AC Magnetic Field Target Localization
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Solution Overview
Problem
Existing magnetic tracking systems for target localization in 3D spaces face challenges in accurately determining device positions and pairing, especially in indoor environments, due to interference and the need for high power consumption, which affects battery life and navigation accuracy.
Innovation Solution
The use of alternating current (AC) magnetic fields emitted by transmitters with unique frequencies, sensed by devices with 3-axis magnetometers, allows for accurate positioning and pairing without requiring new hardware, leveraging existing coils and sensors, and optimizing power consumption for low battery impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnetic tracking systems use fixed transmitters to generate magnetic fields for target localization, then position determination capability is improved, but power consumption increases affecting battery life
Solution Approach 1:
The system uses periodic AC magnetic field transmissions at specific frequencies (e.g., 100-1000 Hz) instead of continuous transmissions. The transmitter emits magnetic fields in periodic cycles, and the receiver detects these periodic signals to determine position. This periodic operation significantly reduces average power consumption while maintaining localization accuracy, as the transmitter is not continuously active.
Solution Approach 2:
The system changes the frequency parameter of magnetic field transmissions to enable multiple transmitters to operate simultaneously without interference. Each transmitter operates at a unique frequency, allowing the receiver to distinguish between different transmitters and accurately determine position. This frequency differentiation enables efficient multi-transmitter operation with reduced individual power requirements.
2Measurement precision
If multiple transmitters operate simultaneously for accurate positioning, then localization precision is improved, but signal interference increases
Solution Approach 1:
Each transmitter is assigned a unique local quality in the form of a specific frequency characteristic. This frequency differentiation allows the receiver to distinguish between signals from different transmitters using frequency-selective detection. The local quality assignment eliminates signal interference while enabling simultaneous operation of multiple transmitters for accurate 3D localization.
Solution Approach 2:
Multiple transmitters operate periodically at different frequencies rather than continuously at the same frequency. The periodic transmission with frequency modulation allows the receiver to separate and process signals from different transmitters independently, preventing interference while maintaining localization precision through multi-transmitter cooperation.
3Device complexity
If existing coils and sensors are used for magnetic field transmission and sensing, then device complexity is reduced, but measurement precision may be limited
Solution Approach 1:
The system extracts additional information from existing sensors by analyzing frequency-domain characteristics of magnetic field signals. Instead of relying solely on amplitude measurements, the receiver detects frequency shifts, phase differences, and temporal patterns in the AC magnetic fields. This parameter-based information extraction enhances positioning accuracy using standard off-the-shelf magnetometers without requiring specialized high-precision sensors.
Solution Approach 2:
The periodic AC magnetic field transmissions enable existing sensors to operate in their optimal frequency range, improving signal-to-noise ratio and measurement precision. The periodic modulation allows standard magnetometers to detect signals more effectively by filtering out DC offsets and low-frequency noise, thereby achieving higher positioning accuracy with conventional 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
This solution provides accurate device positioning, efficient power usage, and enhanced navigation capabilities, including device pairing and lost device tracking, with no additional hardware needed, benefiting applications like indoor navigation and real-time applications.
Implementation Method 1
a magnetic field sensor in the device senses one or more AC magnetic fields emitted by one or more transmitters in a 3D space
Implementation Method 2
alternating current (AC) magnetic fields emitted by transmitters
Implementation Method 3
a first AC magnetic field emitted by a first transmitter located in the 3D space at a first frequency
Data Source
AI summary
A device operates in pairing mode, indoor navigation mode or search mode. For each mode, a magnetic sensor in the device senses one or more alternating current (AC) magnetic fields emitted by one or more transmitters in a three-dimensional (3D) space, and uses the one or more AC magnetic fields to determine a position of the device relative to the one or more transmitters or another device. In pairing mode, relative position vectors computed from two or more AC magnetic fields allows the device to choose the closest transmitter for pairing. In indoor navigation mode, multiple detections of AC magnetic fields emitted by multiple transmitters assist a user in navigating an indoor space. In search mode, a companion device and a lost device each sense an AC magnetic field from a transmitter, and he AC magnetic fields are used to determine a relative position vector from the companion device to the lost device.