Showing papers by "Saab Automobile AB published in 2014"

Factorized Geometrical Autofocus for Synthetic Aperture Radar Processing

Abstract: This paper describes a factorized geometrical autofocus (FGA) algorithm, specifically suitable for ultrawideband synthetic aperture radar. The strategy is integrated in a fast factorized back-projection chain and relies on varying track parameters step by step to obtain a sharp image; focus measures are provided by an object function (intensity correlation). The FGA algorithm has been successfully applied on synthetic and real (Coherent All RAdio BAnd System II) data sets, i.e., with false track parameters introduced prior to processing, to set up constrained problems involving one geometrical quantity. Resolution (3 dB in azimuth and slant range) and peak-to-sidelobe ratio measurements in FGA images are comparable with reference results (within a few percent and tenths of a decibel), demonstrating the capacity to compensate for residual space variant range cell migration. The FGA algorithm is finally also benchmarked (visually) against the phase gradient algorithm to emphasize the advantage of a geometrical autofocus approach.

Dashboards for continuous monitoring of quality for software product under development

Abstract: This chapter contributes with a systematic overview of good examples on how dashboards are used to monitor quality of software products under development – both using multiple measures and a single indicator which combines quality and development progress. In this chapter we extract recommendations for building such dashboards for practitioners by exploring how three companies use dashboards for monitoring and controlling external and internal quality of large software products under development. The dashboards presented by each company contain a number of indicators each, and have different premises due to the domain of the product, its purpose and the organization. We describe a number of common principles behind a set of measures, which address the challenge of quantifying readiness to deliver of software products to their end customers. The experiences presented in this chapter come from multiple case studies at Ericsson, two studies at Volvo Car Corporation (VCC) and one at Saab Electronic Defense Systems in Sweden. All companies have a long experience with software development and have undergone a transition into Agile and Lean software development; however the experience with these new paradigms differs from two to five years depending on the company. The difference in the experience provide a possibility to observe that companies with longer experience tend to focus on using measures to support self-organized teams whereas companies with shorter experience tend to focus on using measures to communicate the status from teams to management.

Challenges in Future Avionic Systems on Multi-Core Platforms

Abstract: Modern avionic system development is undergoing a major transition, from federated systems to Integrated Modular Avionics (IMA) where several applications with mixed criticality will reside on the same platform. Moreover, there is a departure from today's single core computing, and we need to address the problem of how to guarantee determinism (in time and space) for application tasks running on multiple cores and interacting through shared memory. This paper summarizes the main challenges and briefly describes some active directions in research regarding temporal partitioning. It also outlines the forthcoming research that we will pursue for quantifying time bounds on memory access related interference, to ensure determinism and comply with certification requirements.

Transparency of Automated Combat Classification

Abstract: We present an empirical study where the effects of three levels of system transparency of an automated target classification aid on fighter pilots' performance and initial trust in the system were evaluated. The levels of transparency consisted of 1 only presenting text---based information regarding the specific object without any automated support, 2 accompanying the text-based information with an automatically generated object class suggestion and 3 adding the incorporated sensor values with associated uncertain historic values in graphical form. The results show that the pilots needed more time to make a classification decision when being provided with display condition 2 and 3 than display condition 1. However, the number of correct classifications and the operators' trust ratings were the highest when using display condition 3. No difference in the pilots' decision confidence was found, yet slightly higher workload was reported when using display condition 3. The questionnaire results report on the pilots' general opinion that an automatic classification aid would help them make better and more confident decisions faster, having trained with the system for a longer period.

