Aircraft Location via ADS-B Beacon Time Bias Calibration
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Solution Overview
Problem
The temporary unavailability of GNSS satellite signals can immobilize civil aeronautical navigation, as existing aircraft rely heavily on satellite navigation systems for secure location and navigation, particularly during approach phases.
Innovation Solution
A method utilizing onboard systems like DME, IRS, and ADS-B communication beacons, where ADS-B beacons are calibrated for time biases and pseudo-distances are calculated to determine aircraft location, with optional Kalman filter hybridization of data from multiple sources to ensure secure navigation without GNSS signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If GNSS satellite navigation signals are used for aircraft location, then navigation accuracy and reliability are improved, but the system becomes vulnerable to signal unavailability and immobilization of civil aeronautical navigation
Solution Approach 1:
The patent introduces ground-based ADS-B beacons as intermediary reference points between aircraft and the navigation system. These beacons receive GNSS signals and re-broadcast position information, creating an intermediate layer that allows aircraft to determine location through multi-hop communication even when direct GNSS signals are unavailable, thus resolving the vulnerability to signal unavailability
Solution Approach 2:
The patent combines multiple navigation systems (GNSS, DME, IRS, ADS-B) into a hybrid navigation architecture. By merging data from these diverse sources and using fusion algorithms, the system maintains navigation reliability when one or more individual systems fail, addressing the contradiction between relying on GNSS and protecting against its unavailability
2Measurement precision
If hybridization of GNSS data with DME/IRS location data is used to calculate secure position, then location accuracy is improved, but the system complexity increases
Solution Approach 1:
The patent designs the hybrid navigation system to perform multiple functions: it can operate in GNSS-denied environments, provide integrity monitoring, and work with various combinations of available sensors (DME, IRS, ADS-B). This multi-functionality allows a single system architecture to handle different operational scenarios without requiring separate specialized systems for each mode
Solution Approach 2:
The patent dynamically adjusts system parameters based on available data quality and quantity. The hybridization algorithm changes its weighting and fusion parameters depending on which sensors are available and their respective accuracies, allowing the system to maintain optimal location accuracy while adapting to varying system configurations and reducing unnecessary complexity
3Measurement precision
If calibration of ADS-B beacons time biases is performed using time discrepancy calculation, then location precision is improved, but the calibration process complexity increases
Solution Approach 1:
The patent implements self-service calibration where the ADS-B beacon system automatically calibrates its own time biases using the aircraft's known position information and measured signal travel times. The system uses the aircraft's published position (which is known and verified) as a reference to back-calculate and correct the beacon's clock bias, eliminating the need for external calibration equipment or complex manual calibration procedures
Solution Approach 2:
The patent establishes a feedback loop where the calibrated time bias information is continuously refined using ongoing measurements from multiple aircraft. The system uses the collective data from multiple aircraft-beacon interactions to continuously adjust and improve the accuracy of time bias calibration, maintaining high location precision through iterative refinement rather than complex one-time calibration
Data Source
AI summary
The present invention relates to a method for locating an aircraft (Ak), the said aircraft (Ak) being equipped with at least one device for sending and receiving ADS-B signals, a set of ADS-B communication beacons being deployed on the ground, the position of each of the said ADS-B beacons being known, the said locating method comprising:a step of calibrating the time biases of the ADS-B beacons with a view to correcting the synchronization discrepancies when sending, by means of the calculation of the time discrepancy existing between the ADS-B beacons (B1, B2) upon reception of downgoing ADS-B signals sent by a set of aircraft equipped with at least one device for sending ADS-B signals;a step of calculating the pseudo-distances between the said aircraft (Ak) and the said ADS-B beacons deployed on the ground, on the basis of the upgoing ADS-B signals.