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.

SAR Processing Without a Motion Measurement System

Abstract: This paper leads a discussion on how to form a Synthetic Aperture Radar (SAR) image without knowing the relative track. That is, within the scope of factorized geometrical autofocus (FGA). The FGA algorithm is a base-2 fast factorized back-projection (FFBP) formulation with six free geometry parameters (per subaperture pair). These are tuned step by step until a sharp image is obtained. This innovative autofocus concept can compensate completely for an erroneous geometry. The FGA algorithm has been applied successfully on two ultrawideband (UWB) data sets, acquired by the CARABAS II system at very high frequency (VHF)-band. The relative tracks are known (measured accurately). We, however, adopt and modify a basic geometry model. A linear equidistant track at fixed altitude is initially assumed. Apart from deviations due to linearization, a ~2.5-m/s along-track velocity error is also introduced. Resulting FGA images are compared to reference images and verified to be focused. This indicates that it is feasible to form a wavelength-resolution SAR image at VHF-band without support from a motion measurement system. The execution time for the examples in this paper is about five times longer with autofocus than without. Hence, the FGA algorithm is now fit for use on a regular basis.

Error calculation techniques and their application to the antenna measurement facility comparison within the European antenna centre of excellence

Abstract: This paper gives an overview of the ongoing activities under the Antenna Measurement activity of the Antenna Centre of Excellence (ACE) network within the EU 6th framework research program. In particular, in this work an attempt is made to establish a common uncertainty estimation criteria in spherical near field and far field antenna measurement systems. The results from this activity are important instruments to verify the measurements accuracies for antenna measurement ranges as well as to investigate and evaluate possible improvements in measurement set-ups and procedures. These results will be used in the facility comparison campaigns in order to calculate a reference pattern for each of the high accuracy reference antennas (VAST 12, SATIMO SH800 and SATIMO SH2000) measured during the last 4 years by different institutions in Europe and US. (6 pages)

Likelihood ratio test for incoherent wavelength-resolution SAR change detection

Abstract: The paper introduces a new likelihood ratio test for incoherent wavelength-resolution SAR change detection where the assumption of bivariate zero-mean circular Gaussian processes for noise and clutter is replaced by bivariate Rayleigh processes. This replacement brings a higher average probability of detection and/or lower false alarm rate. Hence, the experimental result shows that an average probability of detection is up to 98% with few low false alarms.

Method and device for a safety belt

Abstract: For a safety belt (2) in a vehicle, the belt is tightened in the event of a collision for at least 300 ms, at the same time as the maximum pull on the safety belt is limited to a predetermined value during the whole tightening process. This is made possible by a tightening device (15) being arranged to be able to operate for at least 300 ms and by there being a load-limiting device (14) between the tightening device (15) and the belt.