SOE Wireless Network Timing Using Carrier Phase Synchronization
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Solution Overview
Problem
Conventional location detection systems in wireless networks face limitations in accuracy due to noise, interference, and power constraints, particularly in determining the time of flight (TOF) using reference clocks with limited frequency, leading to resolutions of 30 meters or 30-100 nanoseconds, which are not sufficient for precise geolocation and event sequencing.
Innovation Solution
Implementing a method that synchronizes reference clocks across anchors and tags using multiple carrier frequencies to measure the fractional part of the reference clock cycle, allowing for precise determination of time of flight through phase difference analysis, thereby enhancing accuracy beyond conventional methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional reference clocks with limited frequency are used to measure time of flight, then the system operation is simple and power consumption is low, but the measurement precision is insufficient with resolutions of 30 meters or 30-100 nanoseconds
Solution Approach 1:
The patent introduces carrier phase information as an intermediary measurement mechanism. Instead of directly measuring time of flight with limited-resolution reference clocks, the system uses carrier phase differences as an intermediate metric that can be measured with much higher precision, then converts this phase information into accurate time of flight measurements through mathematical processing.
Solution Approach 2:
The patent changes the measurement parameter from direct time measurement using low-frequency reference clocks to carrier phase measurement. By measuring the phase difference of high-frequency carrier signals, the system achieves significantly higher temporal resolution without being constrained by the reference clock frequency, thereby improving measurement precision while managing system complexity.
2Measurement precision
If higher frequency reference clocks are used to improve time measurement resolution, then the measurement precision improves, but the power consumption increases significantly
Solution Approach 1:
The system uses carrier phase as an intermediary that allows high-precision time measurement without requiring high-frequency reference clocks. The carrier wave's phase information serves as a mediator that encodes fine time resolution, enabling the system to achieve nanosecond or sub-nanosecond precision while keeping the reference clock frequency and associated power consumption low.
Solution Approach 2:
The patent replaces the mechanical approach of using high-frequency oscillators (which consume significant power) with a signal processing approach. By measuring carrier phase differences and converting them to time of flight, the system achieves equivalent or superior time resolution without the power penalty of high-frequency reference clocks, effectively substituting a power-intensive mechanical solution with a more efficient computational method.
3Measurement precision
If conventional TOF measurement methods are used, then the system is simple to implement, but noise and interference significantly degrade the measurement accuracy
Solution Approach 1:
The patent introduces carrier phase measurement as an intermediary that is inherently more robust to noise and interference. Phase information can be extracted through coherent integration and correlation techniques that provide processing gain, effectively filtering out random noise. This intermediary measurement approach allows the system to achieve high location detection accuracy even in noisy environments where conventional TOF methods would fail.
Solution Approach 2:
The system employs feedback mechanisms where the measured carrier phase differences are used to continuously refine and correct the time of flight estimates. By using the phase information as feedback, the system can compensate for variations and noise, improving the robustness and accuracy of location detection against harmful environmental factors.
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
Achieves precise geolocation and event sequencing with resolutions improved by an order of magnitude, reducing noise susceptibility and power consumption, enabling accurate positioning and event logging with nanosecond precision.
Implementation Method 1
measuring a fractional part of a reference clock cycle using carrier phase analysis
Data Source
AI summary
A method for monitoring a sequence-of-events (SOE) wireless network includes placing a gateway and multiple sensors at fixed locations with known relative distances. A sampling frequency is determined based on the inverse of a required timestamp precision, and a synchronization update period is established. The sensors are synchronized with the gateway, and in response to the occurrence of an event, each sensor captures and transmits event data to the gateway. The gateway receives the event data, corrects the time information to obtain corrected event data, combines the corrected data from all sensors, and orders the combined data according to the corrected time information to generate an accurate sequence of events.