Abstract: A process for recycling waste sulfuric acid by decomposing organic contaminants by use of light energy, comprising exposing a waste sulfuric acid containing contaminants to a focused radiation emission having an irradiation intensity within the range of from 0.01 to 100 MW/m.sup.2 in a reaction chamber shaped as a directly-absorbing receiver, wherein the chamber is maintained at a temperature within the range of from 200.degree. C. to 1000.degree. C. to form sulfur trioxide and water as sulfuric acid decomposition products. The process also includes forming sulfur dioxide and oxygen, starting materials for sulfuric acid, by cleavage of the decomposition product sulfur trioxide by maintaining the reaction chamber at a temperature between 400.degree. C. and 1500.degree. C. The process, particularly adapted for irradiations with direct solar radiation.

Abstract: A control system for steering a road vehicle having front-wheel and rear-wheel steering, comprising a wheel base l (in m), a rear cornering stiffness c.sub.h (in N/rad), a center of gravity distance l.sub.v (in m) from the front axle and a mass m (in kg) and provided with a decoupled control circuit, a predetermined yaw damping D.sub.G is adjusted according to a damping parameter ##EQU1## via the steering of the rear wheels through an angle .delta..sub.h (in rad). Herewith the yaw rate r (in rad/s), travelling velocity v (in m/s) and steering wheel angle .delta..sub.L (in rad) are measured and the angle .delta..sub.h =(l/v-k.sub.D) (w.sub.h -r) is calculated by a microprocessor, whereby w.sub.h is formed as command variable from the measured steering wheel angle (.delta..sub.L) by a prefilter (F.sub.h) associated with the rear-wheel steering.

Abstract: Improved Viterbi decoding of radio signals of the type calculating a metric increment ##EQU1## wherein .lambda..sub.k is calculated at time intervals indexed by k, i is a data bit position index, y is a received value, x is a coded bit of a predetermined sequence, and a is a fading factor, uses a metric addition B.sub.k according to the equation ##EQU2## where B.sub.k is a function of the quantityu.sub.k L.sub.k =log.sub.10 P(u.sub.k =+1)/P(u.sub.k =-1)!.If the channel is binary symmetrical, B.sub.k =u.sub.k L.sub.k /L.sub.0k where L.sub.0k =log (1-P.sub.0k)/P.sub.0k ! and P.sub.0k is the binary symmetrical channel error probability. If the channel is a gaussian and fading channel then B.sub.k =u.sub.k L.sub.k / (E.sub.s /N.sub.0) log.sub.10 e! where E.sub.s /N.sub.0 is the channel signal-to-noise ratio and log.sub.10 e is approximately equal to 0.434.

Abstract: In an apparatus for orbit control of at least two co-located geostationary satellites a single interface is provided in the form of an orbit database for exchanging orbit and maneuver data between four independent decoupled function blocks of an orbit control system having a matched function scope, i.e. between a first function block for orbit determination and maneuver estimation/maneuver calibration, a second function block for maneuver planning, a third function block for monitoring the relative movement and a fourth function block for predicting specific events and ephemerides (FIG.

Abstract: To reduce the mass of internally or externally toothed gears, a thin metal ring having internal or external toothing is made and bonded to a ring of fibrous composite material. Furthermore, to make rings for gears having internal or external toothing, fabric hoses of fibrous composite materials having a fibre orientation of .+-.45.degree. are applied in a number of layers in the peripheral direction to the bottom and side flanks of a U-shaped groove-like depression of a rotating production device; the remaining free space in the interior of the applied fabric hose layers is filled with a unidirectionally wound roving, thereby forming an integral ring after the curing or hardening. Moreover, to make rings for gears having internal or external toothing, two thin-walled rings of fabric laminates serving as shear walls and having a fibre orientation of .+-.45.degree.

Abstract: A wing made of composite fibre materials, especially carbon fibre reinforced plastics, comprises shell components having a thin-walled, pre-formed wing skin and tubular rods as stringers. The stringers are provided with a connection element and a compression plate at the fuselage end of the wing. The external sides of the compression plates are all in one plane. The wing is attached by screws, which are screwed through the connection element at the fuselage side into the connection elements of the rods forming the stringers. The rods forming the stringers are adhered to the inside of the wing skin. The spaces between the rods may be filled with a light, compression-proof material.

