Multi-Loop GNSS Tracking Architecture for Weak Signal Sensitivity
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Solution Overview
Problem
GPS receivers face challenges in accurately calculating position, velocity, and time in degraded signal environments, such as urban areas and tunnels, due to obstructed satellite signals, leading to inaccurate navigation data and a need for improved sensitivity and robustness in signal tracking.
Innovation Solution
A multi-loop GNSS tracking architecture with hardware and/or software implementation, including a multi-level lock detection algorithm and variable bandwidth tracking loops, to enhance sensitivity and speed of signal locking, allowing for accurate navigation in challenging conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GPS receiver uses conventional single-loop tracking architecture, then device complexity is low, but measurement precision of weak signals deteriorates
Solution Approach 1:
The patent divides the tracking architecture into multiple independent loops (coarse tracking loop and fine tracking loop) that operate in parallel. Each loop is optimized for specific signal strength ranges, with the coarse loop handling strong signals and the fine loop handling weak signals. This segmentation allows the system to achieve high measurement precision across varying signal conditions without requiring a single overly complex loop structure.
Solution Approach 2:
The patent transitions from a single-dimensional tracking approach to a multi-dimensional architecture by adding multiple tracking loops with different bandwidths and sensitivity characteristics. This dimensional expansion in the tracking architecture enables the system to simultaneously process signals of varying strengths and achieve enhanced overall measurement precision without proportionally increasing complexity.
2Measurement precision
If GPS receiver uses narrow bandwidth tracking loop for enhanced sensitivity, then measurement precision improves, but speed of signal acquisition deteriorates
Solution Approach 1:
The patent segments the tracking process into two phases handled by different loops: the coarse tracking loop with wider bandwidth provides fast initial signal acquisition and locking, while the fine tracking loop with narrower bandwidth provides enhanced precision for weak signals. This temporal and functional segmentation resolves the contradiction between speed and precision by applying different bandwidth characteristics at different stages of signal tracking.
Solution Approach 2:
The system dynamically switches between or combines the outputs of the coarse and fine tracking loops based on signal conditions. This dynamic adaptation allows the receiver to optimize between speed and precision in real-time, using the coarse loop when speed is critical and the fine loop when precision is paramount, thereby resolving the static contradiction between bandwidth, speed, and sensitivity.
3Reliability
If GPS receiver uses data aiding technique, then reliability in weak signal environments improves, but adaptability to various signal environments deteriorates
Solution Approach 1:
The patent designs a multi-loop tracking architecture that serves multiple functions: the coarse loop handles strong signal environments with fast acquisition, the fine loop handles weak signal environments with enhanced sensitivity, and both loops can operate together in intermediate conditions. This universal design allows the same system to adapt to various signal environments without requiring external data aiding, thereby maintaining both reliability and adaptability across diverse operational conditions.
Data Source
AI summary
The present invention is related to location positioning systems, and more particularly, to a method and apparatus for making accuracy improvements to a GPS receiver's navigation calculations. According to a first aspect, the invention provides an extreme sensitivity GNSS tracking architecture. According to other aspects, the architecture includes multiple loops per channel, with the loops implemented with hardware and/or software. According to still further aspects, the architecture includes a multi-level lock detection algorithm designed to provide a trade-off between sensitivity and speed that is not possible with existing tracking architectures.