Inertial Navigation System Atom Optic Kalman Filter Drift Correction
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Solution Overview
Problem
Conventional inertial navigation systems face challenges in accuracy due to the limited bandwidth and noncontinuous output of atom optic instruments, which are sensitive to both acceleration and rotation, making it complex to separate these sensitivities and requiring continuous navigation solutions.
Innovation Solution
The integration of atom optic instruments with conventional navigation systems using a Kalman filter to process periodic high-accuracy measurements from atom optic instruments, providing corrections to conventional navigation systems for improved accuracy and mitigating drift during downtime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If atom optic instruments are used to improve measurement accuracy, then measurement precision is improved, but the output becomes noncontinuous and limited bandwidth
Solution Approach 1:
The patent combines atom optic instruments with conventional inertial navigation systems to merge the high accuracy of atom optic measurements with the continuous operation capability of conventional systems. The atom optic instrument provides periodic corrections while the conventional system fills in during downtime, achieving both accuracy and continuity.
Solution Approach 2:
A Kalman filter is introduced as an intermediary to process and combine measurements from both atom optic instruments and conventional inertial sensors. The filter optimally integrates the discontinuous high-accuracy atom optic data with continuous conventional sensor data, resolving the contradiction between accuracy and continuity.
2Speed
If direct extraction of acceleration and angular rate information is attempted, then instantaneous velocity can be obtained, but the complexity of separating acceleration sensitivity from rotational sensitivity increases
Solution Approach 1:
Instead of directly extracting acceleration and angular rate from the atom optic instrument output, the patent extracts only the position change information and uses a Kalman filter to derive velocity and other parameters. This avoids the complex separation of acceleration and rotational sensitivity while still providing the needed navigation parameters.
3Duration of action of moving object
If conventional inertial navigation systems are used to provide continuous navigation, then continuous operation is maintained, but accuracy deteriorates due to sensor drift
Solution Approach 1:
The system uses feedback by periodically correcting the conventional inertial navigation system with high-accuracy measurements from the atom optic instrument. The Kalman filter processes these corrections and feeds them back to update and correct the drift in conventional sensors, maintaining both continuity and 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 enhances navigation accuracy by utilizing the nature of atom optic instrument measurements to provide continuous navigation capabilities, overcoming the limitations of direct acceleration and angular rate extraction, and ensuring continuous operation despite the finite lifetime of the atom cloud.
Implementation Method 1
Atom optic instruments use matter wave interferometry involving laser cooled atoms and molecules
Implementation Method 2
quantum mechanical interference of matter waves, or deBroglie waves, associated with particles of non-zero mass
Implementation Method 3
Optical interferometric inertial sensors include Sagnac effect devices that are typically ring laser or fiber optic interferometers
Data Source
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AI summary
The invention is related to a method and an inertial navigation system for combining continuous signal output from a first inertial sensor (14) with discontinuous signal output from a second inertial sensor (12) . The first inertial sensor (14) acquires continuous data with respect to a navigation frame of reference for a parameter used in inertial navigation and the continuous data is processed to produce estimated values of the parameter. The second inertial sensor (12) acquires discontinuous data with respect to a case frame of reference indicative of the parameter with respect to a case (25) containing the second inertial sensor (12) . The discontinuous data is processed to produce measurements of the parameter at selected times,- and the estimated values of the parameter and the measurements of the parameter are processed at selected times with a Kalman filter to provide corrections to the estimated values of the parameter at the selected times.