Guided Wave Radar Interface Detection with Sliding Window Peaks

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Solution Overview

Problem

Radar level gauges face challenges in accurately measuring the interface between mixed or emulsified product layers in tanks due to fluctuating echo amplitudes, making it difficult to maintain stable and precise readings.

Innovation Solution

A guided wave radar level gauge employing a sliding window peak detection algorithm to identify interface peaks, using threshold amplitudes to detect a first peak and applying a sliding window algorithm when no interface peak is found, enhancing adaptability and accuracy in fluctuating conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a threshold-based peak detection method is used to identify interface peaks, then the detection process is simple and fast, but the detection accuracy deteriorates when echo amplitudes fluctuate due to mixed or emulsified product layers

Engineering Contradiction:
Improvedetection speedVSAvoidinterface detection accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent applies dynamics by transitioning from a static threshold-based detection method to a dynamic sliding window algorithm. The sliding window continuously adapts to local signal characteristics by comparing each point with its neighboring points within the window, allowing the detection threshold to vary dynamically based on local signal conditions rather than using a fixed global threshold. This enables accurate peak detection even when echo amplitudes fluctuate due to mixed or emulsified product layers.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the detection parameter from a fixed amplitude threshold to a dynamic reference based on local signal statistics. The sliding window algorithm calculates the maximum value within the window and uses it as a dynamic reference point, changing the detection criterion from absolute amplitude comparison to relative comparison within the local context. This parameter transformation allows the system to adapt to varying echo amplitudes caused by emulsified interfaces.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If a sliding window peak detection algorithm is applied to detect interface peaks in fluctuating signals, then the measurement precision is improved, but the device complexity increases

Engineering Contradiction:
Improveinterface detection accuracyVSAvoidsignal processing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the continuous received signal into discrete sliding window segments. Each window processes a small portion of the signal independently, comparing points only within that local segment. This segmentation approach breaks down the complex task of analyzing the entire signal into simpler, manageable local comparisons, reducing overall computational complexity while maintaining high detection precision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent uses partial action by implementing a sliding window that processes only a portion of the signal at a time rather than analyzing the entire signal simultaneously. The window moves through the signal in steps, performing partial detections at each position. This partial processing approach reduces computational load compared to global signal analysis while still achieving accurate peak detection through cumulative local assessments.

Inventive Principle:
Principle #16Partial or excessive action

3Device complexity

If conventional peak detection methods are used, then the device complexity remains low, but the reliability of interface detection deteriorates in emulsified or mixed product scenarios

Engineering Contradiction:
Improvesignal processing simplicityVSAvoiddetection stability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent implements feedback by using the maximum value within the sliding window as a dynamic reference that feeds back into the peak detection decision process. The algorithm continuously adjusts its detection criterion based on the local signal maximum, creating a feedback loop that adapts to changing signal conditions. This feedback mechanism enhances detection reliability by ensuring that peak identification is always relative to the current local signal context rather than a fixed predetermined threshold.

Inventive Principle:
Principle #23Feedback

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

The system provides more accurate and reliable interface detection in complex tank environments by filtering out noise and identifying meaningful peaks, even in scenarios with unclear boundaries between product layers.

Implementation Method 1

Radar level gauge (RLG) systems are in wide use for determining the filling level of a product contained in a tank. Radar level gauging is generally performed either by means of non-contact measurement, whereby electromagnetic signals are radiated towards the product contained in the tank, or by means of contact measurement, often referred to as guided wave radar (GWR), whereby electromagnetic signals are guided towards and into the product by a probe acting as a waveguide.

Methodology Applied
Scientific EffectRadar: Radar

Implementation Method 2

The transmitted electromagnetic signals are reflected at the surface of the product, and the reflected signals are received by a receiver or transceiver comprised in the radar level gauge.

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 3

control circuitry configured to: transmit a signal along the probe; receive a reflected signal; detect a first peak in the received signal, the first peak having a first amplitude exceeding a first threshold amplitude; determine that no second peak having an amplitude exceeding a second threshold amplitude is detected; apply a sliding window peak detection algorithm to the signal to detect a second peak in the signal; and determining a location of a material interface based on the location of the second peak.

Methodology Applied
Scientific EffectSignal processing:

Data Source

PatentEP4607160A1Guided wave radar level gauge and method of determining a location of an interface using the guided wave radar level gauge
Publication Date: 2025.08.27 ROSEMOUNT TANK RADAR
  • EP4607160A1 patent drawingFigure 1~2
  • EP4607160A1 patent drawingFigure 3A~3B
  • EP4607160A1 patent drawingFigure 4A~4B

AI summary

A guided wave radar level gauge (100) for determining a fill level of a product (102) contained in a tank (104) comprising: a measurement unit (106); a probe (110); and control circuitry configured to: transmit a signal along the probe; receive a reflected signal; detect a first peak in the received signal, the first peak having a first amplitude exceeding a first threshold amplitude; determine that no second peak having an amplitude exceeding a second threshold amplitude is detected; apply a sliding window peak detection algorithm to the signal to detect a second peak in the signal; and determining a location of a material interface based on the location of the second peak.