S. Montenegro - Academia.edu (original) (raw)

Papers by S. Montenegro

Feuer übt einen immer größeren Einfluss auf das Ökosystem der Erde aus. Der Einfluss ist jedoch n... more Feuer übt einen immer größeren Einfluss auf das Ökosystem der Erde aus. Der Einfluss ist jedoch noch ungenügend erforscht, da nur unzureichende Messdaten im globalen Maßstab zur Verfügung stehen. Bisher gab es keine Sensorik im Orbit, die auf Feuerfernerkundung zugeschnitten ist. Mit der DLR-Kleinsatellitenmission BIRD (Bi-spectral Infrared Detection) wird erstmals eine neue Generation von Infrarotsensoren in Kombination mit einer modifizierten WAOSS-Kamera (Weitwinkel-Stereo-Kamera für die Mars-96-Mission) im Weltraum erprobt, die für die wissenschaftliche Fernerkundung von Vegetationsbränden, Vulkanausbrüchen, Kohlefeuern und anderen hot-spot-Ereginissen geeignet ist. Am 22. Oktober 2001 04:53:00 Uhr UTC wurde der DLR-Kleinsatellit BIRD mit einer indischen Trägerrakete vom Typ PSLV-C3 zusammen mit dem indischen Hauptsatelliten TES und dem ESA-Kleinsatelliten PROBA erfolgreich vom indischen Raketenstartplatz Shar aus gestartet. Mit BIRD werden nicht nur eine neue Generation von Inf...

Proceedings of the 6th workshop on Aspects, components, and patterns for infrastructure software, 2007

The application of aspect-oriented programming (AOP) to the embedded operating system domain is s... more The application of aspect-oriented programming (AOP) to the embedded operating system domain is still a very controversial topic, as this area demands high performance and small memory footprint. However, recent studies quantifying aspects overheads in AspectC++ show that the resource cost is very low. Therefore, operating system development may benefit with the modularization of crosscutting concerns and system specialization offered by AOP. This paper addresses our experience in applying aspects to synchronization (mutual exclusion) and logging in a real-time embedded operating system (BOSS). Furthermore, we present our ideas for future investigation in aspect-oriented implementations for fault tolerance, middleware customization and platform variability.

DASIA 2003, 2003

The increasing complexity of future satellite missions requires adequately powerful onboard compu... more The increasing complexity of future satellite missions requires adequately powerful onboard computer systems. The obvious performance gap between state-of-the-art microprocessor technology (“commercial-off-the-shelf”, COTS) and available radiation hard

Critical real-time embedded systems need to apply fault tolerance strategies to deal with operati... more Critical real-time embedded systems need to apply fault tolerance strategies to deal with operation time errors, either in hardware or software. In this paper we present the ongoing work to provide application fault tolerance by means of implementing middleware transparent support over the BOSS embedded operating system. The middleware uses a publishersubscriber protocol and enables the execution of several fault tolerance strategies with minimum burden to the application level software * .

DASIA. Noordwijk: …, 2005

BOSS: Software and FPGA Middleware for the "flying laptop" Microsatellite Sergio Monten... more BOSS: Software and FPGA Middleware for the "flying laptop" Microsatellite Sergio Montenegro*, Hans-Peter Röser**, Felix Huber*** Presented by Sergio Montenegro. *FhG FIRST Kekulestr 7 12489 Berlin www.first.fhg.de/~sergio sergio@first.fhg.de Tel +49 30 63981878 ...

… Flying Missions and …, 2002

ABSTRACT–A powerful onboard navigation processor dedicated to the GPS-based guidance, navigation,... more ABSTRACT–A powerful onboard navigation processor dedicated to the GPS-based guidance, navigation, and control of satellite formations in real-time has been built up. The system features an industrial Power PC 823e processor supporting multiple Global ...

61st International …, 2010

A simple test setup has been developed at Institute of Aerospace Information Technology, Universi... more A simple test setup has been developed at Institute of Aerospace Information Technology, University of Würzburg, Germany to realize basic functionalities for formation flight of quadrocopters. The test environment is planned to be utilized for developing and validating the algorithms for formation flying capability in real environment as well as for education purpose. An already existing test bed for single quadrocopter was extended with necessary inter-communication and distributed control mechanism to test the algorithms for formation flights in 2 degrees of freedom (roll / pitch). This study encompasses the domain of communication, control engineering and embedded systems programming. Bluetooth protocol has been used for inter-communication between two quadrocopters. A simple approach of PID control in combination with Kalman filter has been exploited. MATLAB Instrument Control Toolbox has been used for data display, plotting and analysis. Plots can be drawn in real-time and rece...

The German small satellite BIRD carries an elaborate GPS-based Onboard Navigation System (ONS) wh... more The German small satellite BIRD carries an elaborate GPS-based Onboard Navigation System (ONS) which provides precise real-time orbit determination as well as orbit and event prediction capabilities. The ONS supports the BIRD Attitude Control System to allow for a nadir pointing of the spacecraft during payload image sessions and enables a geocoding of BIRD sensor images on-the-flight. The analysis of the BIRD ONS flight data indicates an orbit determination accuracy of 5 m for position and 0.006 m/s for velocity. In the absence of GPS data for a two hour period, the ONS predicts the BIRD position with an accuracy of better than 110 m. In addition to the ONS, a Real-time Twoline Generator is operated which estimates Twoline elements from GPS data onboard the spacecraft. This enables orbit forecasts over one week with timing errors of less than 5 s.

