Radar Detector Signal Discrimination via Harmonic Analysis
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Solution Overview
Problem
Conventional radar detectors often falsely recognize electromagnetic waves leaked by nearby detectors as radar signals, particularly in the Ka band, due to harmonic spectra overlap, leading to nuisance alerts.
Innovation Solution
A radar detector system that scans for signals that are harmonics of nuisance local oscillator frequencies and suppresses alerts if companion signals are detected, using multiple processing stages and signal conditioning circuitry to differentiate between legitimate and false alarm signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If radar detectors scan multiple frequency bands to detect radar signals, then detection capability is improved, but false alarms increase due to harmonic spectra overlap from nearby detectors
Solution Approach 1:
The patent segments the detection process into multiple processing stages: a first processing stage that detects signals in radar bands and a second processing stage that detects companion signals at different frequencies. This segmentation allows the system to analyze signal patterns across multiple frequency domains to distinguish legitimate radar signals from false alarms caused by harmonic spectra overlap.
Solution Approach 2:
The patent implements feedback by using the detection results from the second processing stage to modulate the alert output of the first processing stage. When companion signals are detected in the second stage, the system provides feedback to suppress false alarm alerts from the first stage, thereby reducing false alarms while maintaining reliable detection capability.
2Adaptability or versatility
If multiple local oscillators are used to scan different bands, then frequency coverage is improved, but electromagnetic wave leakage increases causing nuisance alerts
Solution Approach 1:
The patent introduces an intermediary detection mechanism that monitors for companion signals at frequencies related to the local oscillators. By detecting the presence or absence of these companion signals, the system can identify when electromagnetic wave leakage from multiple local oscillators is causing nuisance alerts, and subsequently suppress false alarms while maintaining broad frequency coverage.
3Measurement precision
If harmonic spectra from local oscillators are monitored, then signal discrimination capability is improved, but device complexity increases
Solution Approach 1:
The patent divides the signal discrimination function into two separate processing stages, each responsible for detecting specific frequency characteristics. The first stage monitors radar band signals while the second stage monitors companion signals at related frequencies. This segmentation improves signal discrimination capability by analyzing multiple frequency domains without requiring a single overly complex processing stage.
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
Effectively reduces false alarms by identifying and suppressing signals that are harmonics of local oscillator frequencies from nearby detectors, improving the accuracy of radar signal detection and reducing unnecessary alerts.
Implementation Method 1
The mixer combines the electromagnetic signals received by the antenna with a local oscillator signal that is repeatedly swept to scan one or more of the X, Ku, K and Ka bands to convert the frequency of the received signals in the swept bands to a predetermined intermediate frequency at the mixer output
Implementation Method 2
Due to the location of the local oscillators, their corresponding mixer and antenna, conventional radar detectors leak electromagnetic waves corresponding to the fundamental frequency of the local oscillators and their corresponding harmonic spectra via the antenna
Data Source
AI summary
A radar detector is operated to suppress nuisance radar alerts by identifying a first signal in radar band of interest, e.g., having a frequency that is a harmonic of a first nuisance local oscillator frequency leaked from a nearby radar detector and identifying a second signal having a frequency that is a harmonic of a second nuisance local oscillator frequency leaked from the radar detector where the first and second local oscillators are companion signals. A detector is also provided that suppresses nuisance radar alerts by detecting a first signal in a radar band, providing a first alert designating the detection of the first signal, determining that the first signal is a nuisance signal, providing a second alert designating that the first signal is a false alarm, and turning off the second alert after a predetermined period.