Christiane Edinger

UAS in civil airspace: Demonstrating “sense and avoid” capabilities in flight trials

The mission spectrum of future UAS (unmanned arial system) will require its integration into civil airspace. Among all technologies and procedures that are currently discussed and developed to enable UAS operations in civil controlled airspace, collision avoidance is emerging as a key issue for UAS access to civil airspace. This paper reports about the Sense & Avoid research activities that have been carried out in the frame of the German WASLA-HALE project. Algorithms for sense and avoid have been developed and tested in both simulated scenarios and real flight trials. For the flight trials, DLRpsilas test aircraft ATTAS equipped with a radar sensor served as a UAV demonstrator, and a two other DLR test aircraft, a Dornier Do 228 and a DR-400 served as intruders to the ATTAS aircraft. In the first flight trials, all data coming from the radar sensor have been recorded and processed offline. The developed algorithms showed very promising results. The real target could have been separated form ghost targets, the trajectory of the intruder was predicted with sufficient accuracy and the avoidance algorithm gave correct avoidance advisories. The second flight campaign successfully demonstrated autonomous avoid manoeuvres based on the described sense and avoid algorithms.

Sectorless ATM — A concept to increase en-route efficiency

Feasibility of a new air traffic management concept is examined which might increase the efficiency of en-route operations by up to 100%. The concept follows the idea of a sector-less airspace organization. Aircraft entering the airspace (e.g. the German airspace or the entire European Airspace) will be assigned to one controller who is in charge of controlling the aircraft from entry point (or TMA exit point) to exit point of the airspace (or TMA entry point). First simple real time simulations revealed very promising results. The concept seems to enable an easy transition into a user preferred trajectory (direct-to) operations whilst at the same time increasing ATCOs efficiency and airspace capacity.

First results on flight rules and conflict avoidance maneuvers for a sectorless ATM concept

The idea of sectorless ATM (Air Traffic Management) envisages the airspace as a whole instead of dividing it into sectors. The dismissal of sectors, however, necessitates the definition of a complete and unambiguous set of flight rules in order to regulate which aircraft has to introduce an avoidance maneuver in case of a conflict. This paper describes the research on flight rules conducted within DLRs research project on sectorless ATM and describes the developed rule set in detail. Since in a sectorless concept only one specified aircraft amongst the ones in conflict is responsible for the conflict resolution different kinds of avoidance maneuvers than nowadays are necessary. This paper specifies the avoidance maneuvers that have been developed for automatic conflict resolution by DLRs traffic simulator. In particular, vertical conflict resolution often combines horizontal and vertical avoidance to allow for inaccuracies of the vertical movement and trajectory prediction. The conflict resolutions are also offered as suggestions to the controller, who can either choose one of them or develop his or her own solution. It is debated why for short and medium-term conflict resolutions the automatically generated solutions might seem more sensible or efficient than for long-term conflict resolutions. It is explained that in long-term situations the system can be able to analyze situations more thoroughly than the controller. The discussion elaborates on possibilities to implement and apply these findings in a sectorless ATM concept.

Curved approaches and airborne spacing for efficient closely spaced parallel runway operations in IMC

In this contribution the existing RPAT concept for simultaneous approaches to closely spaced parallel runways is further elaborated to be implemented in low visibility. Besides RNP capabilities this concept uses as well ASAS spacing capabilities. The basic procedure design aspects and the required airborne functions are described. The airborne spacing will first be initiated by a 4D approach in which the trajectory of the target aircraft is being predicted based on position information provided by ADS-B or TIS-B. The ASPA function itself is then used to adjust the spacing such that after the S-curve the RPAT aircraft is parallel or slightly behind the target aircraft. Further on, results from simulations trails and initial flight trials will be presented. It is foreseen to fully flight test this concept in fall/winter 2010 at Braunschweig airport.

Green approaches without trade-off: Final results from the FAGI-project

A fundamental contribution to satisfying future demands in air transport like gain of capacity, reduction of environmental impact, improved flight efficiency and high predictability is often the term “4D”. However, having a look at todays fleet only one out of nine aircraft is currently able to, e.g., fulfill a requested time of arrival with high accuracy. Therefore, a successful transition to a 4D-trajectory based operations strongly depends on how especially the unequipped aircraft without an onboard flight management system fit into the concept. In 2007–2009, the FAGI (Future Air Ground Integration) project investigated a new concept facilitating the transition to 4D-trajectory based air traffic management operations.

A Simulation Environment for Analyzing the Impact of Volcanic Ash on Trajectory-Based Air Traffic Management

Large areas of the European airspace have been affected by volcanic ash clouds during the past volcanic eruptions resulting in widespread disruption to air traffic. Future strategies for the air transportation system should reduce negative impacts during a volcanic eruption. To assist in these investigations this contribution shows an successful approach for a simulation environment which optimizes trajectories during a volcanic eruption. The existing simulation environment provided by DLR’s Institute of Flight Guidance is expanded with some newly developed components in order to meet the new requirements. It is described how the existing computation of realistic trajectories was associated with the new component for trajectory optimization. The optimization algorithm is illustrated by a single trajectory optimization. An exemplary air traffic analysis based on data which was recorded during the Grimsvotn eruption shows first results.

4D without airborne FMS

One part of the answer to future demands in air transport like gain of capacity, reduction of environmental impact, improved flight efficiency and high predictability is often the term ldquo4Drdquo. Having a look at todaypsilas fleet only one out of nine aircraft is able to fulfill a requested time of arrival with a tolerance of +/-6 seconds. Therefore, the success of a concept based on advanced airborne capabilities and their integration in a 4D-ATM environment hardly depends on how especially the unequipped aircraft without flight management system (FMS) fit into the concept. DLRpsilas Institute of Flight Guidance investigates a new concept based on 4D-trajectories for both modern aircraft equipped with a flight management system and unequipped aircraft. This paper introduces a navigation performance adapted concept that allows high throughput for airports dealing with mixed traffic. Furthermore, heaving already much experience with guidance of 4D-equipped aircraft, an example implementation of a ground based guidance module for 4D-uncapable aircraft is presented.