Heliyon, 2020

Dessert organisms like sandfish lizards (SLs) bend and generate thrust in granular mediums to sca... more Dessert organisms like sandfish lizards (SLs) bend and generate thrust in granular mediums to scape heat and hunt for prey [1]. Further, SLs seems to have striking capabilities to swim in undulatory form keeping the same wavelength even in terrains with different volumetric densities, hence behaving as rigid bodies. This paper tries to recommend new research directions for planetary robotics, adapting principles of sand swimmers for improving robustness of surface exploration robots. First, we summarize previous efforts on bio-inspired hardware developed for granular terrains and accessing complex geological features. Later, a rigid wheel design has been proposed to imitate SLs locomotion capabilities. In order to derive the force models to predict performance of such bio-inspired mobility system, different approaches as RFT (Resistive Force Theory) and analytical terramechanics are introduced. Even in typical wheeled robots the slip and sinkage increase with time, the new design intends to imitate traversability capabilities of SLs, that seem to keep the same slip while displacing at subsurface levels.

Results in Engineering, 2019

This short letter proposes more consolidated explicit solutions for the forces and torques acting... more This short letter proposes more consolidated explicit solutions for the forces and torques acting on typical rover wheels, that can be used as a method to determine their average mobility characteristics in planetary soils. The closed loop solutions stand in one of the verified methods, but at difference of the previous, observables are decoupled requiring a less amount of physical parameters to measure. As a result, we show that with knowledge of terrain properties, wheel driving performance rely in a single observable only. Because of their generality, the formulated equations established here can have further implications in autonomy and control of rovers or planetary soil characterization.

International Conference on Recent Advances in Space Technologies, 2003. RAST '03. Proceedings of, 2003

... H. Kayal', W. Barwald'. K. BrieR', E. Gill', W. Halle', 0. Montenbru... more ... H. Kayal', W. Barwald'. K. BrieR', E. Gill', W. Halle', 0. Montenbruck', S. Montenegro', R. Sandau'. T. Terzibaschian' 1) DLR. ... 0 a pair of new-star sensors with different look angles (see fig. 5), 0 high precision reaction wheels for micro-satellites (see fig. ...

Small Satellites for Earth Observation, 2005

International Journal of Artificial Intelligence & Applications, 2014

The present paper describes an improved 4 DOF (x/y/z/yaw) vision based positioning solution for f... more The present paper describes an improved 4 DOF (x/y/z/yaw) vision based positioning solution for fully 6 DOF autonomous UAVs, optimised in terms of computation and development costs as well as robustness and performance. The positioning system combines Fourier transform-based image registration (Fourier Tracking) and differential optical flow computation to overcome the drawbacks of a single approach. The first method is capable of recognizing movement in four degree of freedom under variable lighting conditions, but suffers from low sample rate and high computational costs. Differential optical flow computation, on the other hand, enables a very high sample rate to gain control robustness. This method, however, is limited to translational movement only and performs poor in bad lighting conditions. A reliable positioning system for autonomous flights with free heading is obtained by fusing both techniques. Although the vision system can measure the variable altitude during flight, infrared and ultrasonic sensors are used for robustness. This work is part of the AQopterI8 project, which aims to develop an autonomous flying quadrocopter for indoor application and makes autonomous directed flight possible.

TransNav, the International Journal on Marine Navigation and Safety of Sea Transportation, 2014

A number of public codes exist for GPS positioning and baseline determination in off-line mode. H... more A number of public codes exist for GPS positioning and baseline determination in off-line mode. However, no software code exists for DGPS exploiting correction factors at base stations, without relying on double difference information. In order to accomplish it, a methodology is introduced in MATLAB environment for DGPS using C/A pseudoranges on single frequency L1 only to make it feasible for low-cost GPS receivers. Our base station is at accurately surveyed reference point. Pseudoranges and geometric ranges are compared at base station to compute the correction factors. These correction factors are then handed over to rover for all valid satellites observed during an epoch. The rover takes it into account for its own true position determination for corresponding epoch. In order to validate the proposed algorithm, our rover is also placed at a predetermined location. The proposed code is an appropriate and simple to use tool for post-processing of GPS raw data for accurate position determination of a rover e.g. Unmanned Aerial Vehicle during post-mission analysis. http://www.transnav.eu the International Journal on Marine Navigation and Safety of Sea Transportation Volume 8 Number 3

… of Data Systems on Aerospace-DASIA, 2005

BOSS/EVERCONTROL are a real-time embedded operating system and middleware, which were designed fo... more BOSS/EVERCONTROL are a real-time embedded operating system and middleware, which were designed for safety and simplicity and to allow their own mathematically formal verification (on which work is currently in progress). Nowadays, ...