DFS ADS-B Implementation in High Density Radar Controlled Airspace – Experiences and Challenges

Abstract

The German Air Navigation Service Provider (ANSP) DFS Deutsche Flugsicherung (DFS) is operating a surveillance infrastructure mainly based on radars and multilateration systems, which provides surveillance information and receives aircraft derived data. The implementation and use of the new surveillance technology Automatic Dependent Surveillance – Broadcast (ADS-B) has to provide benefits in terms of safety, performance or costs. DFS operations require a permanent double surveillance coverage for the area of responsibility. This requirement actually means triple surveillance coverage (in order to provide a seamless service also in case of system outages or planned down times). DFS is implementing ADS-B as the third surveillance layer to reduce costs. Each surveillance layer has to fulfil the performance and safety requirements independently. The fulfilment of safety requirements, integrity and continuity, will require validation of the passively received ADS-B information.Data integrity and continuity need to be considered w.r.t. safety requirements, but may also have to address security. The integrity of ADS-B data can be ensured either by comparison with data from other surveillance sensors (dependent validation) or by analyzing the properties of the data itself (independent validation). The independent validation of the ADS-B data is a necessary prerequisite for providing a self-contained independent surveillance layer using the ADS-B technology. In a first step, DFS will implement ADS-B as a dependent layer: (1) for validation of the assumption on surveillance performance, (2) to gain experience on data integrity and data continuity, (3) to prepare possible mitigations e.g. against spoofing or jamming and (4) to recognize potential shortcomings in the airborne installations and identify possible mitigations. This first step will support necessary developments (e.g. ADS-B Validation Unit) to move with ADS-B towards the use as an independent surveillance layer reducing infrastructure costs and improve radio spectrum protection.

Evaluation of passive solar calculations in SAP

“…The wider gap in heating load in the single-glazed house is due to the nonlinear effect mentioned in section 4. 13. The fact that the heating load increases even though the solar gain does as well, confirms the common knowledge that the higher losses from the single-glazed windows are dominant.…”

“…This program was chosen since it has been extensively tested and used in modelling passive solar houses(5.6), in comparison with other detailed simulations and design methods (7) including BREDEM-S(8.9). SERI-RES has also been checked against results obtained with the program ESp_r (12,13) in modellin a passive solar test cell in the EC-PASSYS program (10)(11)(12)(13) . Some calculations were performed with the UK program APACHE, available from IES, Glasgow.…”

“…2 13. Use ofSAP tables In the SAP documentation under 'Worksheet calculations', it is stated that linear interpolation should be used where appropriate for SAP tables 1 to 14.…”

Comparison of ADS-B Verification Methods: Direct TDOA and MLAT

“…implementation onto the existing systems called multilateration (MLAT) [5], [39]- [45] is possible without any significant change, and ideally, with only a software upgrade of the central processor. This is of benefit for air navigation service providers.…”

Estimation of Flight-Phase-Specific Jet Aircraft Parameters for Noise Simulations

“…A study of uncertainties in aircraft noise calculations determined standard uncertainties of 133 m (436 ft) laterally and of 27 m (89 ft) vertically for radar data in Switzerland [5]. A study by the German Air Navigation Service Provider (ANSP) showed that ADS-B data are generally subject to smaller uncertainties than radar data, but present the challenge that the uncertainties are created by the on-board sensors of the aircraft rather than by an on-ground detection [6]. Thus ADS-B data quality varies between aircraft.…”