Wi-Fi IoT Positioning via TDOA and Subnet Master Nodes
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Solution Overview
Problem
Conventional indoor positioning technologies for natural persons in large indoor areas face challenges with low precision, high cost, and high power consumption, and lack centralized management and navigation services, especially when dealing with a large number of targets.
Innovation Solution
A Wi-Fi IoT device network-based positioning method that utilizes synchronized subnets, TDOA information, and subnet master nodes to compute the position of targets through signal arrival time differences, leveraging the redundant resources of IoT devices for real-time monitoring and tracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If RSSI-based positioning algorithms are used with few communication base stations or Wi-Fi hotspots, then positioning can be implemented, but positioning reliability is low and error is high due to low density deployment and complicated degradation conditions
Solution Approach 1:
The patent creates virtual base stations by utilizing existing Wi-Fi IoT devices as reference points for positioning. Instead of deploying dedicated communication base stations, the system copies the positioning function across numerous existing IoT devices, transforming them into reference nodes that provide TDOA measurement capabilities.
Solution Approach 2:
The patent makes Wi-Fi IoT devices serve multiple functions: their original IoT functionality plus serving as positioning reference points. This multi-functionality allows the same devices to perform both their designated IoT tasks and provide positioning support, increasing system reliability without additional infrastructure.
2Measurement precision
If UWB technologies are used for positioning with TOA, TDOA, or AOA information, then positioning precision is relatively high with simpler algorithms, but hardware cost is high and power consumption is high due to customized circuits and high operating bands
Solution Approach 1:
The patent substitutes the specialized UWB hardware system with a software-based TDOA positioning solution running on existing Wi-Fi devices. Instead of replacing mechanical/electrical UWB circuits, it uses signal processing and time difference calculations on standard Wi-Fi hardware, dramatically reducing power consumption and cost while maintaining acceptable precision.
Solution Approach 2:
The patent uses inexpensive, widely available Wi-Fi IoT devices instead of expensive UWB equipment. By leveraging the ubiquity and low cost of Wi-Fi technology, the system achieves positioning capabilities without requiring costly specialized hardware, making large-scale deployment economically viable.
3Measurement precision
If UWB technologies are used for positioning, then positioning precision is relatively high, but hardware cost is high due to complicated customization and design of circuits
Solution Approach 1:
The patent replaces specialized UWB hardware circuits with software-based processing on standard Wi-Fi devices. This substitution eliminates the need for complicated circuit customization and design, using instead readily available Wi-Fi chipsets and software algorithms to achieve positioning functionality.
Solution Approach 2:
The patent makes existing Wi-Fi IoT devices serve dual purposes: their original IoT function and positioning reference point. This universality eliminates the need for separate positioning hardware, reducing manufacturing complexity and cost while leveraging the existing Wi-Fi infrastructure.
4Area of stationary object
If conventional positioning technologies are used for a large number of targets in a large indoor physical range, then positioning coverage is achieved, but centralized positioning information management and navigation services are not supported
Solution Approach 1:
The patent merges positioning information from multiple distributed Wi-Fi IoT devices into a unified centralized management system. By collecting TDOA data from numerous reference points and processing it centrally, the system achieves both large-area coverage and centralized control capabilities, enabling navigation services for multiple targets simultaneously.
Solution Approach 2:
The patent divides the large indoor area into multiple zones covered by different Wi-Fi IoT devices, with each device serving as a localized reference point. The centralized system then integrates these segmented local measurements into comprehensive positioning information for the entire large area, enabling scalable management of multiple targets.
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 enables precise, cost-effective, and low-power indoor positioning and navigation for multiple targets in large areas, utilizing the redundant resources of Wi-Fi IoT devices, achieving high precision and efficient data processing with centralized management.
Implementation Method 1
a positioning target device transmits a data packet; each of all the positioning monitoring nodes in the subnet or all the other positioning monitoring nodes in the subnet except the subnet master node, respectively within an information receiving and transmitting range thereof, receives the data packet
Implementation Method 2
utilizes TDOA information of receiving signal between subnet devices, so as to realize method and system for real-time positioning and monitoring a large number of targets in a large physical range
Data Source
AI summary
The present invention relates to a positioning method and system based on a Wi-Fi IoT device network, wherein positioning monitoring nodes in a subnet respectively receives, within an information receiving and transmitting range thereof, a data packet sent by a same positioning target device, records corresponding data packet receipt clock information, and provides the data packet receipt clock information and identification information of the positioning target device to the subnet master node; the subnet master node utilizes signal arrival time differences between a plurality of positioning monitoring nodes receiving the data packet from the same positioning target device, and mutual physical distances between the positioning monitoring nodes, to compute the distance differences of the positioning target device with respect to the plurality of positioning monitoring nodes, and determine a position of the positioning target device in a physical coverage range of the subnet. The present invention may achieve the real-time positioning and monitoring of a large number of targets in a large physical range.