Correlating Radio Signals with Transmitter Paths

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional geolocation methods face challenges in accurately locating moving transmitters emitting arbitrary signals, especially when their paths change frequently, as they introduce additional Doppler shifts that are difficult to distinguish using moving receivers.

Innovation Solution

The method involves correlating potential transmitters with received radio signals by calculating and comparing time and frequency differences of arrival (TDOA and FDOA) based on image data of transmitter paths, using discrete filters and cross-correlation techniques to associate received signals with specific transmitters, even when receivers are in motion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional geolocation methods are used to locate moving transmitters, then the basic geolocation function is provided, but additional Doppler shifts from frequently changing paths cannot be distinguished, reducing measurement precision

Engineering Contradiction:

Improvetransmitter location precisionVSAvoidDoppler shift distinction difficulty

Core Design Contradiction:

Measurement precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The patent segments the continuous signal processing into discrete time segments, where each segment corresponds to a specific transmitter path segment from image data. By processing signals in segmented fashion and associating each segment with specific image data, the method can distinguish between different Doppler shifts caused by different path changes, thereby improving measurement precision for moving transmitters.

Inventive Principle:

Principle #1Segmentation

2Loss of information

If image data is used to track transmitter paths, then visibility coverage is improved, but momentary breaks in visibility cause loss of signal association

Engineering Contradiction:

Improvetransmitter path information lossVSAvoidsignal association reliability

Core Design Contradiction:

Loss of informationVSReliability

Solution Approach 1:

The patent performs preliminary correlation between image data and radio signal data when both are available and reliable. By establishing associations during periods of good visibility and signal quality, the system creates a baseline that can be used to maintain associations during momentary breaks in visibility, reducing information loss and maintaining reliability.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors the quality and availability of both image data and radio signal data, using this feedback to adjust the correlation process. When visibility breaks occur, the feedback mechanism allows the system to maintain associations based on previously established correlations and predicted transmitter paths, preventing complete loss of signal association.

Inventive Principle:

Principle #23Feedback

3Measurement precision

If multiple receivers are used to measure TDOA and FDOA, then geolocation accuracy is improved, but device complexity increases

Engineering Contradiction:

Improvegeolocation accuracyVSAvoidreceiver system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent makes the receiver system multi-functional by enabling it to perform both traditional geolocation measurements (TDOA, FDOA) and the new function of correlating measurements with image data of transmitter paths. This universal approach allows the same receiver infrastructure to support enhanced geolocation for moving transmitters without requiring separate dedicated systems, thereby improving accuracy while managing complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 geolocation of moving transmitters by imaging their paths and associating radio signals with vehicle trajectories, enabling long-duration coherent integration and resolving multiple co-channel signals, even during momentary breaks in visibility.

Implementation Method 1

Both known and novel methods exist that use multiple receivers having known locations to solve for the position of unknown transmitters... using time difference of arrival (TDOA) and/or frequency difference of arrival (FDOA) at multiple observing receivers

Methodology Applied

Scientific EffectDoppler effect: Doppler Effect

Implementation Method 2

TOA=TOT+Range/Vg, where TOA is the time of arrival; TOT is the time of transmission; Range is the distance between the receiver and transmitter; and Vg is the group velocity or velocity of the modulation envelope

Methodology Applied

Scientific EffectTime of flight: Time of Flight

Data Source

PatentUS8471766B2Method of correlating known image data of moving transmitters with measured radio signals

Publication Date: 2013.06.25 RINCON RESEARCH CORP

AI summary

Systems and methods of correlating potential transmitters with received radio signals is provided. Image data is provided including paths traveled by potential transmitter. Potential transmitters are identified within the image data along with path segments traveled by potential transmitters. A first and second transmitter calculate certain parameters of received signals assuming that signals originated along the path segments. The calculated signal parameters are then compared to measured signal parameter to determine whether a transmitter is associated with a particular path.