Radar Level Gauge Frequency Regulation via Time Delay

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Solution Overview

Problem

Current pulsed radar level gauge systems require a substantial power-up time and energy consumption due to the need for stable frequency difference regulation, which is typically achieved by monitoring and regulating the frequency difference over hundreds of samples, resulting in prolonged startup times and inefficient energy use.

Innovation Solution

The method involves controlling the second pulse generating circuitry based on time delay rather than direct frequency difference measurements, allowing for faster stabilization and reduced energy consumption by operating in a feedback configuration with the same parameter settings, enabling more frequent restarts of measurement sweeps and adjusting the duration of measurement sweeps based on tank dimensions and filling levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If frequency difference regulation is performed by monitoring and regulating over hundreds of samples, then frequency stability is improved, but startup time increases to 20-30 seconds

Engineering Contradiction:
Improvefrequency stabilityVSAvoidstartup time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by performing frequency regulation in advance during a calibration phase before measurement mode begins. The system pre-regulates the frequency difference between transmission and reference signals by monitoring hundreds of samples and storing the optimal frequency offset value. This preliminary regulation ensures frequency stability is established before actual measurements start, eliminating the need for lengthy regulation during operational startup.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent segments the system operation into distinct phases: calibration phase and measurement phase. During calibration, the system performs comprehensive frequency regulation over hundreds of samples to establish stable frequency difference. During measurement, the pre-determined frequency offset is used directly without requiring repeated regulation. This segmentation allows the system to achieve both frequency stability and fast startup by concentrating the time-consuming regulation activity in a separate preparatory phase.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If frequency difference Δf is kept low (Hz or tens of Hz) for sufficient time expansion, then measurement precision is improved, but regulation stability time increases to 20-30 seconds

Engineering Contradiction:
Improvetime expansion precisionVSAvoidregulation duration
Core Design Contradiction:
Measurement precisionVSDuration of action of moving object

Solution Approach 1:

The patent performs the lengthy regulation process in advance during calibration, determining the optimal frequency offset that provides sufficient time expansion for accurate measurements. This pre-established frequency offset is then used throughout measurement operations, eliminating the need for continuous regulation and enabling fast startup while maintaining measurement precision.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent creates a copy of the frequency relationship established during calibration and applies it during measurement. The optimal frequency offset value determined during calibration is stored and reused during measurement operations, allowing the system to maintain the precise time expansion characteristics without repeating the lengthy calibration process.

Inventive Principle:
Principle #26Copying

3Reliability

If hundreds of samples are monitored for frequency difference, then frequency regulation accuracy is improved, but energy consumption increases

Engineering Contradiction:
Improvefrequency regulation accuracyVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent implements periodic action by performing comprehensive frequency regulation only during the initial calibration phase, then switching to a lower-power measurement mode that uses the pre-determined frequency offset without continuous monitoring and adjustment. This periodic regulation approach concentrates energy-intensive operations in a brief calibration period while minimizing energy consumption during extended measurement operations.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent performs frequency regulation in advance during calibration before measurement mode begins. By establishing the optimal frequency offset beforehand and storing it for reuse, the system avoids the continuous energy consumption that would result from ongoing monitoring and regulation during measurement operations, significantly reducing overall energy usage while maintaining regulation accuracy.

Inventive Principle:
Principle #10Preliminary action

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 significantly reduces the startup time and energy consumption of pulsed radar level gauge systems, particularly beneficial for battery-powered systems, by allowing for more frequent and efficient filling level measurements.

Implementation Method 1

the distance to the surface of the product is generally determined based on the time between transmission of an electromagnetic signal and reception of the reflection thereof in the interface between the atmosphere in the tank and the product contained therein

Methodology Applied
Scientific EffectTime of flight: Time of Flight

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 system

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 3

providing a first signal output by a first pulse generating circuitry to an input of a resonator element... the time delay between the first signal and an output signal from the resonator element corresponds to a predetermined frequency difference between the first signal and the output signal from the resonator element

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP2513615B1Radar level gauge system and corresponding method
Publication Date: 2018.11.07 ROSEMOUNT TANK RADAR
  • EP2513615B1 patent drawingFigure 1~2
  • EP2513615B1 patent drawingFigure 3~4
  • EP2513615B1 patent drawingFigure 5a~5b

AI summary

A method of, and a system for determining a filling level of a product contained in a tank using a radar level gauge system, the method comprising the steps of: generating a transmission signal using first pulse generating circuitry outputting a first signal having a first oscillation frequency; generating, using second pulse generating circuitry comprising a resonator element having an input and an output, a reference signal in the form of a second pulse train having a second pulse repetition frequency, differing from the first pulse repetition frequency. The step of generating the reference signal comprises the steps of: providing the first signal to the input of the resonator element comprised in the second pulse generating circuitry; controlling at least one parameter of the second pulse generating circuitry; and providing the output signal from the resonator element to the input of the resonator element.