Radar Multipath Ray Tracing for Through-Wall Target Detection
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Solution Overview
Problem
Radar systems face limitations in target location determination due to severe multipath environments in urban structures, particularly in Sense Through the Wall (STTW) radar systems, which affect the detection and tracking of moving targets.
Innovation Solution
A method that identifies possible multipath ray paths by recursively determining signal paths from a target to a sensor and exploiting time-reversal symmetry, allowing for real-time implementation in a multi-hypothesis tracker (MHT) to improve target location accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional ray tracing methods are used to identify multipath signal paths, then measurement precision of target location is improved, but computation time increases making real-time implementation infeasible
Solution Approach 1:
The patent pre-calculates and stores image locations for all possible wall reflections before radar operation. During real-time tracking, the system only needs to query pre-computed image locations and check which ones correspond to actual multipath signals, rather than performing full ray tracing calculations. This preliminary preparation of reflection geometry data enables real-time implementation while maintaining accurate multipath identification for target location determination.
2Reliability
If comprehensive multipath analysis is performed to improve target detection reliability, then probability of detection is improved, but device complexity increases
Solution Approach 1:
The patent segments the complex multipath analysis problem into distinct components: (1) pre-computing image locations for each wall reflection, (2) identifying which image locations correspond to valid multipath signals during tracking, and (3) using segmented signal analysis to distinguish direct-path from multipath returns. This segmentation allows comprehensive multipath analysis to be performed through a series of simpler, modular operations rather than a single complex analysis, improving detection reliability while managing system complexity.
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 method enhances the probability of target detection and reduces false alarm rates by efficiently calculating sensor image locations and determining valid signal paths, improving radar performance in complex environments.
Implementation Method 1
an electromagnetic wave may propagate radially outwards from a transmitter
Implementation Method 2
Reflection occurs when a ray encounters a surface (e.g., a side of a building or a target) and leaves the surface in a different direction, in which the angle of incidence equals the angle of reflection
Data Source
AI summary
A method of detecting a target in a room using a radar system having a transmitter for irradiating the object, a sensor for receiving reflected radiation, and circuitry for analyzing the reflected radiation to determine at least one characteristic thereof, the method including determining at least one parameter for each wall of a plurality of walls of a room containing the target; determining possible signal paths between the target and the sensor for paths including up to N reflections based on the at least one parameter of each wall and the location of the sensor; calculating target image locations based on the possible signal paths; and processing the received radiation to determine a target location based on target image locations.