Numerical and Experimental Investigations on Highly Integrated Subsonic Air Intakes

Abstract: Aerodynamic integration of air intakes and the optimization of their performance are challenging tasks for innovative design of advanced unmanned aerial vehicles (UAVs). The extension of Computational Fluid Dynamics (CFD) into application areas such as dynamic intake distortion prediction and thus engine/intake compatibility is made possible by modern hybrid methods and increasing computer resources. Within the Aerodynamics Action Group AD/AG-46 “Highly Integrated Subsonic Air Intakes” of the Group for Aeronautical Research and Technology in EURope (GARTEUR), CFD computations were carried out for the EIKON UAV configuration, which was designed and wind tunnel tested at FOI in Sweden. The major objectives of AD/AG-46 were to investigate the capability of Detached Eddy Simulation (DES) methods for the analysis of unsteady flow phenomena of serpentine air intakes and the accuracy levels of the computations. Numerical results for a variety of wind tunnel conditions were compared with Reynolds-Averaged Navier-Stokes (RANS) and unsteady RANS (URANS) data as well as with experimental results. The impact of not considering the wind tunnel walls in the CFD calculations on the computational results was investigated, revealing that the ventilated walls of the T1500 wind tunnel eliminate the blockage of the model within the closed test section and that free stream conditions can be applied for the computational boundary conditions. Since intake lip shaping is a vital design parameter impacting the intake internal flow and performance, the original geometry was compared with a modified cowl while maintaining low-observability features of the W-shaped cowl design. A trade-off study between boundary layer diversion versus ingestion was performed numerically by applying Euler boundary conditions to the walls of the numerical model of the UAV configuration, thus simulating the total removal or diversion of the boundary layer. The computed inviscid results were compared with the viscous data, quantifying the losses in total pressure recovery and the increase in distortion for the ingested test cases. Internal flow control in the intake duct of the UAV configuration was studied by numerically applying vortex generators, and the results were compared with experimental data. Numerical models were employed in order to simulate micro-jets as active flow control devices in the serpentine duct. Increasing of jet velocities resulted in smaller areas of flow separation and thus led to beneficial total pressure recoveries and distortion parameters. At DLR in Gottingen experiments with a generic high aspect ratio diverterless intake model were performed in the cryogenic blowdown wind tunnel DNW-KRG with the goal of contributing to a better understanding and correlation of installed performance predictions of highly integrated innovative intake designs. In a parametric study the combined effects of boundary layer ingestion and an S-shaped intake diffuser on total pressure recovery and distortion at the engine face were investigated as a function of Mach number, Reynolds number, boundary layer thickness, and intake mass flow ratio.

New Graphical Processing Technique for Fast Shadowing Computation in PO Surface Integral

Abstract: This paper presents a new graphical processing technique for fast computation of PO surface integral. In contrast with the original graphical processing approach introduced by the authors in 1993, the new one combines a novel shadowing computation algorithm together with the conventional facet-based Gordon's formula, instead of the pixel-based Asvestas' approximation. The resulting hybrid approach needs more CPU power for very complex radar targets, but is free from the pixel discretization noise inherent to graphical processing. It has the same accuracy as conventional Physical Optics computation, but shadowed facets detection is more than 10 times faster than with the most efficient alternative algorithms of O(N log N) computational cost.

Simulation and modeling of laser range profiling and imaging of small surface vessels

Abstract: The detection and classification of small surface targets at long ranges is a growing need for naval security. Simulations of a laser radar at 1.5 μm aimed for search, detect, and recognition of small maritime targets will be discussed. The data for the laser radar system will be based on present and realistic future technology. The simulated data generate signal waveforms for every pixel in the sensor field-of-view. From these we can also generate two-dimensional (2-D) and three-dimensional (3-D) range and intensity images. The simulations will incorporate typical target movements at different sea states, vessel courses, effects of the atmospheric turbulence and also include different beam jitter. The laser pulse energy, repetition rate as well as the receiver and detector parameters have been the same during the simulations. We have also used a high resolution (sub centimeter) laser radar based on time correlated single photon counting to acquire examples of range profiles from different small model ships. The collected waveforms are compared with simulated wave forms based on 3-D models of the ships. A discussion of the classification potential based on information in 1-D, 2-D, and 3-D data separately and in combination is made versus different environmental conditions and system parameters.

