Wireless Clock Synchronization for Indoor Range Measurement
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Solution Overview
Problem
Current satellite positioning systems face challenges in accurately measuring the round trip time (RTT) or time of flight (TOF) between wireless stations, which affects the precision of range measurements, especially in indoor environments where clock synchronization between devices is not effectively managed.
Innovation Solution
The method involves synchronizing clocks between wireless stations using parameters characterizing the state of a grand master clock, accounting for expected clock drift, and employing a burst of messages to compute accurate RTT or TOF measurements, thereby enhancing the accuracy of range calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If satellite positioning systems are used for outdoor navigation, then positioning service is enabled, but measurement precision deteriorates in indoor environments due to clock synchronization issues
Solution Approach 1:
The patent introduces a grandmaster clock as an intermediary reference that both wireless stations use to synchronize their local clocks. This mediator enables accurate time synchronization between devices in indoor environments where satellite signals are unavailable, thereby maintaining both service availability and measurement precision.
Solution Approach 2:
The system implements a feedback mechanism where wireless stations exchange timing information and clock state parameters to continuously adjust and synchronize their local clocks with the grandmaster clock reference, ensuring accurate RTT/TOF measurements for indoor positioning.
2Measurement precision
If round trip time measurement is performed between wireless stations, then range measurement is obtained, but measurement precision deteriorates due to clock drift between devices
Solution Approach 1:
The patent performs preliminary clock synchronization between wireless stations using the grandmaster clock reference before conducting RTT/TOF measurements. By pre-synchronizing the clocks and accounting for expected drift, the system ensures accurate range measurements without being compromised by clock synchronization issues during the measurement process.
Solution Approach 2:
The system dynamically adjusts timing parameters and compensates for clock drift by incorporating expected drift values into the RTT/TOF calculation algorithm, thereby maintaining measurement precision despite inherent clock drift between devices.
Data Source
AI summary
Disclosed are methods and systems for synchronizing clocks maintained at different devices in a wireless communication network. A first wireless transceiver device may receive one or more messages from a second wireless transceiver device with parameters indicative of a first clock state. The first wireless transceiver device may then synchronize a second clock state maintained at the first wireless device based, at least in part, on the one or more parameters indicative of the first clock state.