Active Magnetic Orientation and Position Sensing with Pulse References
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Solution Overview
Problem
Existing wearable tracking systems using inertial and magnetic sensors face issues with drift and noise due to interference from the Earth's magnetic field and surrounding ferromagnetic materials, particularly in indoor and industrial environments, leading to unreliable orientation and position measurements.
Innovation Solution
An active magnetic orientation and position measurement system utilizing a switchable reference module with solid-state magnetic sensors and transmitters that generate alternating DC pulses, allowing for compensation of zero offset and noise by measuring magnetic vectors in opposite directions, and integrating inertial sensors for improved data fusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the Earth's magnetic field is used as a reference for orientation measurement, then absolute orientation can be obtained, but the system becomes unreliable in indoor and industrial environments due to interference from ferromagnetic materials
Solution Approach 1:
The patent introduces an active magnetic transmitter as an intermediary reference source between the solid-state magnetic sensor and the Earth's magnetic field. The transmitter generates a controllable magnetic field that serves as a local reference, mediating the measurement process to eliminate dependence on the Earth's magnetic field which is susceptible to interference from ferromagnetic materials in indoor environments.
Solution Approach 2:
The system changes the reference parameter from the Earth's magnetic field to an actively generated magnetic field with controllable characteristics. By adjusting the transmitter's output parameters (frequency, amplitude, direction), the system adapts to different measurement conditions and eliminates the harmful effects of environmental magnetic interference.
2Measurement precision
If alternating DC pulses are used to generate magnetic vectors in opposite directions, then zero offset and noise are compensated, but the system complexity increases due to the need for switchable reference modules and pulse generation circuits
Solution Approach 1:
The system employs periodic alternating DC pulses to generate magnetic vectors in opposite directions. This periodic action enables the solid-state magnetic sensor to measure both positive and negative magnetic field directions, allowing computational compensation of zero offset and noise through differential measurement techniques.
Solution Approach 2:
The patent creates a copy of the magnetic measurement process by taking measurements in opposite directions. By generating symmetric magnetic vectors (+B and -B) through alternating pulses and comparing the sensor responses, the system copies the measurement procedure under inverted conditions to eliminate offset errors.
3Measurement precision
If multiple sensors are used together for sensor fusion to measure 3D orientation, then measurement accuracy and reliability are improved, but the device complexity and power consumption increase
Solution Approach 1:
The patent merges inertial sensors (accelerometer and gyroscope) with solid-state magnetic sensors in an integrated measurement unit. This combination leverages the complementary strengths of each sensor type: inertial sensors provide high-frequency dynamic information while magnetic sensors provide absolute orientation reference, achieving accurate 3D orientation measurement through sensor fusion.
Solution Approach 2:
The active magnetic transmitter serves multiple functions: it generates the magnetic field for orientation measurement, provides a stable reference signal for noise cancellation, and enables both absolute and relative position determination. This multi-functionality reduces the need for separate dedicated components.
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 provides accurate, drift-free, and noise-reduced orientation and position measurements by eliminating external interference and using a local reference, enhancing the efficiency and reliability of motion capture systems.
Implementation Method 1
at least one driver circuit and at least one transmitter coil for generation excitation current in the form of altering DC pulses, applied to a pulse magnetic field
Implementation Method 2
The at least one solid-state magnetic sensor is configured to receive signal from the at least one magnetic transmitter
Data Source
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AI summary
The invention relates to an active magnetic orientation and position measurement system and method, which utilize solid-state magnetic sensors (210) and local altering pulsed magnetic sources.