Self-Disciplined Oscillator Holdover for GPS Outage Synchronization
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Solution Overview
Problem
Existing synchronization technologies in packet-based networks and IoT devices face challenges in maintaining precise time and frequency synchronization, especially in the absence of GPS signals, leading to network instability, increased operational expenses, and compliance issues.
Innovation Solution
A low-cost self-disciplined oscillator with an adaptive drift correction algorithm and self-disciplined circuit using all-silicon delay lines, which maintains synchronization by adjusting the oscillator's frequency and phase through environmental data and sensor inputs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional synchronization elements (PRC and distribution clocks) are used in packet-based networks, then time and frequency synchronization can be maintained under normal conditions, but the system becomes vulnerable to GPS outages, jamming, and spoofing threats
Solution Approach 1:
The patent changes the operational parameters of the oscillator by introducing a self-disciplining mechanism that adjusts the oscillator's frequency and phase based on environmental sensor data. This allows the system to maintain synchronization reliability without depending on external GPS signals, effectively changing how the synchronization parameter is maintained from external reference to self-regulated based on environmental compensation
Solution Approach 2:
The oscillator system performs self-discipline by using its own environmental sensors to detect and compensate for temperature and other environmental variations. This self-service capability allows the system to maintain accurate synchronization without external GPS assistance, making it immune to jamming and spoofing threats while maintaining reliability
2Duration of action of moving object
If holdover mode is implemented to maintain synchronization during GPS outages, then service continuity is ensured, but the maximum allowed excursions of output clock may be exceeded under severe disruptions
Solution Approach 1:
The system performs preliminary action by pre-characterizing the oscillator's environmental sensitivity through self-disciplining during normal operation. Environmental sensors continuously monitor temperature and other conditions, and the system pre-compensates for expected drift based on historical data and environmental trends, so that when GPS outage occurs, the oscillator is already prepared to maintain accuracy longer than traditional holdover modes
Solution Approach 2:
The self-disciplining mechanism implements continuous feedback by monitoring the oscillator's actual performance against environmental conditions and adjusting control parameters in real-time. This feedback loop allows the system to maintain clock accuracy during holdover by continuously compensating for environmental drift, exceeding the performance of traditional fixed-parameter holdover modes
3Device complexity
If simple oscillators are used in IoT devices to reduce cost and power consumption, then device complexity and energy use are reduced, but time synchronization precision deteriorates
Solution Approach 1:
The patent substitutes environmental sensing and software-based compensation mechanisms for complex hardware synchronization systems. Instead of using expensive, high-precision crystal oscillators or atomic clocks, the system uses simple oscillators combined with environmental sensors and digital compensation algorithms, achieving high precision through intelligence rather than hardware complexity
Solution Approach 2:
The system changes the control parameters of the simple oscillator by continuously adjusting its frequency and phase based on environmental sensor feedback. This parameter adaptation allows a low-cost, simple oscillator to achieve the time synchronization precision previously only attainable with complex, expensive hardware systems
Data Source
AI summary
A novel, simple, and low-cost oscillator solution that meets new industry standards and addresses the growing issue of GNSS vulnerability is described. The solution identifies the technologies and products that can provide protection against GNSS anomalies and outages. The solution is based on a simple low-cost oscillator with holdover capability using a self-disciplined circuit that supports future IoT devices and network.