Abstract: A method and apparatus for determining the velocity of wind (or another fluid) in which one or more receiving acoustic detectors at (e.g. a location (A(r,t))) on the ground are arranged to measure the phase direction of arriving waves from one or more sound sources (at locations S(r,t)), all of which may be fixed or moving. A mean value of the wind and its gradient can be obtained along the sound rays (R) between the sources and the detectors. Typical sources may be aircraft or other flying vehicles or objects, or sound sources arranged particularly for the wind measurement. For example at airports, where conventionally the positions of the air vehicles are often rather accurately known, several sets of detectors can be provided for monitoring the wind conditions and for issuing alarms in the case where extreme winds or wind changes are detected.

Abstract: A sub-combat unit to be separated from a flying body, comprises a warhead, a target detector and two diametrically disposed carrier surfaces designed and arranged to impart to the sub-combat unit a rotation for scanning of the target area in a helical pattern during the fall of the sub-combat unit down towards the target area. The two carrier surfaces are pivotable between a closed position and an opened position in which the two carrier surfaces form a retarding area for controlling the fall velocity of the sub-combat unit and a flow influencing means is provided at at least one of the two carrier surfaces for creating a turbulent area immediately above the carrier surface for completely relieving the carrier surfaces even for large differences in the direction of the impinging wind.

Abstract: The invention relates to a sub-combat unit which is disposed to be separated from a flying body, for example a carrier shell or the like, over a target area, the sub-combat unit comprising a warhead (4), a target detector (5) and two diametrically located carrier surfaces (1, 2) which impart to the sub-combat unit a rotation for scanning the target area in a helical pattern during the fall of the sub-combat unit down towards the target area, and both of the carrier surfaces (1, 2) being pivotally disposed from a collapsed position to an opened position where both of the carrier surfaces form a retarding area for the fall velocity of the sub-combat unit. The sub-combat unit is designed such that the relationship between the largest main inertia moment and the other main inertia moments of the sub-combat unit lies within the range of between 1.05 and 1.15.

Abstract: This invention is concerned with an indicator apparatus for determination of the trajectory or the trajectory direction of a projectile travelling at supersonic speed. It comprises pressure sensitive transducers (T.sub.1 -T.sub.4), which have fixed positions relative to each other or move relative to each other in a defined way, and which are devised to measure the pressure wave generated by the projectile. Also, there are means to produce electrical signals from the transducers, which represent the pressure values sensed by the transducers. Using said signals from each pressure transducer the computing circuits determine a value for a time instance when the pressure wave pass the transducer. From these time values and the geometrical quantities, which specify the position of each transducer in relation to a spatial coordinate system, the computing circuits evaluate the direction of the projectile trajectory more or less accurately.