Alerting system for Mode S interrogator code conflicts: Latvian ANSP selects DFS application

The Latvian air navigation service provider Latvijas Gaisa Satiksme (LGS) will introduce the Mode S Interrogator Code Conflict Alerter (MICCA) of the German air navigation service provider DFS Deutsche Flugsicherung which detects and displays Mode S target acquisition problems in real time. The main feature of the application is to identify interrogator code conflicts which can result in aircraft not being detected by one or more Mode S sensors. By taking on this technology, LGS is fulfilling the European Commission's requirements contained in Article 7 of Regulation (EC) 262/2009, which states that the ANSPs of Member States must provide monitoring of such interrogator code conflicts in a timely manner. The installation of the application, the adaptation to the local infrastructure and the training of personnel are scheduled to be completed by February 2014.

The DFS application MICCA detects incorrect, delayed and missing Mode S target acquisitions which occur, for example, in connection with interrogator code conflicts. Such conflicts arise when two Mode S sensors with overlapping coverage areas use the same interrogator code for target acquisition. As a consequence, aircraft may not be detected by one or more of the Mode S systems in the overlapping area.

DFS developed the application in-house and has been using it to monitor its Mode S facilities since 2010.

"It is important to quickly identify target acquisition problems so that the system monitoring can accurately assess the performance levels of radar stations in real time and, if needed, take corrective action in a timely manner" according to Aleksejs Javorskis, Deputy Chief of Radar Division at LGS.

MICCA can display target acquisition problems in real time using various methods of data visualisation. One possibility is to display the number of problems for each sensor on a time axis. Another possibility is to represent the exact location where a delay occurred in aircraft target acquisition or where there was no acquisition at all.