ADS-B Base Station Position Validation via Time Windows

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Solution Overview

Problem

ADS-B systems lack the ability to validate the correctness of position information received from aircraft, leading to potential inaccuracies and reduced trustworthiness, which can cause false alarms and impact air traffic management.

Innovation Solution

An ADS-B base station method that receives and decodes interrogation and reply signals from secondary surveillance sources to determine the expectation time windows for verifying the position information in ADS-B signals, enhancing the confidence level of the received position data without additional radio spectrum usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If ADS-B systems use aircraft-determined position information from GNSS or inertial navigation sensors, then the system enables automatic surveillance with reduced operator input, but the position information may contain deliberate or stochastic errors that reduce reliability

Engineering Contradiction:
Improveautomation of surveillanceVSAvoidposition information reliability
Core Design Contradiction:
Extent of automationVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where the ADS-B base station receives position information from aircraft and cross-validates it against independently determined position data. The system continuously monitors and compares the aircraft-reported position with the base station's calculated position, creating a closed-loop validation system that enhances reliability while maintaining automation.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The base station acts as an intermediary that receives and validates position information from aircraft before using it for surveillance purposes. By introducing this intermediate validation layer, the system can automatically process ADS-B signals while filtering out potentially erroneous position data through cross-validation against independent measurement methods.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If ADS-B base stations rely solely on received position information from aircraft, then the system maintains simplicity in operation, but the base station cannot validate the correctness of the position data

Engineering Contradiction:
Improveoperational simplicityVSAvoidposition information validation
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The base station performs self-validation by independently determining position information using its own sensors and measurements, then comparing this self-determined data with the aircraft-reported position. This self-service approach allows the system to maintain operational simplicity while achieving validation through autonomous cross-checking without requiring external validation systems.

Inventive Principle:
Principle #25Self-service

3Reliability

If the system validates position information using additional verification methods, then the trustworthiness of position data increases, but the complexity of the system increases

Engineering Contradiction:
Improveposition data trustworthinessVSAvoidvalidation system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The base station is designed with multi-functionality, serving both as an ADS-B signal receiver and as an independent position determination system. By making the base station universal in its functions, the patent avoids adding separate validation equipment, thereby enhancing position data trustworthiness while minimizing the increase in system complexity through shared infrastructure.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Device complexity

If ADS-B systems accept position information without validation, then false alarms are reduced in system complexity, but air traffic management safety is compromised

Engineering Contradiction:
Improvevalidation process complexityVSAvoidfalse alarms and safety risks
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

The system performs preliminary validation of position information by cross-checking aircraft-reported positions against independently determined positions before using the data for air traffic management decisions. This preliminary action filters out potentially erroneous data in advance, reducing false alarms and safety risks without requiring complex real-time validation during critical operations.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3336580B1Method and ADS-b base station for validating position information contained in a mode s extended squitter message (ADS-b) from an aircraft
Publication Date: 2021.03.31 THALES MANAGEMENT & SERVICES DEUTSCHLAND GMBH
  • EP3336580B1 patent drawingFigure 1
  • EP3336580B1 patent drawingFigure 2
  • EP3336580B1 patent drawingFigure 3

AI summary

The invention refers to a method and a base station (10) for validating information regarding the position (X1, Y1) of a target-aircraft (1), the information (X1, Y1) contained in an ADS-B signal (20) periodically broadcast by the target-aircraft (1), the method being executed in the ADS-B base station (10) and comprising the steps of: - receiving the ADS-B signal (20) from the target-aircraft (1) at the base station (10), - extracting the position information (X1, Y1) contained in the ADS-B signal (20), - detecting, receiving and decoding an interrogation signal (21) from a secondary surveillance source (2, 3; 10, 11) directed to the target-aircraft (1) and detecting and receiving a reply signal (22) transmitted by the target-aircraft (1) in response to the interrogation signal (21), - determining a time of arrival (TOA) of the received interrogation signal (21) and of the received reply signal (22) at the base station (10), - based on the time of arrival (TOA) of the interrogation signal (21) and on the position information (X1, Y1), determining at least one expectation time window, in which the reply signal (22) from the target-aircraft (1) is expected to be received by the base station (10), - determining whether the reply signal (22) from the target-aircraft (1) is received during one of the at least one expectation time window, and - if the reply signal (22) from the target-aircraft (1) is received by the base station (10) during one of the at least one expectation time window, enhancing the confidence level of the position information (X1, Y1) contained in the ADS-B signal (20).