ESA Feed Beam Stabilization for Confocal Reflector Pointing Errors

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Solution Overview

Problem

Large high-frequency reflector antennas face significant beam pointing errors due to size increases, which reduce signal gain, and rely on externally provided RF signals that are susceptible to interference and jamming in contested environments.

Innovation Solution

The implementation of a system that includes a star tracker and laser distance measuring elements to determine orientation and distance information, allowing the electronically scanned array feed to adjust steering and mitigate pointing errors without relying on external RF signals, thereby stabilizing the antenna beam electronically.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the size of the main reflector is increased to achieve higher beam magnification, then the gain of the antenna is improved, but the sensitivity to beam pointing errors increases

Engineering Contradiction:

Improveantenna gainVSAvoidbeam pointing accuracy

Core Design Contradiction:

PowerVSMeasurement precision

Solution Approach 1:

The system uses star tracker and laser ranging sensors to continuously measure the actual orientation and position of the main reflector, feeding this information back to a control system that calculates pointing errors and generates correction commands to the ESA feed, thereby maintaining accurate beam pointing despite thermal and mechanical disturbances

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent replaces traditional mechanical auto-tracking systems that rely on external RF signals with an electronic beam stabilization system using star trackers and laser ranging for measurement, and electronic phase adjustment of the ESA feed for correction, eliminating mechanical moving parts and external signal dependencies

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If traditional auto-tracking systems using external RF signals are employed to reduce pointing errors, then beam pointing accuracy is improved, but the system becomes vulnerable to interference and jamming in contested environments

Engineering Contradiction:

Improvebeam pointing accuracyVSAvoidsusceptibility to interference and jamming

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The system substitutes RF-based auto-tracking with optical/mechanical sensing using star trackers for orientation measurement and laser ranging for position measurement, combined with electronic beam steering control, creating a jamming-resistant tracking system that operates independently of external RF signals

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system uses inherent celestial references (stars) and active laser ranging to self-determine its orientation and position without requiring external cooperative targets or externally provided tracking signals, making it autonomous and resistant to interference

Inventive Principle:

Principle #25Self-service

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution effectively reduces thermally and mechanically induced pointing errors, maintaining beam accuracy and increasing communication capacity by eliminating the need for external tracking signals, making the system robust against jamming and suitable for large aperture antennas.

Implementation Method 1

a star tracker element coupled to the feed structure and configured to determine orientation information relative to star alignment

Methodology Applied

Scientific EffectStar tracking:

Implementation Method 2

laser distancing measuring elements coupled to the feed structure and configured to determine distance measurements relative to the main reflector

Methodology Applied

Scientific EffectLaser ranging: LIDAR

Implementation Method 3

these pointing errors can be used by the ESA feed to adjust steering of a signal towards a target

Methodology Applied

Scientific EffectElectromagnetic radiation steering:

Data Source

PatentUS11901630B1Confocal phased array fed reflector antenna beam stabilization

Publication Date: 2024.02.13 LOCKHEED MARTIN CORP

AI summary

Provided herein are various improvements to antenna stabilization systems, such as employed on confocal phased array reflector antenna arrangements. In one example, a system includes a feed structure for a main reflector, the feed structure comprising an electronically scanned array (ESA) feed and a sub-reflector. The sub-reflector is configured to propagate a signal between the ESA feed and the main reflector. The system also includes a star tracker element coupled to the feed structure and configured to determine orientation information relative to star alignment, and laser distancing elements coupled to the feed structure and configured to determine distance measurements relative to the main reflector. A control system is configured to determine pointing errors of the main reflector based at least on the orientation information and the distance measurements, and these pointing errors can be used by the ESA feed to adjust steering of a signal towards a target.