Saab Automobile AB

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

Design of stability augmentation system using μ-synthesis

Abstract: It is described how the μ-synthesis method was used to design a controller for the HIRM benchmark problem. Controllers for the longitudinal and lateral axes were designed. For the longitudinal axis a fixed-gain controller was designed, but for the lateral axis designs were carried out for a low and a high angle of attack flight case. The main conclusions concerning the use of μ-synthesis are: Handling qualities requirements as formulated in the HIRM problem can easily be incorporated in the design. Robustness to modelling errors can be handled in a straightforward way whereas robustness due to variations in flight case can be more difficult to include. It may be a bit difficult to choose weighting transfer functions that reflect the requirements in an appropriate way, and quite some time is spent on tuning the weighting transfer functions.

Underwater Terrain Navigation During Realistic Scenarios

Abstract: Many ships today rely on Global Navigation Satellite Systems (GNSS), for their navigation, where GPS (Global Positioning System) is the most well-known. Unfortunately, the GNSS systems make the ships dependent on external systems, which can be malfunctioning, be jammed or be spoofed. There is today some proposed techniques where, e.g., bottom depth measurements are compared with known maps using Bayesian calculations, which results in a position estimation. Both maps and navigational sensor equipment are used in these techniques, most often relying on high-resolution maps, with the accuracy of the navigational sensors being less important. Instead of relying on high-resolution maps and low accuracy navigation sensors, this paper presents an implementation of the opposite, namely using low-resolution maps, but compensating this by using high-accuracy navigational sensors and fusing data from both bottom depth measurements and magnetic field measurements. A Particle Filter uses the data to estimate a position, and as a second step, a Kalman Filter enhances the accuracy even further. The algorithm has been tuned and evaluated using both a medium and a high-accuracy Inertial System. Comparisons of the various tuning methods are presented along with their performance results. The results from the simulated tests, described in this paper, show that for the high-end Inertial System, the mean position error is 10.2 m, and the maximum position error is 33.0 m during a 20 h test, which in most cases would be accurate enough to use for navigation. (Less)

Link system for transmission of gearchange movements between a vehicle's gear lever and gearbox

Abstract: of EP0516600Link system for movement transmission between a gear lever and a gearbox in a vehicle, whereby the link system is coupled between a shift rod (2) and a gearchange shaft (4) which extends into the gearbox and whose bearing therein is arranged to absorb bending moments. The end of the shift rod (2) adjacent to the link system is supported by a journal bearing (32) mounted on the gearbox, and the link system includes a rigid planar link element (8), which at its opposing ends has parallel rotary articulations (14,30; 16,24) whereby the link element is coupled at one end to a crank (6) connected to the shift rod, and at the other end to a crank (10) fixed to the gearchange shaft (4).

Evaluation of a geometrical autofocus algorithm within the framework of Fast Factorized Back-Projection

Abstract: The following report deals with a new autofocus algorithm within the framework of time domain SAR processing (Fast Factorized Back-Projection). The strategy, developed at SAAB EDS, relies on varying flight track parameters until a sharp image is obtained. Focus measures are provided by a predetermined object function. After a short introduction and some preliminaries, the algorithm is described in detail, results for two different data sets (collected by the CARABAS II system) are then presented, analyzed and discussed. The analysis emphasizes some promising attributes. Two of the autofocused images are for example sharper than corresponding references. It is also shown that two of the variation parameters are separable, this reduces the required number of geometry hypotheses substantially. However, some issues are also raised. A point-like target is for example easily distorted unless the data is upsampled prior to the processing. For the moment, it is not clear if this problem is related to the back-projection or the autofocus algorithm itself. The time consumption is another distinct downside. The report concludes that a lot of work remains to be done before the algorithm can be considered as functional. A sensitivity study with respect to the variation parameters, as well as a search for alternative object functions should be prioritized. A more conventional autofocus approach is also proposed, to keep options open for the future.

A device for aiming at a mobile target and directing an anti-aircraft gun or the like at same

Abstract: not available for EP0580701Abstract of corresponding document: WO9218823A device for aiming at a mobile target and to direct an anti-aircraft gun is comprising servomotors for directing the barrel, an aiming unit with field glasses (8) and a device for ranging as well as a calculating unit. The aiming unit is pivotally held on a support (2, 5) fixated to the barrel. Means (11) are provided for directly and indirectly measuring the sight line angular velocity. The calculating unit calculates the required lead angle and offset angle of the barrel and is sending corresponding signals to the servomotors. The device is functioning in three phases: during a phase I the barrel angular velocities have a fixed relationship with the sight line angular pivoting achieved by manual action from a neutral position, a series of range measures are taken and the calculating unit is calculating a preliminary target path and target speed, during phase II the range measuring is stopped and the barrel is directed corresponding to the preliminary target path and target speed, during phase III another series of range measures is taken and the calculating unit is calculating definitively the target speed and thereby the correct lead angle and offset angle of the barrel direction, whereby the servomotors are directing the barrel.