Abstract: A target detector (1) for detecting targets provided with transmitter means (3, 5) for simultaneous generation of different electromagnetic waves having different frequencies which are transmitted by means of an emission and detection device (2). The target detector is also provided with receiving means (3, 4, 5) for obtaining, by means of the emission and detection device (2), target signals comprising target information received at different frequencies. A signal processing unit (15, 16, 17) is provided for processing the target signals in combination to obtain target-representing signals.

Abstract: System for determining the angular spin position of an object (1) spinning about an axis situated within certain limits near the surface (2) of a celestial body. The system is provided with means (4, 5, 6) for generating at least one carrier wave (7, 8) reaching as far as the surroundings of the object (1) and up to and interfering with the surface (2). The system is further provided with directional receiving antenna means (16) fitted to the object (1) and a receiving system (19) linked thereto for determining the angular spin position of the object (1) with respect to the surface (2) on the basis of the angular spin position of the object (1) with respect to the polarization direction of the carrier wave (7, 8).

Abstract: The invention relates to an FM-CW radar apparatus where the frequency sweep duration (R) corresponding with the transmitted signal is increased to obtain a mixing signal which is operational in a wider frequency range than the frequency sweep of the transmitted signal. This has the effect that processing of echo signals of sufficient length can be realized, also from objects which are located near the limits of the radar range.

Abstract: Switching power supply for generating a voltage for a pulsating load (2), in particular for generating a helix voltage for a TWT. The switching power supply is provided with a dc voltage source (1), a buffer (12) from which the load (2) is powered, and switches (3) and a control circuit (5) for regulating the charging of the buffer from the dc voltage source (1), whereby the power supply is provided with a circuit coupled to the dc voltage source (1), which circuit consists of a current source (6), the above-mentioned switches (3) and a primary (9) of a converter (7). The buffer (12) is powered from the secondary (11) of the said converter (7). The control circuit (5) controls the switches (3) by means of a signal which is a function of the rhythm of the pulsating load and the voltage across the buffer.

Abstract: System of orthogonal code generators, where a first code generator (1) generates a code sequence from a running counter reading (2) which sequence is different from the code generated by a second code generator (1') directed by the same counter reading. Each code generator comprises a number of individually arranged and counter-reading directed subcode generators (3.i), each generating a subcode (g.sub.i) together representing the code, where at least one subcode generator 3.i of the first code generator (1) generates a subcode (g.sub.i) which is different from the subcode g.sub.i ' of the similarly arranged subcode generator (3.i') of the second code generator (1').

Abstract: A frequency hopping communication system whose transmitters and receivers after synchronization hop over a frequency series of a first type. To synchronize the transmitters and receivers, sync data from a transmitter are transmitted and received in portions spread over a frequency series of a second type in order to protect the transmission of sync data against jamming and eavesdropping.

Abstract: A local area network operates on the multiple bus system and with a plurality of interface modules connected between the multiple bus system and data-processing/generating subsystems. Each interface module is provided with several autonomously operating bus adapters connected to separate lines of the multiple bus system including locally controlled buffer memory means. Each interface module is further provided with a local distribution circuit connected to the buffer memory means of the interface module and to a host interface unit for the subsystem to be connected to the interface module.

Abstract: Universal waveguide joint, provided with at least two waveguide segments (1-7) slidable over each other, whereby one end of at least one of the waveguide segments (1-7) has a convex surface and the end of another respective waveguide segment, slidable over said convex surface, a concave surface.

Abstract: An energy converter of the type utilizing a series-resonant bridge circuit (1) containing at least two thyristors (6A, 7A, 6B, 7B) with diodes (8A, 9A, 8B, 9B) antiparallel connected thereto, a high-frequency output transformer (12), and an energy buffer (2). A control circuit (3) is incorporated for generating trigger pulses for the appropriate thyristors in response to the energy of the buffer (2). The energy converter further comprises a switching circuit (24) connected in at least one of the supply lines of the supply source to the series-resonant circuit for ensuring that the diode, antiparallel connected to the last-conducting thyristor, starts to draw current immediately after this thyristor is blocked. The control circuit (3) furthermore generates signals indicative of the presence of current flowing through the diodes, which signals control the supply of the trigger pulses to the thyristors.

