Air Traffic Control

Algorithms for tracking civil aircraft

Air Traffic Control


Project goal

For air traffic control, air traffic controllers must be informed at all times about the current air situation picture, consisting of the position and speed of all aircraft. The task of a Surveillance Data Processing System (SDPS) is to generate so-called tracks for all aircraft from the data from various radar stations.


The aim of this project was to develop an algorithm for such an SDPS that calculates a highly accurate and, above all, reliable air situation picture from all available data and information. This algorithm was implemented and integrated as a software module in an existing SDPS with very high quality requirements.


In terms of data processing, the greatest challenge in an SDPS is the use of many different radar technologies. Examples of this are primary radar, secondary radar according to the Mark X and Mark XII standards, Automatic Dependent Surveillance – Broadcast (ADS-B) and Wide Area Multilateration (WAM). The different sensor technologies have different measurement models, noise distributions, error patterns and measurement rates.


The data from the different radar technologies must be processed in real time in an SDPS and merged with one another in order to generate a precise, common air situation picture. The algorithms and their implementation in a software module must calculate the tracks very efficiently, yet precisely and reliably.

Development approach

Development of an algorithm for data association: assignment of distorted radar measurements to aircraft

Algorithm development for track updates: Optimal calculation of position and speed in 3D, update and processing of other variables such as Mode C and Mode S transmitted by the aircraft

Development of the algorithms beyond the current state of research and technology

Development, evaluation and optimization of the algorithms in a rapid prototyping environment

Implementation in C ++ according to the V model and standards (e.g. EUROCAE ED-153) with coding rules

Tests: Comprehensive unit tests, partially automated tests with real data, development of a simulation tool for testing with simulated data

Result and benefit

Very precise and reliable position determination of the aircraft

Internal representation in a global coordinate system for worldwide tracking

Automatic detection and compensation of outliers, disturbances and reflections

Detection of flight maneuvers, such as climbing and descending flight or turning maneuvers

Simultaneous monitoring of the calibration parameters of all radar stations for the automatic deactivation of defective systems

Redundant system for instantaneous takeover of data processing in the event of failures

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