A system for monitoring a remote underwater location

Abstract: A system for monitoring a remote underwater location using an unmanned underwater vessel ( 5 ). The system includes an unmanned surface vessel ( 8 ), a communication unit ( 7 ) for submerged location and connected to the unmanned surface vessel ( 8 ) and in which the unmanned surface vessel has a position tracking control system for controlling the position of that vessel on a body of water and relative to the unmanned underwater vehicle ( 5 ). The communication unit ( 7 ) has a first wireless communication arrangement for communication with the unmanned underwater vehicle, a second wired communication arrangement ( 10 ) for communication with the unmanned surface vessel and the unmanned surface vessel has a third communication arrangement for communication with an operator or observer ( 1 ) remote from the unmanned surface vessel and the unmanned underwater vehicle. The three communication arrangements are arranged in series such that, in use, the operator or observer may communication with the unmanned/autonomous underwater vehicle via the unmanned surface vessel, the wired connection between the unmanned surface vessel and the communication unit, and the wireless connection between the communication unit and the unmanned underwater vehicle

Method and system for estimating information related to a vehicle pitch and/or roll angle

Abstract: The present disclosure relates to a method (200) for estimating information related to a vehicle pitch and/or roll angle. The method comprises a step of obtaining (220) a first estimate of the information related to the pitch and/or roll angle. The method is characterized by the steps of capturing (210) an image of an area covering at least a part of the horizon using a camera mounted on the airborne vehicle, and determining (240) an improved estimate of the information related to the pitch and/or roll angle based on the first estimate of the information related to the pitch and/or roll angle, and a digital elevation model.

Polarimetric subsurface SAR imaging outcome of theoretical development and CARABAS III tests

Abstract: This is a preliminary report on theoretical and experimental results regarding SAR imaging of buried targets. The work has been motivated by the CARABAS III radar development ongoing at Saab. The radar operates in the two bands with centre frequencies 55 and 220 MHz and with a bandwidth equal to the centre frequency. The radar design went partly parallel with a theoretical modelling work for subsurface targets. Theory predicted that the best options for discriminating the weak subsurface returns from surface returns was to use of shallow depression angles and polarimetry. However in this case returns will be very weak and radar operation must be short range. The radar is designed to comply with these requirements and performing our first dedicated subsurface detection experiments in the autumn 2013, the results obtained vividly support the theoretical predictions made.

Loss Mechanisms in the Electrically Small Loop Antenna [Antenna Designer's Notebook]

Abstract: The characteristics of an electrically small loop antenna are readily calculable. Being an inherently high-Q device, it requires careful tuning. Its performance as a transmitting antenna is sometimes limited by low radiation efficiency because of inherent losses, combined with a radiation resistance that varies as the fourth power of frequency. An apparent anomaly, frequently encountered in practice, is that the measured Q factor differs significantly from that calculated or obtained by computer simulation. This finding has led some to believe that the loop has a higher radiation resistance than conventional analytical techniques would imply. However, this conclusion is unfounded. Experimental evidence presented here indicates that Q factors close to those predicted can be achieved when appropriate consideration is given to reducing the loss associated with the tuning-capacitor mechanism, in particular. The ground loss (another significant factor) is also calculable, but since it decreases rapidly with increasing loop height above ground, its effect can readily be reduced. Vital to the experimental program that accompanied this work was an effective method - using a toroidal transformer - of measuring the total resistance of the loop.

Hybrid RANS-LES Modeling Using a Low-Reynolds-Number k−ω Based Model

Abstract: Hybrid RANS-LES modeling is proposed using a Low-Reynold-Number (LRN) k − ω model. The model is demonstrated in a zonal RANS-LES approach and in an embedded LES approach. The model is calibrated and evaluated using Decaying Homogeneous Isotropic Turbulence (DHIT), turbulent channel flow and turbulent flow over a hump. The effect of different LES length scales on log-layer mismatch and turbulence resolving capability is demonstrated using the proposed model. Interface conditions are proposed in the embedded LES approach in order to reduce the grey area zone in the LES domain downstream of the RANS region. To further improve the development of turbulence resolving flow in the LES region downstream of the interface, anisotropic turbulent velocity fluctuations from synthetic turbulence are added. The hybrid RANS-LES modeling approaches that are presented, using the LRN k − ω based model, show that predictions of turbulence resolving flows are in reasonable agreement with experimental data and DNS data. Moreover, the choice of the LES length scale using the proposed model is shown to be of great importance in reducing the log-layer mismatch.

