Low Power Radar Level Gauge Using Segmented Frequency Steps

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Solution Overview

Problem

Conventional FMCW radar level gauge systems are power hungry, making them unsuitable for applications with limited energy and power, such as field devices powered by a two-wire interface or wireless devices, and are also costly and large, which is a challenge in the process industry.

Innovation Solution

A compact and cost-efficient radar level gauge system using an integrated microwave circuit with a microwave signal source configured for reduced phase noise, allowing for a significant reduction in energy consumption while maintaining measurement performance, featuring a signal propagation device, a microwave signal source, a mixer, and processing circuitry that independently control the measurement sweep and sampling intervals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional FMCW radar level gauge systems are used, then high measurement accuracy is achieved, but power consumption is high

Engineering Contradiction:
Improvefilling level measurement accuracyVSAvoidpower consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The measurement sweep is divided into multiple discrete frequency steps instead of continuous sweeping. The microwave signal source generates a sequence of frequency steps, and the sampler captures intermediate frequency signals at specific sampling times. This segmentation allows the system to achieve necessary measurement accuracy while reducing the duration of microwave signal generation, thereby lowering power consumption for applications with limited energy supply.

Inventive Principle:
Principle #1Segmentation

2Reliability

If conventional FMCW radar systems are used, then reliable filling level determination is achieved, but device size and cost increase

Engineering Contradiction:
Improvemeasurement reliabilityVSAvoidsystem size and cost
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system dynamically adjusts the relationship between frequency step duration and sampling time interval. By making these parameters independently controllable and optimizing their relationship, the system achieves reliable measurements with reduced hardware requirements. The dynamic configuration allows adaptation to different measurement scenarios without requiring oversized components, thus reducing device complexity while maintaining reliability.

Inventive Principle:
Principle #15Dynamics

3Productivity

If high update frequency measurements are performed, then real-time monitoring capability is improved, but power consumption increases

Engineering Contradiction:
Improvemeasurement update frequencyVSAvoidenergy consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The system employs periodic frequency steps with discrete sampling times instead of continuous measurement. By carefully designing the period of frequency steps and the sampling interval, the system can achieve higher update frequencies when needed while allowing longer idle periods between measurements. This periodic operation pattern enables real-time monitoring capability while significantly reducing average power consumption compared to continuous measurement systems.

Inventive Principle:
Principle #19Periodic 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

The system achieves high accuracy and reliability in filling level determination with reduced power consumption, enabling operation on limited power sources and lower costs, suitable for applications like two-wire communication interfaces or local energy sources, with the ability to perform measurements frequently.

Implementation Method 1

a signal propagation device arranged to propagate an electromagnetic transmit signal towards a surface of the product and to return an electromagnetic reflection signal resulting from reflection of the electromagnetic transmit signal at the surface

Methodology Applied
Scientific EffectElectromagnetic wave propagation: Electromagnetic Induction

Implementation Method 2

a mixer coupled to the microwave signal source and to the signal propagation device, and configured to combine the transmit signal and the reflection signal to form an intermediate frequency signal

Methodology Applied
Scientific EffectFrequency mixing: Heterodyne

Data Source

PatentEP3114437B1Low power radar level gauge system
Publication Date: 2021.04.28 ROSEMOUNT TANK RADAR
  • EP3114437B1 patent drawingFigure 1a~1b
  • EP3114437B1 patent drawingFigure 2a~2b
  • EP3114437B1 patent drawingFigure 3

AI summary

The present invention relates to a radar level gauge system (1) comprising a signal propagation device; a microwave signal source (45); a microwave signal source controller (31, 55); a mixer (48) configured to combine a transmit signal from the microwave signal source and a reflection signal from the surface to form an intermediate frequency signal; a sampler (51, 52) configured to sample the intermediate frequency signal and processing circuitry (55) configured to determine the filling level based on the intermediate frequency signal. The microwave signal source and the sampler are independently controllable.