Base Data Extrapolator for RTK Navigation
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Solution Overview
Problem
Existing navigation systems face challenges in accurately predicting base data over long intervals, especially under conditions of disrupted communication links, which affects the precision of rover coordinate determination in differential navigation systems.
Innovation Solution
An extrapolator that predicts only the information components necessary for error compensation, using a first-order polynomial extrapolation method and digital filtering techniques to minimize computational resources and maintain accuracy over extended prediction intervals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If base data is extrapolated over long intervals to maintain operation during disrupted communication links, then reliability is improved, but measurement precision deteriorates
Solution Approach 1:
The patent segments the base data into three distinct components: computed component (satellite motion and clock corrections), common component (base clock drift affecting all satellites), and information component (spatially varying atmospheric and multipath errors). This segmentation allows different extrapolation strategies to be applied to each component, maintaining precision while enabling long-interval prediction for reliability.
Solution Approach 2:
The patent extracts and removes the common component (base clock drift) from the base data before extrapolation, as this component can be independently determined and does not require long-interval prediction. This leaves only the information component to be extrapolated, reducing the extrapolation interval effectively and maintaining precision while supporting long overall operation periods.
2Measurement precision
If complex extrapolation methods are used to maintain accuracy over long intervals, then measurement precision is improved, but device complexity increases
Solution Approach 1:
By segmenting base data into computed, common, and information components, the patent enables simple first-order polynomial extrapolation to be applied only to the information component. The computed component uses straightforward satellite ephemeris data, and the common component is determined independently, avoiding the need for complex extrapolation algorithms while maintaining high accuracy.
3Measurement precision
If all base parameters are predicted to maintain accuracy, then measurement precision is improved, but use of energy increases
Solution Approach 1:
The patent extracts the common component (base clock drift) from the base data before extrapolation, as this component can be independently determined through averaging across multiple satellites and does not require energy-intensive extrapolation. Only the information component undergoes extrapolation, significantly reducing computational energy consumption while maintaining precision.
Solution Approach 2:
By segmenting base data into components with different prediction requirements, the patent enables energy-efficient processing: the computed component uses simple ephemeris calculations, the common component is determined by averaging, and only the information component requires extrapolation. This selective approach minimizes energy consumption while preserving accuracy.
Data Source
AI summary
Base data received at a rover receiver is extrapolated to a rover measurement time referenced to a clock in the rover receiver. The base data comprises a plurality of base parameters, such as pseudo-ranges and full phases, calculated at base epochs from data received from navigation satellites. Base data is decomposed into a computed component, a common component, and an information component. Only the information component is extrapolated, thereby increasing the extrapolation time interval (during which base data are missing) over which an acceptable accuracy in determination of rover coordinates may be provided. The extrapolated base data is calculated by adding the computed component updated to the rover measurement time, the information component extrapolated to the rover measurement time, and the common component. A second-order recursive digital filter is used to generate the extrapolation function.