Frequency-Domain Windowing for Multipath Mitigation in PNT Estimation
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Solution Overview
Problem
Precision position, navigation, and timing (PNT) estimation is limited by multipath effects, which cause significant side-peaks in correlation functions, and altering the transmitted signal to mitigate this can degrade other system performance aspects.
Innovation Solution
The method involves channelizing an input signal into multiple carrier-specific signals, correlating each against a reference signal, applying a frequency-domain window function to the correlation results, and integrating these weighted results to produce an integrated correlation output that mitigates multipath effects without altering the transmitted signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the transmitted signal is altered to reduce correlation side-peaks, then precision PNT estimation is improved, but data link performance is degraded
Solution Approach 1:
The patent segments the correlation processing into multiple frequency bins corresponding to different carriers. Each frequency bin is processed independently with its own window function, allowing selective suppression of side-peaks in the PNT estimation path while preserving the original signal characteristics for communication purposes.
Solution Approach 2:
The patent introduces a frequency-domain window function as an intermediary element that selectively attenuates correlation side-peaks. This intermediary operates in the frequency domain on correlation results rather than on the transmitted signal itself, thereby mitigating multipath effects without altering the original signal's data link performance.
2Object-generated harmful factors
If a window function is applied in the time domain, then correlation side-peaks are reduced, but the main peak broadens reducing timing precision
Solution Approach 1:
The patent transitions the windowing operation from the time domain to the frequency domain. By applying window functions to frequency bins rather than time samples, the patent achieves side-peer suppression without the time-domain penalty of main peak broadening, thereby preserving timing precision while reducing multipath interference.
Data Source
AI summary
Systems and methods for mitigating multipath effects on precision PNT estimation are disclosed. Frequency-domain windowing techniques are disclosed and utilized to mitigate multipath effects on precision PNT estimation for systems employing coherent communication signals. More specifically, to mitigate multipath effects an input signal, the input signal may be channelized into a plurality of carrier-specific signals, and each carrier-specific signal may be correlated against a reference signal to produce a corresponding carrier-specific correlation result. A window function may be applied to the carrier-specific correlation results for the plurality of carriers to produce a set of carrier-specific weighted correlation results. The set of carrier-specific weighted correlation results may be integrated to produce an integrated correlation output, which may then be utilized to facilitate PNT estimation.