Aircraft Sensor Short Detection via Beat Frequency Analysis
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Solution Overview
Problem
Aircraft sensors often experience measurement failures or reduced accuracy due to shorts between proximate measurement circuits, which can be difficult to detect as they may provide similar operator indications across common channels.
Innovation Solution
The system employs alternating current sources with unique frequencies reduced by capacitors, generating interference waveforms that, when rectified and smoothed, allow for the detection of shorts through beat frequencies, enabling identification of implicated sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If sensors are placed in proximity for measurement, then measurement coverage is improved, but short detection becomes difficult
Solution Approach 1:
The patent applies periodic action by introducing alternating current at different frequencies to sensor channels. When a short exists between proximate sensors, the interference signal produces a beat frequency that varies periodically over time, enabling detection of the short condition through frequency analysis of the periodic interference pattern.
Solution Approach 2:
The patent implements preliminary action by proactively injecting test signals into sensor channels before normal operation to detect potential shorts. The system preemptively applies alternating current at specific frequencies to create detectable interference patterns that reveal short conditions before they affect actual measurements.
2Device complexity
If common indication channels are used for multiple sensors, then system complexity is reduced, but short detection accuracy deteriorates
Solution Approach 1:
The patent uses periodic action with distinct alternating current frequencies for different sensor channels. When sensors share common indication channels, the different frequencies create unique beat frequency patterns that can be analyzed to identify which specific sensors are involved in a short, maintaining detection accuracy despite channel sharing.
Solution Approach 2:
The patent applies parameter changes by varying the frequency of alternating current injected into different sensor channels. This frequency parameter differentiation allows the system to distinguish between shorts involving different sensors even when they share common indication channels, preserving measurement precision while reducing system complexity.
3Measurement precision
If alternating current is injected into sensor channels, then short detection capability is improved, but sensor measurement accuracy deteriorates
Solution Approach 1:
The patent implements periodic action by injecting alternating current at specific frequencies that are distinct from normal sensor operating frequencies. The periodic nature of the test signal creates detectable beat frequencies when shorts are present, while the frequency separation ensures the test signal does not interfere with normal measurement accuracy.
Solution Approach 2:
The patent uses an intermediary approach by introducing alternating current through a controlled test signal that acts as a mediator between the detection system and the sensor channels. This intermediary signal enables short detection through frequency analysis while being designed to minimize interference with normal sensor measurements through careful frequency selection.
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
This method non-intrusively detects shorts in aircraft sensor systems, reducing measurement errors and providing accurate indications of shorted channels, thereby improving sensor reliability.
Implementation Method 1
the alternating current sources are reduced by a capacitor before passing through the sensor system
Implementation Method 2
the alternating current measurement system further includes a rectifier circuit disposed to rectify the alternating current
Implementation Method 3
generating interference waveforms that, when rectified and smoothed, allow for the detection of shorts through beat frequencies
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
Disclosed is a short detection system for an aircraft. The system includes a pair of alternating current sources (120, 170) defined by respective frequencies being offset by a predetermined value. The system includes a pair of sensor systems (101, 151) including respective measurement circuits (103, 153) coupled to respective sensor apparatuses to measure at least one parameter of an environment. The system includes an alternating current measurement system (105, 155) that includes a frequency isolation system e.g. a low pass filter (114, 164) having a cutoff frequency greater than the predetermined value such that a beat indicative of a difference between the respective frequencies passed through the pair of sensor systems is isolated by the low pass filter. The system indicates a short among the pair of sensor systems when the beat is present.