Asynchronous TDoA Localization With Decoupled Wireless Synchronization
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Solution Overview
Problem
Existing RF-based indoor localization technologies face challenges with multipath effects, signal attenuation, and high deployment costs due to the need for multiple anchors, leading to inaccurate and unreliable location services.
Innovation Solution
Decouple synchronization from ranging operations in wireless networks by using time difference of arrival (TDoA) to estimate location, allowing for asynchronous systems that reduce network congestion and enable precise localization with fewer anchors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple anchors are deployed for RF-based localization, then localization coverage is improved, but deployment cost increases
Solution Approach 1:
The patent makes existing wireless infrastructure (WiFi access points, cellular base stations) perform dual functions: their original communication function and localization anchor function. By enabling these existing devices to serve as anchors for TDoA localization, the system achieves reliable localization coverage without requiring dedicated anchor deployments, thereby reducing the quantity of additional hardware needed.
Solution Approach 2:
The system utilizes the existing wireless communication infrastructure to provide localization services. The wireless nodes themselves participate in the localization process by transmitting signals that are received by multiple anchors, and the system automatically performs TDoA calculations using the existing network infrastructure, making the localization service self-sustaining without requiring separate dedicated systems.
2Ease of operation
If synchronization is coupled with ranging operations, then network coordination is simplified, but network congestion increases
Solution Approach 1:
The patent separates the synchronization function from the ranging operation. Synchronization is achieved through shared clock references or periodic sync messages independent of the actual localization signal exchanges. This segmentation allows ranging operations to proceed without being bottlenecked by synchronization overhead, reducing network congestion while maintaining coordination simplicity through dedicated sync mechanisms.
Solution Approach 2:
The system implements periodic synchronization updates at optimized intervals rather than continuous synchronization. This periodic approach maintains time coordination between nodes while minimizing the frequency of sync traffic, thereby reducing overall network congestion during active ranging operations while still providing adequate synchronization for accurate TDoA measurements.
3Measurement precision
If TDoA measurement is performed with synchronized receivers, then localization precision is improved, but system complexity increases
Solution Approach 1:
The patent introduces a central coordinator or uses existing network infrastructure as an intermediary to manage synchronization. Rather than requiring complex peer-to-peer synchronization between all receiver pairs, the intermediary provides a centralized time reference or coordination mechanism that simplifies the synchronization architecture while still enabling accurate TDoA measurements across the network.
Solution Approach 2:
The system replaces complex hardware-based synchronization mechanisms with software-based time stamping and post-processing algorithms. By using precise software time recording at each receiver and performing TDoA calculations centrally or distributedly after data collection, the system achieves high measurement precision without requiring complex real-time hardware synchronization infrastructure.
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 enhances localization accuracy and reliability in indoor environments by minimizing multipath errors and reducing the number of required anchors, thereby lowering deployment costs and improving network efficiency.
Implementation Method 1
RF circuitry for transmitting and receiving communications in the wireless network architecture
Implementation Method 2
determine time difference of arrival (TDoA) information of the reception of the first communication between each of the first and the second wireless nodes
Data Source
AI summary
In one embodiment, an asynchronous wireless system for localization of nodes comprises a first wireless node being configured to receive a first communication from a third wireless node having an unknown location, to determine time difference of arrival (TDoA) information of the reception of the first communication between each of the first and a second wireless node, to determine TDoA ranging including a relative or absolute position of the third wireless node using the time difference of arrival information, and to synchronize the first and second wireless nodes based on a second communication with the synchronization being decoupled in time from the first communication. In another embodiment, a computer implemented method comprises receiving, with first and second wireless anchor nodes, packets from a wireless arbitrary device and performing time difference of arrival ranging upon reception of the packets between each of the first and the second wireless anchor nodes.