GBAS Lever Arm Survey Bootstrapping for Rapid Startup
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Solution Overview
Problem
Current survey technologies for Ground-Based Augmentation Systems (GBAS) face challenges in achieving high integrity and fast system startup for precision approach and automatic landing operations, as existing methods require extensive data collection and analysis, often taking days to ensure accuracy and reliability, which is inadequate for time-critical aviation operations.
Innovation Solution
The method involves 'bootstrapping' pseudo-range and carrier-phase stages to quickly produce highly accurate, high-integrity receiver-to-receiver lever arm surveys through differential GNSS processing, integrating the survey with the warm-up of integrity monitors to reduce startup time, using lever arm estimates from previous stages to resolve carrier phase ambiguities and improve accuracy in subsequent stages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional survey methods are used to achieve high integrity and accuracy, then measurement precision is improved, but loss of time increases significantly
Solution Approach 1:
The patent applies preliminary action by performing a rapid initial survey to establish approximate lever arm values before GBAS operations begin. This preliminary survey data is then refined during initial GBAS operations, allowing the system to achieve high accuracy without requiring days of pre-survey validation. The preliminary action enables the system to bypass traditional lengthy survey validation while maintaining measurement precision.
Solution Approach 2:
The survey process is segmented into multiple stages: an initial rapid survey stage that provides approximate lever arm values, followed by a refinement stage where the data is improved during initial GBAS operations. This segmentation allows the system to separate the time-critical survey function from the accuracy-refinement function, reducing overall startup time while maintaining high measurement precision through progressive refinement.
2Reliability
If extensive data collection and analysis are performed to ensure high integrity, then reliability is improved, but productivity decreases
Solution Approach 1:
The system performs preliminary integrity monitoring and validation during the initial survey and early GBAS operations. By conducting integrity checks progressively rather than requiring complete validation before any operations, the system achieves high reliability without sacrificing productivity. The preliminary integrity data is continuously refined as more operational data becomes available.
Solution Approach 2:
The survey and integrity validation process continues continuously during initial GBAS operations rather than being completed separately beforehand. This continuous refinement approach allows the system to maintain high integrity standards while keeping the GBAS operational, thereby improving productivity without compromising reliability. The useful action of survey validation occurs concurrently with system operation.
3Measurement precision
If manual survey and validation processes are used, then measurement precision can be achieved, but device complexity increases
Solution Approach 1:
The GBAS system performs self-validation of its survey data during initial operations using its own integrity monitoring capabilities. Rather than requiring external manual validation processes, the system uses its built-in integrity monitors to automatically validate and refine lever arm measurements. This self-service approach maintains measurement precision while reducing the complexity of external survey validation processes.
Solution Approach 2:
The system implements feedback loops where initial survey data is continuously refined based on integrity monitoring results from early GBAS operations. The integrity monitor feedback automatically adjusts and improves lever arm accuracy without requiring complex manual intervention. This automated feedback mechanism maintains high measurement precision while simplifying the overall survey process complexity.
Data Source
AI summary
FAST provides a method of “bootstrapping” a pseudo-range (PR) stage and one or more carrier-phase (CP) stages to quickly produce a highly accurate, high integrity receiver-to-receiver lever arm survey based on differential GNSS processing. The lever arm estimates of a previous stage are used to resolve the carrier phase ambiguities of the next stage. The method can be integrated with the warm-up of the integrity monitors to reduce the entire survey and warm-up startup time to 90 minutes or less, which is critical for mobile and make shift and precision approach and (automated) landing operations.