GNSS Receiver Sub-Carrier Tracking Ambiguity Resolution
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Solution Overview
Problem
Current GNSS receivers face challenges in delivering high-precision position and time measurements, especially in noisy and multipath environments, due to the ambiguity of BOC signal autocorrelation peaks, which can lead to ranging errors and require multiple tracking loops, increasing complexity and power consumption.
Innovation Solution
A GNSS receiver architecture that includes multiple signal processing channels for non-ambiguous and ambiguous pseudo range calculations, allowing for dynamic switching between techniques based on signal quality and multipath reflections, to improve robustness and reduce complexity by calculating unbiased position and time measurements from a combination of both types of pseudo ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple tracking loops are used to resolve BOC signal autocorrelation ambiguities, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent divides the tracking system into two independent types of tracking loops: ambiguous tracking loops that process full BOC signals for high precision, and non-ambiguous tracking loops that process code-only signals for reliability. This segmentation allows each loop type to specialize in its strength while the combination resolves the overall contradiction.
Solution Approach 2:
The patent merges results from both ambiguous and non-ambiguous tracking loops through a unified PVT calculation that resolves pseudo-range ambiguities. By combining the high-precision ambiguous measurements with the reliable non-ambiguous measurements, the system achieves both precision and reduced complexity.
2Reliability
If multiple tracking loops are used to resolve BOC signal autocorrelation ambiguities, then reliability is improved, but use of energy increases
Solution Approach 1:
The patent segments the tracking function across different loop types, allowing non-ambiguous loops to provide reliable fallback measurements that improve overall system reliability. This segmentation enables the system to maintain reliability without requiring every loop to be fully redundant, thus reducing energy consumption.
Solution Approach 2:
The patent changes the processing parameters of different tracking loops - ambiguous loops use full BOC signal processing for precision, while non-ambiguous loops use simplified code-only processing for reliability and energy efficiency. This parameter differentiation allows the system to achieve reliability without proportionally increasing energy use.
3Measurement precision
If ambiguous pseudo range measurements are used, then measurement precision is improved, but reliability deteriorates due to side peak locking
Solution Approach 1:
The patent introduces non-ambiguous tracking loops as an intermediary layer that provides reliable reference measurements. These non-ambiguous loops act as a mediator that validates and constrains the ambiguous measurements, preventing side peak locking while preserving the precision benefits of ambiguous tracking.
Solution Approach 2:
The patent implements feedback mechanisms where non-ambiguous pseudo-range measurements are used to validate and correct ambiguous measurements. The PVT calculation uses both measurement types with feedback loops that detect and correct side peak locking events, maintaining both precision and reliability.
Data Source
AI summary
A GNSS receiver and the associated method, for calculating an unbiased position and time measurement from a plurality of satellite positioning signals, the receiver comprising:a plurality of circuits configured to receive positioning signals from a plurality of satellites in GNSS constellations,a plurality of first and second signal processing channels configured for processing a first selection of said positioning signals and determining associated first pseudo ranges,a computer logic,wherein:the computer logic is configured to calculate the unbiased position and time measurement from pseudo ranges being determined from positioning signals originating from distinct satellites.A GNSS receiver further comprising a second computer logic configured to calculate a second unbiased position and time from the first position and time, and the second signal processing signals.