Interferometric Positioning Using Light Receiving Units

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Solution Overview

Problem

Existing systems for determining the position and orientation of two objects relative to each other are costly due to complex retroreflector production, require powerful and expensive light sources for low light yield, and are time-consuming to adjust, with complex signal assignment processes.

Innovation Solution

The system uses coherent radiation, a beam splitter, light receiving units instead of retroreflectors, and optical path length adjustment devices to determine distances interferometrically, increasing light yield and reducing costs, with simpler signal assignment and faster measurement times.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If retroreflectors are used to determine distances interferometrically, then measurement capability is provided, but production complexity and costs increase

Engineering Contradiction:
Improvedistance determination capabilityVSAvoidproduction complexity of retroreflectors
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the light-receiving function from complex retroreflectors and concentrates it in simple light receiving units positioned on the carrier. This eliminates the need for complex retroreflector production while maintaining the interferometric measurement capability, as the light receiving units directly detect the measuring beam without requiring retroreflector components.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces expensive, complex retroreflectors with simple, inexpensive light receiving units that can be easily manufactured and replaced. These light receiving units perform the essential function of detecting the measuring beam without the complex structure of retroreflectors, thereby reducing production costs and complexity.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Measurement precision

If retroreflectors are used in the measuring branch, then distance measurement is enabled, but light yield decreases requiring powerful and expensive light sources

Engineering Contradiction:
Improvedistance measurement capabilityVSAvoidlight yield in measuring branch
Core Design Contradiction:
Measurement precisionVSLoss of energy

Solution Approach 1:

The patent removes retroreflectors from the measuring branch and replaces them with simple light receiving units. This extraction eliminates the light losses associated with retroreflector reflection and redirection, significantly improving light yield. The light receiving units directly detect the measuring beam with minimal energy loss, allowing the use of less powerful and more cost-effective light sources.

Inventive Principle:
Principle #2Taking out (Extraction)

3Measurement precision

If retroreflectors are used for distance determination, then measurement functionality is provided, but signal assignment becomes complex and expensive

Engineering Contradiction:
Improvedistance determination accuracyVSAvoidsignal assignment complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the measurement function from retroreflectors and assigns it to simple light receiving units with unique identifiers. This simplifies signal assignment because each light receiving unit can be directly identified and its signals tracked without the complex signal routing and assignment required by retroreflector systems. The evaluation unit can easily associate measured distances with specific carrier locations based on the identifiers of the light receiving units.

Inventive Principle:
Principle #2Taking out (Extraction)

4Measurement precision

If retroreflectors are used with fixed optical paths, then distance measurement is possible, but adjustment time increases due to sequential distance determinations

Engineering Contradiction:
Improvedistance measurement capabilityVSAvoidadjustment time for path length determination
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent combines multiple distance measurements into a single simultaneous measurement process. By positioning multiple light receiving units on the carrier and using a beam combining unit to merge their signals, the system can determine multiple distances at the same time rather than sequentially adjusting optical paths for each measurement. This significantly reduces adjustment time while maintaining measurement precision.

Inventive Principle:
Principle #5Merging (Combining)

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 reduces production costs, enhances signal quality, and simplifies the measurement process by eliminating retroreflector-related issues and allowing for flexible optical path adjustments, enabling efficient determination of object positions and orientations.

Implementation Method 1

a light source of coherent radiation

Methodology Applied
Scientific EffectCoherent radiation: Coherent Light

Implementation Method 2

an interference signal that depends on the distances between the locations

Methodology Applied
Scientific EffectInterference: Interference

Implementation Method 3

the retroreflectors reflect radiation emitted by the at least one emitter

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP2227671B1Arrangement and method for determination of a position and/or orientation of two objects relative to one another
Publication Date: 2013.07.10 GPS OPTICS
  • EP2227671B1 patent drawingFigure 1
  • EP2227671B1 patent drawingFigure 2
  • EP2227671B1 patent drawingFigure 3

AI summary

The invention relates to an arrangement and a method for determination of a position and/or orientation of a first object (4.1) and of a second object (4.2) relative to one another. The invention comprises, inter alia, a light source (1) of coherent radiation, a first beam splitting unit (2), by means of which light from the light source (1) can be split between a measurement branch (3.0) and at least one reference branch (3.1 to 3.3), a light emission device (5), which can be fixedly fitted to the first object (4.1), and at least three light receiving units (10.1 to 10.3), which can be fixedly fitted to the second object (4.2). Light of the measurement branch (3.0) can be radiated to the light receiving units (10.1 to 10.3) by the light emission device (5). By combination and superimposition of the light of the measurement branch (3.0) received by the light receiving units (10.1 to 10.3) and of light of the at least one reference branch (3.1 to 3.3), distances between the light emission device (5) and the light receiving units (10.1 to 10.3) can be determined interferometrically and a position and/or orientation of the two objects (4.1) and (4.2) relative to one another can be determined from said distances.