Optical Air Data Signal Gating for Higher Signal-to-Noise Ratio
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Solution Overview
Problem
Conventional optical air data systems (OADS) suffer from low signal-to-noise ratio (SNR), which affects the accuracy and sensitivity of air data parameter measurements, increases computational resources, and diminishes spatial and temporal resolutions.
Innovation Solution
The OADS is enhanced by time-sequentially providing optical signals to individual emitters, enabling optical sensors only during expected return signal reception, and using mechanical or electronic shutters to reduce noise, thereby increasing SNR.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If optical sensors are enabled continuously to capture return signals, then signal reception is maintained, but noise increases and signal-to-noise ratio decreases
Solution Approach 1:
The optical sensor is enabled only during specific time windows when return signals are expected, rather than continuously. The shutter is opened for a limited duration corresponding to the expected signal reception period, then closed. This periodic enabling reduces noise accumulation while maintaining signal reception capability during critical periods.
Solution Approach 2:
The system predicts when return signals will be received and opens the shutter in advance of the actual signal arrival. This preliminary action ensures the sensor is ready to capture the signal without requiring continuous operation, thereby reducing noise while maintaining reception reliability.
2Area of stationary object
If multiple optical emitters operate simultaneously, then spatial coverage is improved, but computational resources and system complexity increase
Solution Approach 1:
The optical signal is divided into multiple time segments, with each segment being directed to a different optical emitter sequentially. Instead of all emitters operating simultaneously, the system cycles through emitters in time slots, reducing the number of active components at any given moment while maintaining comprehensive spatial coverage over time.
3Measurement precision
If computational resources are increased to compensate for low SNR, then measurement accuracy improves, but system cost and complexity increase
Solution Approach 1:
Instead of relying on heavy computational processing to improve signal quality, the system uses a mechanical shutter to physically isolate the signal reception period. This mechanical approach improves SNR at the source without requiring proportional increases in computational resources, thereby reducing overall system complexity while maintaining accuracy.
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 approach improves the resolution, accuracy, and sensitivity of air data parameters while reducing computational resources and costs.
Implementation Method 1
a laser configured to emit a pulsed optical signal including a train of pulses
Implementation Method 2
generating data with a camera's optical sensor from the incident return optical signal
Data Source
Figure 1A
Figure 1B~1D
Figure 2A~2B
AI summary
Techniques are provided which improve the signal to noise ratio of an optical air data system. A pulsed optical signal is sequentially provided to different optical emitters. Upon receiving the pulsed optical signal, each optical emitter emits an optical beam along a unique line of sight to a unique region of the atmosphere. A return optical signal is reflected and/or scattered back to an optical receiver. The return optical signal is detected to provide data about the return optical signal. Using data about the pulsed optical signal and each return optical signal, optical air data parameters can be derived with improved accuracy and/or sensitivity.