Autofocus and analysis of geometrical errors within the framework of fast factorized back-projection

Abstract: This paper describes a Fast Factorized Back-Projection (FFBP) formulation that includes a fully integrated autofocus algorithm, i.e. the Factorized Geometrical Autofocus (FGA) algorithm. The base-two factorization is executed in a horizontal plane, using a Merging (M) and a Range History Preserving (RHP) transform. Six parameters are adopted for each sub-aperture pair, i.e. to establish the geometry stage-by-stage via triangles in 3-dimensional space. If the parameters are derived from navigation data, the algorithm is used as a conventional processing chain. If the parameters on the other hand are varied from a certain factorization step and forward, the algorithm is used as a joint image formation and autofocus strategy. By regulating the geometry at multiple resolution levels, challenging defocusing effects, e.g. residual space-variant Range Cell Migration (RCM), can be corrected. The new formulation also serves another important purpose, i.e. as a parameter characterization scheme. By using the FGA algorithm and its inverse, relations between two arbitrary geometries can be studied, in consequence, this makes it feasible to analyze how errors in navigation data, and topography, affect image focus. The versatility of the factorization procedure is demonstrated successfully on simulated Synthetic Aperture Radar (SAR) data. This is achieved by introducing different GPS/IMU errors and Focus Target Plane (FTP) deviations prior to processing. The characterization scheme is then employed to evaluate the sensitivity, to determine at what step the autofocus function should be activated, and to decide the number of necessary parameters at each step. Resulting FGA images are also compared to a reference image (processed without errors and autofocus) and to a defocused image (processed without autofocus), i.e. to validate the novel approach further.

Charge deployment system for ordnance neutralisation

Abstract: A charge deployment system for ordnance neutralisation. The system is suited to deploying multiple disposal charges to neutralise multiple items of ordnance, in particular mines, in a single sortie. The system comprises: at least one deployment unit (102, 104, 106), the or each unit comprising: a housing (110) for stowing a charge in a stowed position; means for mounting a charge within the deployment unit; means for controllably moving a charge and mounting means from the stowed position to a deployment position; and means for controllably releasing a charge from the mounting means; and, a controller for controlling the or each moving means. It further relates to an unmanned vehicle, such as an unmanned underwater vehicle, comprising such a charge deployment system for ordnance neutralisation.

Mitigation methods for FOPEN radar impact on wireless communications

Abstract: The paper provides methods for suppressing interference from ultra wide band FOPEN radar on communication signals within the FOPEN band. The paper accounts for theory, simulations and experiments concerning these methods. A foregoing analysis of the required radar emission thresholds, is provided in another paper, submitted to ITS 2014.

Transmission cross section for apertures and arrays calculated using time-domain simulations

Abstract: Continuing advancements regarding computer technology and simulation software means that the shielding performance of increasingly complex apertures can be calculated numerically. Having access to analytical equations that can be used to reduce the computational burden is, however, still desirable. Transmission cross sections are presented for a number of geometrically simple apertures and arrays in perfectly conducting, and infinitely thin, ground planes when illuminated by a plane wave incident from the normal direction. Comparisons are made between results obtained from numerical simulations, analytical equations as well as semi-analytical calculations obtained by combining analytical equations with numerical results. A previously reported transmission line model is shown to provide results in very good agreement with numerical simulations even for apertures with a relatively small value of the length-to-width ratio. For linear arrays of slot apertures excellent agreement is obtained between purely analytical results and numerical results. The final part of the paper presents a benchmark study illustrating the convergence of two different time-domain simulation software. It is also illustrated how the accuracy of the numerical results can be improved by taking into account the discretization of the computational domain.

