Guided Munition Roll Orientation from In-Flight Sensor Fusion
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Solution Overview
Problem
Existing methods for determining rocket roll orientation during flight require the rocket to remain stationary, preventing it from engaging targets at short and intermediate ranges due to the unknown initial roll orientation and spinning rate, which complicates estimation.
Innovation Solution
A method using on-board sensors to measure lateral acceleration and turn rate, integrating these measurements to calculate a gravity direction vector, allowing continuous orientation estimation without restricting rocket maneuverability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing methods are used to estimate rocket roll orientation, then measurement precision is improved, but the rocket cannot perform maneuvers and engagement time is delayed
Solution Approach 1:
The patent transitions from static orientation estimation (requiring the rocket to remain stationary) to dynamic estimation that works during active maneuvers. The system continuously updates roll orientation estimates while the rocket performs maneuvers, eliminating the need to pause engagement operations for orientation determination.
Solution Approach 2:
The orientation estimation process is made continuous rather than discrete. The system continuously processes sensor data from accelerometers and gyroscopes to provide real-time roll orientation estimates, allowing the rocket to maintain continuous target engagement capability without interruption for orientation measurement cycles.
2Measurement precision
If the rocket remains stationary for orientation estimation, then measurement precision is improved, but productivity is reduced
Solution Approach 1:
The system enables dynamic orientation estimation that functions during rocket maneuvers rather than requiring stationary conditions. This allows the rocket to maintain productivity by engaging targets without pausing for orientation measurements, as the estimation algorithm processes data continuously during flight and maneuvering operations.
3Productivity
If the rocket performs maneuvers during orientation estimation, then productivity is improved, but measurement precision deteriorates
Solution Approach 1:
The patent specifically addresses dynamic conditions by using sensor fusion algorithms that process data from both accelerometers and gyroscopes. This dynamic estimation approach maintains measurement precision even during maneuvers, unlike traditional methods that require stationary conditions, thereby allowing simultaneous target engagement and orientation determination.
Solution Approach 2:
The system uses feedback from multiple sensors (accelerometers and gyroscopes) to continuously refine the roll orientation estimate during maneuvers. This feedback mechanism compensates for the disturbances introduced by maneuvers, maintaining estimation accuracy while the rocket remains active and productive.
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 and continuous determination of rocket roll orientation, enabling engagement of targets at shorter ranges by providing real-time guidance and control capabilities.
Implementation Method 1
an accelerometer to provide a measurement of the lateral acceleration of the rocket
Implementation Method 2
a rate sensor to provide a measurement of the lateral turn rate of the rocket
Data Source
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AI summary
Techniques are provided for determination of a guided-munition orientation during flight based on lateral acceleration, velocity, and turn rate of the guided-munition. A methodology implementing the techniques, according to an embodiment, includes obtaining a lateral acceleration vector measurement and a velocity of the guided-munition, and calculating a ratio of the two, to generate an estimated lateral turn vector of the guided-munition. The method also includes integrating the estimated lateral turn vector, over a period of time associated with flight of the guided-munition, to generate a first type of predicted attitude change. The method further includes obtaining and integrating a lateral turn rate vector measurement of the guided-munition, over the period of time associated with flight of the guided-munition, to generate a second type of predicted attitude change. The method further includes calculating a gravity direction vector based on a difference between the first and second types of predicted attitude change.