Abstract: In an airborne SAR system for determining the topography of a terrain, two complete, correlated SAR images with different amplitude modulation in the cross-track direction are obtained and recorded by switching of two antenna patterns which can be generated by means of a monopulse antenna. The desired terrain information is extracted from the amplitude relationship of the two SAR images.It is furthermore possible to extract the terrain information from polarimetric SAR data via crosstalk parameters.

Abstract: A rod connection arrangement includes a connection element for connecting a cylindrical reinforcing rod to a cylindrical main rod, with the reinforcing rod extending at an angle to the axis of the main rods. Each rod respectively consists of a core of compression material surrounded by a fiber composite wall having fabric layers with fibers that cross at an angle. The connection element consists of an arcuate body having a central axis and an inner surface with a radius substantially equal to an outer radius of the main rod. The arcuate body preferably extends over an arc of less than 360 degrees. The connection element further consists of an integrally formed joint plate projecting radially outwardly from an outer surface of the arcuate body. The joint plate is preferably formed by two layers of a fabric material imbedded in a rein matrix wherein fibers of the fabric layers cross at an angle of substantially .+-.45 degrees.

Abstract: A rotor blade is made of fibre-reinforced synthetic resin and comprises a moulded core with central, front and rear elements and a foot end fastening element, a unidirectional fibre layer being wound longitudinally of the core, a first cross-binding lying over the fibre layer and a second cross-binding forming a covering for the entire assembly.

Abstract: In a system for locating a plurality of objects and obstructions and for detecting and determining the rolling status of moving objects, such as aircraft, ground vehicles, and the like, in the area of an airport, a short-range radar network is provided having at least three radar stations. Via simple stationary non-rotating transmitting antennas with coherent time-pulsed microwaves or other microwave signal forms, a large sector in the azimuth of about 90.degree. is illuminated, and the associated fixed receiving antennas, which have fixed subdivided sector characteristics, with one receiving channel per subsector, also receive signals from the other stations for bistatic measurements. The separation of the signals of individual stations is effected by selecting different frequencies, or alternatively, a time triggering of transmitted signals and receiver gates or by station-specific modulation codes. Illumination zones are chosen so there are no shadow zones caused by, e.g., buildings.

Abstract: An apparatus for the three-dimensional determination of flows has a light source for briefly illuminating a light section (3) and a stereoscopic recording device (10). The stereoscopic recording device (10) comprises two equivalent objectives (11, 12) aligned parallel to each other as well as perpendicular to the plane (22) of the light section (3), and behind the objectives (11, 12) two optical sensor fields (15, 16) aligned parallel to the plane (22). A forward displacement device for the synchronized forward displacement of the projections of the light source (3) onto the two sensor fields (15, 16) has two revolving mirrors (13, 14) aligned parallel and rotating in synchronization about a common axis of rotation (23) as well as in synchronization with the light source, whereby the axis of rotation (23) runs parallel to an imaginary line joining the two objectives (11, 12).

Abstract: In a method of extracting motion errors of a carrier bearing a coherent imaging radar system from radar raw data, after calculating the entire azimuth spectrum (S(f,i)) and before correlation the azimuth spectrum is broken down over the entire bandwidth into n subspectra (S.sub.1 (f,i) . . . . S.sub.n (f,i)). Associated time-consecutive n subspectra of the two azimuth spectra are correlated with each other; by means of an expected frequency shift (v.sub.er) a window width is defined. From the curve (K.sub.0 (f,i)) obtained by correlation of the azimuth spectrum and from the subcurves (K.sub.i (f,i) . . . . K.sub.n,(f,i)) obtained by subcorrelations the maximum curve value within the window is determined.From the expected frequency shift (v.sub.er) and a just calculated frequency shift (V(i)) the new frequency shift (v'.sub.er) to be expected is determined. After simultaneous performing of the method steps described above over several strips of range gates (N.sub.

Abstract: A method for identification of dynamic characteristic quantities in a linear system having an electronic model, the electronic model having a complex signal flow with a complex residual a.sub.i =a'.sub.i +ja".sub.i, and a complex inherent value b.sub.i =b'.sub.i +jb".sub.i of the `i`th degree freedom describing model parameters a'.sub.i,a".sub.i,b.sub.i ', and b".sub.i for each degree of the system. The various signal flows are arranged parallel to one another for the various degrees of freedom, and are excited by the same signal `f` as the linear system. A difference e(n) determined at the time `n` between a model response `y` and a similar system response `d`, the system response having been time delayed by one unit of time, is used for adapting the model parameters for the system for the point in time (n+1), using variable step sized coefficients .alpha.'.sub.i (n),.alpha.".sub.i (n),.beta.'.sub.i (n),&.beta.".sub.i (n) for determining the accuracy of the adaptation to the system.

