Optical Air Data Sensor Bias Correction via Inertial Aiding
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Solution Overview
Problem
Current LiDAR air data systems experience measurement bias due to high pitch, roll, and yaw rates in aircraft, limiting their practicality on certain platforms.
Innovation Solution
Incorporating inertial sensors to measure rotation rates and a processor unit that corrects line-of-sight velocities for rotation-induced bias, allowing for accurate air data parameter computation by subtracting bias from measured signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If remote measurement is used to collect air data outside the boundary layer, then measurement accuracy is improved, but measurement bias increases due to high pitch, roll and yaw rates
Solution Approach 1:
The patent introduces an intermediary correction mechanism that uses inertial sensor data and computational algorithms to mediate between the raw LiDAR measurements and the final air data output. The system calculates bias correction values based on the relationship between the optical transceiver position, vehicle center of gravity, and measured rotation rates, then applies these corrections to eliminate measurement bias while preserving the advantages of remote measurement.
2Adaptability or versatility
If LiDAR-based air data systems are used on high-performance jet aircraft with high rotation rates, then mission profile expansion is achieved, but measurement bias renders the system impractical
Solution Approach 1:
The patent changes the operational parameters of the LiDAR system by dynamically adjusting measurements based on real-time inertial sensor data. The system modifies the air data calculations by incorporating correction terms that account for pitch, roll, and yaw rates, thereby adapting the system to function reliably on high-performance aircraft platforms that previously caused measurement bias.
3Measurement precision
If optical transceiver is positioned away from vehicle center of gravity, then remote measurement capability is improved, but rotation rate induced bias increases
Solution Approach 1:
The patent converts the harmful effect of rotation rate induced bias into a beneficial correction mechanism. By deliberately positioning the optical transceiver away from the center of gravity to enable remote measurement, the system then uses inertial sensors to measure the rotation rates that cause bias, and computationally corrects for these same rotation rates, thereby transforming the harmful bias into a correctable parameter that enhances measurement 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 enables the use of LiDAR-based air data systems on a broader range of aircraft platforms, eliminating errors and improving performance, especially on high-performance jet aircraft.
Implementation Method 1
The optical transceiver is configured to transmit light along the at least one line-of-sight into an external interaction air region and collect a scattered portion of the transmitted light from the external interaction air region
Implementation Method 2
The inertial sensors are configured to measure one or more rotation rates of the vehicle and generate rotation rate data
Implementation Method 3
computing at least one line-of-sight velocity based on the collected scattered portion of the transmitted light detected by the optical air data sensor; correcting the at least one line-of-sight velocity for rotation rate induced bias
Data Source
AI summary
An air data system comprises an optical air data sensor onboard a vehicle, and includes an optical transceiver at a first location that is spaced apart from a second location on the vehicle corresponding to the vehicle center of gravity. The optical transceiver has at least one line-of-sight that is fixed relative to body axes of the vehicle, transmits light along the line-of-sight into an external interaction air region, and collects a scattered portion of the transmitted light. The system also includes onboard inertial sensors configured to measure rotation rates of the vehicle and generate rotation rate data. An onboard processor communicates with the air data sensor and the inertial sensors. The processor computes at least one line-of-sight velocity based on the collected scattered portion of the transmitted light, corrects the line-of-sight velocity for rotation rate induced bias, and computes air data parameters based on the corrected line-of-sight velocity.