Backscatter Tag Array Localization Using Virtual LOS Multipath
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Solution Overview
Problem
Existing localization technologies face challenges in non-line-of-sight (NLOS) scenarios due to blockages and obstructions, requiring extensive deployment and environment profiling, limiting accuracy to decimeter levels and prohibiting applications in complex indoor environments.
Innovation Solution
A backscatter NLOS localization technology using a triangular tag array with retro-reflective tags and a radar system that determines virtual radar positions through geometric surveying, enabling sub-cm accuracy without multipath environment profiling or manipulation, utilizing specularly reflected multipath signals to create a virtual LOS path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If LOS localization techniques are used, then sub-cm accuracy is achieved, but application is limited to open spaces and cannot operate in NLOS scenarios with blockages
Solution Approach 1:
The patent introduces multipath reflected signals as an intermediary medium to enable localization in NLOS scenarios. By utilizing signals that reflect off surfaces in the environment, the system creates virtual LOS paths between the radar and tags, allowing localization to proceed even when direct line-of-sight is blocked by obstacles.
Solution Approach 2:
The patent converts the previously harmful multipath reflected signals, which were considered noise and interference in traditional LOS localization, into a beneficial resource for NLOS localization. By deliberately utilizing these reflected signals, the system transforms environmental obstructions from obstacles into useful localization pathways.
2Adaptability or versatility
If NLOS localization with multipath environment profiling is used, then localization in blocked environments is enabled, but deployment complexity and costs increase due to requiring 100+ reference tags or meta-surfaces
Solution Approach 1:
The patent enables the localization system to self-configure by automatically identifying and utilizing available reflected signal paths in the environment. The radar system performs environment profiling on-demand without requiring pre-deployed reference tags or meta-surfaces, allowing the system to adapt to any NLOS environment with existing reflective surfaces alone.
Solution Approach 2:
The patent creates a universal NLOS localization solution that works across diverse environments using only the radar and tags. By making the system independent of environment-specific infrastructure like reference tags or meta-surfaces, it achieves multi-functionality across different NLOS scenarios without increasing deployment complexity.
3Adaptability or versatility
If NLOS localization with reference tags is used, then localization capability is provided, but accuracy is limited to decimeter level rather than sub-cm
Solution Approach 1:
The patent changes the operational parameters of the radar system by utilizing frequency modulation and exploiting the phase characteristics of multipath reflected signals. This enables the system to achieve sub-cm accuracy in NLOS conditions by measuring time-of-flight and phase differences with high precision, overcoming the decimeter-level accuracy limitation of conventional NLOS methods.
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
Achieves sub-cm accuracy in 3D localization and sub-1° orientation in yaw, pitch, and roll directions, allowing operation in complex indoor environments with arbitrary reflectors and obstacles, and expanding the applicable range of backscatter localization.
Implementation Method 1
a radar system including a radar configured to output a radar signal and receive a plurality of groups of retro-reflective signals generated by the tag array reflecting the radar signal
Implementation Method 2
retro-reflective signals generated by the tag array reflecting the radar signal
Implementation Method 3
utilizing specularly reflected multipath signals to create a virtual LOS path
Data Source
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AI summary
Disclosed herein is a localization system including: a tag array including one group of retro-reflective backscatter tags; and a radar system including a radar configured to output a radar signal and receive a plurality of groups of retro-reflective signals generated by the tag array reflecting the radar signal. The radar system is configured to determine the positions of one or more virtual radars of the radar reflected on one or more radio reflectors based on the propagation paths of the plurality of groups of retro-reflective signals, and is configured to determine the position of the tag array by a surveying method using the positions of the one or more virtual radars determined above.