ART-K Position Estimation with Bridge Parameters
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Solution Overview
Problem
Current GNSS positioning systems using carrier phase measurements face challenges in achieving rapid and stable position estimation due to long convergence times and sensitivity to signal outages, limiting their usability in real-time applications.
Innovation Solution
The implementation of a delta-phase approach in the Absolute Real-Time Kinematic (ART-K) processing technique, which ties successive position updates together using carrier phase differences, and the use of bridge parameters to reset float solutions during ambiguity jumps, reducing noise levels and enabling faster convergence and recovery from outages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If carrier phase measurements are used for GNSS positioning, then measurement precision is improved, but convergence time increases
Solution Approach 1:
The patent applies preliminary action by using code-based position estimates during the initialization phase before carrier phase measurements converge. The system performs preliminary positioning using pseudoranges and code measurements, then transitions to carrier phase-based precise positioning once convergence criteria are met, thereby reducing the effective convergence time while maintaining high precision.
Solution Approach 2:
The patent implements dynamics by dynamically switching between different positioning modes (code-based and carrier phase-based) based on convergence status. The system adapts its behavior according to the convergence state, transitioning from rough initial estimates to high-precision measurements as the system converges, optimizing both speed and accuracy throughout the positioning process.
2Measurement precision
If float solutions are continuously updated in ART-K processing, then position estimation accuracy is improved, but sensitivity to signal outages increases
Solution Approach 1:
The patent applies beforehand cushioning by implementing bridge parameters that prepare the system for potential signal outages. When outages occur, the bridge parameters enable rapid recovery by providing pre-computed correction information, cushioning against the full impact of the outage and reducing the need to discard accumulated float solutions.
Solution Approach 2:
The patent uses bridge parameters as an intermediary mechanism between continuous float solution updates and signal outages. These bridge parameters act as a buffer or mediator that allows the system to maintain stability during outages by providing transition information, reducing direct sensitivity to signal interruptions.
3Productivity
If bridge parameters are used to reset float solutions during ambiguity jumps, then recovery speed is improved, but device complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-computing bridge parameters during normal operation so they are ready for use when ambiguities jump occur. This advance preparation enables rapid recovery without requiring complex real-time calculations during the critical recovery moment, improving speed while managing complexity through offline computation.
Data Source
AI summary
A method of determining the position of a GNSS receiver antenna includes steps of acquiring input data which includes observations at the GNSS receiver antenna of signals of at least clock and position information of GNSS satellites, for each of a plurality of epochs. Float parameters of a state vector from the input data of each epoch are then estimated. The float parameters include receiver antenna position, receiver clock, and at least one ambiguity per satellite. A jump in the at least one ambiguity of at least one satellite from one epoch to another epoch is detected. Then bridge parameters from the input data of at least one epoch and from the estimated float parameters are estimated. The bridge parameters include values sufficient to update the float parameters to compensate for the jump, and the bridge parameters are then used to update the float parameters.