Shared-Aperture Optical Sensor for Low-Aberration Tx/Rx Imaging
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Solution Overview
Problem
Gimbaled optical sensors face challenges in effectively combining active and passive signal processing within a common aperture configuration, particularly in guiding munitions and autonomous vehicles, where precise pointing control and image quality are critical but often compromised by optical imperfections and separate transmit and receive paths.
Innovation Solution
The implementation of a Tx/Rx Aperture Sharing Element (ASE) with a center region for transmitting active signals and an annular region for receiving passive emissions and active returns, coupled with a filter wheel for separate image processing, allows for co-boresighted or offset signal transmission and reception, maintaining image quality and enabling open-loop and closed-loop control systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a common Tx/Rx telescope is used for both transmit and receive, then device complexity is reduced, but optical imperfections and aberrations increase
Solution Approach 1:
The aperture is segmented into a central region for transmit signals and an annular region for receive signals. This segmentation allows separate optical paths for Tx and Rx within a common telescope, reducing optical aberrations while maintaining device simplicity.
Solution Approach 2:
Different regions of the aperture are assigned different functions: the central region handles transmit signals while the annular region handles receive signals. This local differentiation optimizes optical quality for each function while using a shared telescope structure.
2Object-affected harmful factors
If separate Tx and Rx paths are used, then optical quality is improved, but device complexity increases
Solution Approach 1:
The transmit and receive paths are merged into a common telescope structure, reducing device complexity. The aperture is shared between Tx and Rx functions, eliminating the need for separate telescopes while maintaining optical quality through regional differentiation.
Solution Approach 2:
The common telescope serves multiple functions: it transmits active signals through the central aperture region and receives passive emissions through the annular aperture region. This multi-functionality reduces the number of components while maintaining separate optical paths for each function.
3Loss of information
If an ASE is positioned in the aperture to separate signals, then signal separation is improved, but optical imperfections increase
Solution Approach 1:
The ASE is positioned to extract and separate transmit and receive signals at the aperture plane, where separation occurs before the signals enter the telescope optics. This early extraction minimizes the introduction of optical imperfections while achieving effective signal separation.
4Measurement precision
If co-boresighted configuration is used, then pointing precision is improved, but optical aberrations increase
Solution Approach 1:
The aperture configuration is made asymmetric with a central circular region for transmit and an surrounding annular region for receive. This asymmetric design enables co-boresighted pointing where both Tx and Rx share the same optical axis, improving pointing precision while the regional separation minimizes optical aberrations.
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 configuration enhances the gimbaled optical sensors' ability to transmit active signals and receive passive signals over a range of wavelengths, achieving near diffraction-limited performance and precise pointing control, while minimizing optical aberrations and improving guidance capabilities in guided munitions and autonomous vehicles.
Implementation Method 1
A center region (reflective or transmissive) of the ASE free-space couples the optical transmit signal from the off-gimbal access point into the free-space optical path and to the common Tx/Rx telescope for transmission towards a scene
Implementation Method 2
An annular region (transmissive or reflective) of the ASE couples the returned transmit signal and passive emissions from the scene received by the common Tx/Rx telescope to the off-gimbal detector
Implementation Method 3
An annular region (transmissive or reflective) of the ASE couples the returned transmit signal and passive emissions from the scene received by the common Tx/Rx telescope to the off-gimbal detector
Implementation Method 4
A free-space optical path along the first and second gimbal axes couples light from the common Tx/Rx telescope to an off-gimbal detector
Data Source
AI summary
Optical sensors and particularly gimbaled optical sensors transmit an active signal at a given wavelength(s) and receive passive signals over a range of wavelengths and the active signal in a common aperture. The sensor includes a Tx/Rx Aperture Sharing Element (ASE) configured with a center region that couples the active signal to the telescope for transmission and an annular region that couples the passive emissions and the returned active signal to the detector. A filter wheel may be positioned behind the ASE to present separate passive and active images to the detector. These optical sensors may, for example, be used with guided munitions or autonomous vehicles.