Inertial Navigation Calibration via Lightning Magnetic Pulses

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Solution Overview

Problem

Inertial navigation units deployed in underground applications experience growing errors in location determination over time, reducing their reliability.

Innovation Solution

A method and system that utilize a network of magnetometers above ground and a co-located magnetometer with the inertial navigation unit underground to detect and compare magnetic pulses, such as those generated by lightning strikes, to correct the location determination by analyzing the wavefront shape, velocity, and direction of the magnetic pulses and applying corrections to the inertial navigation unit via low-frequency signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If inertial navigation units are deployed in underground applications, then location determination capability is improved, but error accumulation over time increases

Engineering Contradiction:

Improvelocation determination capabilityVSAvoidlocation accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The system uses magnetometers to detect magnetic pulses and provides feedback corrections to the inertial navigation unit. The magnetometer measurements are compared with expected values, and correction values are applied to compensate for drift, creating a closed-loop feedback system that maintains accuracy over time.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

Magnetic pulses serve as an intermediary reference signal that can be detected both by surface magnetometers and by the magnetometer co-located with the underground inertial navigation unit. This intermediary allows indirect calibration without requiring direct line-of-sight or external infrastructure.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Duration of action of moving object

If inertial navigation units operate for extended periods, then continuous location tracking is improved, but error accumulation increases

Engineering Contradiction:

Improveoperational durationVSAvoidlocation accuracy

Core Design Contradiction:

Duration of action of moving objectVSMeasurement precision

Solution Approach 1:

The system performs periodic calibration by detecting magnetic pulses that occur naturally over time. Each magnetic pulse provides an opportunity to correct accumulated errors, transforming continuous operation into a series of periodic recalibration events that reset the error accumulation cycle.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The system maintains continuous operational capability while periodically correcting errors. The inertial navigation unit continues tracking location without interruption, and the magnetic pulse detection provides continuous opportunities for calibration, ensuring both uninterrupted operation and sustained accuracy.

Inventive Principle:

Principle #20Continuity of useful action

3Measurement precision

If magnetometer calibration is performed using surface magnetometers, then location correction is improved, but system complexity increases

Engineering Contradiction:

Improvelocation correction accuracyVSAvoidsystem complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The same magnetometer hardware co-located with the inertial navigation unit serves multiple functions: it detects magnetic pulses for calibration, provides navigation data, and enables correction without requiring separate dedicated calibration equipment. This multi-functionality reduces overall system complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The inertial navigation unit performs its own calibration using the magnetometer already integrated into it. The unit compares its own magnetometer readings with corrections derived from surface magnetometer data, eliminating the need for external calibration equipment or complex calibration systems.

Inventive Principle:

Principle #25Self-service

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 timely and reliable calibration of inertial navigation units, reducing location errors and enhancing their accuracy by leveraging frequent natural magnetic pulses for continuous correction.

Implementation Method 1

receive a magnetic pulse, such as a magnetic pulse generated by a lightening strike, with a plurality of first magnetometers and with a second magnetometer co-located with the inertial navigation unit

Methodology Applied

Scientific EffectMagnetic pulse detection: Magnetometer

Data Source

PatentUS8392140B1System and method for calibrating a location determined by an inertial navigation unit

Publication Date: 2013.03.05 THE BOEING CO

AI summary

A method, system and inertial navigation unit are provided in order to facilitate location determination by calibrating a location determined by an inertial navigation unit. The method may receive a magnetic pulse, such as a magnetic pulse generated by a lightening strike, with a plurality of first magnetometers and with a second magnetometer co-located with the inertial navigation unit. The method may also compare a representation of the magnetic pulse received by the plurality of first magnetometers to a respective representation of the magnetic pulse received by the second magnetometer. Further, the method may correct the location determined by the inertial navigation unit as a result of the comparing of the representation of the magnetic pulse received by the plurality of first magnetometers to the respective representation of the magnetic pulse received by the second magnetometer.