Uwe Klingauf

A flexible and scalable SLAM system with full 3D motion estimation

For many applications in Urban Search and Rescue (USAR) scenarios robots need to learn a map of unknown environments. We present a system for fast online learning of occupancy grid maps requiring low computational resources. It combines a robust scan matching approach using a LIDAR system with a 3D attitude estimation system based on inertial sensing. By using a fast approximation of map gradients and a multi-resolution grid, reliable localization and mapping capabilities in a variety of challenging environments are realized. Multiple datasets showing the applicability in an embedded hand-held mapping system are provided. We show that the system is sufficiently accurate as to not require explicit loop closing techniques in the considered scenarios. The software is available as an open source package for ROS.

Comprehensive simulation of quadrotor UAVs using ROS and gazebo

Quadrotor UAVs have successfully been used both in research and for commercial applications in recent years and there has been significant progress in the design of robust control software and hardware. Nevertheless, testing of prototype UAV systems still means risk of damage due to failures. Motivated by this, a system for the comprehensive simulation of quadrotor UAVs is presented in this paper. Unlike existing solutions, the presented system is integrated with ROS and the Gazebo simulator. This comprehensive approach allows simultaneous simulation of diverse aspects such as flight dynamics, onboard sensors like IMUs, external imaging sensors and complex environments. The dynamics model of the quadrotor has been parameterized using wind tunnel tests and validated by a comparison of simulated and real flight data. The applicability for simulation of complex UAV systems is demonstrated using LIDAR-based and visual SLAM approaches available as open source software.

Hector Open Source Modules for Autonomous Mapping and Navigation with Rescue Robots

Key abilities for robots deployed in urban search and rescue tasks include autonomous exploration of disaster sites and recognition of victims and other objects of interest. In this paper, we present related open source software modules for the development of such complex capabilities which include hector_slam for self-localization and mapping in a degraded urban environment. All modules have been successfully applied and tested originally in the RoboCup Rescue competition. Up to now they have already been re-used and adopted by numerous international research groups for a wide variety of tasks. Recently, they have also become part of the basis of a broader initiative for key open source software modules for urban search and rescue robots.

Considerations on symbology, data requirements and operational concept for integral NOTAM visualization on airport moving map displays

Surface Movement is one of the most challenging phases of flight. To support the flight crew in this critical flight phase and to prevent serious incidents and accidents, of which Runway Incursions are the by far most safety-critical, the electronic airport moving map display has evolved as the key technology to increase the flight crews situational awareness on the airport surface over the past decade. However, the airport moving map is limited to quasi-static airport information due to the envisaged 28 day update cycle of the underlying Aerodrome Mapping Database (AMDB), and thus does not include information on safety-relevant short-term and temporary changes such as runway closures or restrictions. Currently, these are conveyed on paper through the Pre-Flight Information Bulletin (PIB), a plain-language compilation of current Notices to Airmen (NOTAM) and other information of urgent character. In this context, the advent of airport moving map technology leads to a disparity in the conspicuousness of information, resulting in the danger that e.g. a runway that is not displayed as closed on the airport moving map might be perceived as open even if contrary NOTAM information exists on paper elsewhere in the cockpit. This calls for an integrated representation of PIB/NOTAM and airport moving map information. Piloted evaluations conducted by the Institute of Flight Systems and Automatic Control have already confirmed the high operational relevance of presenting runway closures on an airport moving map. Based on the results of these trials, this paper expands our previous work by addressing the various pre-requisites of an integral NOTAM visualization, ranging from the development of appropriate symbology to an operational concept enabling the transition from conventional to electronic, machine-readable NOTAM information without shifting responsibility and workload from the dispatcher to the flight deck. Employing Synthetic Vision techniques, a complete symbology set for various cases of runway closures and other applicable runway and airport restrictions is derived, and the requirements on the underlying machine-readable NOTAM data are discussed. Finally, the concept of an electronic Pre-Flight Information Bulletin (ePIB) is used to facilitate the gradual integration of this technology in an airline operational workflow.

Prevention of runway incursions due to closed runways or unsuitable runway choices by enhanced crew situational awareness and alerting

