True North Heading via Gyroscope Orientation and Error Correction
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Solution Overview
Problem
Conventional navigation systems for determining the orientation of a vehicle or platform are influenced by factors like signal strength and local magnetic field variations, and gyroscope-based systems, while reliable, can be expensive due to the need for high-accuracy instruments like ring-laser or fiber optic gyroscopes.
Innovation Solution
The use of gyroscopes of different accuracies, where a higher-accuracy gyroscope is oriented to be sensitive to azimuth changes in the east/west direction, and a lower-accuracy gyroscope is placed perpendicular to it, with multiple gyroscopes aligned in the same direction to improve measurement accuracy by error correction, and the system includes a rotary stage to align the y-axis gyroscope with the east/west direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-accuracy gyroscopes (ring-laser or fiber optic) are used to determine vehicle heading, then measurement precision and reliability are improved, but system cost increases significantly
Solution Approach 1:
The system divides the gyroscope array into multiple independent sensing elements arranged in specific geometric patterns (e.g., orthogonal configurations). By segmenting the measurement function across multiple lower-cost gyroscopes rather than relying on a single high-accuracy instrument, the system achieves comparable heading precision while reducing individual component costs and overall system complexity.
Solution Approach 2:
The patent combines outputs from multiple lower-accuracy gyroscopes through mathematical processing and data fusion algorithms. By merging the measurements from several inexpensive gyroscopes arranged in specific orientations, the system synthesizes a heading measurement that approaches the accuracy of expensive ring-laser or fiber optic gyroscopes, thereby reducing overall system cost while maintaining measurement precision.
2Ease of manufacture
If conventional magnetic compass or strap-down magnetic vector sensor is used to measure heading, then system cost is reduced, but measurement precision deteriorates due to signal strength and local magnetic field variations
Solution Approach 1:
The system replaces magnetic field-based sensing (prone to environmental interference) with mechanical gyroscopic sensing. By using gyroscopes that measure rotational motion rather than magnetic field orientation, the system eliminates susceptibility to magnetic anomalies, signal strength variations, and other confounding magnetic influences, thereby improving measurement precision while maintaining cost-effectiveness through the use of multiple standard gyroscopes.
3Measurement precision
If multiple gyroscopes are used to improve measurement accuracy through error correction, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The system employs dynamic error correction where the computational processing adapts to the specific error characteristics of each gyroscope in the array. By implementing real-time calibration and error compensation algorithms that adjust to measured performance, the system achieves high measurement accuracy without requiring overly complex hardware configurations, thereby managing device complexity through intelligent software-based solutions.
Solution Approach 2:
The patent utilizes parameter changes in the geometric arrangement of gyroscopes (such as orthogonal orientations and specific spatial configurations) to optimize error cancellation. By carefully selecting and adjusting the spatial parameters and orientation angles of the gyroscope array, the system achieves enhanced measurement precision through geometric error compensation, reducing the need for complex electronic correction circuits and simplifying overall system design.
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 the accuracy of determining true north heading by reducing measurement errors and improving sensitivity to azimuth changes, making the system more cost-effective and reliable across various environments.
Implementation Method 1
These systems use the Earth's rotational rate vector as a reference to directly determine the heading of the vehicle
Data Source
AI summary
A true north heading is determined by using gyroscopes of differing accuracy and orienting a gyroscope of a higher accuracy to a direction that is more sensitive to azimuth change (e.g., an east/west direction). A gyroscope with a lower accuracy is placed perpendicular to the gyroscope with a higher accuracy and can be oriented towards a north or south direction. The gyroscopes may be placed on a rotatable platform to properly orient the gyroscopes. The higher-accuracy gyroscope may be implemented by using multiple gyroscopes oriented in the same direction.