Abstract: The invention relates to a system for determining the angular spin position of an object (1) spinning about an axis. The system thereto comprises means (7) for transmitting at least two superimposed phase-locked and polarized carrier waves to obtain the angular spin position. The system further comprises at least two loop antennas (10), connected to the object (1), and receiving means (13) for processing in combination the antennas-received signals.

Abstract: A radar system for low-level target tracking comprises a first and a second radar apparatus, both apparatus operating at their own frequency, but employing one and the same tracking antenna. A target being tracked in range and angle coordinates by the first radar apparatus can be tracked in angle coordinates by the second apparatus and in range by the first radar apparatus when the target arrives within the range of the second radar apparatus. A preferred digital embodiment of this system is obtained by utilizing a common signal processing unit including a matched filter.

Abstract: An arrangement for combining the output signals from a plurality of transmission units (2, 3) tuned to the same frequency and included in the arrangement, while each arrangement is by itself capable of functioning as a transmission unit (2) whose output signal can be combined with that of another transmission unit (3). For each pair of transmission units (2, 3) to be combined the arrangement incorporates control circuitry (5) for generating a control signal used to effect combination of the output signals of the pair of transmission units (2, 3) in phase. The control circuitry (5) includes a sum and difference network (6) connected to the transmission units (2, 3) and a detector (7), for example a phase-sensitive detector, for deriving the control signal from the output signals of the sum and difference network (6), the sign of the control signal being of special importance.

Abstract: A pulse radar apparatus is provided with a transmitter and receiver unit (1), a video extractor (2) connected thereto for obtaining digitized plotting data, a plot processor (3) for determining the track positions with the associated digital data from the plotting data obtained in consecutive antenna revolutions, and a display system (5) for presenting both the video signals from the transmitter and receiver unit (1) and the track positions with the associated digital data. The pulse radar apparatus is furthermore provided with a data converter (4) deriving video signals from the plotting data, which video signals, after mixing with the video signals from the transmitter and receiver unit (1) are presented on the display (5) on a real-time basis.

Abstract: Described is a pulse radar apparatus having a repetition period containing m wobbles. The pulse radar apparatus is provided with: a transmitting and receiving unit (2), whereby the received target echoes are sampled and digitized; an n-point DFT processing unit (3); a threshold circuit (4); and a cluster combiner circuit (5) comprising means to form a cluster covering one single target using the signals obtained from the threshold circuit (4). Due to the wobbles, additional information arises in the DFT spectra. From the range, azimuth, local maximum values of the DFT spectrum and the associated output channel number of the DFT processing unit (3), a classification unit (6) determines whether a target is a multiple-time-around target. The classification unit (6) is also able to determine the target doppler frequency, even if this frequency exceeds the average pulse repetition frequency.

Abstract: A digital pulse compression filter for use in a radar or sonar transmitting and receiving unit to process sampled and digitized signals. The sampling frequency (f.sub.s) is equal to about four times the center frequency (f.sub.o) and greater than about twice the bandwidth (.DELTA.f) of these signals. The pulse compression filter (5) comprises a time correlation circuit (7) supplied on the one hand with the sampled and digitized signals and on the other hand with signals representing a replica of the radar or sonar transmitter pulse, whereby one of the two types of signals supplied to the correlation circuit (7) is correlated with the orthogonal components of the other type of signals supplied to the correlation circuit (7) to obtain the orthogonal components of the compressed pulse.

