Aircraft Attitude Estimation with Fluid Velocity Drift Correction
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Solution Overview
Problem
Traditional methods for attitude determination in aircraft navigation suffer from drift over time and are unsuitable for long-duration flights due to the lack of absolute attitude fixes, and reliance on GPS systems is not feasible in GNSS denied or jammed environments.
Innovation Solution
A computer-implemented method that determines aircraft attitude using accelerometer, gyroscope, and fluid velocity measurements to calculate the upwards direction in the body frame, independent of current attitude, and corrects for gyroscope drift, allowing navigation without GPS reliance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional methods integrate gyroscope measurements to estimate attitude, then attitude estimation can be obtained, but drift accumulates over time making it unsuitable for long-duration flights
Solution Approach 1:
The patent implements feedback by using accelerometer measurements to continuously monitor and correct gyroscope drift. The system integrates accelerometer data to detect gravitational direction and compares it with gyroscope-based attitude estimates, generating correction signals that compensate for accumulated drift and maintain accurate attitude determination over extended flight durations.
Solution Approach 2:
The patent introduces accelerometer measurements as an intermediary element to bridge the gap between short-term gyroscope accuracy and long-term stability requirements. By using accelerometer-derived gravitational reference as a mediator, the system can periodically reset or correct gyroscope integration errors without relying on external GPS systems.
2Measurement precision
If GPS or GNSS systems are used to correct attitude estimates, then accuracy can be maintained, but the system becomes unsuitable for GNSS denied or jammed environments
Solution Approach 1:
The patent enables the inertial navigation system to be self-sufficient by using onboard accelerometer measurements to self-correct gyroscope drift without external GPS assistance. The system services its own accuracy requirements by leveraging the gravitational reference available through accelerometers, making it autonomous and adaptable to GNSS-denied environments.
Solution Approach 2:
The patent changes the reference parameter from external GPS signals to internal accelerometer measurements of gravitational acceleration. This parameter substitution allows the system to maintain attitude accuracy through a different physical reference (gravity vector) that remains available regardless of GPS availability, thereby improving environmental adaptability.
3Adaptability or versatility
If accelerometer measurements are used to determine upward direction, then GPS independence is achieved, but fluid velocity effects must be compensated
Solution Approach 1:
The patent extracts and separates the fluid velocity compensation calculation from the basic attitude determination logic. By identifying and isolating the aerodynamic acceleration component caused by fluid flow, the system can subtract this specific disturbance from the total accelerometer measurements, leaving a cleaner gravitational reference for attitude estimation without requiring complete redesign of the entire navigation system.
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 reduces accuracy errors and prevents attitude drift, enabling accurate navigation in GNSS-denied environments and improving inertial navigation systems for autonomous aircraft.
Implementation Method 1
obtaining an indication of aircraft acceleration from an accelerometer
Implementation Method 2
obtaining an indication of aircraft angular velocity from a gyroscope
Data Source
AI summary
A computer-implemented method for determining attitude of an aircraft for navigation, in particular for autonomous or semi-autonomous aircrafts for use in GNSS-denied or jammed environments. The method comprises obtaining an indication of aircraft acceleration from an accelerometer, obtaining an indication of aircraft angular velocity from a gyroscope, and obtaining an indication of fluid velocity around and/or over the aircraft. Based on these indications, the upwards direction in body frame may be determined for the aircraft, wherein the upwards direction is defined relative to Earth's horizon. The attitude of the aircraft may then also be determined for navigation, based on the identified upwards direction in the aircraft body frame.