RF Receiver Interference Detection via Order Statistic Filtering
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Solution Overview
Problem
Current RF interference detection methods in radar receivers face challenges in accurately distinguishing between degrading interference and thermal noise, leading to excessive false detections and inadequate identification of performance-degrading interference, especially due to variability in receiver-chain gain and temperature effects.
Innovation Solution
The implementation of automated real-time signal analysis using order statistical filtering to characterize changing densities and distributions of signal features, estimating thermal noise and interference-plus-noise levels through frequency domain representations and applying normalization techniques to determine an interference metric for accurate detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the detection threshold is raised to reduce false detections, then false alarm rate decreases, but the ability to detect lower levels of degrading interference deteriorates
Solution Approach 1:
The patent segments the detection process into two distinct phases: thermal noise estimation using short time intervals and interference detection using extended time intervals. This segmentation allows each phase to be optimized independently - noise estimation achieves accuracy through multiple short samples, while interference detection achieves sensitivity through longer integration, resolving the contradiction between false alarm rate and detection sensitivity
Solution Approach 2:
The patent performs preliminary thermal noise estimation before conducting interference detection. By first characterizing the thermal noise level through statistical analysis of multiple short time intervals, the system establishes a baseline that enables subsequent interference detection to operate with optimal sensitivity without excessive false alarms
2Ease of operation
If thermal noise level is estimated using current methods, then detection can be performed, but accuracy deteriorates due to receiver-chain gain variability and temperature effects
Solution Approach 1:
The patent employs periodic sampling of thermal noise across multiple time intervals at different temperatures and operating conditions. This periodic measurement approach, combined with statistical analysis, captures the variability in receiver-chain gain and temperature effects, enabling accurate thermal noise estimation that accounts for these changing conditions
Solution Approach 2:
The patent implements feedback through iterative statistical analysis of thermal noise measurements. The system continuously refines its thermal noise model by comparing measurements across multiple time intervals and using order statistics to extract accurate noise levels, compensating for receiver-chain gain variability and temperature effects
Data Source
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AI summary
An interference detection methods and receivers for receiving an RF signal including a desired RF signal and an intermittent interference signal, estimating thermal noise of the receiver by statistically analyzing a plurality of time intervals of data of the received RF signal, including at least one data interval not including the interferer, estimating an intermittent-interference-plus- noise level by statistically analyzing an extended time interval of the data, determining an interference metric based on a ratio of the estimates, and evaluating the interference metric against one or more thresholds to detect the presence or absence of degrading RF interference. The statistical analysis may include application of order statistic filtering.