Navigation Data Validation System for Aircraft
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Solution Overview
Problem
Current navigation systems face challenges in achieving high navigational accuracy, particularly in aircraft navigation, due to total system errors that include path definition, navigation system, and flight technical errors, which can be exacerbated by GPS position errors and altitude inaccuracies, especially in approaches without Instrument Landing Systems.
Innovation Solution
The system employs a combination of SBAS-aided satellite navigation, inertial systems, air-data computers, radar systems, and terrain data to monitor and validate navigation data, generating alerts for pilots and autopilots to ensure accurate lateral and altitude positioning within specified tolerances, thereby reducing navigation system errors and allowing for lower decision altitudes and heights during approaches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If GPS-based navigation is used to increase airspace capacity and operational efficiency, then navigation speed and route flexibility are improved, but navigation accuracy and reliability deteriorate due to GPS position errors and system faults
Solution Approach 1:
The patent combines multiple independent navigation systems (GPS, inertial navigation system, air data computer, radar altimeter, terrain database) into an integrated navigation system. The processor fuses data from all these sources to generate a validated navigation solution, thereby maintaining the speed and flexibility of GPS while compensating for its reliability shortcomings through redundant independent sources.
Solution Approach 2:
The patent introduces an independent validation system that acts as an intermediary between the primary GPS navigation and the pilot/autopilot. This validation system monitors GPS position and altitude data against expected values derived from inertial navigation, air data, and terrain information, generating alerts when discrepancies indicate potential GPS faults, thus mediating the reliability issue without sacrificing GPS operational efficiency.
2Measurement precision
If lower RNP levels (higher accuracy) are required for instrument approaches, then navigational accuracy is improved, but the complexity of the navigation system increases due to need for multiple independent validation sources
Solution Approach 1:
The patent designs a validation system where a single processor performs multiple functions: it processes GPS data, inertial navigation data, air data computer information, radar altimeter signals, and terrain database queries simultaneously. This multi-functional approach achieves high navigational accuracy through cross-validation without proportionally increasing system complexity, as one processing unit handles all validation tasks rather than requiring separate dedicated systems for each function.
Solution Approach 2:
The patent changes the operational parameters of the navigation system by dynamically adjusting alert thresholds and validation criteria based on flight phase and RNP level requirements. The system can operate at different accuracy levels by modifying validation stringency, allowing lower RNP levels when needed without permanently configuring the system for maximum complexity. The alert limit and decision altitude parameters are adjustable based on operational requirements.
3Reliability
If GPS alert limit time-to-alert is reduced to detect position errors earlier, then navigation safety is improved, but the likelihood of false alerts increases due to normal navigation variations
Solution Approach 1:
The patent implements a feedback mechanism where the validation system continuously compares GPS-derived position and altitude with independently calculated expected values from inertial navigation and air data. When discrepancies exceed dynamically adjusted thresholds, alerts are generated. The system learns from normal navigation variations and adjusts alert thresholds accordingly, providing timely safety warnings while filtering out false alerts caused by expected navigation tolerances.
Solution Approach 2:
The patent makes the alert thresholds and validation criteria dynamic rather than static. The system adjusts alert limits based on flight phase, aircraft performance characteristics, and observed navigation system behavior. During normal operations, tighter tolerances trigger alerts, but the system adapts to legitimate navigation variations over time, maintaining high safety standards while reducing false alert rates through dynamic parameter adjustment.
Data Source
AI summary
Present novel and non-trivial systems and methods for validating navigation data are disclosed. A processor receives navigation data from an external source such as a global positioning system (“GPS”); receives navigation data from a second source comprised of multiple sources; determines the validity of the GPS navigation data; and alerts the pilot if validity of the data falls outside a limit. In an embodiment related to lateral information (i.e., geographic position) data, the second navigation data is comprised of both GPS data and data provided from an internal source. In an embodiment related to altitude information data, the second navigation data is comprised of both GPS data and data provided by multiple internal sources.