Through-Wall mmWave Tank Level Sensing for Multipath Accuracy
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Solution Overview
Problem
Existing methods for measuring fluid levels in storage tanks face challenges in accuracy and ease of installation, particularly when dealing with multiple types of fluids and requiring compliance with FCC regulations for RF power transmission.
Innovation Solution
A millimeter wave (mmWave) radar system that emits a chirp signal to measure fluid levels, using advanced algorithms and filters to filter out extraneous signals, and wireless telemetry to transmit data remotely, with a self-contained monitor that can be easily installed on various tank types without direct contact with the fluid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional sensors (mechanical float, ultrasonic, hydrostatic pressure) are used to measure fluid levels, then measurement capability is achieved, but the system requires matching the sensor type to specific liquid attributes, chemical properties, viscosity, pressure, and temperature conditions, increasing device complexity and reducing adaptability
Solution Approach 1:
The radar-based level measurement system is designed to universally measure fluid levels across different fluid types (chemicals, oils, water, etc.) without requiring sensor changes. The electromagnetic radar waves can penetrate various tank materials and work with different fluid properties, eliminating the need to match specific sensor types to specific liquid attributes, thereby achieving multi-functionality and broad adaptability.
Solution Approach 2:
The patent replaces mechanical sensing systems (mechanical floats, contact-based pressure sensors) with a non-contact electromagnetic radar system. This substitution eliminates the need for mechanical components that interact directly with the fluid, removing the constraint of matching sensor materials to fluid chemical properties, and simplifies the system by removing complex sensor selection requirements.
2Measurement precision
If millimeter wave radar is used to measure tank levels, then measurement accuracy and adaptability to different fluids are improved, but creating a narrow beam width with limited power to pass FCC requirements while maintaining accurate measurement capability becomes challenging
Solution Approach 1:
The system dynamically adjusts radar transmission parameters including frequency modulation (chirp signals), pulse duration, and power levels to optimize measurement accuracy while remaining within FCC power limits. By changing these parameters adaptively, the system achieves precise fluid level measurement without exceeding regulatory RF power constraints.
Solution Approach 2:
The radar system uses periodic chirp signal transmission with frequency modulation to achieve accurate range measurement. The periodic emission of frequency-swept pulses allows the system to maintain measurement precision while distributing energy transmission over time, thereby adhering to average power limits imposed by FCC regulations.
3Ease of operation
If a self-contained tank level monitor with integrated display, keypad, radar, GPS, and cellular/satellite transmission capabilities is implemented, then ease of installation and remote data transmission are improved, but device complexity increases
Solution Approach 1:
The patent integrates multiple previously separate functions (level measurement radar, display unit, user interface keypad, GPS location tracking, and cellular/satellite telemetry) into a single self-contained tank level monitor. This consolidation simplifies installation by eliminating the need for separate external devices and interconnections, while the integrated architecture manages complexity through unified system design.
Solution Approach 2:
The self-contained monitor performs autonomous operation, automatically measuring fluid levels, displaying data locally, and transmitting information remotely without requiring external control systems. The integrated system serves itself by combining all necessary functions in one unit, reducing installation complexity while maintaining comprehensive functionality.
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 mmWave radar system provides accurate and reliable fluid level measurements, meeting FCC requirements, and allows for easy installation on both plastic and metal tanks, with remote data transmission and adaptable to different chemical attributes.
Implementation Method 1
A millimeter wave (mmWave) radar system that emits a chirp signal to measure fluid levels
Implementation Method 2
The mmWave radar system emits a chirp signal that reflects off objects and fluids and a return signal that is received by a receiving antenna
Implementation Method 3
The received signal is mixed with the outgoing signal to generate a signal having an intermediate frequency which is directly proportional to the distance to one or more levels of fluid in the tank
Data Source
AI summary
Methods and systems for determining fluid levels in a tank comprise a mmWave control unit configured to generate and transmit a millimeter wave chirp. The control unit transmits the chirp into the tank through a Luneburg lens and receives one or more chirp reflections from the tank. For each tank level reading, three or more chirp configuration profiles are used in order to ensure accurate depth measurements due to multi-path reflections in most tanks. The control unit mixes the chirps with the chirp reflections to generate a set of responses for each chirp configuration profile. The responses are compared and the two best responses are selected and averaged. The set of averaged responses are then processed using a ballot and vote process to determine the distance reading that is likely to provide the most accurate tank level.