Evaluation Results of Multilateration at Narita International Airport

The multilateration (MLAT) is a new surveillance system which has been introduced for air traffic control in recent years. This paper describes evaluation results of performance tests for MLAT conducted at Narita international airport (Narita airport) for airport surface surveillance. Increasing aviation demand has brought expansions of major airports. As a result, the airport layout and operations have become more complex. In order to ensure safe and smooth operations in this situation, an essential requirement will be the provision to air traffic controllers of accurate and highly reliable surveillance information. And this requirement needs introducing advanced surveillance system, such as MLAT. MLAT detects signals from SSR transponder (Secondary Surveillance Radar), and measures a target position by the TDOA technique (Time Difference of Arrival). To achieve high performance in MLAT, an appropriate antenna allocation is the most important. In the evaluation tests, performance degradation by signal interference occurred at a terminal area especially. This paper points out a typical problem caused by an inappropriate antenna installation. In addition, this paper proposes an idea for improvement to mitigate the performance degradation. The results of evaluation tests indicated that the idea for improvement is effective to resolve the problem.