Offset Aperture Gimbaled Optical System for Conformal Dome Aberration Correction
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Solution Overview
Problem
Conformal domes in optical systems introduce significant wavefront aberrations due to their non-spherical shapes, particularly at the tip, which existing optical correctors struggle to effectively correct for, limiting the field-of-regard and optical performance.
Innovation Solution
An offset aperture gimbaled optical system with an optically corrected conformal dome, where the optical aperture is radially offset from the rotation axis, and an aspheric transparent arch corrector is positioned adjacent to the dome to correct for aberrations, ensuring the optical corrector rotates with the optics assembly and is fixed relative to the second rotation axis, thereby avoiding discontinuities and maintaining the field-of-regard.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conformal dome with non-spherical shape is used, then aerodynamic performance is improved, but wavefront aberration increases significantly
Solution Approach 1:
An optical corrector is introduced as an intermediary element between the conformal dome and the optics assembly. This corrector specifically addresses the wavefront aberrations introduced by the non-spherical dome shape, allowing the system to maintain both aerodynamic performance and optical quality
Solution Approach 2:
The optical corrector modifies the wavefront parameters by introducing compensating aberrations. Through careful design of the corrector's surface geometry and position, the system changes the optical path parameters to cancel out the harmful wavefront distortions caused by the conformal dome
2Object-affected harmful factors
If an optical corrector is placed on the roll gimbal to cover the FOV, then aberration correction is improved, but the nod range of motion is limited
Solution Approach 1:
The optical corrector is designed to cover only the necessary field of view requirements rather than attempting to cover the entire possible nod range. This partial coverage approach allows the nod gimbal to achieve its full range of motion while the corrector provides sufficient aberration correction for the operational FOV
Solution Approach 2:
The optical correction function is segmented from the mechanical gimbal system. The optical corrector handles aberration correction for the FOV while the gimbals independently handle the mechanical positioning and full range of motion, allowing both functions to operate optimally without interference
3Weight of moving object
If a half-arch corrector is used, then weight is reduced, but the optical train must roll an extra 180 degrees to cover the same FOR
Solution Approach 1:
The optical corrector is integrated with the roll gimbal system so that the corrector rotates simultaneously with the optics assembly during normal roll operations. This merging eliminates the need for separate 180-degree roll movements, as the corrector maintains proper orientation throughout the full range of motion without requiring additional rotation time
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
The offset aperture design reduces optical aberrations and enhances packaging efficiency, allowing for multiple offset aperture optics assemblies behind the conformal dome, maintaining a continuous field-of-regard without sacrificing performance.
Implementation Method 1
A transparent optical corrector in the form of an aspheric transparent arch having a shape responsive to the shape of the dome may be placed on the roll gimbal in the optical path between the conformal dome and the optics assembly to encompass the FOV of the optics assembly and compensate for the aberrations introduced by the non-spherical window
Data Source
AI summary
An offset aperture gimbaled optical system comprises a gimbal and an optics assembly that is mounted on an inner gimbal and offset radially from an axis of symmetry (and rotation axis) of a conformal dome. An optical corrector adjacent the inner surface of the conformal dome encompasses the field-of-view of the optics assembly as the inner gimbal rotates about its rotation axis. The corrector is fixed with respect to the inner gimbal's rotation axis while it rotates about the axis of symmetry. The optical corrector comprises an aspheric transparent arch having an optical corrector shape and position responsive to a shape of the conformal dome at the offset position of the optics assembly. In different applications, the offset aperture provides for reduced optical aberrations and improved utilization of the available packaging volume to accommodate multiple offset aperture optics assemblies.