Inertial Navigation Error Correction via Recursive Kalman Filtering
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Solution Overview
Problem
Existing systems for determining the position of a vehicle lack accuracy without external aiding sources like GPS, particularly in applications requiring precise range, bearing, and elevation data, such as gun placement and aiming systems.
Innovation Solution
An inertial navigation system (INS) integrated with a computer-based system using gyroscopes and accelerometers, enhanced with a recursive Kalman filter for data smoothing and error correction, allowing for accurate relative position measurement between two points without GPS, employing a method that involves stationary positioning at multiple points to update and correct error states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a standalone inertial navigation system is used to determine position, then the system can operate without external aiding sources, but the measurement precision of relative position deteriorates
Solution Approach 1:
The system implements feedback by returning the INS to previously visited points (Point A, Point B) to remeasure positions and use these remeasured values to correct accumulated errors in the inertial navigation data, thereby improving relative position accuracy while maintaining independence from external aiding sources
Solution Approach 2:
The system performs preliminary positioning at specific points (Point A, Point B) and stores these position values for later use as reference points for error correction, enabling the system to compensate for drift before it significantly degrades measurement precision
2Device complexity
If traditional inertial navigation data processing is used, then the system structure remains simple, but the productivity deteriorates due to lengthy offline data processing requirements
Solution Approach 1:
The system performs preliminary data smoothing and error correction during the field survey using a recursive filter, so that position results are substantially free from errors before leaving the survey area, eliminating the need for lengthy offline processing and enabling real-time productivity
Solution Approach 2:
The system performs its own error correction and data smoothing using onboard computational resources and stored reference position data, making the system self-sufficient and eliminating dependence on external processing facilities, thereby improving productivity while maintaining simple system structure
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 precise, real-time determination of relative positions between two or more points with improved accuracy and reduced need for offline data processing, effectively addressing the limitations of standalone INS systems.
Implementation Method 1
Inertial data is provided to INS 10, at least in one embodiment, from one or more gyroscopes 30
Implementation Method 2
Inertial data is provided to INS 10, at least in one embodiment, from one or more gyroscopes 30 and accelerometers 40
Data Source
Figure 1~2
Figure 3
AI summary
A method for determining the relative position of two points using an inertial navigation system is described. The method comprises estimating position error states and a position solution with an INS (10) at a first position, estimating position error slates and a position solution with the INS at a second position, and rcttirning the INS to the first position. Estimates of the first and second position error states are adjusted based on correlations developed during a transition returning the INS from the second position to the first position.