Variable Attenuation Function for Laser Distance Measurement Adaptability

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Solution Overview

Problem

Existing electronic distance measurement systems lack adaptability due to fixed attenuation functions, leading to suboptimal detection sensitivity across varying measurement scenarios, particularly in scenarios with differing target reflectivities and distances.

Innovation Solution

The system employs a variable attenuation function and offset relative to the send pulse, allowing for dynamic adjustment of detection sensitivity based on characteristics of the return pulse, such as amplitude and travel time, to accommodate different measurement needs by modifying measurement parameters for subsequent measurements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a fixed attenuation function is used, then the system is simple to implement, but the detection sensitivity cannot adapt to varying measurement scenarios with different target reflectivities and distances

Engineering Contradiction:
Improveadaptability to varying measurement scenariosVSAvoidcomplexity of attenuation function control
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies dynamics by transitioning from a fixed attenuation function to a variable attenuation function that dynamically adjusts based on the detected return pulse characteristics. The attenuation function is modified in response to the actual measurement conditions, allowing the system to adapt to different target reflectivities and distances while maintaining manageable complexity through automated adjustment.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements feedback by using the detected return pulse characteristics (amplitude, timing) to automatically modify the attenuation function for subsequent measurements. This closed-loop approach allows the system to learn from each measurement and optimize detection sensitivity for the next measurement without manual intervention, resolving the adaptability-complexity contradiction.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If detection sensitivity is increased to detect weak return pulses from distant or low-reflectivity targets, then measurement range expands, but false detections from noise increase

Engineering Contradiction:
Improvedetection sensitivityVSAvoidaccuracy of distance measurement
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent uses dynamic attenuation adjustment to optimize the balance between detection sensitivity and false detection. By varying the attenuation function based on the specific measurement conditions and return pulse characteristics, the system achieves high sensitivity for weak return pulses while maintaining reliability through adaptive thresholding that distinguishes genuine signals from noise.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent applies parameter changes by modifying the attenuation function parameters (timing, magnitude) based on the detected return pulse characteristics. This allows the system to adjust detection sensitivity dynamically, enhancing the ability to detect weak return pulses from distant or low-reflectivity targets while maintaining measurement accuracy through intelligent parameter adaptation.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If the attenuation function is adjusted for each measurement to optimize detection sensitivity, then measurement accuracy improves, but the time required for setup and calibration increases

Engineering Contradiction:
Improveaccuracy of distance measurementVSAvoidtime for parameter setup
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent implements self-service by enabling the system to automatically adjust its own attenuation function based on detected return pulse characteristics. This eliminates the need for manual setup and calibration, as the system autonomously optimizes detection parameters for each measurement, improving accuracy without requiring operator intervention or time-consuming configuration.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent uses feedback mechanisms to automatically modify attenuation function parameters based on real-time measurement results. This closed-loop approach allows the system to self-optimize for each measurement, achieving high accuracy without manual setup, as the system learns from previous measurements and automatically adjusts parameters for subsequent measurements.

Inventive Principle:
Principle #23Feedback

4Adaptability or versatility

If a variable attenuation function is used to accommodate different measurement scenarios, then adaptability improves, but the complexity of controlling and modifying the attenuation function increases

Engineering Contradiction:
Improveadaptability to different measurement scenariosVSAvoidcomplexity of attenuation function modification
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent simplifies the complexity of variable attenuation control by implementing feedback-based automatic adjustment. The system uses detected return pulse characteristics to automatically modify the attenuation function, eliminating the need for complex manual control mechanisms. This feedback approach makes the variable attenuation function manageable and intuitive, balancing adaptability with controlled complexity.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent applies self-service by enabling the system to automatically manage its own attenuation function adjustments. The system monitors detected return pulse characteristics and autonomously modifies the attenuation function accordingly, reducing the operational complexity of working with variable attenuation while maintaining high adaptability to different measurement scenarios.

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 enhances the accuracy and efficiency of distance measurements by optimizing detection sensitivity for varying conditions, enabling precise distance measurement over a wide range of distances and target types without operator intervention.

Implementation Method 1

A laser transmitter transmits a plurality of laser pulses toward a target

Methodology Applied
Scientific EffectLaser: Laser

Implementation Method 2

In time-of flight distance measurement, the time delay between emission and reception of a laser pulse allows for distance calculation

Methodology Applied
Scientific EffectTime of flight: Time of Flight

Implementation Method 3

The emitted pulse travels to a reflector and back to a detector where it is received

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP2890998B1Distance measurement methods and apparatus
Publication Date: 2018.04.25 TRIMBLE AB
  • EP2890998B1 patent drawingFigure 1
  • EP2890998B1 patent drawingFigure 2
  • EP2890998B1 patent drawingFigure 3A~3B

AI summary

Methods and apparatus are presented for distance measurement using laser pulses in which at least one of an attenuation function and an offset of the attenuation function relative to the send pulse is variable to accommodate differing measurement needs. In some embodiments, at least one of an attenuation function and an offset of the attenuation function is fixed relative to the send pulse for some number of measurement cycles and information derived from the result is used to modify either or both of the attenuation function and offset of the attenuation function relative to the send pulse for subsequent measurement.