Showing papers by "Saab Automobile AB published in 1987"

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.

Method to join end fittings in a pressure vessel and pressure vessels fabricated according to the method

Abstract: A pressure vessel of composite material built up by fiber wound around an elongated hollow body having at least one end fitting with an axially extending peripheral surface which has a plurality of protrusions distributed over the surface with portions of the fiber material passing over the end fitting and applied around the protrusions as to be peripherally and axially distributed thereover and molded into the composite material. The pressure vessel may also include two end fittings with different radii with the body having on an axially limited portion thereof radially extending pin-like protrusions distributed around its circumference with the fibers being wound in different directions relative to the axis on opposite sides of the protrusions with the directions being adapted to the radii of the end fittings.

Arrangement for preventing mist and ice formation on the side window of a motor vehicle.

Abstract: Le dispositif decrit sert a empecher la formation de buee et de givre sur les fenetres d'un vehicule a moteur, plus particulierement sur les fenetres laterales arriere des portes dudit vehicule. The device described is used to prevent fogging and frost on the windows of a motor vehicle, especially on the rear side windows of the doors of the vehicle. Les dispositifs connus destines a empecher la formation de buee et de givre sur les fenetres laterales arriere d'un vehicule proposent l'utilisation d'air dirigee contre lesdites fenetres par des conduits provenant du systeme de ventilation normale du vehicule. Known devices intended to prevent fogging and icing on the rear side windows of a vehicle propose the use of air directed against said windows by pipes from the vehicle normal ventilation. Dans le but de trouver une solution fonctionnant efficacement et avantageuse du point de vue de l'assemblage et de la production, la presente invention se caracterise essentiellement par le fait qu'un ventilateur (12) et un conduit d'entree et de sortie (11 et 13) sont disposes entre un panneau externe et interne (7 et 6) dans la porte du vehicule au-dessous de la fenetre (4) en question. In order to find a solution that works effectively and advantageous from the point of view of assembly and production, the present invention is essentially characterized in that a fan (12) and an inlet and outlet conduit ( 11 and 13) are arranged between an inner and outer panel (7 and 6) in the vehicle door below the window (4) in question. Le ventilateur (12) aspire l'air de l'interieur du vehicule et le dirige contre la fenetre (4), faisant ainsi disparaitre la buee et le givre qui s'y etaient formes. The fan (12) draws air from inside the vehicle and directs against the window (4), and by removing the fog and frost that had formed it.

Method for indicating holes in a target having an acoustic chamber.

Abstract: not available for EP0238495Abstract of corresponding document: WO8603285In a method for indicating holes in a wall (1) upon firing at a target having an acoustic chamber (4) which is defined forwardly by said wall (1) and in which microphones (5) are arranged to receive the soundwaves generated by a fired projectile (6) entering said chamber, a quantity corresponding to the sound velocity within the acoustic chamber (4) is calculated on the basis of differences in the transit time of the soundwaves to the microphones (5). The calculated quantity is then compared with a reference value. A hole indication signal is provided when the deviation of the calculated quantity from the reference value exceeds a predetermined value.

A method for the determination of the optimal altitude for a vehicle, flying at a low altitude over a sea surface.

Abstract: of EP0250039In a method and a corresponding device for determining the optimal altitude for altitude control for a vehicle (1), flying at a low altitude over a sea surface, like an anti-ship missile, the distance between the sea surface and the vehicle is measured by an altimeter (2), placed in the vehicle. The altimeter gives an altitude signal, corresponding to this distance, which is varying due to the wave structure of the sea surface. The altitude signal is processed in a signal processing unit (3), which gives to the steering means (4) of the vehicle (1) an altitude control signal, which is dependent on the difference between the actual altitude of the vehicle and the optimal altitude (Ho). The altitude signal is filtered in the signal processing unit (3) to eliminate any superimposed signals, the frequencies of which lie outside of a predetermined range of frequencies, comprising the range of frequencies of the wave movement. The rms-value of the filtered altitude signal is determined in the signal processing unit (3). An acceptable risk of a wave hit for the vehicle (1) is established. The optimal altitude (Ho) is calculated, considering the rms-value determined and the established risk of a wave hit for the vehicle (1).