Timing Receiver 1PPS Correction for GNSS Jitter Holdover
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
GNSS receivers often experience jitter in 1 pulse per second signals due to climate interference and poor reception, leading to inaccurate synchronization in slave devices.
Innovation Solution
A method involving a timing receiver with a counter, comparator, queue, estimation circuit, and signal generating circuit to correct 1 pulse per second signals by accumulating count values, storing difference values, and generating a reference count value to output a corrected signal, thereby mitigating jitter and ensuring synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a GNSS receiver directly outputs the 1PPS signal from satellite decoding, then the system structure remains simple, but the signal exhibits jitter of tens to thousands of nanoseconds due to climate interference and poor reception angles
Solution Approach 1:
The patent introduces an intermediate correction system between the GNSS receiver and slave devices. This system includes a correction value calculator that computes timing differences, a queue for storing historical correction values, and a signal generator that produces corrected 1PPS signals. This intermediary structure filters out jitter while maintaining synchronization accuracy without requiring complex modifications to the GNSS receiver itself.
Solution Approach 2:
The system performs preliminary correction by calculating timing differences between the received 1PPS signal and a reference time source before outputting the signal to slave devices. Historical correction values are stored in advance in a queue, allowing the system to compensate for anticipated jitter and provide pre-corrected signals, thereby improving synchronization accuracy proactively rather than reactively.
2Reliability
If the GNSS receiver cannot receive satellite signals, then the 1PPS signal becomes seriously misaligned within 15 minutes, but adding redundancy systems increases device complexity
Solution Approach 1:
The patent implements beforehand cushioning by maintaining a queue that stores multiple historical correction values (e.g., N=1024 values). When GNSS signals are unavailable, the system can retrieve and apply previously calculated correction values to maintain accurate timing. This cushioning mechanism ensures synchronization reliability for extended periods without requiring complex redundant hardware systems.
Solution Approach 2:
The system continuously monitors the timing difference between the received 1PPS signal and the reference time source, calculates correction values, and feeds them back into the signal generation process. This feedback loop allows the system to dynamically adjust and maintain synchronization accuracy, providing high reliability without needing complex redundant architectures.
3Measurement precision
If jitter correction is implemented using complex algorithms, then synchronization accuracy improves, but the processing time and computational resources increase
Solution Approach 1:
The patent applies partial action by implementing a practical correction mechanism that uses a finite queue of historical correction values (N values) rather than attempting to analyze infinite historical data. The queue depth N is optimized to provide sufficient correction accuracy while limiting computational burden. This approach achieves adequate timing accuracy without excessive processing time or resource consumption.
Data Source
AI summary
The disclosure provides a method for correcting a 1 pulse per second (1PPS) signal and a timing receiver. In the embodiments of the disclosure, the proposed method allows the timing receiver to provide a corrected 1PPS signal with better quality to back-end slave devices, thereby ensuring that the synchronization effect of the slave devices is not overly affected by jitter in a single 1PPS signal.