Radio Frequency Distance Ranging with Shortest-Path Peak Detection
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Solution Overview
Problem
Conventional radio frequency distance estimation methods using phase-based ranging techniques are inaccurate due to multi-path interference and signal attenuation, leading to uncertainties in phase difference measurements.
Innovation Solution
A method that identifies the second, smaller peak in the time domain channel response, which corresponds to the shortest path, by setting a threshold based on the largest peak amplitude and using inverse Fourier transforms to enhance accuracy, even in the presence of multi-path effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional phase-based ranging techniques are used to determine distance, then the method is simple to implement, but multi-path interference causes uncertainty in phase difference measurements and reduces distance estimation accuracy
Solution Approach 1:
The patent extracts and processes the channel impulse response to identify individual multipath components separately. By transforming the frequency domain channel response to time domain and detecting peaks corresponding to different paths, the system isolates the direct path signal from reflected signals, enabling accurate distance measurement even in multipath environments
Solution Approach 2:
The patent introduces a channel impulse response processing intermediary that transforms the raw channel response into a time-domain representation. This intermediary processing step allows the system to distinguish between direct and reflected paths by analyzing peak positions and amplitudes, thereby mitigating multi-path interference effects
2Reliability
If signals traveling along different paths are received, then complete signal reception is achieved, but frequency-dependent increases and decreases in received signal strength occur, further decreasing measurement accuracy
Solution Approach 1:
The patent segments the received channel response into distinct multipath components by identifying individual peaks in the time-domain channel impulse response. Each peak corresponds to a specific propagation path, allowing the system to separately analyze and select the direct path component for distance calculation, thereby eliminating interference from other paths
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
Improves distance estimation accuracy by correctly identifying the shortest path peak, reducing errors to within 1 meter or less in most simulations, compared to conventional methods which can be off by several meters.
Implementation Method 1
A radio frequency device transmits a plurality of radio frequency signals with different frequencies towards a target and receives radio frequency signals reflected from the target
Implementation Method 2
receives radio frequency signals reflected from the target
Implementation Method 3
determining a time domain channel response (TDCR) from a frequency domain channel response (FDCR) of the received radio frequency signal by performing an inverse Fourier transform
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
A method of determining a distance between a radio frequency device (2) and a target (18) is disclosed in which the radio frequency device (2) receives a radio frequency signal (16) from the target (18). The method comprises determining a time domain channel response from the received radio frequency signal (16), determining an amplitude of a largest peak in the time domain channel response, determining an amplitude of a second, earlier, peak in the time domain channel response, comparing the second peak amplitude to a threshold based on the largest peak amplitude, identifying the largest peak as a shortest path peak if the second peak amplitude is less than the threshold, identifying the second peak as a shortest path peak if the second peak amplitude is greater than the threshold, and calculating the distance between the radio frequency device (2) and the target (18) based on a time corresponding to the shortest path peak.