Passive DF and EOIR Seeker Layout for Compact Munition Nosecones
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Solution Overview
Problem
Missiles and guided munitions face challenges in incorporating both passive direction finding (DF) and electro-optical infrared (EOIR) imaging systems within compact volumes, necessitating a solution that enables target detection and aimpoint refinement without active electronic components.
Innovation Solution
An integrated imaging and passive DF seeker system is developed, featuring a set of N log periodic array (LPA) antenna elements mounted on a conical ground chassis within the nosecone, self-shielded from EOIR and active seeker systems, capable of scanning ultra-wide band frequencies for target detection and geolocation, combined with EOIR imaging for aimpoint refinement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If passive DF and EOIR imaging systems are integrated within compact volumes, then target detection range and aimpoint accuracy are improved, but device complexity increases
Solution Approach 1:
The patent implements nesting by placing the LPA antenna elements and ground chassis inside the nosecone structure, with the EOIR imager positioned centrally within the electronics stack. The ground chassis with N-sided polygonal cross section is nested within the available volume, efficiently utilizing the compact space to accommodate both passive DF and active imaging systems without increasing overall device complexity
Solution Approach 2:
The patent employs dimensional optimization by configuring the ground chassis with an N-sided polygonal cross section and tapering it conically along the longitudinal axis. This geometric transformation allows the antenna elements to be arranged in three-dimensional space efficiently, separating them from the EOIR imager in the radial dimension while maintaining compact overall volume
2Object-affected harmful factors
If LPA antenna elements are self-shielded from EOIR and active seeker systems, then electromagnetic interference is reduced, but the available volume for antenna elements decreases
Solution Approach 1:
The patent applies segmentation by dividing the nosecone interior into distinct functional zones: the ground chassis with LPA antenna elements occupies the peripheral volume, while the EOIR imager is positioned centrally within the electronics stack. The tapered conical ground chassis creates natural electromagnetic shielding through spatial separation, reducing interference without requiring additional shielding materials that would consume volume
Solution Approach 2:
The patent utilizes asymmetric configuration where the ground chassis has an N-sided polygonal cross section rather than a symmetric circular shape. This asymmetric geometry allows optimized placement of antenna elements at specific angular positions around the nosecone, maximizing their separation from the centrally located EOIR imager and improving electromagnetic isolation while efficiently utilizing the available volume
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 system provides sufficient target detection range and aimpoint accuracy by integrating passive DF and EOIR imaging within a compact form factor, enhancing the missile's guidance capabilities.
Implementation Method 1
The LPA antenna elements individually or collectively scan bands or sub-bands within the ultra-wide band (UWB) frequency range to identify signals of interest (SoI) associated with potential targets
Implementation Method 2
the antenna elements self-shielded from the EOIR imager and from other processing/sensing systems within the electronics stack (e.g., active Ka-band/W-band radar seeker systems) by the ground chassis
Implementation Method 3
the imaging system includes an electro-optical infrared (EOIR; e.g., short wave IR (SWIR)) imager configured for target discrimination and aimpoint refinement
Data Source
AI summary
An integrated imaging and passive directional finding (DF) system for a guided munition or weapons platform includes an electro-optical infrared (EOIR) imager within a nosecone of the weapons platform and configured for imaging of a detected target. The passive DF system includes an array of long periodic array (LPA) antenna elements, each element disposed on a face of a tapered conical ground chassis having a polygonal cross section, the LPA antenna elements self-shielded from the EOIR imager and other electronic components by the ground chassis. Each LPA antenna element scans for signals of interest (SoI) within the ultra-wide band (UWB) frequency range. Geolocation or passive direction finding (DF) based on detected signals of interest may be performed to guide the weapons platform into imaging range of one or more targets of interest, where EOIR imaging may take over for target discrimination and aimpoint refinement.