Satellite Network Time Synchronization via Centralized Hub
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Solution Overview
Problem
In satellite communication networks, achieving highly accurate time and frequency synchronization for multiple remote devices is challenging, as traditional methods require individual GPS receivers for each device, leading to inefficiencies and increased costs.
Innovation Solution
A hub device with a high-precision clock oscillator generates time packets that are transmitted to remote devices, which use low-precision oscillators to synchronize their real-time clocks, allowing for centralized time synchronization without the need for individual GPS receivers, using Precision Time Protocol (PTP) to adjust and maintain synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If individual GPS receivers are used for each remote device to achieve highly accurate time and frequency synchronization, then synchronization accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The patent merges the time synchronization function from individual remote devices to a centralized hub device. The hub device contains a single high-precision GPS receiver that provides time reference to all remote devices through the satellite network, eliminating the need for multiple GPS receivers while maintaining synchronization accuracy across the network
Solution Approach 2:
The patent introduces an intermediary time synchronization mechanism using NCR counters and time packets. The hub device acts as an intermediary, translating GPS time references into network-compatible time packets that are distributed to remote devices, enabling centralized time distribution without requiring each device to have direct GPS access
2Device complexity
If a centralized hub device with high-precision oscillator is used to provide time synchronization to multiple remote devices, then device complexity is reduced, but synchronization accuracy may deteriorate due to signal transmission delays
Solution Approach 1:
The patent implements feedback mechanisms where the hub device monitors transmission delays and adjusts time packet generation accordingly. Remote devices send timing feedback to the hub, enabling the system to compensate for variable signal transmission delays and maintain synchronization accuracy despite the centralized architecture
Solution Approach 2:
The patent uses preliminary timing adjustments by incorporating predicted transmission delay compensation into the time packet generation process. The hub device pre-calculates and embeds delay compensation values in time packets before transmission, allowing remote devices to achieve accurate synchronization without requiring complex real-time delay measurement
3Ease of manufacture
If remote devices use low-precision oscillators, then cost is reduced, but timekeeping stability deteriorates
Solution Approach 1:
The patent enables remote devices to self-correct their timekeeping by automatically comparing their local oscillator-driven counters with hub-provided time packet references. The devices perform self-adjustment of their NCR counters based on received time packets, compensating for low-precision oscillator drift without requiring manual calibration or higher-cost components
Solution Approach 2:
The patent replaces reliance on mechanical/physical oscillator precision with an electronic/software-based time correction system. Instead of depending on high-precision physical oscillators, the system uses digital time packet processing and counter adjustment algorithms to achieve accurate timekeeping, substituting physical precision requirements with computational correction
Data Source
AI summary
A remote device comprising a remote clock oscillator with relatively low precision, a receiver that receives time packets transmitted periodically from the hub device via the satellite, each time packet including a hub real time clock (RTC) value and a hub network clock reference (NCR) value, a remote RTC counter that represents a remote RTC value at the remote, a remote NCR counter that represents a remote NCR value at the remote, and processing circuitry that extracts the hub RTC value and the hub NCR value from a current time packet, compares contents of the current time packet with contents of a previously received time packet, and adjusts the remote RTC counter based on the result of the comparison to synchronize the remote RTC value at the remote with the hub RTC value.