Sensor System Error Reduction via Complementary Signal Processing
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Solution Overview
Problem
Existing orientation sensor systems face challenges in achieving high accuracy, especially in environments with ferrous materials, and require external calibration, which limits their use in diverse applications such as vehicle navigation and weapon orientation.
Innovation Solution
A sensor system incorporating a three-axis magnetometer, dual three-axis accelerometers, and a microprocessor with self-calibration capabilities, capable of operating in the presence of ferrous materials, and using complementary signal processing to reduce errors and improve accuracy, allowing for real-time orientation measurements with low power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional orientation sensors are used in environments with ferrous materials, then the sensors can operate in diverse applications, but measurement accuracy deteriorates due to interference from ferrous materials
Solution Approach 1:
The patent uses the interference from ferrous materials as a diagnostic tool. By measuring the distortion of the Earth's magnetic field caused by ferrous materials and analyzing the pattern of interference, the system identifies the presence and orientation of ferrous objects. This converted harm enables the system to compensate for the interference and maintain accurate orientation measurements even in the presence of ferrous materials.
Solution Approach 2:
The system continuously monitors magnetic field measurements and compares them against expected Earth's magnetic field patterns. When deviations are detected that indicate ferrous material interference, the system adjusts its calculations and orientation determinations in real-time based on the measured interference pattern, maintaining measurement accuracy through continuous feedback correction.
2Measurement precision
If external calibration is performed to improve measurement accuracy, then orientation precision improves, but the system requires external calibration equipment and procedures which reduces ease of operation
Solution Approach 1:
The system performs self-calibration by using the Earth's magnetic field as a reference. The sensor suite automatically determines its orientation relative to the Earth's magnetic field and uses this information to calibrate its measurements without requiring external calibration equipment or procedures. This self-service approach eliminates the need for external calibration while maintaining high measurement accuracy.
Solution Approach 2:
The system performs initial calibration during manufacturing by aligning the sensor axes with the Earth's magnetic field at a known location. This preliminary action establishes a reference frame that allows the system to operate accurately without requiring subsequent external calibration, as the calibration is completed once during production.
3Measurement precision
If high accuracy orientation sensing is achieved using three-axis magnetometers, then measurement precision improves, but the system becomes more complex and requires multiple sensors
Solution Approach 1:
The patent combines a three-axis magnetometer with a three-axis accelerometer into a single integrated sensor system. By merging these sensors and sharing common processing electronics and software, the system achieves high-accuracy orientation sensing while reducing overall system complexity compared to using separate independent sensor systems. The combined system processes data from both sensors through unified algorithms.
Solution Approach 2:
The sensor system is designed to perform multiple functions: determining orientation relative to the Earth's magnetic field, detecting ferrous materials, and providing navigation information. By making the system universal and multi-functional, the patent reduces the need for separate specialized sensors and systems, thereby reducing overall complexity while maintaining high measurement precision for the primary orientation function.
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
The system achieves high accuracy (better than 0.10 degrees) with long-term stability and low power consumption, enabling reliable operation on ferrous vehicles and objects, and eliminates the need for external calibration, thus enhancing its versatility and accuracy.
Implementation Method 1
A two-terminal fluxgate coil, and a switching circuit that includes two configurations for coupling terminals of the coil to the driver
Implementation Method 2
The set of sensors includes two accelerometers substantially aligned along a common axis and fixed in opposite orientations
Data Source
AI summary
A sensor system includes a first measurement subsystem including a driver and a measurement component. The measurement component includes a set of sensors for generating complementary signals representing each of one or more characteristics. The complementary signals representing a characteristic include related error components. The driver is configured to accept the complementary signals for a characteristic and to determine a measurement value for the characteristic by combining the complementary signals to reduce effects of the error components in the complementary signals.