Segmented Code-Phase Correlator for GPS Signal Acquisition
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Solution Overview
Problem
The process of acquiring GPS satellite signals is time-consuming and energy-intensive due to the need to search for proper carrier frequency, phase, and code offset, especially with significant Doppler shifts, which burdens the de-spreading and acquisition process.
Innovation Solution
A segmented code-phase correlator architecture is developed, allowing for parallel processing and reducing the post-correlation memory size by decoupling code-phase search length from integration length, enabling faster and more efficient correlation through forward and backward shifting of code register segments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a full search over all code offsets (1023 or 2046 steps) is performed to acquire GPS satellite signals, then the signal acquisition is complete and accurate, but the time and energy required for acquisition increases significantly
Solution Approach 1:
The patent segments the code-phase search space into multiple smaller regions, allowing the correlator to search through code offsets in discrete segments rather than performing a complete sequential search. This segmentation enables parallel processing of different code-phase regions, reducing the time required to cover the entire search space while maintaining complete coverage for accurate signal acquisition.
2Reliability
If a full search over all code offsets (1023 or 2046 steps) is performed to acquire GPS satellite signals, then the signal acquisition is complete and accurate, but the energy consumed during the de-spreading and acquisition process increases significantly
Solution Approach 1:
The patent segments the code-phase search space into multiple smaller regions, allowing the correlator to search through code offsets in discrete segments rather than performing a complete sequential search. This segmentation enables parallel processing of different code-phase regions, reducing the time required to cover the entire search space while maintaining complete coverage for accurate signal acquisition.
3Productivity
If a parallel correlator architecture is used to reduce acquisition time, then the processing speed increases, but the post-correlation memory size increases significantly
Solution Approach 1:
The patent segments the code-phase search space into multiple smaller regions, where each segment can be processed independently with its own reduced memory requirements. This segmentation allows parallel processing to proceed with proportionally smaller memory buffers for each parallel channel, avoiding the exponential memory growth that would occur with a single full-parallel correlator.
Solution Approach 2:
The patent introduces a new dimension to the processing architecture by organizing parallel correlators to process different code-phase segments simultaneously. This dimensional organization allows the system to achieve high processing throughput while distributing memory requirements across multiple independent processing channels, effectively reducing the memory burden on any single channel.
Data Source
AI summary
A method and an apparatus is disclosed for efficient cross correlation of a plurality of signal vectors. Incoming data is partitioned into several segments and processed according to an algorithm where data rotation is a function of post-correlation memory size.