3D Mapping Using Microwave Parallax and Passive Reflectors
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Solution Overview
Problem
Conventional methods for determining the distance and movement of objects using radio frequency signals face limitations in range resolution due to bandwidth constraints, particularly in frequency-modulated continuous-wave (FM-CW) and phase-modulated continuous-wave (PM-CW) radars, which require significant bandwidth and affect resolution.
Innovation Solution
A method utilizing continuous-wave radio frequency signals and parallax principles to determine the distance of objects by activating one transmitter at a time, scanning in both azimuth and elevation, and using the angular difference between transmitters and receivers to calculate distances, forming 3D and 4D maps with minimal signal bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If FM-CW or PM-CW radars are used to determine distance by evaluating frequency difference, then distance measurement capability is improved, but bandwidth consumption increases significantly
Solution Approach 1:
The patent introduces a passive reflector as an intermediary element between the transmitter and target object. The reflector receives the transmitted signal and re-radiates it toward the target, enabling distance measurement without requiring the transmitted signal itself to have high bandwidth. The phase information is preserved through the reflector's passive re-radiation, allowing accurate distance determination while using continuous wave signals with minimal bandwidth consumption.
2Measurement precision
If range resolution is improved by increasing signal bandwidth, then measurement precision is improved, but device complexity and bandwidth requirements worsen
Solution Approach 1:
The patent replaces the conventional approach of using wideband modulated signals (electromagnetic field manipulation) with a passive reflective mechanism. Instead of modifying the transmitted signal's frequency or phase through complex modulation schemes, the system uses a passive reflector to preserve and redirect the signal, achieving high range resolution through geometric configuration rather than signal bandwidth expansion.
3Measurement precision
If time of flight measurement is used to determine distance, then distance measurement capability is improved, but timing marker requirements increase system complexity
Solution Approach 1:
The patent inverts the conventional active radar approach by using a passive reflector instead of an active transponder or timing marker on the target. The reflector passively returns the transmitted signal without requiring any active components, timing markers, or complex signal processing on the target side. Distance is determined by analyzing the phase relationship between transmitted and received signals through the passive reflector, eliminating the need for timing markers.
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 enables the creation of 3D and 4D maps of objects with improved range resolution by leveraging parallax angles, allowing for precise distance determination of stationary and moving objects while minimizing bandwidth consumption.
Implementation Method 1
A method utilizing continuous-wave radio frequency signals and parallax principles to determine the distance of objects by activating one transmitter at a time, scanning in both azimuth and elevation, and using the angular difference between transmitters and receivers to calculate distances
Implementation Method 2
changing the direction of the first transmitter along both azimuth and elevation until the first transmitter reaches a first direction defined by first and second angles at which the power of the first RF signal as reflected off the object and received by a receiver reaches a maximum value
Data Source
Figure 1A~1B
Figure 2~3A
Figure 3B
AI summary
An object's distance is determined using either two RF transmitters and an RF receiver, or a two RF receivers and an RF transmitter. When using two RF transmitters, the direction of the first transmitter is changed until it reaches a first direction defined by a first angle at which the power of the RF signal—transmitted by the first transmitter—reflected off the object and received by the receiver reaches a maximum value. The direction of the second transmitter is also changed until it reaches a second direction defined by a second angle at which the power of the second RF signal—transmitted by the second transmitter—reflected off the object and received by the receiver reaches a maximum value. The distance between the object and the first transmitter is defined by the distance between the two transmitters, the second angle, and the difference between the first and second angles.