Automatic Dependent Surveillance (ADS) is a new surveillance system using a data link for air traffic services. Basic ADS Block, one of the data blocks in ADS report, includes a three-dimensional position, time and Figure of Merit (FOM). FOM is a newly-adopted performance index represented by 8 levels that notifies the capability of on-board navigation system to air traffic controllers. Each level is defined by 95% probabilities of position determination errors.

We evaluated positioning errors of Inertial Reference System (IRS) with respect to GPS-derived positions, to validate the correctness of FOM levels by flight tests. We also evaluated GPS-derived altitude variation with respect to Air Data Computer (ADC)-derived ones.

We devised a new method to analyze the IRS positioning errors and showed the variations of IRS positioning errors to the flight progress.

A number of major airport expansion projects are under way or planned to cope with air traffic growing in recent years. In such large-scale airports, maintaining safety and efficiency operation on the airport surface is a key consideration. Although Air Route Surveillance Radar (ARSR) and Airport Surveillance Radar (ASR) are already using the digital targets that carry a data block associated with aircraft call sign on the display, Airport Surface Detection Equipment (ASDE) radar uses raw video information.

The Airport Surface Surveillance System (ASSS) for Airport Control Service is the same system as Radar Data Processing system (RDP) for Area Control Service and Automated Radar Terminal System (ARTS) for Terminal Radar Control Service in displaying the digital targets. The main sensor of ASSS is ASDE radar. ASSS will greatly enhance the safety and efficiency of the airport surface operations, and reduce the workload of ground controller. Flight testing using the prototype system installed at Sendai airport is carried out since December 1994. This paper reports the outline of this system, the responses of controller questionnaire for new ASDE display and the results of the first tests at Sendai airport.