Multimode Shared Aperture Seeker Dual-Mode Diffuser
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Solution Overview
Problem
Conventional shared aperture dual-mode seekers have a narrow field of view, requiring gimbal mechanisms to achieve a wider field of regard, which results in large obscurations and reduced collection aperture efficiency.
Innovation Solution
A multimode seeker system utilizing a dual-mode diffuser to expand the linear field of view of the semi-active laser (SAL) seeker without impacting the imaging infrared (IIR) seeker, allowing both modes to utilize the full aperture and operate in non-gimbaled systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a narrow field of view optical system is used, then the system can achieve high optical efficiency and large aperture, but the field of view is limited requiring gimbal mechanisms to expand the field of regard
Solution Approach 1:
The patent transforms the SAL detector from a point detector into an extended linear detector by diffracting the laser radiation across its surface. This dimensional change allows the detector to simultaneously receive laser radiation from multiple angular positions, effectively expanding the field of view without requiring mechanical gimbaling of the entire optical system.
Solution Approach 2:
The patent changes the spatial distribution parameter of the laser radiation by introducing a diffuser that spreads the focused laser spot across the extended surface of the SAL detector. This parameter change enables the detector to capture laser radiation over a wider angular range while maintaining the high optical efficiency of the original narrow field of view optical system.
2Adaptability or versatility
If gimbal mechanisms are added to expand the field of regard, then the angular coverage is increased, but large obscurations are introduced that waste collection aperture area
Solution Approach 1:
The patent replaces the mechanical gimbal system with an optical diffraction-based solution. Instead of mechanically moving the entire optical system to scan different angles, the patent uses a diffuser to optically spread the laser radiation across the detector surface, achieving angular coverage expansion without mechanical moving parts and without obscuring the aperture.
3Measurement precision
If the SAL detector is focused for high sensitivity, then the detection sensitivity is maximized, but the linear field of view is narrow
Solution Approach 1:
The patent effectively segments the detection function across the extended surface of the SAL detector. By diffracting the laser radiation into multiple spatial locations on the detector surface, each region can be optimized for sensitivity while collectively covering a wider angular range, thus resolving the contradiction between focused sensitivity and broad field of view.
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 solution enables a wider field of view for the SAL seeker while maintaining the performance of the IIR seeker, maximizing target detection range and minimizing space requirements, suitable for strap-down systems.
Implementation Method 1
diffracting the laser radiation includes broadening the beam diameter of the laser radiation to produce a linear field of view of the SAL detector of approximately ±12°
Implementation Method 2
focusing the infrared radiation onto the imaging detector
Implementation Method 3
receiving the infrared radiation and the laser radiation includes passing the infrared radiation and the laser radiation though a window that is substantially optically transparent to the infrared radiation and the laser radiation
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A multimode shared aperture seeker incorporating a dual-mode diffuser and methods of operation thereof. According to one example, a non-gimbaled multimode seeker includes an IIR seeker including an FPA and an optical system that receives infrared radiation via a system optical apertuie and focuses the infrared radiation onto the FPA, and a SAL seeker including a SAL detector positioned in an optical path between the system optical aperture and the FPA and configured to detect laser radiation received via the system optical aperture. The SAL detector is substantially transparent to the infrared radiation. The multimode seeker further includes a dual-mode diffuser positioned in the optical path between the system optical aperture and the optical system. The diffuser is configured to spread the laser radiation to broaden a linear field of view of the SAL seeker, and to transmit the infrared radiation substantially undiffracted to the optical system.