Coherent Multi-Channel Correlation Combining for GNSS Acquisition
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Solution Overview
Problem
GNSS receivers face significant computational challenges during satellite acquisition due to the need to identify satellites under unknown synchronization conditions, requiring numerous computations to find correlation peaks across multiple channels.
Innovation Solution
A multi-hypothesis combination circuit and method that coherently combines correlation outputs from multiple channels using sign sequences to generate a combination output, improving sensitivity and reducing computational load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the GNSS receiver performs traditional acquisition by searching for correlation peaks across multiple channels independently, then it can identify satellites under unknown synchronization conditions, but the computational load becomes excessively high
Solution Approach 1:
The patent combines correlation outputs from multiple channels (data channel and pilot channel) into a single coherent combination output. By merging the correlation results and applying sign sequences based on hypothesized synchronization states, the system achieves satellite acquisition with significantly reduced computational complexity compared to independent channel searching.
Solution Approach 2:
The patent changes the approach from searching for peak correlation values across multiple independent channels to computing coherent combinations of correlation outputs with different sign sequences. This parameter change in the acquisition methodology transforms the problem from a multi-peaked search to a more efficient combination computation that leverages the known relationship between channels.
2Adaptability or versatility
If the GNSS receiver processes multiple channels separately to maintain flexibility in handling different synchronization states, then it can adapt to unknown PRN code phases, but the device complexity and processing time increase
Solution Approach 1:
The patent performs preliminary action by pre-defining sign sequences that correspond to different hypothesized synchronization states before the acquisition process. These sign sequences encode the expected relationships between channels under various synchronization conditions, allowing the receiver to test multiple hypotheses simultaneously through coherent combination rather than sequentially searching each channel.
Solution Approach 2:
The coherent combination circuit performs multiple functions simultaneously: it processes correlation outputs from multiple channels, applies different sign sequences representing various synchronization hypotheses, and generates combination outputs that can identify satellites across different PRN code phases. This multi-functional approach maintains adaptability while reducing overall processing time.
Data Source
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AI summary
A multi-hypothesis combination circuit (100) includes a coherent combination circuit (102) and a selection circuit (104) . The coherent combination circuit (102) generates a plurality of coherent combination outputs by performing coherent combination according to a plurality of correlation outputs and a plurality of sign sequences, wherein the plurality of correlation outputs correspond to a plurality of channels, respectively, and each of the plurality of coherent combination outputs is derived from the plurality of correlation outputs and one of the plurality of sign sequences. The selection circuit (104) generates and outputs a combination output of the multi-hypothesis combination circuit (100) according to the plurality of coherent combination outputs.