Bit Transition Enhanced Direct Position Estimation
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Solution Overview
Problem
The joint processing of primary and secondary codes in traditional two-step GNSS position estimation is complex and resource-intensive, especially in challenging conditions like multipath propagation and weak signal scenarios, due to the need for additional processing resources for correct alignment of secondary PRN codes.
Innovation Solution
A method and system for bit transition enhanced direct positioning estimation (DPE) that synchronizes both primary and secondary codes, identifies bit transitions, and modifies the coarse position alignment using an augmented cross-ambiguity function, enabling single-step position estimation considering both primary and secondary code alignments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If joint processing of primary and secondary codes is implemented in traditional two-step position estimation, then positioning accuracy is improved, but device complexity and processing resource requirements increase
Solution Approach 1:
The patent merges the code tracking loop and carrier tracking loop into a single joint processing framework that simultaneously processes both primary and secondary codes. This unified approach integrates previously separate processing steps, allowing the system to achieve improved positioning accuracy through combined code-carrier processing while managing complexity through systematic integration rather than separate handling of each code component.
2Measurement precision
If secondary PRN code alignment is performed to improve positioning accuracy, then measurement precision is improved, but processing resources and time are consumed
Solution Approach 1:
The patent performs preliminary alignment of the secondary PRN code with the primary code during the acquisition phase by identifying bit transitions and establishing code phase relationships before final position estimation. This preliminary action ensures that the secondary code is properly synchronized with the primary code in advance, enabling accurate joint processing without requiring extensive additional processing time during the main acquisition and tracking phases.
3Reliability
If secondary code is integrated into single-step DPE, then positioning robustness in weak signal conditions is improved, but device complexity increases
Solution Approach 1:
The patent implements a universal joint processing framework that simultaneously handles both primary and secondary codes within a single direct position estimation (DPE) algorithm. This multi-functional processing structure enables the system to exploit information from both code components for enhanced positioning robustness in challenging conditions such as weak signals and multipath propagation, while maintaining a unified processing architecture that manages complexity through integrated rather than separate handling of multiple code types.
Data Source
AI summary
Embodiments of the present invention provide a method, system and computer program product for bit transition enhanced direct position estimation (DPE) from global navigation satellite system (GNSS) signals and includes the reception in a GNSS receiver of signals from multiple, different satellites in multiple satellite constellations adapted for use with the GNSS. The method estimates the GNSS receiver parameters position, velocity, clock bias, clock drift, and optionally and if unknown, the receiver time. The method generates a model of the received GNSS signals that depends on the receiver parameters. Uniquely, the method includes the synchronization of both a primary code and also a secondary code in the received GNSS signal model, in addition to time delays, Doppler shifts, and other relevant parameters for positioning. Finally, if the secondary code of a particular signal is unknown, the method determines the combination of bit transitions that maximizes the optimization problem.