GNSS Secondary Code Phase Determination via Dot Product Integration
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Solution Overview
Problem
Current GNSS receivers face challenges in accurately determining the secondary code phase, especially when navigation data is present, which complicates bit synchronization and reduces the integration interval, leading to less accurate signal tracking and navigation.
Innovation Solution
A receiver device with a circuit that tracks the RF satellite signal, generates encoded sequences of in-phase and quadrature-phase components, compares them with expected secondary code transitions, and coherently integrates the secondary code phase to extend the integration interval, allowing for concurrent detection of secondary code phase and navigation data symbol transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the secondary code phase is determined in the presence of navigation data, then bit synchronization can be achieved, but the integration interval is reduced and measurement accuracy deteriorates
Solution Approach 1:
The patent segments the signal processing into two distinct phases: first determining the secondary code phase using a reduced integration interval, then using that phase information to enable a longer integration interval for subsequent measurements. This segmentation resolves the contradiction by separating the functions of phase acquisition and precision measurement.
Solution Approach 2:
The patent performs preliminary determination of the secondary code phase as a prerequisite step before conducting high-precision measurements with extended integration intervals. This preliminary action enables the system to overcome the navigation data interference first, then achieve accurate measurements with optimal integration times.
2Measurement precision
If the integration interval is extended to improve signal tracking accuracy, then measurement precision improves, but the ability to synchronize with navigation data symbols deteriorates
Solution Approach 1:
The patent divides the time resources into two segments: a first time period dedicated to determining secondary code phase and navigation data symbol timing, and a second time period for extended integration interval measurements. This temporal segmentation allows the system to achieve both synchronization and high-precision tracking without conflict.
Solution Approach 2:
The patent performs preliminary synchronization operations (secondary code phase determination and navigation data symbol timing) before conducting extended integration measurements. This preliminary timing alignment enables subsequent long-interval integrations to maintain synchronization while achieving high measurement precision.
3Adaptability or versatility
If the receiver processes both in-phase and quadrature-phase signals concurrently, then navigation data decoding capability improves, but device complexity increases
Solution Approach 1:
The patent merges the processing of in-phase and quadrature-phase signals into a unified framework where both signals are processed concurrently to determine secondary code phase and navigation data symbols. This combining approach enables the receiver to decode navigation data from either signal while maintaining reduced integration intervals, achieving versatility without proportionally increasing complexity.
Data Source
AI summary
A receiver device to receive an incoming radio frequency (RF) satellite signal from a satellite vehicle includes a processor and computer-readable storage media. The computer-readable storage media is communicably connected to the processor and has instructions stored thereon that, when executed by the processor, causes the processor to track the incoming RF satellite signal in code phase and carrier frequency, the incoming RF satellite signal having a primary pseudorandom (PRN) code and a secondary PRN code modulated thereon, generate an encoded sequence of dot product values of adjacent integrated in-phase (I) and quadrature-phase (Q) components of the incoming RF satellite signal, compare the encoded sequence with expected secondary code chip transitions, determine a secondary code phase for the secondary PRN code based on the comparison, and coherently integrate the secondary code phase with the incoming RF satellite signal to increase an integration interval.