Mobile Sensor Source Localization via Particle Reception Rate

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Solution Overview

Problem

Existing methods for locating particle or molecule sources in diffuse environments, such as chemical leaks or explosives, face challenges due to the randomness of advection and mixing processes, which makes it difficult for robots to reliably measure local concentration gradients, limiting their range and efficiency.

Innovation Solution

A method and system that utilize a mobile sensor to detect particles or molecules, determine diffusion parameters, design a lattice on the search space, compute probabilities for each node to be the source, and evaluate movement to maximize the expected rate of information gain, allowing for source localization even in dilute environments without relying on local concentration gradients.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If chemotactic search strategy using local concentration gradients is used, then source localization can be achieved, but the range of application is severely limited and search time increases to several minutes

Engineering Contradiction:
Improvesource localization accuracyVSAvoidsearch time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent changes the measurement parameter from local concentration gradient (which requires high concentration and long averaging time) to reception rate of particles/molecules (which provides reliable signal even in dilute environments). This parameter change enables both faster search (reducing loss of time) and maintains localization accuracy (measurement precision) across a wider range of conditions.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If waiting is used to improve signal-to-noise ratio by averaging, then measurement precision improves, but average concentration decays rapidly with distance making waiting worse than exploratory motion

Engineering Contradiction:
Improvesignal-to-noise ratioVSAvoidaverage concentration
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent switches from measuring average concentration (which decays exponentially with distance) to measuring reception rate of individual particles/molecules. The reception rate provides a reliable signal even when average concentration is very low, eliminating the need to wait for sufficient signal accumulation and allowing effective search at greater distances from the source.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If local concentration gradient measurement is used, then source direction can be determined, but the method is not feasible for robots located far away from the source

Engineering Contradiction:
Improvelocal gradient measurementVSAvoidsearch range
Core Design Contradiction:
Measurement precisionVSLength of stationary object

Solution Approach 1:

The patent replaces local concentration gradient measurement with reception rate measurement. The reception rate of particles or molecules provides a reliable signal that does not require the robot to be close to the source or to wait for sufficient signal accumulation, thereby extending the effective search range while maintaining the ability to determine source direction.

Inventive Principle:
Principle #35Parameter changes

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 enables efficient and rapid localization of particle or molecule sources in diffuse environments by maximizing the expected rate of information gain, reducing search time and improving the accuracy of source detection, even in conditions where local gradients are unreliable.

Implementation Method 1

locating the source of diffused particles or molecules using their reception rate

Methodology Applied
Scientific EffectDiffusion: Diffusion

Implementation Method 2

the air or liquid flow in which the odorous substance diffuses in a chaotic way

Methodology Applied
Scientific EffectAdvection: Advection

Data Source

PatentEP2041636B1Method and systems for locating a source of particle, molecule, or fragment of molecule using their reception rate
Publication Date: 2009.11.18 SHRAIMAN BORIS
  • EP2041636B1 patent drawingFigure 1
  • EP2041636B1 patent drawingFigure 2
  • EP2041636B1 patent drawingFigure 3

AI summary

A method and systems for locating a source of particles, molecules, or fragments of molecules using particle, molecule, or fragment of molecule reception rate is disclosed. According to the invention, the particle, molecule, or fragment of molecules diffusion parameters in the search space are determined and a lattice is designed on the search space. After having determined whether or not at least one particle, molecule, or fragment of molecule is detected by a sensor, a probability is computed for each node of said search space lattice. The probability associated to each node of the search space lattice corresponds to the probability that the particle, molecule, or fragment of molecule source is located on the node. Then, the move of the sensor is evaluated according to the entropy of the computed probabilities.