GNSS Positioning Using Global and Local Correction Streams
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Solution Overview
Problem
Current GNSS positioning systems based on carrier phase measurements face challenges in achieving quick, stable, and precise position estimation due to limitations in integer ambiguity resolution and the need for reliable correction streams.
Innovation Solution
The method involves combining global correction streams with local correction streams to supplement GNSS observations from satellites with and without available correction data, using a positioning engine that processes signals from multiple satellites to estimate parameters such as integer ambiguities, thereby enhancing position determination accuracy and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If carrier phase measurements are used for positioning, then position precision is improved (up to centimeter-level or millimeter-level), but the integer ambiguity problem arises making cycle determination ambiguous
Solution Approach 1:
The patent introduces correction streams as an intermediary element that carries precise satellite clock and orbit information from reference stations to the receiver. This intermediary data enables the resolution of integer ambiguities by providing accurate reference measurements that help determine the correct cycle counts in carrier phase measurements, thus achieving high precision positioning without being stuck in the ambiguity problem
2Measurement precision
If local correction streams are used for GNSS observations, then positioning accuracy is improved, but the system becomes vulnerable when local correction data is unavailable for some satellites
Solution Approach 1:
The patent merges multiple correction streams (local correction streams and global correction streams) into a unified correction system. The positioning engine combines data from both local reference stations and global satellite-based augmentation systems, allowing the receiver to use available correction data from either source. This merging approach ensures that positioning accuracy is maintained even when local correction data is unavailable for certain satellites, as global correction streams can compensate for those gaps
3Ease of manufacture
If code-based positioning using C/A code is used, then the system is simple and publicly accessible, but positioning accuracy is limited to approximately 15 meters
Solution Approach 1:
The patent employs a composite positioning approach that combines multiple measurement types (code measurements and carrier phase measurements) and multiple correction sources (local and global correction streams). By integrating these different elements, the system achieves high precision positioning accuracy while maintaining accessibility through the use of publicly available C/A code signals augmented with correction data from various sources
Data Source
AI summary
Method to estimate parameters derived at least from GNSS signals useful to determine a position, including obtaining at least one GNSS signal observed at a GNSS receiver from each of a plurality of GNSS satellites; receiving global correction information useful to correct at least the obtained GNSS signals from a first set of GNSS satellites, wherein the global correction information includes correction information which is independent from the position to be determined; receiving local correction information useful to correct at least the obtained GNSS signals from a second set of GNSS satellites, wherein the local correction information includes correction information which is dependent on the position to be determined; processing the obtained GNSS signals from the first set of GNSS satellites by using the global correction information; and processing the obtained GNSS signals from the second set of GNSS satellites by using the local correction information.