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.

Nanosecond optical parametric oscillator based on large-aperture periodically poled RbTiOAsO(4).

Abstract: We report on optical parametric oscillators (OPO's) based on periodically poled RbTiOAsO4 (PP RTA), which are pumped by Q-switched solid-state lasers. With a diode-pumped Nd:YVO4 laser (pulse energy, 800 ?J; pulse duration, 5.5??ns; repetition rate, 1??kHz) the PP RTA OPO generated 1.58??m signal and 3.26??m idler radiation with a signal pulse energy of 45 ?J. The large aperture of 3 mm×3 mm of the PP RTA crystal also permitted OPO operation with pump pulse energies as high as 65??mJ, provided by a flash-lamp-pumped Q-switched Nd:YAG laser (pulse duration, 20??ns; repetition rate, 10??Hz). With this pump source the OPO generated signal pulse energies as high as 17??mJ, corresponding to an efficiency of 26%. The performance of this OPO shows that large-aperture PP RTA crystals are well suited for pulsed nanosecond OPO operation with pump pulse energies of tens of millijoules.

Measuring radar cross section at short distance

Abstract: Radar cross sections (RCS) must be measured at large distance. We exclude here the special near-field methods. The distance (R) must be so large that different RCS contributions are added in the same way as at infinite distance. This leads to the rule R > 2D^{2}/\lambda if the target cross range is confined within \pm D/2 and a phase error of \pi /4 is tolerated. It is shown, however, that if the RCS is measured as a function of an angle and is low-pass filtered with a cut off period of \phi_{c} (radians), the distance requirement could be changed to R > 4D\phi^{-1}_{c}(1 - \lambda/2\phi_{c}D)) . All RCS measurements at such distances give approximately the same result after low-pass filtering. We assume that a set of isotropic point scatterers, accurately describes the target.

On the theory of noise Doppler radar

Abstract: Presently, there is an increasing interest in noise modulated radar in a wide spectrum of applications, such as surveillance, tracking, altimetry, and sub-surface profiling. Wide-band signals with high range resolution, reduced ambiguities and high ECCM performance can be achieved. In this paper, the theory of noise modulated radar is treated. Point target response, side-lobe level, and time compression due to motion effects are analysed. The processing involved correlates the received signal and the delayed reference signal. An alternative method correlates only their signs, making it possible to reduce the requirements on the analog-to-digital converters to one bit. Both approaches are studied and degrading effects from additive noise are analysed.