NSS Receiver Accuracy Estimation via Residual Combination
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Solution Overview
Problem
Navigation satellite systems (NSS) face limitations in providing accurate positioning due to signal distortion through the atmosphere, especially with code-based approaches offering only 15-meter accuracy, while carrier phase measurements can achieve centimeter-level precision but are ambiguous, posing challenges in determining the integer ambiguity.
Innovation Solution
A method that estimates expected accuracy by combining precise and less-precise observation residuals from NSS signals, eliminating the need for a priori noise models, and using a processing entity to compute state variables and residuals, allowing for reliable accuracy estimation without relying on noise models.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If code-based positioning is used, then the positioning system is simple to operate, but the positioning accuracy is limited to approximately 15 meters
Solution Approach 1:
The patent combines code-based positioning and carrier phase-based positioning into a unified system. The code-based component provides simple operation and initial position estimates, while the carrier phase-based component delivers high-precision measurements. The integration allows the system to achieve centimeter-level accuracy while maintaining ease of operation through automated ambiguity resolution algorithms.
2Measurement precision
If carrier phase measurements are used, then the positioning precision can reach centimeter-level, but the integer ambiguity problem makes the system more complex
Solution Approach 1:
The patent implements self-service through automated integer ambiguity resolution algorithms that automatically resolve the phase ambiguity without requiring manual intervention. The system uses statistical methods and mathematical models to autonomously determine the correct integer values, making the complex carrier phase processing transparent to the user while maintaining centimeter-level precision.
Solution Approach 2:
The patent transforms the ambiguous carrier phase measurements into unambiguous position information by changing the mathematical parameters through integer ambiguity resolution. The system processes the fractional phase measurements and applies parameter transformations to resolve the integer cycles, converting the complex ambiguous data into precise position coordinates.
3Device complexity
If a priori noise models are used for accuracy estimation, then the estimation process is simplified, but the accuracy estimate may be unreliable due to model biases
Solution Approach 1:
The patent implements feedback-based accuracy estimation that uses actual measurement residuals and observed data quality to dynamically adjust accuracy estimates. Instead of relying on fixed a priori noise models, the system continuously monitors the quality of carrier phase and code measurements and updates the accuracy estimation based on real-time feedback from the measurement residuals, thereby improving reliability while accounting for actual system performance.
Data Source
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AI summary
Some embodiments of the invention relate to methods carried out by an NSS receiver and/or a processing entity capable of receiving data therefrom, for estimating parameters derived from NSS signals useful to determine a position, and for estimating an expected accuracy. The method comprises receiving (s10) input data comprising NSS signals observed by the NSS receiver and/or information derived from said NSS signals; operating (s20) an estimation process, hereinafter referred to as "estimator", using state variables and computing the values of its state variables based on the received input data; obtaining (s30) a combination of residuals from the estimator, each residual being associated with at least one observed NSS signal; and estimating (s40) an expected accuracy based on the combination of residuals and/or information derived therefrom. Systems and computer programs are also disclosed. Some embodiments may for example be used for safety-critical applications such as highly automated and autonomous driving.