Abstract: A ship's hull including a first hull part arranged as a hard-chine-hull disposed on a second hull part in the shape of a super-slender float. During in service conditions, only the aft half of the first hull part intersects the water surface so that two separate bow waves develop. By appropriate selection of hull widths and by disposition of the first hull part on the second hull part, the bow waves are in phase opposition. This reduces the wave-induced drag of the ship's hull considerably, especially near the critical speed.

Abstract: The invention relates to a phased array antenna by means of which, besides normal radar transmissions, also a guidance of a number of semi-active homing missiles towards a number of targets can be effected. The main problem to be solved here is that a rear-reference signal for each missile remains present to a sufficient extent also during the periods covering normal radar transmissions. The invention solves this problem by transmitting rear-reference signals for all missiles deployed simultaneously with radar transmitter signals.

Abstract: A radar apparatus provided with a transmitting unit, antenna unit and a receiver unit. The transmitting unit transmits pulses having a modulation for enabling pulse compression on reception. As an ECCM feature, the radar apparatus is further provided with a blanking circuit. The blanking circuit includes two filters, one filter being responsive to the first half of the transmitting pulse only and the other filter being responsive to the second half of the transmitting pulse only. Blanking occurs if both filters simultaneously produce an output.

Abstract: Radar apparatus provided with a transmitting unit (1), having a transmit phase shifter for providing each transmitted pulse in a burst with a selected phase shift, and a receiving unit (7), having a receive phase shifter (9) for cancelling the selected phase shift upon reception. This enables unimpeded radar transmissions and causes an operational repeater jammer to be misled.

Abstract: The invention relates to an arrangement and a method for suppressing spurious targets, particularly those caused by birds, in an infrared search device. Potential targets that show comparatively strong fluctuations are qualified as spurious targets. Only targets moving against a homogeneous background are subjected to an evaluation.

Abstract: The invention relates to a microwave antenna for the generation of a beam with adjustable parameters. Use is made of a reflective Fresnel zone plate that is written into a thin layer of silicon by means of a laser plus deflection means. A reflector is positioned behind the Fresnel zone plate for reflecting microwave radiation that is not reflected by the Fresnel zone plate.

Abstract: Radar system for the generation of two-dimensional or three-dimensional position indications of targets. Three-dimensional position indications are obtained by periodically canting the antenna about a canting axis, such that the antenna beam plane makes an angle with a normal on the earth's surface and by combining azimuth data and range data obtained at different canting angles. For a radar system provided with dual-axis stabilization means, these means may also provide for the canting of the antenna means.

Abstract: Transmission-line network of the foam stripline type. To reduce dielectric losses in the foam, part of the foam in the region of the stripline is removed so that the wave properties of the transmission-line network are not impaired. The removed foam forms ducts that may be used for the forced cooling of the stripline using air or other cooling agents.

Abstract: A radar apparatus having a phased array antenna with a large number of transmit and receive modules, a control unit and a video processor. The control unit generates a number of pulse bursts per azimuth-elevation direction, all of which shows slight carrier frequency differences. The video processor determines a doppler spectrum and compared successive spectra for each pulse burst. As a result of the frequency differences, clutter does not show much of a shift while targets which are subject to fold-back in the frequency domain will show considerable shift. A threshold based on a mean spectrum therefore enables detection.

Abstract: A multipatch antenna including radiating patches (2) positioned on a dielectric sheet (1). The patches (2) are capacitively fed by probes (7) ending in the dielectric sheet (1) near the patches (2). By positioning the probes (7) near selected edges of the radiating patches (2), a selected polarization direction of the radiation field can be realized. By positioning several probes (7) near a radiating patch (2), a radiation field with an adjustable polarization direction or a radiation field with an extremely low cross-polarization can be obtained.

Abstract: The invention relates to an information system for a ship (1), and in particular for providing information about the position of ship's crew members when a calamity occurs. For that purpose the ship's crew members are provided with an identification means having a built-in transponder and the ship is provided with a number of detectors (3i) and with a central unit (5).

