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.

Low-cost TRM technologies for phased array radars

Abstract: Low-cost enabling technologies for T/R modules (TRMs) in phased array radars are proposed and analyzed in terms of technology, performance, and cost aspects. Phase and amplitude controlling integrated circuits (ICs) realized in a low-cost standard silicon process are demonstrated. The design of several ICs at the S-, C-, on X-band has shown that silicon germanium is a strong contender for gallium arsenide. This also applies to TRMs suited for military active phased array antenna (AESA) radars. The circuits presented in this paper are manufactured by austriamicrosystems in their 0.35 µm SiGe-BiCMOS process with an fT of around 70 GHz. A TRM packaging concept based on soldered surface-mount technology and organic substrates is also demonstrated. A cost analysis concludes that by using the proposed packaging concept and the SiGe core-chip technology, the TRM production cost can be potentially reduced by 70% compared to traditional ceramic hermetic packaging with core chip in GaAs technology.

Reduced Mode-Tree Expansion Rates in Jump Markov Estimators

Abstract: In jump Markov linear systems, estimators usually consider possible mode changes at each measurement occasion This paper shows that mode-tree expansion in jump Markov estimators can be done at rates lower than the measurement rate, with great savings in computations In fact, even gains in performance can be made by choosing the right mode expansion rate The paper shows the results from Monte Carlo simulations of a simple two-mode Markov system The estimators used are the pruned optimal Bayesian estimator and the generalized pseudo Bayesian of order 2 The estimators are run with mode-tree expansions at the measurement rate as well as with reduced rates The results show considerable savings in computations and optimum RMSE performance for a mode-tree expansion rate 2-4 times the highest mean transition rate of the modes A tractable approximation of the CRLB for jump Markov linear systems is also introduced as a performance reference for the cases tested

A method and an arrangement for estimating 3d models in a street environment

Abstract: The present invention relates to a method for estimating 3D-models in a street environment using stereo sensor technique, the sensors comprised being arranged in pairs. The invention also refers to an arrangement for estimating 3D-models in a street environment using stereo sensor technique, comprising at least one pair of sensors (16, 17, 18) mounted on a bracket (33), each pair of sensors being positioned in a common plane. The invention solves the problem to measure stereo effects under difficult contrast conditions. According to the invention a method is proposed that ensures that the sensors of each pair comprised, are positioned based upon contrast information such that low levels of contrasts in an image plane are avoided. An arrangement is also proposed that involves that comprised pairs of sensors (16, 17, 18) are mutually positioned relative to an essentially horizontal plane (22) of the bracket (33) such that the sensors (16a, 16b, 17a, 17b, 18a, 18b) of a sensor pair (16, 17, 18) is positioned horizontally at a distance from each other and one of the sensors above the horizontal plane of the bracket (33) and the other under the horizontal plane (22).

A fixture device for manufacture of aeronautical structures and a method for applying the device

Abstract: The present invention regards a fixture device for holding in mutual position a first structural article (3) relatively a second structural article (5). The the fixture device (1) comprises a fixing arrangement (7) connectable to a coupling arrangement (9) of the respective first and second structural article (3, 5). The invention also regards a method for manufacture of a structure (43) by holding in mutual position a first structural article (3) relative a second structural article (5). The method includes the steps of providing the first and second structural article (3, 5); providing the fixing (7) and the coupling arrangement (9, 10); positioning the first structural article (3) and the coupling arrangement (9, 10); coupling the fixing arrangement (7) to the coupling arrangement (9, 10) of the first structural article (3); coupling the coupling arrangement (9, 10) of the second structural article (5) to the fixing arrangement (7); repeating the previous steps; and releasing the fixing (7) and the coupling (9, 10) arrangement from the structure (43) after mounting of complementary structural articles (19) to the structural articles (3, 5). The invention also regards a production line (61) for manufacture of a structure (43), wherein the production line (61) comprises a robot apparatus (63) adapted to perform the present method.

A method for determining the base line for a synthetic aperture of a sar using gnss

Abstract: The present invention relates to a method for determining a synthetic aperture of a synthetic aperture radar, SAR, system using information from a global navigation satellite system, GNSS, which includes a plurality of satellites each transmitting a radio frequency signal comprising a unique pseudo random number, PRN. The method comprises: receiving the radio frequency signal from a group of satellites in the GNSS, determining a first maximum correlation peak of the PRN of the received radio frequency signal from each satellite in the group of satellites, determining the phase shift between the first determined maximum correlation peak and a second determined maximum correlation peak of a received PRN from the same satellite at a later time, for each satellite in the group of satellites, determining a line-of-sight, LOS, movement of the SAR system relative each of the satellites in the group of satellites by means of the determined phase shift for each satellite in the group of satellites, and determining a synthetic aperture using the LOS movement relative each satellite in the group of satellites.