Saab AB

About: Saab AB is a company organization based out in Thun, Switzerland. It is known for research contribution in the topics: Signal & Antenna (radio). The organization has 862 authors who have published 928 publications receiving 8807 citations. The organization is also known as: Saab AB & Svenska Aeroplan AB.

System, computer program product and method for adjusting gain in a control system

Abstract: The present invention relates to a method for adjusting angle of attack feedback gain (KDALFD) based characteristics and position of mounted stores, and a control system using said method.

Comparing Multi-Objective Approaches for Air Route Planning in Hostile Environments

Abstract: Route planning for aircraft that should fly in hostile environmentscan be regarded as a multi-objective optimization problem, where the route should enable the aircraft to accomplish its mission tasks with a minimum risk exposure and minimum fuel consumption. This work compares different approaches for multi-objective route planning that have been suggested in the literature regarding their formulation of objectives as well as how they handle the decision maker’s preferences. It is concluded that most route planners minimize threat exposure and route length, but can also include altitude and flight dynamics constraints. Preferences regarding the objectives can be included in the route planning algorithms with weights or priorities. An alternative approach is that the route planner suggests a number of routes and thereafter lets the decision maker select the best one.

Power arrangement for preventing circulating loop currents within the arrangement

Abstract: Power supply arrangement for distribution of power from a DC power source having a positive terminal and a negative terminal to at least a first and a second DC power consumer, comprising: a first DC power consumer connected to the negative terminal of the DC power source, a first DC-DC switching power converter connected to the first DC power consumer, and connected to the positive terminal of said DC power source, a second DC power consumer connected to the negative terminal of the DC power source, a second DC-DC switching power converter connected to the second DC power consumer, and connected to the positive terminal of said DC power source, wherein a unit comprising a capacitor connected in parallel with an electrical device is arranged in each of the first and second return lines, wherein said electrical device has a diode function, whereby circulating ground loop currents are prevented.

Influence of turbulence modelling and grid resolution in computations of the DPW7 CRM configuration

Abstract: The work report our efforts dedicated to the seventh AIAA Drag Prediction Workshop, and forms a continuous investigation presented at earlier workshops. Here we have summarized our investigation of modelling and simulation methods applied to the Common Research Model wing-body tail-less configuration. Our joint contribution to DPW7 concerns mandatory RANS calculations at flow conditions specified at a Mach number of 0.85 and results from hybrid RANS-LES calculations using the flow solver M-Edge. An investigation of the sensitivity to the grid and turbulence RANS model is carried out from calculations on three successively refined grid families with two turbulence models, including the Explicit Algebraic Reynolds Stress Model (EARSM) and the Spalart-Allmaras (SA) model. Further hybrid RANS-LES calculations were carried out with the more refined grids from two grid families. The RANS results show good grid convergence with results that vary 4 drag counts or less within a grid family. Numerical results with EARSM give higher drag compared to SA and are in general somewhat closer experimental results, mainly due to a more upstream position of the shock on the wing. Hybrid RANS-LES computations produces different solutions on two different types of grids. On the unstructured grid both IDDES-SA and HYB0 models fail to capture the flow features in the outboard section of the wing leading to under prediction of the lift coefficient. On the structured grid, the computation has perceived reasonably well the mean flow but a smeared turbulence resolving capability is observed. This is closely associated to insufficient grid resolution.

Spurious-free flexible frequency converter and a satellite communication repeater architecture

Abstract: A method for frequency conversion within a satellite-based repeater system. An uplink radio frequency signal having a frequency f RF is received. A first and at least a second local oscillator signal having frequencies f L01 and f LO2 , respectively, is generated. The uplink signal is mixed at a first frequency conversion stage with the first local oscillator signal to generate an intermediate signal having a frequency f MF . The intermediate signal is mixed at a second frequency conversion stage with the at least second local oscillator signal to generate a downlink signal having a frequency f IF . The generation and mixing of the signals are performed such that: f LO1 and f LO2 >f RF and f IF f MF =f LO1 −f RF , and f IF =f LO2 −f MF .