GNSS PLL Frequency Switching for 5G Coupling Noise
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Solution Overview
Problem
The integration of 5G communication capabilities with GNSS positioning in electronic devices leads to clock drift issues due to coupling noise between 5G antennas and GNSS-related components, resulting in unstable output frequencies for phase locked loops (PLLs) and subsequent errors in GNSS positioning.
Innovation Solution
A method and electronic device configuration that monitor for GNSS positioning errors, determine the stability of the output frequency of a first PLL used for demodulating GNSS signals, and switch to a more stable output frequency of a second PLL or a basic frequency input to both PLLs when instability is detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If GNSS-related components and 5G communication components are placed adjacently to enable both functions in one device, then device integration and functionality are improved, but coupling noise is generated causing clock drift and frequency instability in the PLL output
Solution Approach 1:
The patent divides the frequency generation system into multiple independent PLLs (first PLL for GNSS, second PLL for 5G), each isolated from the other. This segmentation prevents coupling noise from the 5G component from affecting the GNSS component, resolving the contradiction between integration and frequency stability.
Solution Approach 2:
The patent introduces a frequency switching mechanism as an intermediary between the two PLLs. When clock drift is detected in the first PLL, the system switches to the second PLL's output frequency, mediating the impact of coupling noise and maintaining GNSS positioning accuracy despite the adjacent placement of 5G components.
2Device complexity
If a single PLL is used for both GNSS and 5G communication, then device complexity is reduced, but clock drift occurs due to coupling noise between 5G antenna and GNSS components
Solution Approach 1:
The patent segments the frequency generation into separate PLLs for GNSS and 5G functions. Although this increases component count, it prevents coupling noise from degrading positioning accuracy, thus resolving the contradiction between complexity reduction and measurement precision.
Solution Approach 2:
The patent dynamically changes the frequency parameter by switching between different PLL outputs based on detected clock drift conditions. This parameter change allows the system to maintain positioning accuracy even when multiple PLLs are used, addressing the contradiction between complexity and precision.
3Measurement precision
If frequency switching between multiple PLLs is implemented to address clock drift, then positioning accuracy is improved, but system complexity and switching overhead increase
Solution Approach 1:
The patent implements a feedback mechanism where the processor continuously monitors clock drift in the first PLL and automatically switches to the second PLL when instability is detected. This feedback-based approach maintains positioning accuracy while using a relatively simple switching mechanism, resolving the contradiction between precision improvement and complexity increase.
Data Source
AI summary
Disclosed is a method for global navigation satellite system (GNSS) positioning and an electronic device performing the method. According to an example embodiment, the method includes monitoring whether an error of the GNSS positioning occurs, determining, when the error of the GNSS positioning is detected, whether a first output frequency of a first phase locked loop (PLL) used for demodulating a GNSS signal received from a satellite for the GNSS positioning is stable, and changing, when the first output frequency of the first PLL is unstable, a frequency used for demodulating the GNSS signal to a second output frequency of a second PLL or a basic frequency input to the first PLL and the second PLL.