Lightning Pulse Geolocation via Waveform Feature Comparison

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Solution Overview

Problem

Current methods for time alignment and geolocation of lightning pulses separated by microseconds are inefficient and costly, requiring dense arrays of sensors operating at high frequencies, which limits their effectiveness and increases costs.

Innovation Solution

A method using broadband low-frequency to medium-frequency signals received by networks of sensors separated by tens to hundreds of kilometers, which aligns and geolocates lightning pulses by extracting and comparing waveform features such as pulse duration, rise time, and peak-to-zero time, allowing for accurate time alignment and geolocation with fewer and less costly sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If dense arrays of VHF sensors are used for time alignment and geolocation of lightning pulses, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:
Improvetime alignment precisionVSAvoidsensor array density
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent changes the frequency parameter from VHF to LF-MF range and modifies the signal processing approach by using waveform feature comparison instead of traditional time difference of arrival methods. This allows achieving comparable measurement precision with significantly reduced sensor array density, as LF-MF signals propagate differently and can be effectively processed with fewer sensors spaced tens to hundreds of kilometers apart.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical/physical constraint of dense sensor arrays with a signal processing approach based on waveform feature extraction and comparison. Instead of relying on physical proximity of sensors to achieve precise time alignment, the system uses characteristic waveform features (rise time, peak time, duration) that can be identified and compared across distributed sensors, substituting physical density with algorithmic processing.

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

2Measurement precision

If VHF sensors operate at high frequencies for lightning detection, then measurement precision is improved, but use of energy and cost increase

Engineering Contradiction:
Improvelightning pulse detection accuracyVSAvoidsensor operating cost
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent changes the operating frequency parameter from VHF to LF-MF range. LF-MF signals have different propagation characteristics that allow for effective detection with lower energy consumption. The waveform feature comparison method also reduces processing energy requirements compared to high-frequency signal processing, as the features can be extracted from lower bandwidth signals.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If sensors are placed close together in dense arrays, then time alignment precision is improved, but loss of time for data transmission and processing increases

Engineering Contradiction:
Improvepulse timing alignmentVSAvoiddata transmission delay
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent extracts and uses only the essential waveform features (rise time, peak time, duration) from the complete lightning pulse signals. This extraction approach reduces the amount of data that needs to be transmitted and processed while retaining sufficient information for accurate time alignment. By focusing on key features rather than complete waveforms, the system minimizes data transmission time while maintaining precision.

Inventive Principle:
Principle #2Taking out (Extraction)

4Device complexity

If broadband LF to MF signals are used with distributed sensors, then device complexity is reduced, but measurement precision may worsen

Engineering Contradiction:
Improvesensor network configurationVSAvoidgeolocation accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent substitutes the mechanical advantage of dense sensor arrays with a signal processing methodology based on waveform feature comparison. The system extracts characteristic features from LF-MF signals and uses their temporal and morphological relationships to achieve accurate geolocation. This substitution allows distributed sensors to achieve precision comparable to dense arrays through intelligent processing rather than physical proximity.

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

Solution Approach 2:

The patent introduces waveform features as intermediary elements that mediate between the distributed sensors and the geolocation calculation. Instead of directly using raw sensor data from multiple locations, the system extracts intermediate waveform features (rise time, peak time, duration) that capture the essential timing and shape information. These features serve as mediators that enable accurate time alignment and geolocation even when sensors are widely spaced.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentUS10649018B2Time alignment of lightning emissions at LF-MF using waveform feature comparison
Publication Date: 2020.05.12 VAISALA
  • US10649018B2 patent drawing
  • US10649018B2 patent drawing
  • US10649018B2 patent drawing

AI summary

A method to generate data to geolocate lightning pulses may include detecting in an environment EMF generated from the lightning pulses. The method may include producing lightning-EMF from the detected EMF where the lightning-EMF may represent the EMF generated from the lightning pulses. The method may include extracting a lightning-waveform-feature set from the lightning-EMF data, including extracting one or more waveform features for each of the lightning pulses from the lightning-EMF data. The method may also include transmitting the extracted lightning-waveform-feature set to a server to perform time alignment on multiple extracted lightning-waveform-feature sets received from multiple lightning-detection sensors and to geolocate the lightning pulses based on the time-aligned extracted lightning-waveform-feature sets.