GNSS Receiver Acquisition Track Correlation Hypothesis Combination
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Solution Overview
Problem
Modern GNSS receivers face challenges in achieving high sensitivity and speed of measurements due to the large number of signal hypotheses that need to be tested during the acquisition and tracking phases, which can be impaired by noise and interference.
Innovation Solution
The system combines acquisition and track correlation hypotheses to improve the effective signal-to-noise ratio (SNR) by selecting a subset of peaks from the acquisition phase and integrating them with track non-coherent summations (NCS) to enhance signal metrics such as lock detection, multipath mitigation, and range measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the receiver tests a large number of signal hypotheses during acquisition and tracking, then the coverage of signal search space is improved, but the processing time and computational complexity increase significantly
Solution Approach 1:
The patent segments the large number of signal hypotheses into multiple groups or subsets. Instead of testing all hypotheses simultaneously or sequentially in a single pass, the receiver divides the search space and processes different groups in an iterative manner, allowing parallel processing and reducing the time required for each individual hypothesis test while maintaining comprehensive coverage.
Solution Approach 2:
The patent performs preliminary coarse acquisition testing to identify candidate hypotheses before committing to full tracking. By pre-screening hypotheses using simplified metrics or shorter integration times, the system eliminates unlikely candidates early in the process, reducing the number of hypotheses that require extensive processing time during the tracking phase.
2Measurement precision
If the receiver integrates signals over longer periods to improve sensitivity, then the signal-to-noise ratio increases, but the measurement speed decreases
Solution Approach 1:
The patent segments the total integration period into multiple shorter coherent integration intervals. By dividing a long integration time (e.g., 10 seconds) into several shorter segments (e.g., five 2-second intervals), the system achieves the same sensitivity improvement while enabling periodic measurements and updates, thus maintaining measurement speed and allowing for time-critical applications.
Solution Approach 2:
The patent implements periodic measurement opportunities within the integration process. Instead of requiring a single continuous long integration, the system performs measurements at regular intervals during the integration period, allowing the receiver to provide updated position or signal information periodically while still accumulating the full integration time for maximum sensitivity.
3Measurement precision
If the receiver tests multiple code phase and carrier frequency hypotheses, then the accuracy of signal parameter estimation is improved, but the number of hypotheses to be tracked increases
Solution Approach 1:
The patent performs preliminary coarse acquisition to identify the most likely code phase and carrier frequency hypotheses before initiating full tracking. By using initial rough estimates and filtering out obviously incorrect hypotheses early in the process, the system reduces the number of hypotheses that need to be maintained during tracking, thereby reducing computational complexity while preserving estimation accuracy for the remaining candidate hypotheses.
Data Source
AI summary
An apparatus, a method, a method of manufacturing an apparatus, and a method of constructing an integrated circuit are provided. The apparatus includes a memory; and a processor configured to acquire K values with N peaks, where K and N are integers; select J of the N peaks and include the J peaks in track, where J is an integer less than or equal to N; determine a metric using acquisition non-coherent summations (NCSs) and track NCSs of coherent correlations; determine to not abandon the measurement based on the metric; and form a measurement responsive to determining to not abandon.