Showing papers by "Saab Automobile AB published in 2005"

Forward-backward iterative physical optics algorithm for computing the RCS of open-ended cavities

Abstract: The forward-backward methodology is combined with the iterative physical optics (IPO) algorithm to improve convergence for cavity scattering problems. Wave propagation inside elongated cavities, such as jet engine inlet ducts, follows a predominant down-and-back path. The forward-backward method allows the IPO currents on the cavity walls to be updated sequentially (forward) and reverse-sequentially (backward) along the waveguide axis. A relaxation parameter is introduced to help control the convergence characteristics, making the new algorithm mathematically equivalent to the classical iterative method of symmetric successive over-relaxation. The fast far-field approximation (FaFFA) accelerates the matrix-vector products in the IPO formulation, and an equivalent surface impedance is used to characterize thin material linings in the cavity.

A systemic model for driver-in-control

Abstract: Models of driving have traditionally been couched either in terms of guidance and control or in terms of human factors. There is, however, a need for more powerful models that can match the rapidly growing complexity and sophistication of modern cars. Such models must provide coherent and consistent ways of describing driver performance to help engineers develop and validate technical concepts for semi- and fully automated systems in cars. This paper presents a qualitative model for Driver-in-Control (DiC) based on the principles of cognitive systems engineering. The model describes driving in terms of multiple, simultaneous control loops with the joint driver-vehicle system (JVDS) as a unit. This provides the capability to explain how disturbances may propagate between control levels. The model also enables new functions to be evaluated at the specific level at which they are aimed, rather than by their effects on global driving performance.

Radar level gauge system

Abstract: A method and a system for radar-based gauging of a filling level of a filling material is disclosed, wherein the tank has at least one interfering structure. The method comprises: transmitting at a first time moment a microwave signal towards the surface of the filling material; receiving microwave signals as reflected against the surface of the filling material and as reflected against said at least one interfering structure; calculating based on propagation times of the transmitted and reflected microwave signals at least two distances to reflective surfaces in the tank; and repeating at a second time moment the transmitting, the detecting and the calculating, wherein said first time moment is timely separated from said second time moment. Based on the several repeated measurements, the distance to the surface of the filling material is determiend as the calculated distance that exhibits the greatest change between said first and second time moments. Based on this time difference analysis, it is possible to discinguish moving surfaces very easy and acurate. The method is specifically advantageous in overfill or high level alarm systems.

Effect of button location on driver's visual behaviour and safety perception

Abstract: Although buttons are a frequently used type of control in car interiors, little research has been undertaken on how the usage of buttons affects the visual behaviour of the driver. In this study, the aim was to analyse the effect of push button location and auditory feedback on drivers' visual time off road and safety perception when driving in a real traffic situation. The effect of six button locations (five on the centre stack, one near the gear stick) was tested. Drivers' visual behaviour was studied in real traffic on a motorway. An eye tracking system recorded the visual behaviour of eight drivers who, in 96 repeated trials each, were instructed to press a specific button. Data analysis focused on the drivers' visual time off road and safety perception in relation to the location of the button to be pressed. Auditory feedback did not show a significant effect on visual time off road. The time off road increased significantly as the angle increased between the normal line of sight and button location for the five buttons placed on the centre stack. Results for the button located close to the gear stick, with the highest eccentricity, produced a short time off road. This unexpected finding is discussed in terms of three potential explanations: 1) the role of perceptual discrimination; 2) risk perception; and 3) motor control.

Control of exhaust to a turbo of internal combustion engine

Abstract: An internal combustion engine has a plurality of cylinders, and each cylinder has at least one first and one second exhaust port with associated respective first and second exhaust valves. At least one first and one second exhaust manifold are flow-connected to the respective first and second exhaust ports. A turbo unit for supercharging the charge air delivered to the cylinders comprises at least one first and one second exhaust gas turbine respectively flow connected to the first and the second exhaust manifolds. An exhaust gas chamber flow-connects the first and the second exhaust manifolds upstream of the exhaust gas turbines. The first and second exhaust valves can be deactivated/activated during operation. A throttle valve in the exhaust gas chamber may assume a closed position in order to separate the first and the second exhaust manifolds. A method of operating includes opening and closing different valves at different engine speeds.