Of all incidents on the aerodrome surface, Runway Incursions, i.e. the incorrect presence of an aircraft on a runway, are the by far most safety-critical, resulting in many fatalities if they lead to an accident. A lack of flight crew situational awareness is almost always a causal factor in these occurrences, and like any Runway Incursion, the special case of choosing a closed or unsuitable runway - including mistaking a taxiway for a runway - may have catastrophic consequences, as the Singapore Airlines Flight SQ006 accident at Taipei in 2000 and, most recently, Comair Flight 5191, tragically show. In other incidents, such as UPS Flight 896 at Denver in 2001 departing from a closed runway or China Airlines Flight 11 taking off from a taxiway at Anchorage in 2002, a disaster was only avoided by mere luck. This paper describes how the concept for an onboard Surface Movement Awareness and Alerting System (SMAAS) can be applied to this special case and might help to prevent flight crews from taking off or landing on closed runways, unsuitable runways or taxiways, and presents initial evaluation results. An airport moving map based on an ED-99A/DO- 272A compliant Aerodrome Mapping Database (AMDB) is used to visualize runway closures and other applicable airport restrictions, based on NOTAM and D-ATIS data, to provide the crew with enhanced situational awareness in terms of position and operational environment. If this is not sufficient to prevent a hazardous situation, e.g. in case the crew is distracted, a tailored alerting concept consisting of both visual and aural alerts consistent with existing warning systems catches the crews attention. For runway closures and restrictions, particularly those of temporary nature, the key issue for both extended situational awareness and alerting is how to get the corresponding data to the aircrafts avionics. Therefore, this paper also develops the concept of a machine-readable electronic Pre-flight Information Bulletin (ePIB) to bring relevant NOTAM information to the flight deck prior to the flight, with a possibility to receive updates via data link while the aircraft is airborne.

Rekursives Verfahren zur biasfreien Parameterschätzung mit minimaler Schätzfehlerkovarianz (RMV)

The Extended Kalman Filter (EKF) can be used to obtain unbiased minimum variance state estimates for nonlinear dynamic systems. The present paper discusses a modification of the EKF which allows additionally parameter identification of linear, discrete transfer functions. Besides this modification of the EKF algorithm, a rather pragmatic interpretation of the filter error covariances leads to the RMV algorithm (Recursive Minimum Variance), which is presented in this paper. When describing applications of this algorithm, we restrict ourselves to the estimation of parameters. In contrast to the RLS algorithm (Recursive Least Squares), which is the best-known recursive method for parameter identification of discrete transfer functions, the RMV algorithm delivers unbiased estimates at a comparable computational effort

Control theoretic concept for intuitive guidance of pilots during taxiing

Several international air traffic management (ATM) research programs are currently investigating new guidance technologies to cope with the increasing traffic both in the air and on the ground. The programs show that it is mandatory to introduce a spatial and temporal guidance of aircraft from gate to gate. While the current research programs recommend the use of autopilots during the en-route phase, an automated guidance system for taxiing exhibits some major disadvantages. The proposed concept of keeping the pilot in the loop during taxiing avoids the need for additional aircraft equipment. Instead, we suggest using the taxiway light elements which are already installed at most hub airports but are not used to their full extend. Currently only spatial guidance, known as “follow-the-greens”, is implemented. The proposed concept augments the purely spatial guidance by a temporal component through dynamically triggering the taxiway light elements. The number of lit lights is calculated using methods of automatic control. Therefore a mathematical model of the plane and pilot has been identified in a measurement campaign with airline pilots in a fixed base research flight simulator. Different controller types were implemented and evaluated in a second measurement campaign in corporation with fourteen airline captains.

Conceptual Validation of Advanced Pilot Guidance-Systems - A field test report -

Abstract This paper describes the procedure and results of field tests conducted to conceptually validate new taxiing guidance-systems for pilots within the German Competitive-Airport Initiative (WFF – Wettbewerbsfahiger Flughafen). The systems tested comprised an onboard navigation unit as well as taxiway lighting. A field test with twelve pilots was conducted at Frankfurt Airport. Eight airline pilots were performing eleven scenarios in two fully equipped test buses; four Airbus test pilots were taxiing seven scenarios with the A320 ATRA test aircraft of DLR German Aerospace Center. The pilot groups differed regarding system ratings. The system concept as such was evaluated as supportive by the users.

Simulator Evaluation of a Novel Surface Movement Awareness and Alerting System (SMAAS) for Runway Incursion Avoidance

This paper describes design and simulator evaluation of a holistic onboard surveillance system approach to runway incursion avoidance. Its key features are improved situational awareness and pro-active conflict detection with respect to ownship position, the location of relevant other traffic, potential operational restrictions and clearances assigned by ATC. The number of additional alerts is kept at a minimum.

The European research project ISAWARE II: a more intuitive flight deck for future airliners

Continuously growing worldwide air traffic poses an immense challenge to civil aviation. While the number of flight operations is increasing, the overall number of accidents has to be reduced. In order to reach this ambitious goal, both avionics and the human machine interface (HMI) of the cockpit have to be improved in the onboard domain. An international consortium led by Thales Avionics, one of Europes leading avionics manufacturers, is therefore - as part of the EC project ISAWARE II of the 5th Framework Program - developing integrated surveillance systems and cockpit displays which intuitively provide pilots with an optimum situational awareness during all flight phases. The project already uses parts of the interactive Cockpit Display System (CDS) developed for the Airbus A380 as a basis. Primary Flight Display (PFD) and Navigation Display (ND), the two central cockpit displays, are additionally equipped with a so-called “Synthetic Vision System” (SVS), a database-driven representation of terrain and airport features resembling the real outside world.