Self-locating Mobile Receiver Using TDoA and FDoA
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Solution Overview
Problem
Existing indoor localization systems face challenges such as signal distortion, synchronization issues, and high installation costs due to the need for precise synchronization and wired or wireless communication, which limits their accuracy and reliability in industrial environments.
Innovation Solution
A self-locating mobile receiving device that evaluates signals from unsynchronized transmitters using time difference of arrival (TDoA) and frequency difference of arrival (FDoA) methods without requiring synchronization, employing a recursive filter for position estimation and utilizing inertial measurement units for internal tracking, allowing for passive operation and reduced installation complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If time of flight methods are used for indoor localization, then positioning capability is achieved, but precise synchronization is required which increases system complexity and installation costs
Solution Approach 1:
The receiving device performs self-localization by autonomously evaluating signals from multiple transmitters and determining its own position without requiring external synchronization infrastructure. The device independently calculates time difference of arrival based on signal reception times from unsynchronized transmitters, eliminating the need for complex centralized synchronization systems.
Solution Approach 2:
Instead of having transmitters synchronized and providing timing references to receivers, the invention inverts the approach by having unsynchronized transmitters and enabling the receiver to autonomously determine positions using only the relative timing differences of received signals. The synchronization function is transferred from the transmitter infrastructure to the receiving device's processing capability.
2Reliability
If wired communication is used for synchronization, then reliable communication is achieved, but installation costs and complexity increase
Solution Approach 1:
The system eliminates the need for wired communication infrastructure for synchronization by enabling receivers to autonomously perform self-localization using only wireless signal reception. Each receiving device independently processes signals from transmitters and determines its own position without requiring reliable wired connections to synchronization servers or infrastructure.
Solution Approach 2:
The invention extracts the synchronization requirement from the system infrastructure and removes the need for wired communication completely. By using time difference of arrival methods with unsynchronized transmitters, the system eliminates the harmful factor of wired installation complexity while maintaining positioning functionality.
3Ease of manufacture
If wireless communication is used for synchronization, then installation simplicity is improved, but communication reliability and distance limitations occur
Solution Approach 1:
The receiving device performs self-localization autonomously using only wireless signal reception from transmitters, without requiring any wireless synchronization communication. The device independently evaluates signal timing differences and calculates its position, eliminating reliance on distance-limited wireless synchronization channels while maintaining installation simplicity.
4Measurement precision
If initial calibration is performed to determine transmitter positions, then localization accuracy is improved, but installation costs and skilled personnel requirements increase
Solution Approach 1:
The receiving device performs self-localization by autonomously determining its position based on signal evaluation from transmitters. The system eliminates the need for manual calibration procedures requiring skilled personnel by enabling receivers to independently calculate positions using time difference of arrival methods and signal timing information.
Solution Approach 2:
The system eliminates the need for preliminary calibration steps by designing a localization method that works directly with unsynchronized transmitters and unsupervised receivers. The autonomous evaluation and self-localization capability removes the harmful factor of required initial calibration while maintaining positioning functionality.
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 high accuracy and robustness in localization with reduced costs and installation effort, enabling accurate positioning of mobile devices in indoor environments without the need for synchronization or communication connections between transmitters and receivers.
Implementation Method 1
the receiver to be located may adopt various strategies to evaluate these signals including RSSI (Received Signal Strength Indicator) and TOF (Time of Flight). Instead of determining the absolute time of flight from a transmitter to a receiver, time difference of arrival (TDoA) or frequency distance of arrival (FDoA) systems evaluate the differences of signals travelling on more than one signal path.
Implementation Method 2
time difference of arrival (TDoA) or frequency distance of arrival (FDoA) systems evaluate the differences of signals travelling on more than one signal path.
Implementation Method 3
utilizing inertial measurement units for internal tracking
Data Source
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AI summary
A self-locating mobile receiving device (14) is provided, the device (14) having a receiver (28) for receiving signals from a plurality of transmitters (18a-d), in particular an ultrasonic receiver, and an evaluation unit (36) configured to identify a transmitter (18a-d) from a received signal, to determine a reception point in time of the received signal, and to estimate a position of the receiving device (14) based on transmitter positions and repeated measurements of transmitter (18a-d) identity and associated reception point in time, the transmitter (18a-d) positions being estimated or parameterized in advance. The evaluation unit (36) is further configured to estimate information about transmission points in time and/or mutual offsets of transmission points in time based on the reception points in time so that no synchronization is required.