GNSS Preamble Detection Accuracy via Timing Correlation
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Solution Overview
Problem
Existing reception apparatuses for GNSS signals face errors in detecting the presence or absence of preambles due to bit strings with similar patterns occurring in data other than preambles, leading to incorrect time correction and potential delays in detection processes.
Innovation Solution
A reception apparatus with a processing section that detects the presence or absence of subframe preambles by comparing the reception timing of subframe and frame preambles, utilizing correlators and numerically controlled oscillators to track satellite signals and decode messages, and includes a preamble detection section that uses correlation values to accurately identify preambles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a preamble detection process is performed by detecting a preamble multiple times at six-second intervals, then erroneous detection can be prevented, but a long delay time is caused
Solution Approach 1:
The patent uses feedback by comparing the correlation value of the detected preamble with the correlation value of the previously detected preamble. If the difference between these correlation values is within a predetermined threshold, the preamble detection is confirmed as valid. This feedback mechanism allows for reliable preamble detection without requiring multiple detections at six-second intervals, thereby reducing detection delay while maintaining accuracy.
2Ease of operation
If a bit string having the same pattern as a preamble occurs in data other than preambles, then erroneous detection of preamble presence or absence occurs, but the standard preamble detection process cannot distinguish it
Solution Approach 1:
The patent introduces an intermediary verification step using correlation values. Instead of directly detecting preambles based on bit pattern matching alone, the system calculates correlation values for detected preambles and uses these values as an intermediary to verify authenticity. By comparing correlation values with a predetermined threshold, the system can distinguish true preambles from false bit strings that happen to match the preamble pattern, thereby improving detection accuracy while maintaining operational simplicity.
Data Source
AI summary
The presence or absence of a preamble is detected with accuracy in a reception apparatus that receives a signal including a preamble.A reception section receives a subframe including a subframe preamble and a message and a frame including a frame preamble. A processing section performs a process of detecting the presence or absence of the subframe preamble according to whether or not a given relation holds between a reception timing of the subframe preamble and a reception timing of the frame preamble. A message decoding section extracts the message from the subframe and decodes the message in a case where the presence of the subframe preamble is detected.