, second strut, and third strut restrict movement of the payload, caused by the first actuator and the second actuator, to rotation around a virtual pivot point.