GNSS Signal Acquisition via Partial Correlation Blocks
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Solution Overview
Problem
Global Navigation Satellite Systems (GNSS) receivers face challenges in acquiring signals in indoor environments due to signal degradation, requiring extended integration times and increased computational complexity, especially in portable devices with limited processing power.
Innovation Solution
A method that partitions the received and locally-generated signals into blocks with varying durations to perform correlations, adjusting for hypothesized phase delays and Doppler shifts, allowing for reliable signal acquisition over long intervals while maintaining low computational complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If integration time is extended to compensate for signal degradation in indoor environments, then signal acquisition reliability is improved, but computational complexity increases
Solution Approach 1:
The patent divides the long integration period into multiple shorter intervals, calculating correlation integrals for each interval separately. This segmentation allows the system to maintain reliable signal acquisition over extended periods while keeping the computational burden of each individual calculation manageable, especially for portable devices with limited processing power.
2Reliability
If integration time is extended beyond one data bit duration, then signal degradation compensation is improved, but measurement precision deteriorates due to unknown phase inversions
Solution Approach 1:
The patent performs preliminary calculations of correlation integrals for each interval assuming no phase inversion, then applies corrective signs based on the navigation message data bits. This preliminary action allows the system to extend integration time while maintaining measurement precision by correcting for phase inversions caused by data bit transitions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables reliable signal acquisition in indoor environments with reduced computational burden, even in portable devices, by simplifying the correlation calculations and accurately determining signal timing and frequency alignment.
Implementation Method 1
determining a correlation between the received signal and the locally-generated signal. The correlation is typically performed by calculating both the 'In phase' (I) and the 'Quadrature' (Q) correlation integrals
Implementation Method 2
The data making up the navigation message form a 50 Hz digital signal, used to modulate the phase (phase modulation) of the radio carrier
Implementation Method 3
correcting the results of the correlation integrals for the effect of the data bits of the navigation message and for the Doppler shift
Data Source
AI summary
A method of acquisition of a received signal received from a global navigation satellite system, includes: obtaining a snapshot of the received signal; correlating the snapshot with a locally-generated signal, wherein the correlating includes: trying a phase delay value indicative of a hypothesized phase delay of the locally-generated signal with respect to the snapshot; and obtaining a partition of the snapshot and the locally-generated signal into corresponding pluralities of blocks, and calculating partial correlation integrals for each block of the plurality of blocks. The corresponding pluralities of blocks each include a first block having a time duration related to the phase delay value.