Movement-Distance Measuring Apparatus Using Phase Shift and Reflectors
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Solution Overview
Problem
Existing movement-distance measuring apparatuses face errors in calculating the movement distance of moving objects due to changes in the angle of maximum reflection intensity and antenna misalignment, especially when the fixed surface is not uniformly flat.
Innovation Solution
A movement-distance measuring apparatus with a transmitting and receiving antenna, phase detection circuit, and movement-distance calculation circuit that uses a reflective body with reflectors arranged at constant intervals to calculate the movement distance based on phase shift, reducing errors from angle changes and antenna misalignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the angle of maximum reflection intensity is calculated based on distance from antenna to fixed surface, then the movement distance can be calculated, but error occurs due to misalignment of the antenna
Solution Approach 1:
The patent introduces a reflective body with multiple reflectors as an intermediary between the antenna and the fixed surface. This reflective body serves as a mediator that provides stable reference points for phase shift calculation, eliminating the need for precise antenna alignment with the fixed surface. The reflectors act as intermediate elements that facilitate accurate measurement without requiring direct precise alignment between the antenna and the ultimate target surface.
Solution Approach 2:
The patent changes the measurement parameter from relying on angle of maximum reflection intensity (which requires precise alignment) to using phase shift of reflected waves (which is more tolerant of alignment variations). By changing from amplitude-based measurement to phase-based measurement, the system achieves better measurement precision without requiring high manufacturing precision in antenna alignment.
2Measurement precision
If the angle of maximum reflection intensity is used for calculation, then the movement distance can be determined, but error occurs due to change in angle according to movement
Solution Approach 1:
The reflective body with multiple reflectors serves as a stable intermediary that provides consistent reference points throughout the movement. Instead of directly measuring the angle to the fixed surface (which changes with movement), the system uses the phase shift relative to these stable intermediate reflectors, thereby eliminating the instability caused by changing reflection angles.
Solution Approach 2:
The patent replaces the mechanical/geometric approach of tracking maximum reflection intensity angles with a wave-based phase shift measurement approach. This substitution from geometric angle measurement to electromagnetic wave phase measurement provides greater stability against changes in reflection conditions, as phase shift is less sensitive to angular variations.
3Ease of operation
If phase shift calculation is used without reflectors at constant intervals, then the measurement can be performed, but accuracy decreases due to lack of reference points
Solution Approach 1:
The patent segments the reflective surface into multiple discrete reflectors arranged at constant intervals. This segmentation provides multiple known reference points along the movement path, enabling more accurate phase shift calculations. The segmented structure of equally spaced reflectors creates a systematic reference framework that improves measurement accuracy while maintaining operational simplicity.
Solution Approach 2:
The reflectors are pre-positioned at constant intervals along the expected movement path before the measurement begins. This preliminary arrangement of reference points establishes a known geometric framework that enables accurate phase shift calculations throughout the movement, eliminating the need for real-time alignment or adjustment during 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 solution allows for more accurate measurement of movement distance by eliminating errors caused by changes in the angle of maximum reflection intensity and antenna misalignment, improving the precision of distance calculation.
Implementation Method 1
transmits a radio wave toward reflective means including a plurality of reflectors arranged at constant intervals along a moving path of a moving object, and receives a reflected wave from the reflective body
Implementation Method 2
calculating a phase shift of a reflected wave with respect to a transmitted wave using quadrature detection
Data Source
AI summary
A movement-distance measuring apparatus is provided with: an antenna, a phase detection circuit, a phase-shift calculation circuit, and a movement-distance calculation circuit. The antenna transmits a radio wave toward a plurality of reflectors arranged at constant intervals along a moving path of a moving object, and receives a reflected wave from the reflectors. The phase detection circuit detects a phase of the reflected wave received by the antenna. The phase-shift calculation circuit calculates a phase shift based on the phase detected by the phase detection circuit. The movement-distance calculation circuit calculates a movement distance of the moving object, based on the phase shift calculated by the phase-shift calculation circuit, and based on the interval of the reflectors.