Super-resolution Imaging Radar Using Fourth-Order Correlation

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Solution Overview

Problem

Current imaging radar technologies, such as synthetic aperture radar and inverse synthetic aperture radar, are limited by their reliance on second-order correlations, requiring costly systems, extensive data storage, and significant post-processing, and are unable to achieve high-resolution images without motion or complex setups.

Innovation Solution

The system employs a super-resolution imaging radar technique using high-order correlations of radio frequency energy, with a pulse signal generator, array bucket detector, virtual lens, virtual scanning detector, and coincidence circuit to calculate a cross-time correlation function, generating enhanced-resolution images by propagating bursts of RF energy with ancilla pulses and collecting reflected pulses to form images.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If second-order correlation imaging radar is used, then system complexity is reduced, but resolution is limited to 5-10 meters

Engineering Contradiction:
ImproveresolutionVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent changes the correlation order parameter from second-order to fourth-order correlations. This parameter change enables the system to achieve 0.045 meter resolution (100x improvement) by utilizing higher-order statistical properties of the radar signals, transforming the fundamental limitation of conventional imaging radar without requiring proportional increases in system complexity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces a new dimension of analysis by computing fourth-order correlations instead of traditional second-order correlations. This dimensional change in the correlation computation enables extraction of additional information from the radar signals, achieving super-resolution imaging capability while maintaining system architecture simplicity

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If synthetic aperture radar is used, then resolution can be improved, but data storage requirements and post-processing complexity increase significantly

Engineering Contradiction:
ImproveresolutionVSAvoiddata storage
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent extracts and utilizes only the necessary fourth-order correlation information directly from the radar signals during the imaging process. By computing fourth-order correlations in the spatial domain and using them directly for image formation, the system avoids the need to store and process extensive raw data sets, achieving high resolution with minimal data storage requirements

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical data storage and post-processing system of synthetic aperture radar with a direct fourth-order correlation computation method. This substitution eliminates the need for large data storage infrastructure and complex post-processing algorithms, achieving the same resolution improvement through a more efficient computational approach

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If conventional imaging radar is used, then system cost is reduced, but resolution is limited and no motion is required

Engineering Contradiction:
ImproveresolutionVSAvoidsystem cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent creates a virtual imaging system that copies the functionality of complex mechanical imaging systems through computational methods. By implementing fourth-order correlation processing in software rather than requiring complex hardware systems, the patent achieves super-resolution imaging at a fraction of the cost while maintaining ease of manufacture

Inventive Principle:
Principle #26Copying

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 approach achieves a 100x resolution improvement over current state-of-the-art imaging radar, reducing the point spread function from 5-10 meters to approximately 0.045 meters, eliminating the need for costly and complex systems and extensive data processing.

Implementation Method 1

a pulse signal generator that propagates N number of bursts of radio frequency (RF) energy

Methodology Applied
Scientific EffectElectromagnetic wave propagation: Electromagnetic Induction

Implementation Method 2

an array bucket detector (ABD) collects pulses that are reflected from the object

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 3

The ancilla pulses are propagated through a virtual lens

Methodology Applied
Scientific EffectLens focusing: Lens

Implementation Method 4

a coincidence circuit calculates a cross-time correlation function of the electric fields of the reflected pulses that are collected by the ABD and the virtual ancilla electric field calculated by the processor

Methodology Applied
Scientific EffectCross-time correlation:

Data Source

PatentEP2545395B1Super-resolution imaging radar
Publication Date: 2015.07.29 THE BOEING CO
  • EP2545395B1 patent drawingFigure 1
  • EP2545395B1 patent drawingFigure 2
  • EP2545395B1 patent drawing

AI summary

A system, apparatus, and method are disclosed for a super-resolution imaging radar (SRIR). The SRIR employs a pulse signal generator that propagates bursts of radio frequency (RF) energy. Each burst contains a number of pulses. One pulse of each burst is an ancilla pulse, and the remaining pulses are propagated towards an object. An array bucket detector (ABD) collects pulses that are reflected from the object. Also, the ancilla pulses are propagated through a virtual lens. A virtual scanning detector detects the virtual ancilla electric field. A processor calculates a virtual ancilla electric field, which would be present at the scanning detector. Further, a coincidence circuit calculates a cross-time correlation function of the electric fields of the reflected pulses that are collected by the ABD and the virtual ancilla electric field. The coincidence circuit uses cross-time correlation function results to generate pixels of an image of the object.