Method and system for tracking position of an object using imaging and non-imaging surveillance devices

Abstract: A method and system for tracking the position of objects, such as aircraft and ground vehicles around an airport. A transmission from the object is received at a non-imaging surveillance device of known location, the transmission being used to determine the coordinate position of the object within a given time period. Image data for the object is captured by an imaging surveillance device of known location to provide an image of the object within the same given time period. The coordinate position is correlated with the image to provide composite data about the object within the same given time period. The composite data is displayed to a viewer as a visual depiction of the object.

SEUs Induced by Thermal to High-Energy Neutrons in SRAMs

Abstract: We report on experimental SEU studies using thermal and high-energy neutrons, conducted at the TRIUMF facility, Vancouver. Different SRAM samples were used and many samples showed to be highly susceptible to thermal neutrons. Moreover, a considerable part of the total SEU-rate, at high altitudes as well as down at sea level, may be attributed to thermal neutrons for RAM based devices.

Two-mode radar level gauge system

Abstract: A radar level gauge system for gauging the level of a filling material in a container is disclosed. The system comprises a waveguide extending towards the surface of said filling material; a transmitter for transmitting a microwave signal of a first mode of propagation in the waveguide; and a receiver for receiving the microwave signal reflected against the surface of the filling material and propagating back through the waveguide. Further, it comprises a processing circuitry for determining the filling level of the container based on the reflected microwave signal; and a transition element connecting the waveguide and the transmitter, wherein the transition element is configured to allow a part of the transmitted microwave signal to leak into a second mode of propagation. The first and second modes of propagation are within a frequency band which admits propagation of said microwave signal in the two different modes of propagation in the waveguide, wherein the receiver is arranged to receive the microwave signal in the at least two different modes of propagation.

Radar level gauge system and transmission line probe for use in such a system

Abstract: A radar level gauge system, for measuring a filling level of a content contained in a tank, said radar level gauge system comprising a transmitter arranged outside said tank and configured to transmit microwave energy, a receiver arranged outside said tank and configured to receive reflected microwave energy, and a transmission line probe, comprising at least one probe line, configured to guide transmitted microwave energy towards and from said content, said probe at least partly disposed inside said tank, wherein said transmission line probe further comprises a dielectric enclosing structure enclosing at least a substantial part of said at least one probe line, wherein said dielectric enclosing structure is arranged to reduce the microwave energy attenuating effect caused by said content to be gauged. An advantage with the above system is its improved accuracy when measuring a filling level of a content contained in a tank, as the attenuation introduced by the content is reduced by the dicloctric enclosing structure.

Processing of tank signal in radar level gauge system

Abstract: A method and a system for processing a reflected microwave signal generated by a radar level gauge system arranged to transmit microwaves towards the material in the tank, and receive a reflection of said microwave signal as a tank signal. The tank signal is processes by a plurality of processes, each process being adapted to determine a process variable in a specific region of the tank, each specific region corresponding to a predefined propagation distance range. Such multi-processing of the received tank signal has the advantage that each process can be optimized to that particular region of the tank. More specifically, a process concerned with a particular region of tank only needs to treat a portion of the tank signal.

Light ballistic protection as building elements

Abstract: The present invention concerns a ballistic protection against objects such as projectiles from fire arms, alternatively scatter from for example hand grenades. The protection comprises an enclosure (1, 2, 4, 5, 6, 7, 9) adapted so that the object (10) can penetrate the enclosure (1, 2, 4, 5, 6, 7, 9) in at least one area (2); at least one intermediate layer (3) comprising granules (27) arranged within the enclosure (1, 2, 4, 5, 6, 7, 9), which intermediate layer (3) and enclosure (1, 2, 4, 5, 6, 7, 9) are arranged to deaccelerate said object (10). The invention is further characterized in that: the granules (27) are movable arranged with respect to each other; the space in the intermediate layer (3) that is not occupied by granules (27) is filled by a gas medium to enable contact between adjacent granules (27); the granules (27) have mechanical properties so that a granule (27) is crushed and spread in the intermediate layer (3) when it is hit by an object (10), at the same time as adjacent granules (27) are subjected to impulses with a subsequent energy dissipation so that the object and fragments thereof remains in the protection with a reduced risk for ricochets.

