Radar Antenna Alignment via Laser Tracker Feedback
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Solution Overview
Problem
Modern radar systems with planar antenna arrays face challenges in achieving accurate relative alignment, especially under environmental conditions like thermal expansion and contraction, which affect hemispheric coverage and target tracking precision.
Innovation Solution
A method using laser trackers and retroreflectors within the support structure to measure and correct for physical biases, allowing for continuous alignment adjustments and precise calibration of antenna arrays, incorporating both internal and external measurements to maintain accurate pointing directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple planar antenna arrays are physically supported in close proximity to each other, then hemispheric coverage is achieved, but structural flexure and thermal expansion/contraction adversely affect alignment accuracy
Solution Approach 1:
The patent replaces traditional mechanical alignment methods (theodolites, physical measurements) with an optical-based laser tracker system. The laser tracker continuously measures the positions of retroreflectors mounted on each antenna array, providing real-time alignment data without mechanical contact. This substitution enables precise measurement of relative angular orientations while being immune to structural flexure and thermal effects that plague mechanical measurement systems.
Solution Approach 2:
The system implements continuous feedback by repeatedly measuring the positions of retroreflectors on antenna arrays using a laser tracker. The measured positions are compared against reference data to detect deviations caused by structural flexure or thermal expansion. Correction values are then calculated and applied to maintain accurate relative alignment, creating a closed-loop system that actively compensates for environmental disturbances.
2Measurement precision
If external measurement instruments are placed in proximity to antenna arrays, then alignment measurements can be taken, but some antenna arrays become hidden from view requiring additional instruments
Solution Approach 1:
The patent nests the measurement system within the radar structure itself by mounting retroreflectors on each antenna array and positioning the laser tracker inside the deckhouse. This nested arrangement allows the measurement system to be self-contained and eliminates the need for external instruments. The laser tracker can access all retroreflectors through the deckhouse interior without requiring external placement, thereby simplifying the overall measurement system while maintaining precision.
Solution Approach 2:
The laser tracker serves as a universal measurement instrument that can measure all antenna arrays from a single location inside the deckhouse. By using retroreflectors as universal targets that can be viewed from any angle, the system eliminates the need for multiple specialized external instruments. Each retroreflector can be measured by the same laser tracker regardless of the antenna array's orientation or position, providing multi-functional measurement capability.
3Manufacturing precision
If repeated measurements are made to detect structural distortion, then alignment accuracy is maintained, but measurement time and processing complexity increase
Solution Approach 1:
The patent performs preliminary action by establishing a reference coordinate system and mounting retroreflectors on all antenna arrays before operational use. The initial alignment measurements are taken and stored as reference data. During operation, only differential measurements are needed to detect changes from the reference state, significantly reducing the time and complexity of continuous alignment monitoring while maintaining high accuracy.
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
Enables rapid and precise alignment of radar systems, reducing errors caused by structural flexure and ensuring accurate target tracking over extended engagements by continuously correcting for distortions, thus improving combat system performance.
Implementation Method 1
making repeated measurements between at least one laser tracker located within the support structure and laser targets mounted within the support structure
Implementation Method 2
laser tracker-laser reflector arrangement located within the interior of the support structure for measuring physical alignment biases of the antenna array
Data Source
AI summary
A method for adapting the pointing of a radar system in response to distortion of a deckhouse support structure supporting plural antenna arrays of the radar system is provided. The method comprises the steps of making repeated measurements between at least one laser tracker located within the support structure and laser targets mounted within the support structure, and comparing the current measurements with previous measurements to determine physical bias introduced into the structure.