RF Tracking System Self-Calibration Using Time Difference of Arrival
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Solution Overview
Problem
Current RF tracking systems face challenges in achieving high accuracy and efficient receiver setup, particularly in applications requiring sub-millimeter precision and fast calibration, as existing methods rely on signal amplitude which is inadequate for demanding applications like virtual reality and surgical probes.
Innovation Solution
A position tracking system using at least four RF receiver antennae that calibrate their relative positions through a self-calibration process with a calibration template, utilizing time difference of arrival measurements to determine the three-dimensional position of an RF transmitter, enabling accurate and rapid setup even with randomly located receivers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If signal amplitude detection is used for tracking, then the system is simple to operate, but tracking accuracy is insufficient for high-precision applications
Solution Approach 1:
The patent changes the measurement parameter from signal amplitude to time of arrival (TOA) and time difference of arrival (TDOA). This parameter transformation enables high-precision tracking (sub-millimeter accuracy) while maintaining system simplicity, as the receivers automatically perform TOA/TDOA calculations based on signal propagation time without requiring complex manual calibration procedures.
Solution Approach 2:
The patent replaces the mechanical/amplitude-based tracking system with an electromagnetic time-based system. Instead of measuring signal strength (amplitude), the system measures the time it takes for signals to travel between transmitter and receivers, leveraging the constant speed of light for precise distance calculation. This substitution enables high accuracy without increasing operational complexity.
2Measurement precision
If time of arrival approach is used for high accuracy tracking, then tracking precision improves, but calibration process becomes complicated
Solution Approach 1:
The patent implements self-calibration where the receiver network automatically determines the relative positions of receivers using TOA/TDOA measurements. The system performs calibration computations autonomously based on signals exchanged between receivers and the tracked transmitter, eliminating the need for manual calibration procedures. This self-service approach maintains sub-millimeter accuracy while keeping the calibration process simple and automatic.
Solution Approach 2:
The patent performs calibration computations automatically during the initial system setup phase. The receiver positions are determined in advance using TOA/TDOA measurements from known transmitter locations, and this calibration data is stored for subsequent tracking operations. This preliminary calibration action ensures high tracking accuracy is achieved without requiring complex real-time calibration procedures during operation.
3Area of stationary object
If multiple receivers are placed throughout the tracked area, then tracking coverage is improved, but receiver position calibration becomes time-consuming
Solution Approach 1:
The patent enables the receiver network to automatically perform self-calibration using TOA/TDOA measurements. Each receiver determines its relative position to other receivers and the transmitter through automated computational processes. This self-calibration capability allows multiple receivers to be deployed across large areas without requiring time-consuming manual calibration of each receiver position, significantly reducing setup time while maintaining comprehensive tracking coverage.
Solution Approach 2:
The patent performs calibration computations automatically during initial system setup using signals exchanged between receivers and the transmitter. The relative positions of all receivers are determined in advance through automated TOA/TDOA calculations, and this calibration data is stored for ongoing tracking operations. This preliminary calibration action enables rapid deployment of multiple receivers across large areas without requiring sequential manual calibration of each device.
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 allows for precise and efficient tracking of RF transmitters with high accuracy, meeting the demands of applications requiring sub-millimeter precision without the need for complex calibration procedures, facilitating applications in virtual reality and surgical environments.
Implementation Method 1
an RF transmitter transmitting an RF signal from a plurality of known locations. At least four RF receiver antennae are disposed at undetermined locations within range of the RF transmitter to receive the RF signals
Implementation Method 2
A receiver station is in communication with the at least four RF receiver antennae to initially calibrate a relative position of each RF receiver antenna with respect to the other RF receiver antennae based on the plurality of known locations and on information acquired in response to the RF signals received at the at least four RF receiver antennae
Data Source
AI summary
Position tracking systems and methods for tracking a physical location of a radio frequency (RF) transmitter include an RF transmitter transmitting an RF signal from a plurality of known locations. At least four RF receiver antennae are disposed at unknown locations within range of the RF transmitter to receive the RF signals transmitted from the plurality of known locations. A receiver station in communication with the at least four RF receiver antennae initially calibrates a relative position of each RF receiver antenna with respect to the other RF receiver antennae based on the plurality of known locations and on information acquired in response to the RF signals received at the at least four RF receiver antennae.