Fahrzeugsteuersystem und Verfahren zu dessen Steuerung

Abstract: Fahrzeugsteuersystem (10), das zum Steuern einer Anzahl steuerbarer Kraftfahrzeuguntersysteme (30-80) ausgebildet ist, in Abhangigkeit von zumindest zwei voreingestellten Fahrzeugbetriebsarten, wobei das Steuersystem eine zentrale Steuereinheit (20) zum Steuern der Kraftfahrzeuguntersysteme (30-80) aufweist, und eine Fahrerschnittstelle (90) mit einer Eingabeanordnung (92) und einer Ausgabeanordnung (94) zur Auswahl der Betriebsart, dadurch gekennzeichnet, dass es zumindest einen Sensor (100-130) zur Erfassung momentaner Betriebszustande aufweist, und dass die zentrale Steuereinheit (20) dazu ausgebildet ist, den Zugriff auf zumindest eine der voreingestellten Betriebsarten einzuschranken, in Reaktion auf einen Ausgangswert von zumindest einem Sensor (100-130).

Quadrifilar helix antenna

Abstract: A quadrifilar helix antenna (1) comprising a first and a second set of helical antenna elements (2 a– 5 a, 2 b– 5 b) symmetrically arranged around a longitudinal axis extending through the axial center of the antenna (1). The antenna (1) is excited from feeding points (2 c– 5 c) in a local ground plane at the bottom (6) of the antenna. The helical antenna elements (2 a– 5 a) of the first set are interconnected in respective top ends of the elements at the top (7) of the antenna. The bottom ends of the first set are in galvanic contact with the respective feeding points (2 c– 5 c). The antenna is characterized in that the top ends of helical antenna elements (2 b– 5 b) of the second set are arranged in an open circuit and remain unconnected. The bottom ends of the helical antenna elements (2 b– 5 b) of the second set each includes a connection (2 d– 5 d) to the local ground plane.

Load-bearing bracket intended to be mounted on a longitudinal roof rail of a motor vehicle

Abstract: Load-bearing bracket (10) intended to be mounted on a longitudinal roof rail (12) of a motor vehicle. The bracket (10) comprises a load-supporting bar (14) which is substantially horizontal in the position of use, is directed transversely with respect to the roof rail and has attachments (18) for load-fastening means at the end portions (16) of the bar. On the underside, the bar (14) has an anchoring means (20) in the form of a pair of downwardly projecting, resilient legs (22) which are formed in one piece with the bar (14) so that, when mounted on the roof rail (12), they straddle said roof rail (12) and are anchored thereon. The bar (14) extends as a cantilever support in one or both directions from the anchoring means (20) of the bracket and transversely across the roof rail (12).

A Comparative Study between Proton and Neutron Induced SBUs in SRAMs

Abstract: We report on irradiation induced SEU by high-energy protons and neutrons. The experiments were performed at The (odor) Svedberg Laboratory in Uppsala, Sweden, and at the Weapons Neutron Research (WNR) facility, Los Alamos, USA. A wide range of SRAMs were used to study the differences between proton and neutron induced SEUs at different energies

Microwave sealing for radar level gauges

Abstract: A radar level gauge system is disclosed, having a transmitter for transmitting measuring signals towards the surface of the filling material, a receiver for receiving echo signals from said surface and a fastening structure adapted to secure said transmitter and receiver in a measuring position on a feed-through structure located in an upper boundary of said container. Further, a sealing unit is arranged between said fastening structure and said feed-through, and adapted to provide a pressure seal between the inside and the outside of the container, and in addition, there is provided means for blocking electromagnetic energy, adapted to block net transfer of electromagnetic energy between the inside and the outside of the container through said sealing unit.

