IFF Target Localization Using Dual Electronic Scanning Antenna Arrays

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Solution Overview

Problem

Existing methods for locating a target in space using electronically scanned antenna arrays face challenges in determining the site of the target independently of the IFF interrogation mode and without decoding information from the target's response, leading to uncertainty in azimuth positioning due to deformation of iso-deviation curves with higher pointing angles.

Innovation Solution

A method that processes signals received from multiple antenna arrays to determine the target's site and azimuth using deviation angles and polynomial modeling of deviation angle evolution, without relying on IFF interrogation mode information, by combining signals from elementary antennas to form sum and difference signals and applying half-angle deviation measurement techniques.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If deviation angle measurement is used for azimuth localization, then target identification is achieved, but uncertainty in positioning increases due to iso-deviation curve deformation at higher pointing angles

Engineering Contradiction:
Improveazimuth localization precisionVSAvoidpositioning reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent transitions from single-array 2D localization to dual-array 3D localization by adding the elevation dimension. Each antenna array provides deviation measurements in its own plane, and the intersection of these measurements in 3D space uniquely determines target position, eliminating the ambiguity present in 2D measurements alone.

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

Solution Approach 2:

The patent introduces a geometric relationship as an intermediary between the deviation measurements and target position. By using the known spatial configuration of the two antenna arrays and applying geometric intersection of measurement planes, the system resolves the positioning ambiguity without requiring additional target information.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If IFF interrogation mode information is used for target localization, then identification accuracy is improved, but system complexity increases due to mode-dependent processing

Engineering Contradiction:
Improvetarget identification accuracyVSAvoidlocalization system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent creates a universal localization method that works across all IFF interrogation modes without requiring mode-specific processing. The dual antenna array system and geometric intersection approach provide a single, unified localization mechanism that is independent of the particular IFF mode being used, thereby reducing system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent separates the localization function from the IFF interrogation function. By using dedicated dual antenna arrays for localization measurements independent of the IFF signal processing, the system achieves mode-independent operation without complicating the overall system architecture.

Inventive Principle:
Principle #1Segmentation

3Device complexity

If single antenna array is used for localization, then system simplicity is maintained, but measurement accuracy deteriorates due to iso-deviation curve distortion

Engineering Contradiction:
Improveantenna system complexityVSAvoidtarget position measurement precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent merges two antenna arrays into a unified localization system where the combined measurements from both arrays provide complementary information. The intersection of deviation measurements from different spatial orientations creates a more precise and unambiguous target position determination than either array could achieve alone.

Inventive Principle:
Principle #5Merging (Combining)

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 allows for precise determination of the target's site and azimuth with reduced uncertainty, even at higher pointing angles, by eliminating secondary lobes and ambiguities through amplitude and phase deviation measurements, thereby improving target localization accuracy.

Implementation Method 1

phase difference measurements between antenna elements of different networks

Methodology Applied
Scientific EffectPhase difference measurement:

Implementation Method 2

primary radar locates the target, while a secondary radar, or IFF, identifies it

Methodology Applied
Scientific EffectElectromagnetic radiation: Radar

Data Source

PatentEP2370832B1Method and system for locating a target in an interrogation-response system (IFF)
Publication Date: 2019.02.27 THALES SA
  • EP2370832B1 patent drawingFigure 1~2
  • EP2370832B1 patent drawingFigure 3~4
  • EP2370832B1 patent drawingFigure 5

AI summary

The invention relates to a method and to a system for the location of a target (10) with an azimuth of formula (I) and an elevation angle of formula (II) in space by a carrier, using at least one first electronic scanning antenna array RESEAU_H and at least one second electronic scanning antenna array RESEAU_B, the target emitting a signal in response to an interrogation from the carrier, wherein each of said antenna arrays includes at least one antenna, and the total number of antennas used is at least equal to three.