Target determining method and system

Abstract: The disclosure relates to a system for determining the position of a target. The system comprises a device for determining the position of an observer. The system further comprises a range and direction measuring device. The system even further comprises a coordinate determining module. The coordinate determining module is arranged to receive the position of the observer. The coordinate determining module is further arranged to receive information from the range and direction measuring device. The coordinate determining module is even further arranged to determine initial coordinates of the target based on the position of the observer and the received information from the range and direction measuring device. The system further comprises a wearable presentation device. The wearable presentation device is arranged to receive the determined initial coordinates of the target. The wearable presentation device is further arranged to present a geo-referenced three-dimensional map to the observer. The wearable presentation device is even further arranged to receive input from the observer so as to mark a new position of the target on the geo-referenced three-dimensional map. The wearable presentation device is also arranged to determine final coordinates of the target based on the marked new position of the target. The disclosure also relates to a method, a computer program and a computer program product for determining the position of a target. The disclosure also relates to a system, a method, a computer program and a computer program product for targeting.

Workload of a collision avoidance system for remotely piloted aircraft

Abstract: Active air traffic controllers and remotely piloted aircraft pilots were studied in a real time simulation providing results on actual and desired behaviour of the studied concept of a mid-air collision avoidance system in an air traffic control environment. The workload for the studied system seems to be acceptable at this state, and no major concerns regarding workload were found during the simulations. However, areas where the studied concept may be improved were identified concerning for instance suggested manoeuvre. A general conclusion from the simulations was that it is important that the D&A-system is correctly designed in regard to sensitivity.

A Conceptual Framework for Time Distortion Analysis in Method Components

Abstract: The “software crisis” is still a prevailing problem to many organizations despite existence of advanced systems engineering methods, techniques for project planning and method engineering; systems engineering project still struggle to deliver on time and budget, and with sufficient quality. Existing research stresses that time leakage has a lever effect on economic outcome, which is not addressed in the abovementioned approaches. As part of an on-going research project we therefore extend existing method engineering concept to include time distortion analysis. This allows for analysis of resource use (productivity) in execution of method components. It has the potential to act as a) a tool for improving the execution of systems engineering processes, or b) criteria for selecting method parts to improve the systems engineering processes.

Using Monte Carlo simulation as support for decision making while negotiating a PBL contract

Abstract: In connection with performance-based logistics (PBL) contracts for aircraft fleets it is very important to carefully analyse both operations and maintenance before and during the contract negotiation phase. Monte Carlo Simulation is a valuable methodology in this context since it allows delimiting and exploring a complex parameter space in a transparent and relatively easily visualized manner. With timely analyses it is possible to identify both technical and economic risks and minimize the possible consequences, a process that benefits both parties in the negotiation process. This paper describes a part of this process in connection with the negotiation of a PBL contract for the Swedish Air Force SAAB 105 (SK 60) trainer fleet between Saab AB and the Swedish Defence Materiel Administration (FMV). The information used in the simulations was largely empirical data derived from previous operations of the aircraft system. The main factors that were simulated were operational requirements, fleet size, spares inventories, turn-around times, failure rates and influence of extraneous factors (e. g. weather). The simulations resulted in considerable savings due to reduction of the active fleet size, and increased reclamation of surplus spares and units from retired aircraft.

Wideband waveform design for clutter suppression

Abstract: Modern signal generators offer the capability to synthesize arbitrary wideband waveforms for radar and sonar applications. This makes it possible to optimize signals for specific purposes or scenarios. Herein, we discuss how to design a wideband waveform for clutter suppression. We formulate an optimization in terms of mainlobe and sidelobe properties of the ambiguity function, then we provide an approximate solution based on convex relaxation. Numerical evaluation shows the advantage of selecting a smart signal compared to a conventional waveform design. The advantages are shown as a lower probability of false alarm and a higher probability of correct target detection.

