METHOD AND ADS-B BASE STATION FOR VALIDATING POSITION INFORMATION CONTAINED IN A MODE S EXTENDED SQUITTER MESSAGE (ADS-B) FROM AN AIRCRAFT

摘要

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).