Saab Automobile AB

About: Saab Automobile AB is a based out in . It is known for research contribution in the topics: Radar & Antenna (radio). The organization has 760 authors who have published 890 publications receiving 11811 citations.

Fatigue experience from tests carried out with forged beam and frame structures in the development of the Saab aircraft Viggen

Abstract: A part of the lower side of the main wing at the joint of the main spar with the fuselage frame was investigated. This wing beam area was simulated by a test specimen consisting of a spar boom of AZ 74 forging (7075 aluminum alloy modified with 0.3 percent Ag) and a portion of a honeycomb sandwich panel attached to the boom flange with steel bolts. The cross section was reduced to half scale. However, the flange thickness, the panel height, and the bolt size were full scale. Further, left and right portions of the fuselage frame intended to carry over the bending moment of the main wing were tested. Each of these frame halves consisted of a forward and a rear forging (7079 aluminum alloy, overaged) connected by an outer and inner skin (Alclad 7075) creating a box beam. These test specimens were full scale and were constructed principally of ordinary aircraft components. The test load spectrum was common to both types of specimens with regard to percentage levels. It consisted of maneuver and gust loads, touchdown loads, and loads due to ground roughness. A load history of 200 hours of flight with 15,000 load cycles was punched on a tape. The loads were randomized in groups according to the flight-by-flight principle. The highest positive load level was 90 percent of limit load and the largest negative load was -27 percent. A total of 20 load levels were used. Both types of specimens were provided with strain gages and had a nominal stress of about 300 MN/sq m in some local areas. As a result of the tests, steps were taken to reduce the risk of fatigue damage in aircraft. Thus stress levels were lowered, radii were increased, and demands on surface finish were sharpened.

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 ...

Automatic sensitivity control for radar level gauges

Abstract: A radar level gauge system for determining the filling level of a filling material in a tank is disclosed. The system comprises an antenna device for emitting measuring signals towards the surface of the filling material and a receiver device for receiving echo signals from the tank. Further, the system comprises processing circuitry for determining the filling level of the tank based on said echo signal, wherein said processing circuitry is adapted to amplify the received echo signals in dependence of the distance from which the echo signals originates, in such a way that an echo signal from a lower filling level is more amplified than an echo signal from a higher filling level. The processing circuitry is adjustable to optimize the amplification of the echo signal based on the height of the tank. A corresponding processing circuitry and method of operation is also disclosed.

Qualitative policies for bandwidth priorities in ad-hoc networks

Abstract: The Analytic Hierarchic Process (AHP) is used for presenting a method for setting up policies that define priorities among services sharing a limited measure of bandwidth in an ad-hoc radio network. We examine the issue of ensuring the autonomy of the users of the bandwidth, as well as the issue of ensuring that the priority policies result in efficient bandwidth usage even when the priority decisions involve uncertainty about the dynamics of the network and the services.

On the measurement of shielding effectiveness in a mode stirred chamber

Abstract: In the work presented here, the authors investigate how the isotropic shielding effectiveness measured in a mode stirred chamber (MSC) varies with probe type and position for a generic avionics bay. The measurements are made using six different probes in six positions. In the analysis, the measured received power is compared to the theoretical exponential distribution with good agreement for the entire frequency range, from 400 MHz to 18 GHz. Using confidence intervals, the authors show that for a given probe, shielding effectiveness is not independent of position. Indeed, the measured isotropic shielding effectiveness can vary with more than 10 dB between positions. The possible reason for these somewhat surprising results is assumed to be caused by leakage from one dominant unintentional aperture of the generic avionics bay.