A change process: transition from 2d to 3d by model based defintion

Abstract: The purpose of the study is to investigate factors that are important for the transition from 2D to 3D by Model Based Definition (MBD) Within MBD, 3D models are used as sources of information for design, production, distribution, technical documentation, services and the overall product lifecycle The introduction and development of MBD at Aeronautics can be described in five transitions that illustrate how knowledge enhancement from project to project and between the projects and the linear organization has evolved The largest challenges have been in the start-up of the transitions, people are gathered with different prerequisites, seeing solutions or problems from different perspectives

Navigation based on at least one sensor and a 3d map

Abstract: The invention relates to a method for navigation of an aerial vehicle. The method comprises providing a sensor image from an aerial vehicle sensor. The method also comprises to repeatedly, until at least one predetermined criterion is reached,perform the step of setting input data, where the input data comprises information related to pitch angle, roll angle, yaw angle and three-dimensional position of the aerial vehicle, the step of providing a two-dimensional image from a database based on the input data, where the database comprises three-dimensional geo-referenced information of the environment, and the step of comparing the sensor image and the two dimensional image from the database. The method further comprises using the input data for which the two images correspond best to each other for determining at least one of the following quantities pitch angle, roll angle, yaw angle and three-dimensional position of the aerial vehicle. The invention also relates to a system, a computer program and a computer program product.

Using imprecise computation for virtual and constructive simulations

Abstract: In this work, we raise three critical questions that must be investigated to ameliorate composability of virtual simulation models and to enable adoption of systematic and stringent real-time techniques to enable more scalable simulation models for virtual and constructive simulation. The real-time techniques in question enable us to separate between policies and mechanisms and, thus, the simulation engine can decide dynamically how to run the simulation given the existing resources (e.g., processor) and the goals of the simulation (e.g., sufficient fidelity in terms of timing and accuracy). The three critical questions are: (i) how to design efficient and effective algorithms for making dynamic simulation model design decisions during simulation; (ii) how to map simulation entities (e.g., agents) into (real-time) tasks; and (iii) how to enable a divide and conquer approach to validating simulation models.

Automatic guided vehicle simulation: using participatory learning and genetic algorithms

Abstract: DOI: 10.14684/intertech.13.2014.84-88 This paper discusses a framework that uses computational simulation to improve the performance of unmanned aerial vehicles through the creation and the selection of better navigation rules. For such task, the approaches known as Participatory Learning System and as Genetic Algorithm will be combined. The intent is to provide the mathematical and computational structure to enable unmanned aerial vehicle learning from simulation experiences. Index Terms - Genetic Algorithm, Matlab, Participatory Learning System, Unmanned Aerial Vehicle.

eMaintenance Industrial Applications: Issues and Challenges

Abstract: Achieving business excellence within industries which utilize complex technical systems requires effective and efficient maintenance. Maintenance is an important enabler of business performance. An effective maintenance strategy creates additional values in an organization’s value-generating process. Establishing an effective and efficient maintenance process is highly dependent on supporting Information and Communication Technology (ICT) infrastructure for information logistics that facilitates maintenance decision support. eMaintenance solutions facilitate effective and efficient management and control of maintenance activities through an enhanced utilization of computing; like estimation of Remaining Useful Life (RUL); reduction of No-Fault Found (NFF); and prediction of fault. eMaintenance solutions enable a seamless integration and fusion of information services provided by information intensive systems with embedded components in order to manage increasing and extensively distributed real-time data collected via different data sources (e.g., sensors). Since, the emerging ‘Internet of Things’ is expecting to dramatically change information systems with inherent embedded components, eMaintenance solutions need to be adapted to this new context to fulfill the overall business requirements on an effective and efficient decision-making process; for e.g.,: real-time analysis based on real-time data and context-aware information logistics. However, development and establishment of proper eMaintenance solutions can be facilitated through utilization of an appropriate framework which deals with real-world challenges. This paper explores some of the issues and challenges pertaining to eMaintenance in industrial applications.

Awareness and training : Identification of relevant security skills and competencies

Abstract: In order to identify needed skills and competencies for privacy and security, we propose a systematic process that maps privacy and security threats to related controls that are required to prevent ...