Self-Calibrated Azimuth System Using Gyrocompassing
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Solution Overview
Problem
Conventional pointing and navigation systems face challenges with accuracy and reliability due to environmental magnetic interference, size constraints, and the need for external references, particularly in handheld or dynamic applications.
Innovation Solution
The Self-calibrated Azimuth and Attitude Accuracy Enhancing Method and System (SAAAEMS) uses a 2-axis tactical-grade gyro and two MEMS accelerometers, combined with advanced processing algorithms, to determine azimuth and attitude without magnetometers, enabling autonomous operation and reduced system size and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If magnetometers are used for azimuth measurement, then system size can be reduced and cost lowered, but measurement accuracy deteriorates due to magnetic interference from environmental factors
Solution Approach 1:
The patent removes magnetometers from the system and extracts the azimuth measurement function to be performed solely by the gyrocompassing algorithm using inertial sensors. This eliminates magnetic interference while maintaining compact size by not adding extra sensors.
Solution Approach 2:
The patent replaces the magnetic field-based magnetometer system with a mechanical inertial sensing system (gyroscopes and accelerometers) that determines azimuth through gyrocompassing algorithms, substituting magnetic measurement with inertial measurement principles.
2Measurement precision
If conventional INS with 3-axis high accuracy gyros and 3 accelerometers is used, then measurement accuracy is improved, but system size and cost increase
Solution Approach 1:
The patent extracts and removes redundant sensors from the conventional INS configuration, using only 2 accelerometers for gyrocompassing purposes and reducing gyro requirements, thereby decreasing system size while maintaining necessary measurement accuracy.
Solution Approach 2:
The patent applies partial action by using accelerometers only for gyrocompassing (not for full navigation) and employing a reduced sensor suite sufficient for the specific azimuth and attitude determination application, avoiding the overhead of a complete 3-axis high-accuracy INS system.
3Device complexity
If GPS attitude determination approach is used, then system cost is reduced, but system size increases and external references are required
Solution Approach 1:
The patent implements self-service through autonomous gyrocompassing that determines azimuth and attitude using only onboard inertial sensors without requiring external GPS references or other external systems, making the system self-contained and independent.
Solution Approach 2:
The patent makes the inertial sensor system multi-functional by using the same gyro and accelerometer suite for both gyrocompassing (azimuth determination) and attitude measurement, eliminating the need for separate GPS attitude determination hardware.
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
SAAAEMS provides accurate and reliable azimuth and attitude measurements in various environments, including dynamic conditions, without external references, while minimizing the impact of magnetic interference and maintaining a compact, cost-effective design.
Implementation Method 1
The SAAAEMS is based on an innovative gyrocompassing method of an inertial navigation system (INS)
Implementation Method 2
High-Accuracy triad or 2 accelerometers for vertical angle measurement. This is a conventional approach based on the measurement of the earth's gravity to determine the sensor frame's attitude with respect to the gravitational force direction
Data Source
AI summary
A method and system for Self-calibrated Azimuth and Attitude Accuracy Enhancing are disclosed, wherein SAAAEMS approach is based on fully auto-calibration self-contained INS principles, not depending on magnetometers for azimuth/heading determination, and thus the system outputs and performance are not affected by the environmental magnetic fields. In order to reduce the system size and cost, this new innovative methods and algorithms are used for SAAAEMS system configuration and integration. Compared to a conventional INS for gyrocompassing, AGNC's approach uses a smaller number of high accuracy sensors: SAAAEMS uses only one 2-axis high accuracy gyro (for example, one DTG) instead of 3-axis; the third axis gyro is a MEMS gyro. It uses only 2 high accuracy accelerometers instead of 3, since the two accelerometers are used only for gyrocompassing not for navigation. These two changes to the conventional INS system configuration remarkably reduce the whole system size and cost. SAAAEMS, uses dynamic gyrocompassing processing for isolation of Base motion disturbance/interference and vibration. SAAAEMS provides a method and system for using automatic methods for system calibration.