Satellite Correction Integrity Monitoring for Fast Precise Positioning
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Solution Overview
Problem
Current navigation satellite systems face limitations in achieving precise and reliable position estimation due to distortion in signal transmission through the atmosphere, particularly in safety-critical applications like highly-automated driving and autonomous driving, where centimeter-level accuracy is required but convergence time is prolonged.
Innovation Solution
A method is developed to generate and broadcast correction information, including satellite orbit, clock, ionospheric, and tropospheric corrections, along with integrity information, to ensure the trustworthiness of these corrections, allowing for conditional use of carrier phase ambiguities and positioning solutions after verifying the integrity of the received data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If carrier phase measurements are used for positioning, then position precision is improved (down to centimetre-level or millimetre-level), but the convergence time is prolonged due to the integer ambiguity problem
Solution Approach 1:
The patent applies preliminary action by pre-computing and broadcasting correction information that includes resolved carrier phase ambiguities and integrity data before the user receiver needs them. The processing center performs the complex ambiguity resolution in advance and provides ready-to-use corrections, eliminating the need for user receivers to perform lengthy ambiguity resolution procedures, thus reducing convergence time while maintaining high precision
Solution Approach 2:
The patent introduces an intermediary processing center that acts as a mediator between the reference stations and user receivers. This processing center resolves the integer ambiguity problem centrally and provides corrected carrier phase measurements to user receivers, allowing them to achieve high precision positioning without performing their own ambiguity resolution, thereby significantly reducing convergence time
2Measurement precision
If correction information is broadcast for carrier phase ambiguity correction, then positioning accuracy is improved, but reliability is reduced due to potential integrity issues in the correction data
Solution Approach 1:
The patent implements feedback by computing and broadcasting integrity information that provides feedback on the quality and trustworthiness of the correction data. The processing center monitors the integrity of correction information and communicates this status to user receivers, enabling them to assess whether to trust and use the correction data, thus maintaining reliability while providing high precision corrections
Solution Approach 2:
The patent applies preliminary action by pre-computing and broadcasting integrity information alongside the correction information. This allows user receivers to evaluate the trustworthiness of correction data before using it for positioning, ensuring that only reliable corrections are applied, thereby maintaining both high accuracy and reliability
Data Source
AI summary
Some embodiments of the invention relate to generating correction information based on global or regional navigation satellite system (NSS) multiple-frequency signals observed at a network of reference stations, broadcasting the correction information, receiving the correction information at one or more monitoring stations, estimating ambiguities in the carrier phase of the NSS signals observed at the monitoring station(s) using the correction information received thereat, generating residuals, generating post-broadcast integrity information based thereon, and broadcasting the post-broadcast integrity information. Other embodiments relate to receiving and processing correction information and post-broadcast integrity information at NSS receivers or at devices which may have no NSS receiver, as well as to systems, NSS receivers, devices which may have no NSS receiver, processing centers, and computer programs. Some embodiments may for example be used for safety-critical applications such as highly-automated driving and autonomous driving.