Polarized Light Filter Array for True North Determination

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Solution Overview

Problem

Current methods for determining true north and measuring solar radiation and atmospheric conditions are time-consuming and costly, particularly in applications like navigation, climate forecasting, and green energy engineering, where fast and accurate solutions are needed.

Innovation Solution

An apparatus comprising an array of light sensors with polarized filters, a processing unit to calculate polarization patterns, and a wavelength separator to derive navigational and atmospheric data, utilizing polarization analysis of skylight to determine celestial body location and atmospheric conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If GPS or active laser instruments are used to determine true north or measure solar radiation, then measurement accuracy is improved, but cost and time consumption increase

Engineering Contradiction:
Improvetrue north determination accuracyVSAvoidtime consumption
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces complex mechanical/GPS systems with an optical-polarization-based system. By using polarized filters arranged in specific patterns and analyzing the polarization state of skylight, the system determines true north and solar position without requiring GPS receivers, electronic compasses, or active laser instruments, thereby reducing both time consumption and cost while maintaining measurement accuracy

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

Solution Approach 2:

The patent uses a simplified optical model that copies the essential polarization characteristics of skylight to determine celestial body positions. Instead of using complex instrumentation, it creates a simplified representation of the polarization pattern through carefully arranged polarized filters, enabling fast determination of true north and solar position

Inventive Principle:
Principle #26Copying

2Measurement precision

If complex navigation instruments are used to determine celestial body position, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improvecelestial body position accuracyVSAvoidinstrument complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the polarization analysis into discrete directional components by arranging polarized filters at specific angles (e.g., 0°, 45°, 90°, 135°). Each filter segment captures polarization information from a specific orientation, and the combined data from all segments reconstructs the full polarization pattern, enabling accurate celestial body position determination through simple, modular filter elements

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the orientation parameter of polarized filters to encode directional information. By rotating filters to specific angles and measuring intensity variations across these orientations, the system extracts polarization direction data that reveals celestial body position, transforming a complex angular measurement problem into a series of simple intensity measurements through parameter transformation

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If polarization analysis is performed across multiple wavelength bands, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:
Improveatmospheric condition measurement accuracyVSAvoidwavelength separation system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent designs the polarized filter array to perform multiple functions simultaneously: it analyzes polarization patterns across different wavelength bands, determines celestial body positions, and characterizes atmospheric conditions all through a single optical configuration. The same filter arrangement that measures solar position also provides atmospheric data, eliminating the need for separate instrumentation for each measurement type

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

Enables fast and accurate determination of true north and atmospheric data, improving navigation and climate forecasting efficiency while reducing costs by leveraging polarization patterns in skylight analysis.

Implementation Method 1

an array of polarized light filter cells (121), each cell (121) comprising a first polarized light filter (125) having a first direction of polarization and a second polarized light filter (126) having a second direction of polarization

Methodology Applied
Scientific EffectPolarization: Polarisation

Implementation Method 2

an optical system (110) for directing and/or focusing thereonto skylight or earthlight

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 3

a light sensor (220) for producing data from light received through said at least one polarized light filter

Methodology Applied
Scientific EffectPhotoelectric Effect: Photoelectric Effect

Data Source

PatentEP2480869B1Apparatus and method for navigation
Publication Date: 2021.07.14 LIRHOT SYST LTD
  • EP2480869B1 patent drawingFigure 1
  • EP2480869B1 patent drawingFigure 2~3
  • EP2480869B1 patent drawingFigure 4A

AI summary

An apparatus comprising an array of polarized light filter cells, each cell has a first polarized filter having a first polarization direction and a second polarized filter having a second polarization direction, the second polarization direction different from the first polarization direction; an optical system to direct light onto the array of polarized light filters; and a first and second light sensors to produce data from light received through the first and second polarized filters respectively. Additionally, a method of directing light onto an array of polarized light filter cells, each cell having a first polarized filter having a first polarization direction and a second polarized filter having a second polarization direction different from the first polarization direction; producing data from light received through the first and second polarized filters by respective first and second light sensors; and deriving polarization pattern based on the data.