Aircraft Airspeed Determination via Centripetal Acceleration
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Solution Overview
Problem
Existing aircraft monitoring systems, particularly those without airspeed sensors, face challenges in accurately determining airspeed during turns, especially in windy conditions, as they rely on GPS and gyroscopic measurements which can be prone to errors and require additional equipment like triaxial rate gyros and accelerometers, and gyro slaving to the Earth's gravitational vector is problematic due to centripetal acceleration.
Innovation Solution
A method and apparatus that determine airspeed by calculating centripetal acceleration based on Earth-based reference system data and a rate of rotation in an aircraft-based reference system, using GPS data and a heading gyro or rate sensor, allowing for airspeed determination without the need for airspeed sensors and compensating gyro slaving to accurately respond to the Earth gravity axis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If GPS and gyroscopic measurements are used to determine airspeed during turns, then airspeed can be estimated without airspeed sensors, but measurement precision deteriorates due to errors in GPS and gyro data
Solution Approach 1:
The patent introduces centripetal acceleration as an intermediary parameter that mediates between GPS groundspeed measurements and airspeed determination. By calculating centripetal acceleration from GPS position data and combining it with gyroscopic turn rate measurements, the system creates a new computational pathway that improves airspeed accuracy during turns without requiring direct airspeed sensor measurements.
Solution Approach 2:
The patent replaces the mechanical airspeed sensor (pitot tube) with a computational system that uses GPS and gyroscopic data to calculate airspeed indirectly. This substitution eliminates the mechanical sensor while improving reliability, accepting that measurement precision must be maintained through sophisticated data processing and centripetal acceleration compensation.
2Measurement precision
If triaxial rate gyros and accelerometers are added to improve turn rate measurements, then airspeed determination accuracy improves, but device complexity increases
Solution Approach 1:
The patent extracts and utilizes only the essential components needed for airspeed determination during turns: GPS for groundspeed and position data, and a single-axis rate gyro for turn rate. By taking out the unnecessary triaxial sensors and accelerometers, the system achieves sufficient measurement precision with reduced device complexity, keeping only the minimum required sensors for the specific function.
Solution Approach 2:
The patent makes the GPS system serve multiple functions: it provides groundspeed measurements, position data for trajectory analysis, and enables calculation of centripetal acceleration. This multi-functionality reduces the need for additional dedicated sensors, as the GPS data is leveraged to compensate for the limitations of having fewer sensors.
3Measurement precision
If gyro is slaved to Earth's gravitational vector, then gyro accuracy improves, but harmful factors increase due to centripetal acceleration during turns
Solution Approach 1:
The patent applies preliminary anti-action by calculating centripetal acceleration from GPS data and using this computation to compensate for the harmful centripetal effects during turns. Before the gyro slaving problem can cause significant error, the system pre-calculates the centripetal acceleration vector and applies it as a correction, counteracting the harmful gravitational vector deviation caused by turns.
Solution Approach 2:
The patent implements feedback by continuously monitoring GPS position and groundspeed data to calculate centripetal acceleration, which then feeds back into the gyro slaving process. This feedback loop allows the system to dynamically adjust the gyro reference frame compensation based on actual turn conditions, maintaining gyro accuracy while compensating for centripetal acceleration effects.
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
Enables accurate airspeed determination during turns, reducing reliance on additional sensors and improving gyro accuracy by compensating for centripetal acceleration, thus enhancing aircraft control and safety by preventing overspeeding.
Implementation Method 1
A centripetal acceleration of the aircraft is determined based on the Earth-based reference system data for the first and second positions in conjunction with the time increment
Implementation Method 2
one or more GPS (Global Positioning System) receivers for purposes of monitoring the progress and movement of a craft
Implementation Method 3
a heading gyro or rate sensor, allowing for airspeed determination without the need for airspeed sensors
Data Source
AI summary
The flight of an aircraft is characterized in terms of Earth-based reference system data for a first position and a second position of the aircraft that are separated by a time increment. A centripetal acceleration of the aircraft is determined based on the Earth-based reference system data for the positions in conjunction with the time increment. A rate of rotation is established corresponding to the time increment in an aircraft-based reference system. Aircraft airspeed is determined based on the centripetal acceleration and the rate of rotation. A turn can be detected as characterized by a change in track angle from a prior GPS packet compared to a new packet. Aircraft turns can be detected based on a change in track angle in GPS packets. Compensation can be applied to a gyro based on centripetal acceleration such that the gyro more accurately responds to the Earth gravity axis.