GNSS Receiver Switching Tracking Loops Based on Adjustable Threshold
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Solution Overview
Problem
Conventional GNSS receivers use static switching thresholds to switch between AFC and PLL tracking loops, which can result in decoding errors and phase or frequency tracking errors due to dynamic stress and varying signal strengths, limiting decoding performance and positioning accuracy.
Innovation Solution
A GNSS receiver that adjusts its switching threshold based on dynamic stress and signal strength, allowing for dynamic selection between AFC and PLL tracking loops to enhance decoding and tracking performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a static switching threshold is used to switch between AFC and PLL tracking loops, then the device complexity is reduced, but the decoding performance and positioning accuracy deteriorate under dynamic stress and varying signal strengths
Solution Approach 1:
The patent implements a dynamic switching threshold that automatically adjusts based on signal strength measurements. Instead of using a fixed hardcoded threshold, the system continuously adapts the switching threshold to match current signal conditions, allowing optimal selection between AFC and PLL tracking loops under varying dynamic stress and signal strength conditions
Solution Approach 2:
The patent changes the switching threshold parameter from a static value to a dynamic value that varies with signal strength. The system measures signal strength and uses this information to adjust the switching threshold parameter, enabling the tracking loop selection to adapt to changing operational conditions while maintaining decoding performance
2Ease of operation
If a static switching threshold is used to switch between AFC and PLL tracking loops, then the ease of operation is improved, but the positioning accuracy deteriorates under dynamic stress
Solution Approach 1:
The patent enables the switching threshold mechanism to self-adjust based on measured signal strength conditions. The system automatically monitors signal strength and modifies the switching threshold without requiring external configuration or user intervention, thereby maintaining ease of operation while improving positioning accuracy under dynamic stress
3Speed
If AFC tracking loop is used under high dynamic stress, then the frequency tracking performance is improved, but the decoding performance deteriorates due to inappropriate loop selection
Solution Approach 1:
The patent implements a feedback mechanism where the system measures signal strength and uses this information to determine the appropriate tracking loop. The feedback loop continuously monitors conditions and adjusts tracking loop selection accordingly, ensuring that AFC is used when appropriate for frequency tracking while preventing decoding errors through proper loop selection
Data Source
AI summary
A Global Navigation Satellite System (GNSS) and method for switching between Phase Locked Loop (PLL) and Automatic Frequency Control (AFC) tracking loops inside the GNSS receiver is provided. The GNSS receiver acquires a signal from a satellite of a GNSS satellite constellation and receives information associated with external conditions that impact a decoding performance, or a phase or frequency tracking performance, of the GNSS receiver. The GNSS receiver updates a value of a switching threshold based on the received information and compares a strength of the signal with the updated value. The GNSS receiver selects a tracking loop as one of AFC or PLL, based on the comparison. Thereafter, the GNSS receiver generates, by the selected tracking loop, measurements associated with parameters of a carrier component of the signal and decodes satellite data of the signal based on the measurements.