Two-Antenna Radio Direction Finding With Transmitter Identification

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Solution Overview

Problem

Existing direction finding systems face challenges in accurately determining the direction and identifying radio transmitters, particularly in complex environments, and do not adequately differentiate between friendly and hostile targets.

Innovation Solution

A direction finding system utilizing two antennas separated by an offset vector, with a phase detector and processor to determine the direction to a transmitter based on phase differences, and an identifier to recognize specific transmitters, optionally including a database for signal comparison and a remote control for activation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional direction finding systems are used, then basic direction determination is achieved, but measurement precision and reliability are insufficient in complex environments

Engineering Contradiction:

Improvedirection finding precisionVSAvoidsystem reliability in complex environments

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The system segments the direction finding function into multiple independent antenna elements arranged in specific geometric configurations. Each antenna element processes signals independently through its own phase detector and signal processing chain, then combines results to achieve higher precision and reliability through diversity processing

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces intermediate frequency (IF) conversion as a mediator between the received RF signals and the digital signal processing stage. The IF stage provides stable frequency reference and enables precise phase measurement through heterodyne conversion, improving measurement precision in complex electromagnetic environments

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If direction finding systems lack identification capability, then simple direction determination is possible, but differentiation between friendly and hostile targets cannot be achieved

Engineering Contradiction:

Improvetarget differentiation capabilityVSAvoidtransmitter identification information

Core Design Contradiction:

Adaptability or versatilityVSLoss of information

Solution Approach 1:

The system integrates multiple functions into a single direction finding apparatus: direction determination through phase comparison, signal identification through pattern recognition, and target classification (friendly/hostile) through database matching. This multi-functionality enables both direction finding and transmitter identification without requiring separate systems

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system performs preliminary signal characterization and pattern recognition before final target classification. Received signals are pre-processed to extract identifying features, compared against pre-loaded transmitter databases, and classified before presenting the final direction finding result, ensuring accurate differentiation between friendly and hostile targets

Inventive Principle:

Principle #10Preliminary action

3Measurement precision

If complex signal processing is implemented, then measurement precision improves, but device complexity increases

Engineering Contradiction:

Improvephase difference measurement precisionVSAvoidsignal processing system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical signal processing methods with electronic and digital processing. Instead of using mechanical phase shifters or analog vector summation, the system uses digital signal processing algorithms to compute phase differences and determine direction, reducing mechanical complexity while maintaining or improving precision

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system transforms the complex signal processing problem into simpler parameter measurements by converting received signals to a common reference frequency and measuring only the phase difference parameter. This parameter transformation simplifies the processing while achieving high measurement precision through coherent detection

Inventive Principle:

Principle #35Parameter changes

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

Enables precise direction finding and identification of transmitters, reducing the risk of friendly fire incidents and facilitating the location of friendly objects or individuals in challenging conditions.

Implementation Method 1

determine a difference in phase between the signal as received by the first antenna and the signal as received by the second antenna

Methodology Applied

Scientific EffectPhase difference:

Data Source

PatentUS12392857B2Remote radio direction finder and identifier

Publication Date: 2025.08.19 EUREKA PRO TECH LTD

AI summary

Some embodiments of the current invention relate to finding and identifying a transmitter. In some embodiments, two antennas are separated by an offset, and/or receive a single signal. Optionally, a processor determines a direction to the transmitter of the signal. For example, the determination may be based on a phase difference between the response of the two antennas. Optionally, the device further includes an identification module that may determine an identification associated with the transmitter. For example, the system may be used to find a particular object or person and/or to differentiate between a friend and a foe.