Force transmitting system for a hybrid driven motor vehicle

Abstract: Power transmission system for a hybrid motor vehicle, where the vehicle is alternatively drivable by means of one or the other of two motors which are independent of one another, in particular an internal combustion engine and an electric motor (16), or by combined operation of these motors. The system has an input shaft (12) connected to the internal combustion engine, which shaft can, via a clutch arrangement, on the one hand transmit rotation of the input shaft (12) to an output shaft (14), which is connected to a transmission of the vehicle, and on the other hand transmit rotation of the electric motor (16) to the output shaft (14). The electric motor (16) comprises an annular stator (22) and an annular rotor (24), which are arranged in a common radial plane and coaxially with the output shaft (14), the clutch arrangement comprising a first clutch unit (18), which is arranged so as to be capable of transmitting rotation from the rotor (24) of the electric motor (16) to the output shaft (14), and a second clutch unit (20), which is arranged so as to be capable of transmitting rotation of the input shaft (12) to the output shaft (14) via the rotor (24) of the electric motor (16) and the first clutch unit (18).

Simulation of a magnetic amplifier circuit including hysteresis

Abstract: The purpose of this paper is to demonstrate the feasibility of using a dynamic hysteresis model in simulating a magnetic amplifier (mag amp). The presented model includes static hysteresis, classical eddy currents, and excess losses. The proposed modeling approach is shown to be a feasible tool for designing mag amps.

Emerging verification methods for complex hardware in avionics

Abstract: This paper discusses the additional design assurance strategies stated in RTCA/DO-254, Appendix B - "Design assurance considerations for level A and level B functions." In particular, we address the use of formal specification languages such as the property specification language (PSL) in combination with dynamic (simulation) and static (formal) verification methods for programmed logic devices. Using these methods, we suggest a design assurance strategy for complex programmable airborne electronics compliant with the guidelines of RTCA/DO-254. The strategy is a semi-formal solution, a hybrid of static and dynamic assertion based verification.

Battery unit for e.g. hybrid-driven motor vehicle, has battery cells lying on ramp and with boundary walls, where adjacent cells are oriented in such a way that cells overlap partially in inclined position on support in squamous manner

Abstract: Unit has battery cells (12) lying on a fixed deflecting ramp (40) and including main boundary walls (24, 26). The cells are connected with one another and the walls of adjacent cells are evenly supported on top of one another. The adjacent cells lie on a support and are oriented in such a way that the cells with the walls overlap partially in an inclined position on the support in a squamous manner. An independent claim is also included for a motor-driven vehicle with a battery unit.

An improvement of the SNR during MTI-tracking at low elevations

Abstract: In order to maintain a stable track during low-altitude tracking Saab has developed a signal processing method. The stability of this method requires the signal-to-noise ratio (SNR) to be above a certain level. By utilizing the knowledge of the speed of the tracked target the moving target indication (MTI) filter response can be optimised and, hence, the SNR can be increased.

Efeito de sistemas de preparo do solo e métodos de irrigação sobre a cultura do caupi em várzeas em Roraima

Abstract: Dois experimentos foram conduzidos no Campo Experimental Bom Intento em Boa Vista, RR, de dezembro a marco de 1995/96 e 1996/97, com o objetivo de se avaliar os diferentes sistemas de preparo do solo e de irrigacao sobre a densidade do solo, e a cultura do feijao caupi cultivado em areas de varzea. O delineamento experimental foi em blocos casualizados, no esquema de parcelas subdivididas com quatro repeticoes. O feijao cv. Sempre Verde foi testado sob os sistemas de irrigacao por sulcos e aspersao convencional, em dois sistemas de preparo do solo: grade aradora + grade niveladora, grade aradora + arado de aiveca + grade niveladora. Nao houve diferencas significativas nos componentes de producao nem na produtividade do feijao caupi irrigado, obtendo-se o rendimento medio de graos de 1.853 kg ha-1, porem a densidade do solo aumentou significativamente (p < 0,05), quando o seu preparo foi efetuado pela grade aradora + niveladora.

