Co-Located EOIR and RF Sensors for Low-Drag Guided Munitions
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Solution Overview
Problem
Precision guided munitions (PGMs) face challenges in accommodating both electro-optical infrared (EOIR) and radio-frequency (RF) sensors on the nose of the missile due to limited surface area, which affects targeting accuracy and increases air drag.
Innovation Solution
A co-located sensor system is implemented, where the EOIR sensor and RF sensor share centers aligned with the missile's longitudinal axis, and the RF sensor is designed with unpopulated areas to allow photons to pass through, ensuring that the EOIR sensor captures a full scene without obstruction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If both EOIR and RF sensors are placed on the nose of the missile, then targeting accuracy is improved, but the limited surface area causes obstruction and increased air drag
Solution Approach 1:
The patent transitions from a two-dimensional surface mounting problem to a three-dimensional co-located arrangement. The RF sensor substrate is positioned in the optical path between the EOIR sensor and the target, utilizing the third dimension (depth along the optical axis) to accommodate both sensors without increasing lateral surface area. This dimensional transition allows photons to pass through unpopulated areas of the RF substrate while maintaining both sensor functionalities.
Solution Approach 2:
The RF sensor substrate is designed with unpopulated areas (holes) that allow photons to pass through to the EOIR sensor. This porous-like structure enables the RF sensor to function while minimizing obstruction of the optical path, effectively allowing light transmission through the substrate at frequencies where the material is transparent.
2Adaptability or versatility
If RF sensor substrate is placed in front of EOIR sensor, then both sensors can be co-located, but the substrate may obstruct the optical path
Solution Approach 1:
The RF sensor substrate incorporates unpopulated areas (holes) arranged in a pattern that allows photons to pass through to the EOIR sensor. This design enables the RF sensor to be functional while minimizing obstruction of the optical path, as the holes permit light transmission at frequencies where the substrate material is transparent.
Solution Approach 2:
The patent replaces a solid mechanical substrate with a perforated or porous substrate structure. This substitution allows the RF sensor to be mounted on the substrate while maintaining optical transparency in the unpopulated areas, thereby eliminating the trade-off between RF sensor placement and optical path clearance.
3Volume of moving object
If sensors are placed closer together to reduce size, then SWaP efficiency is improved, but sensor interference and obstruction increase
Solution Approach 1:
The patent resolves the interference problem by moving from lateral separation to axial separation. The RF sensor substrate is positioned in front of the EOIR sensor along the optical axis, allowing both sensors to be closely spaced laterally while maintaining functional independence through depth separation. The unpopulated areas further ensure optical independence.
Solution Approach 2:
The substrate is designed with spatially varying properties: populated areas for RF sensor elements and unpopulated areas for optical transmission. This local differentiation allows the substrate to serve dual functions - supporting RF sensors while permitting optical path clearance in specific regions, thereby maintaining sensor independence despite close proximity.
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 enhances targeting accuracy by allowing both sensors to operate effectively without obstructing each other's vision, while also reducing air drag and improving the size-weight-and-power (SWaP) efficiency of the PGM system.
Implementation Method 1
The one or more antenna substrates include a plurality of holes arranged in a grid pattern configured to let photons pass through the antenna substrates from the window to the image sensor
Implementation Method 2
The image sensor is behind the aperture and is configured to focus at an infinity focus in front of the body
Implementation Method 3
an image sensor configured to capture an image in front of the body
Data Source
Figure 1A
Figure 1B~1C
Figure 2A
AI summary
A precision guided munition (PGM) system is disclosed. The PGM system comprises a body (305) including a nose portion. The nose portion includes an aperture. A window (310) is attached, secured, or adhered to the body at the nose portion. One or more antenna substrates (320) is attached, secured, or adhered to the window. A plurality of radiating elements is attached, secured, or adhered to the one or more antenna substrates. An image sensor configured to capture an image in front of the body. The image sensor (350) is behind the aperture and is configured to focus at an infinity focus in front of the body. The one or more antenna substrates include unpopulated areas configured to let photons pass through the antenna substrates from the window to the image sensor. The photons are parallel or collimated and the captured image does not include features of the antenna substrates.