Abstract: An optical device for measuring the angular position of electromagnetic radiation, such as laser light, incident on the device, includes a lens system defining an input surface for receiving the incident electromagnetic radiation and an output surface towards which the incident radiation within the optical field of vision of the device is deflected by the lens system, a plurality of light guides each having a first end facing and in direct physical and optical contact with the output surface of the lens system, the first ends of the light guides substantially covering the output surface of the lens system, a detector allocated to each respective light guide and connected to its second end, and a calculating unit for determining a present angular position, based on the signal values outputted by the detectors, by calculating ratio between difference signals and sum signals of signal values of the detectors and determining the angular position corresponding to this ratio.

Abstract: A warning apparatus for monitoring a plurality of threat sectors includes a receiving antenna for each threat sector for receiving electromagnetic radiation, an alarm channel for each respective threat sector and an amplifier interconnected between an output of the antenna on an input of the alarm channel. The alarm channel includes a high pass filter, a rectifier, an integrator and a comparator connected in series, an input of the filter constituting the input of the alarm channel, an output of the comparator constituting an output of the alarm channel. A threat sector activator is connected to an output of the comparator and activated by an output signal from the comparator in response to an input signal applied to the comparator from the integrator which exceeds a reference level, the activated threat sector indicator of the respective alarm channel indicating the threatened sector.

Abstract: A laser warning device for sector-by-sector surveillance of the air space, comprises a plurality of module sections such that each surveyed sector is coupled through an optical antenna and an optical buffer to a module section.

Abstract: Laser-warning method and a laser-warning arrangement, which laser-warning arrangement is intended to warn of laser light from a laser beam source which is used for guiding projectiles, missiles and the like, for example laser light from a pulsed laser beam which is directed towards a target area. The time for the laser beam to reach the laser-warning arrangement, the so-called impact time, is calculated from a first amplitude value, measured at a first point in time, of the scattered light from the laser beam and a second amplitude value, measured at a second point in time, of the scattered light from the laser beam, and the measured time difference between the said first and second points in time on the basis that the amplitude raised to a constant is proportional to the distance to the laser beam according to the equation D=K.multidot.A.sup.n, where K and n are constants, D is the perpendicular distance to the laser beam and A is a measured amplitude value.

Abstract: Method and apparatus for determining the direction to a laser beam source includes detecting amplitude peaks in the light occurring when a pulsed laser beam generated by the laser beam source passes through an air space. The detection is carried out with at least one rotating receiver lobe which images the scattered light on an associated fixed detector. The detected amplitude peaks are compared in order to determine the greatest amplitude peak. The angle of rotation value of the receiver lobe, when the greatest amplitude peak is detected, is determined as belonging to a limited angle range within which the direction to the laser beam source is assumed to lie. The apparatus comprises a rotatable optics system, a fixed detector system which detects the magnitude of the light transmitted through the optics system to the fixed detector, and an evaluation part which compares detected amplitude peaks.