Abstract: An optical scanning apparatus having a linear detector array and a lens for focusing an image on the array contained within a camera housing. The housing can be rotated around a first axis so as to scan from side to side. In addition, the linear detector array can be rotated around an axis parallel to the direction of sight of the camera to enhance the signal/noise ratio.

Abstract: The invention relates to a radar apparatus (1, 2, 3) provided with a doppler filterbank (4) and fast thresholds (5.i), for writing per pulse a range-doppler matrix in range-doppler memory (6) and the background level in background memory (7). By unfolding the range-doppler matrices and combining the unfolded range-doppler matrices for all the pulses in a burst in combination means (10), an incoherent combination of the pulses is obtained before an actual detection takes place. This cluster before detect scheme increases the detection probability for weak echoes, without increasing the false alarm rate.

Abstract: The invention relates to a Stirling cooler, comprising a compressor for generating a time-varying pressure in a gaseous medium, a cooling element provided with at least a displacer and at least a regenerator and additionally comprising a connecting line between the compressor and the cooling element. The incorporation of heat flow-reduction means for reducing the heat flow from the compressor to the cooling element causes a sharp drop in temperature on the warm side of the cooling element as a result of which heat sinking will no longer be required.

Abstract: The invention relates to a microwave antenna for the generation of a beam with adjustable parameters. Use is made of a reflective Fresnel zone plate that is written into a thin layer of silicon by means of a laser plus deflection means. A reflector is positioned behind the Fresnel zone plate for reflecting microwave radiation that is not reflected by the Fresnel zone plate.

Abstract: An apparatus for orienting an object mounted on a first plane, for example a radar antenna, with reference to a second plane, for example the deck of a ship. The apparatus includes a stack of three identical, substantially annular housings each of which is provided with an upper surface and a lower surface, these two surfaces not being parallel. Each housing is provided with a drive unit for rotating the upper surface with respect to the lower surface about the housing axis. The drive units are suitable for independently performing the rotations; furthermore control units are provided for controlling the drive units for orienting the object in three degrees of freedom with reference to the second plane.

Abstract: A radar apparatus provided with a Cassegrain antenna to be mounted on the barrel of a gun. The Cassegrain antenna is of the polarization twist type with a flat adjustable mirror being used to generate a lead angle. In addition, gun-induced vibrations transmitted to the Cassegrain antenna are compensated by adjusting the flat mirror so that the radar beam generated by the Cassegrain antenna is not susceptible to these vibrations.

Abstract: A radar apparatus that is provided with auxiliary antennas (5, 10) of an omnidirectional nature. In addition to customary ECCM applications, such as side-lobe suppression and side-lobe blanking, the auxiliary antennas (5, 10) are also used for the emission of frequency-shifted pulses which are emitted simultaneously with radar transmitter pulses. To this effect, the radar apparatus is provided with auxiliary transmitters (8, 13). Furthermore, auxiliary receivers (6, 11) have been provided for analyzing the responses of jammers to the frequency-shifted pulses.

Abstract: Radar apparatus provided with a signal generator (1), transmitter means (2), antenna means (3), receiver means (4), a video processor (6) and an indication device (7) for the generation of a radar picture of the surroundings of the radar apparatus with a first resolution. A selected target, designated with control unit (8), may be displayed on the indication device (7) with a second, higher resolution. To this end signal generator (1) generates in the direction of the selected target control signals for transmitter (2) with an increased bandwidth. Selection and conversion unit (5) matches echoes of these increased bandwidth signals to the bandwidth of video processor (6) and indication device (7).

Abstract: An antenna having antenna modules for an extremely wideband active monopulse phased array system, the modules including a housing provided with four radiators of the rectangular open-ended waveguide type and with an electric circuit. With the antenna modules being suitably stacked, the radiators constitute a substantially continuous antenna surface, the radiators being positioned at the points of intersection of a system of equilateral triangles which make up the antenna surface. After preamplification, phase shift and down-conversion to an intermediate frequency, received signals from a large number of antenna modules are combined to yield a sum beam, an azimuth difference beam and an elevation difference beam.