Fixed-Position RF Time Beacon for Indoor Synchronization
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Solution Overview
Problem
Conventional GPS-based time-transfer systems face limitations in accuracy, particularly in indoor environments and with the transition to 5G standards, due to poor signal penetration, susceptibility to jamming, and increased complexity with multiple antennas and variable latency in signal propagation.
Innovation Solution
A fixed-position RF time beacon system that broadcasts time-transfer messages over a wide area, enabling precise and repeatable time-of-flight with minimal atmospheric effects, using a small number of low-cost beacons that can be synchronized and interconnected for redundancy and security, and allowing bidirectional messaging for error detection and compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If GPS-based time transfer system is used, then time synchronization can be achieved, but signal penetration is poor and accuracy deteriorates in indoor environments
Solution Approach 1:
The patent introduces fixed-position RF time beacons as intermediary devices deployed in the terrestrial environment (including indoor locations) to mediate time transfer between GPS satellites and end users. These beacons receive GPS time signals and re-broadcast them locally, providing a reliable time reference that penetrates indoor environments where direct GPS signals fail, thereby maintaining synchronization accuracy without requiring direct line-of-sight to satellites.
2Reliability
If GPS-based time transfer system is used, then time synchronization can be achieved, but the system becomes susceptible to jamming and security threats
Solution Approach 1:
The fixed-position RF time beacons act as trusted intermediary nodes that authenticate and validate time signals before distributing them to end users. This intermediary layer provides security by verifying signal integrity and preventing unauthorized manipulation, making the system resistant to jamming and spoofing attacks while maintaining accurate time synchronization through verified reference sources.
Solution Approach 2:
The patent implements bidirectional messaging between time beacons and time modules, enabling feedback mechanisms where time modules can report signal quality, error conditions, and synchronization status. This feedback allows the system to detect and respond to jamming or security threats in real-time, maintaining accuracy by switching to alternative reference sources or adjusting synchronization parameters when anomalies are detected.
3Area of stationary object
If multiple antennas and complex signal propagation paths are used for 5G, then coverage is improved, but time synchronization accuracy deteriorates due to variable latency
Solution Approach 1:
The patent performs preliminary measurement and compensation of time-of-flight delays during the installation and calibration phase. The system pre-determines the propagation delay between each fixed-position time beacon and time modules based on known geometric relationships and measured signal characteristics. This preliminary action stores compensation values that are applied during operation, allowing the system to maintain accurate synchronization even with multiple antennas and complex propagation paths, as the variable latency is pre-characterized and corrected.
4Measurement precision
If conventional GPS-based time transfer is used, then time synchronization can be achieved, but deployment and operational costs increase for high accuracy
Solution Approach 1:
The patent employs fixed-position RF time beacons that are significantly cheaper than satellite-based GPS infrastructure while providing sufficient accuracy for 5G applications. These terrestrial beacons use cost-effective RF transmission equipment and can be deployed in standard locations without requiring expensive satellite launches or maintenance. The system achieves high accuracy through the stability of fixed-position timing references and pre-measured time-of-flight compensation, eliminating the need for costly satellite infrastructure while maintaining sub-microsecond synchronization accuracy.
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 achieves timing accuracy of ~1 ns, exceeding 5G standards by two orders of magnitude, with reduced deployment and operational costs, and improved security and reliability, enabling precise synchronization across a metropolitan area.
Implementation Method 1
one or more fixed-position time beacons broadcast radio-frequency (RF) time-transfer messages
Implementation Method 2
enabling precise and repeatable time-of-flight with minimal atmospheric effects
Data Source
AI summary
In various time-transfer systems, one or more fixed-position time beacons broadcast radio-frequency (RF) time-transfer messages to time-keeping modules disposed in remote radio heads and other strategic locations to achieve highly reliable and accurate synchronized time, phase, and frequency transfer over a metropolitan or other wide-field area.