Passive Positioning via Wireless Time Sync Signals
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Solution Overview
Problem
Existing systems for determining a mobile node's position require the transmission and receipt of dedicated signals, whereas there is a need for a method that allows a mobile node to determine its own position without transmitting any signals by passively listening to wireless time synchronization communications, such as IEEE 1588, between multiple nodes in a wireless network.
Innovation Solution
A method and system that enable a receiver to passively determine its own position by receiving and decoding wireless messages between nodes of known positions, using the known positions, reception times, and transmit/receive times of messages exchanged between nodes, without actively transmitting signals, and employing techniques like TDOA multilateration and Kalman filtering for accurate positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dedicated signals are transmitted for position determination, then position accuracy is improved, but signal interference increases and transmission complexity worsens
Solution Approach 1:
The patent converts the harmful effect of signal interference into a benefit by using existing time synchronization signals (which are necessary for network operation) as the basis for position determination. Instead of adding dedicated positioning signals that would increase interference, the system repurposes the already-transmitted IEEE 1588 PTP messages to carry position determination information, thereby eliminating additional signal interference while maintaining position accuracy.
Solution Approach 2:
The patent makes the time synchronization signals serve multiple functions: they simultaneously perform time synchronization for the wireless network and provide the basis for position determination of mobile nodes. This multi-functionality eliminates the need for separate dedicated positioning signals, reducing transmission complexity and signal interference while maintaining position accuracy.
2Adaptability or versatility
If dedicated signals are transmitted for position determination, then position determination capability is improved, but device complexity and transmission overhead worsen
Solution Approach 1:
The patent implements multi-functionality by enabling existing time synchronization infrastructure to simultaneously support both time synchronization and position determination. The same IEEE 1588 PTP message exchange mechanism is used for both purposes, eliminating the need for separate dedicated positioning signal transmission and reducing overall system complexity.
Solution Approach 2:
The system enables mobile nodes to determine their own positions by passively listening to and processing existing time synchronization messages between access points. This self-service approach eliminates the need for complex active signaling between mobile nodes and positioning infrastructure, reducing transmission complexity while maintaining position determination capability.
3Measurement precision
If mobile nodes actively transmit signals for position determination, then positioning accuracy is improved, but energy consumption increases
Solution Approach 1:
The patent enables mobile nodes to passively determine their positions by listening to existing time synchronization messages between access points. This passive reception approach eliminates the need for mobile nodes to actively transmit positioning signals, significantly reducing energy consumption while maintaining positioning accuracy through TDOA multilateration using the received signals.
Solution Approach 2:
The patent converts the limitation of passive reception (which typically provides less positioning information) into a benefit by utilizing the precise time synchronization information already embedded in the IEEE 1588 PTP messages. The time stamps in these messages provide sufficient information for accurate TDOA-based positioning without requiring active transmission from mobile nodes.
Data Source
AI summary
The system and method of the present invention provides a mobile node (e.g., target), such as an aircraft, vehicle or mobile piece of equipment, the ability to determine its own position by passively listening to wireless time synchronization communications, such as IEEE 1588 Precision Time Protocol (PTP) messages, exchanged between nodes over a wireless network.