GNSS Navigation Message Synchronization Using BCH Lookup Tables
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Solution Overview
Problem
Existing GNSS receivers struggle to synchronize error-corrected navigation messages effectively in noisy environments, necessitating a cost-effective and efficient synchronization method for robust signal detection.
Innovation Solution
Implementing a method in GNSS receivers that utilizes BCH error correction coding for synchronization, specifically through consistency testing of the PRN and SOH segments in the first sub-frame of the navigation message, using lookup tables to correct bit errors and achieve frame synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If BCH error correction coding is applied to navigation message, then reliability of signal detection in noisy environments is improved, but device complexity increases
Solution Approach 1:
The navigation message is divided into distinct segments (PRN identifier segment and SOH segment) that are processed separately through consistency testing. This segmentation allows the receiver to test each segment independently against lookup tables, reducing the overall computational complexity while maintaining reliable error correction across the entire message.
Solution Approach 2:
Lookup tables containing all possible valid segment values are pre-computed and stored before signal reception. During synchronization, the receiver simply compares received segments against these pre-prepared tables rather than performing complex real-time error correction calculations, significantly reducing processing complexity while ensuring reliable detection.
2Measurement precision
If consistency testing of PRN and SOH segments is performed, then synchronization accuracy is improved, but processing time increases
Solution Approach 1:
The consistency testing process is divided into separate tests for the PRN identifier segment and the SOH segment. By testing segments independently rather than analyzing the entire navigation message as a single unit, the processing time is reduced while maintaining high synchronization accuracy through cumulative testing of all segments.
Solution Approach 2:
Instead of performing complex mathematical transformations or simulations to achieve synchronization, the invention uses lookup tables that contain pre-computed valid segment values. The receiver simply copies and compares segment values against these tables, achieving high accuracy through direct comparison rather than iterative calculation, thus minimizing processing time.
3Reliability
If error correction coding is implemented in existing GNSS receivers, then robustness against noise is improved, but cost increases
Solution Approach 1:
The consistency testing mechanism serves multiple functions simultaneously: it performs error detection, error correction, frame synchronization, and segment validation all through a single comparative process against lookup tables. This multi-functionality reduces the need for separate dedicated hardware or software modules for each function, lowering overall implementation cost while maintaining robust noise resistance.
Solution Approach 2:
The invention uses simple lookup tables with pre-stored valid segment values instead of complex real-time error correction algorithms. These lookup tables require minimal memory resources and can be easily implemented in software or simple hardware, providing cost-effective error correction capability that can be deployed in existing receivers without expensive hardware modifications.
Data Source
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AI summary
A method and apparatus are provided for performing consistency testing for a Bose-Chaudhuri-Hocquenghem (BCH) error corrected first sub-frame of navigation message broadcast from a satellite of a GNSS. Consistency testing is performed by comparing BCH encoded portion(s)s of data symbols with elements of look up table(s) to see if such portions are similar to element(s) of the look up table(s).