Abstract: A pulse radar apparatus is provided with a transmitter (1), a transmitting antenna (2) and a receiving antenna system (3) with a first and a second receiving channel (4 and 5) coupled thereto. The receiving antenna system (3) comprises N stacked receiving antennas (A.sub.0, A.sub.1, . . . , A.sub.N-1). The first receiving channel (4) comprises N receiving circuits (B.sub.0, B.sub.1, . . . , B.sub.N-1), each connected to a corresponding receiving antenna (A.sub.0, A.sub.1, . . . , A.sub.N-1) and each processing the particular echo signal into two orthogonally phase-detected and digitized video signal components, and a beamformer (14) to derive from said components the orthogonal components I.sub.k, Q.sub.k of the video signal determined jointly by the N receiving circuits in accordance with a receiving beam pattern k corresponding with a specific elevation interval. The second receiving channel (5) comprises N receivers (B.sub.0, B.sub.1, . . . , B.sub.

Abstract: In an apparatus for maintaining the orientation of an antenna system with respect to a beacon, radio signals are received in four quadrants and converted into sum and difference signals, which are transformed in frequency, amplified in an amplifier (6) and detected in a first- and second-phase detector (9, 15) present in a corresponding channel (7, 8) to derive error voltages in first and second time intervals respectively for aligning the antenna system with respect to the beacon. During the tracking mode of the apparatus, the difference and sum signals separately pass in first, second and third, fourth time intervals, respectively. a VCO (21) supplies two orthogonal signals as reference voltages, to the phase detectors. In the tracking mode the VCO driven by a signal derived from the signals obtained in the first channel (7) in the fourth time interval and in the second channel (8) in the third time interval.

Abstract: A pulse radar apparatus is provided with a coherent transmitting and receiving unit with N juxtaposed receiving antennas and N receivers for the reception of echo signals and the processing thereof into two orthogonally phase-detected and digitized video signal components i.sub.r and q.sub.r, where r=0, 1, 2, . . . , N-1. A beamformer is provided to derive from these components the orthogonal components I.sub.k and Q.sub.k of the video signal determined jointly by the N receivers in accordance with a receiving beam pattern k corresponding with a specific elevation interval, where l=0, 1, 2, . . . ,N-1. The orthogonal components I.sub.n, Q.sub.n and I.sub.n+1, Q.sub.n+1 supplied through two adjoining beamformer output channels n and n+1, and derived from the video signals P.sub.n, P.sub.n+1 from echo signals of maximum amplitude received from moving targets, are used for determining the deviation (.DELTA..alpha.) of the elevation value .alpha.

Abstract: An arrangement for a vehicle- or vessel-borne surveillance apparatus is provided with a two-axis, vehicle- or vessel-borne gimbal system (2, 3) and a platform (4) suspended by said gimbal system (2, 3). The platform (4) can be stabilized about the orthogonal axes (AA', BB') of the gimbal system (2,3) with respect to an earth-fixed reference position. The surveillance apparatus (5) is mounted rotatably about an axis (6) perpendicular to the platform (4). The arrangement comprises two linear actuators (7), being mounted directly on the vehicle or vessel, but acting on the platform (4), to permit the above platform stabilization through a mutually equidirectional or opposite motion. The arrangement further comprises a mechanical, universal coupling to transmit the rotational motion produced by a drive mechanism (8), being mounted directly on the vehicle or vessel, to the surveillance apparatus (5).

Abstract: A pulse radar apparatus (2) for target (14) tracking is designed to provide angular error data representing the deviations of projectiles, fired from a gun (3) at the target with respect to the target position line. The l.f.-signal processor of said radar apparatus comprises:a. a signal analyzer (17) having a filter bank for determining Doppler spectral components of echo signals received from the fired projectiles within the target range gate (23) and l.f. detected;b. selection means (18) for selecting the projectile Doppler spectral components from the signal analyzer (17) and filter bank; andc. an angular error generator (24) for generating angular error data from the Doppler spectral components selected by the selection means (18) to correct gun aiming values calculated by a fire control computer (9).