Phase-Based Distance Measurement Using Dual Circular Polarization
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Solution Overview
Problem
Existing distance measurement technologies face accuracy issues due to the difficulty in distinguishing direct waves from reflected waves when the timing of direct wave reception is close to reflected wave reception, leading to incomplete extraction of direct waves.
Innovation Solution
A distance measuring device employing a phase-based method using both right-handed and left-handed circularly polarized radio waves for communication, where the device performs inverse Fourier transforms on received signals to differentiate between direct and reflected waves, enhancing the accuracy of distance measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If directivity switching is used to extract direct waves, then distance measurement accuracy can be improved, but direct waves cannot be sufficiently extracted when the timing of direct wave reception is close to reflected wave reception
Solution Approach 1:
The patent changes the parameter of radio wave polarization from linear to circular, and further to dual circular polarization (right-handed and left-handed). This parameter change enables the system to differentiate between direct waves and reflected waves based on their polarization characteristics, allowing sufficient extraction of direct waves even when timing is close between direct and reflected wave receptions.
Solution Approach 2:
The patent utilizes the asymmetric interaction between circularly polarized waves and reflected waves. Right-handed circularly polarized direct waves reflect to become left-handed circularly polarized, creating a distinguishable asymmetric characteristic. By transmitting and receiving both polarization types, the system can identify and extract direct wave components reliably even in challenging timing conditions.
2Measurement precision
If circularly polarized waves are used for distance measurement, then direct wave identification accuracy is improved, but device complexity increases due to dual polarization transmission and reception
Solution Approach 1:
The patent implements a universal communication system that can transmit and receive both right-handed and left-handed circularly polarized waves using the same antenna and baseband processing infrastructure. This multi-functionality allows the system to handle dual polarization without requiring completely separate transmission and reception paths, thereby limiting the increase in device complexity.
Solution Approach 2:
The patent merges the processing of right-handed and left-handed circularly polarized wave signals through a unified baseband processing unit. By combining the signal processing paths and utilizing shared computational resources for inverse Fourier transform and time waveform analysis, the system reduces the complexity overhead associated with dual polarization operation.
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 allows for precise identification of direct wave components, improving distance measurement accuracy and reducing the influence of multipath interference.
Implementation Method 1
an antenna unit that outputs two types of received signals with a phase difference based on reception of circularly polarized radio waves
Implementation Method 2
a distance measuring unit that measures a distance to the other device based on a first time waveform obtained by performing inverse Fourier transform on frequency characteristics of a signal transmission path obtained based on a received signal by the first radio communication
Data Source
AI summary
A distance measuring device includes: a communication processing unit that performs first radio communication using right-handed circularly polarized waves and second radio communication using left-handed circularly polarized waves as communication for distance measurement using a phase-based method with another device; and a distance measuring unit that measures a distance to the other device based on a first time waveform obtained by performing inverse Fourier transform on frequency characteristics of a signal transmission path obtained based on a received signal by the first radio communication and a second time waveform obtained by performing inverse Fourier transform on frequency characteristics of a signal transmission path obtained based on a received signal by the second radio communication.