Evaluation of Parallel Performance of an Unstructured CFD Code on PC-Clusters

Abstract: This paper presents an evaluation of parallel performance of a computational fluiddynamics solver on PC-clusters. The solver uses unstructured grids and is parallelized bydomain decomposition using ...

Battery unit and vehicle equipped with such a battery unit

Abstract: A battery unit for a motor vehicle, especially an electric-powered or hybrid-powered motor vehicle, includes at least one row of a plurality of separate but linked battery cells. Each cell has parallel, opposing main limit walls. The main limit walls of neighboring battery cells bear substantially flatly one against the other and overlap one another in a sloping position on the support. A fixed deflection ramp is arranged in the vehicle to be able to deflect battery cells upward relative to a horizontal plane or forward or sideways, but out of the row of the battery cells.

Numerical simulation of a battlefield Nd:YAG laser

Abstract: A numeric model has been developed to identify the critical components and parameters in improving the output beam quality of a flashlamp pumped Q-switched Nd:YAG laser with a folded Porro-prism resonator and polarization output coupling. The heating of the laser material and accompanying thermo-optical effects are calculated using the finite element partial differential equations package FEMLAB allowing arbitrary geometries and time distributions. The laser gain and the cavity are modeled with the physical optics simulation code GLAD including effects such as gain profile, thermal lensing and stress-induced birefringence, the Pockels cell rise-time and component aberrations. The model is intended to optimize the pumping process of an OPO providing radiation to be used for ranging, imaging or optical countermeasures.

Low Cost Demonstrator as a Mean for Rapid Product Realization With an Electric Motorcycle Application

Abstract: During the last decade, digital prototyping has become a natural part of any industrial project dealing with product development. The reasons for this differ, but the two most obvious is time savin ...

Schaltung für Mehrfrequenzbereichsradar-Füllstandsmeßgerät

Abstract: Schaltung fur ein Radar-Fullstandsmessgerat zum Messen des Fullstands der Oberflache (6) eines Produkts (2), das in einem Behalter (1) aufbewahrt wird, wobei das Fullstandsmessgerat ein Radar (3) zum Senden von Mikrowellensignalen von einer Mehrbandantenneneinheit (5) auf die Oberflache (6) zum Empfangen von Mikrowellensignalen, die von der Oberflache reflektiert wurden, durch dieselbe Antenneneinheit und zum Ermitteln des Fullstands auf Grundlage einer Bewertung der Zeit beinhaltet, die zwischen den empfangenen und gesendeten Signalen verstrichen ist, und das Radar (3) auf mindestens zwei unterschiedlichen Frequenzbereichen arbeitet, wobei die Schaltung beinhaltet ein erstes Mikrowellen-Bereitstellungs-Mittel zum Bereitstellen eines Mikrowellensignals eines ersten Frequenzbereichs, der eine erste Mittenfrequenz aufweist, ein zweites Mikrowellen-Bereitstellungs-Mittel zum Bereitstellen eines Mikrowellensignals eines zweiten Frequenzbereichs, der eine zweite Mittenfrequenz aufweist, wobei das Verhaltnis zwischen der zweiten und der ersten Mittenfrequenz mit mindestens groser als 1,5:1 und vorzugsweise groser als 2:1 quantifiziert wird, und Schalter, die mittels eines Steuersignals zum Umschalten...

Schlüsselsteuerung einer stromrichtungsabhängigen Vorrichtung

Abstract: Die Erfindung betrifft eine Sperrvorrichtung zur Steuerung eines stromrichtungsabhangigen Stellorgans (13) mit einer Schlusselsperre (1), mit schlusselaktivierten Schaltelementen (6, 8) zum trennbaren Anschluss des Stellorgans (13) an eine Speisespannung (10) und steuerungsaktivierten Schaltelementen (14) fur abwechselndes und gegenseitig ausschliesendes Zuschalten von Strom zum Stellorgan (13) in einer ersten und einer zweiten Richtung.