Abstract: A steering system for a road vehicle with front-wheel steering employs microprocessor integrating feedback of the vehicle yaw rate to the front-wheel steering actuator so as to decouple the yaw movement from the lateral movement of the front axle. Sensors measure vehicle speed, yaw rate (by gyroscope), lateral front axle acceleration (by acceleromether at the front axle), and the angle at which the driver holds the steering wheel. The microprocessor controls the front steering actuator according to a formula whose dependent quantities include the sensor outputs, fixed vehicle parameters (such as wheel base), and a preselected time constant. The vehicle's handling changes when the time constant is varied.

Abstract: A device for coupling at least two spacecrafts, the latter being connected by means of at least two tether lines, between which a plurality of cross-connections are provided which run parallel to each other at a right-angle or any other angle to the tether lines so that the length of the coupled tether lines is far greater than the dimensions transverse to the imaginary longitudinal axis of the tether system. By the introduction and use of such multiple tether systems a redundant system has been made available for tether technology. As a result, the probability of failure or dropout of such a multiple tether system has been greatly reduced or largely excluded.

Abstract: The system includes for planar angular measurements a gyro--preferably a laser gyro--and an angle encoder mounted with their sensitive axes coaxially on a turntable shaft, which is rotatably mounted in a case and driven at constant speed with respect to said case. The angular rate should be high enough to operate the laser gyro above the lock-in rate. For spatial angular measurements and navigation three gyros are mounted with their sensitive axes spatially arranged with respect to the turntable shaft to sense the same component of its angular rate. For avaraging errors due to gyro scalefactor and drift, the turntable is mounted on a second shaft with is axis perpendicular to the turntable. The second shaft is provided with a second an coder and a motor rotating the second shaft. The processing of the signal readout of the gyro(s) and encoder(s) allows to increase the accuracy, resolution and bandwidth of angular measurements with respect to a locally fixed basis or to inertial space.

Abstract: In a method for manufacturing fibre-reinforced structures with a glass matrix, there is used for the glass matrix an SiO.sub.2 colloid dispersed in water as glass former, with which the fibres are impregnated, and the impregnated fibres are heated in the final form of the structure to the sintering temperature of the SiO.sub.2 colloid.

Abstract: A method of steering road vehicles having front-wheel and rear-wheel steering is provided in which by an integrating feedback of a measured yaw rate signal to the front-wheel steering the yaw motion is decoupled from the lateral motion of the front axle, the problem of steering thereby being split into two subproblems to be solved separately, that is into a lateral track guiding of the front axle by a signal which a driver generates with the steering wheel, and into an automatic control of the yaw motion, and the eigenvalues of the yaw motion can be shifted as desired by feedback of the measured yaw rate signal to the rear-wheel steering in such a manner that the choice of the yaw eigenvalues has no influence on the steering transfer function from the steering wheel to the lateral motion of the front axle.When employing the steering method according to the invention the driver no longer has to worry at all about the yaw motion of his vehicle; it is stable.

Abstract: In each arm of a Michelson interferometer (IF) a retroreflector (110; 110') having its aperture plane aligned perpendicularly to the optical axis is mounted on a respective holder (106; 106') which in turn is rigidly connected to one end of a shaft (105; 105') rotatably mounted in a connecting member (103; 103'). To the other end of the shaft (105; 105') a first gear (107.sub.1 ; 107.sub.1 ') is secured which is coupled via a toothed belt (909; 109') to an identically configured second gear (107.sub.2 ; 107.sub.2 ') which concentrically to a drive shaft (102; 102') of an electric motor (101; 101') is rigidly connected to the housing (1010; 1010') thereof. At a predetermined distance from the shaft (105; 105') the drive shaft (102; 102') is fixedly connected to the connecting member (103; 103') so that on rotation of the motor drive shafts (102; 102') the length of the optical paths is shortened in one interferometer arm and lengthened synchronously therewith in the other interferometer arm, or vice versa.

Abstract: The calibration of time-depending measurement uncertainties of gyros and inertial systems by the differences of angular and/or velocity and/or positional measurements which are carried out and repetitiously executed with a view to undetermined reference directions and/or fixed locations varying with time. The differentiation allows to forego precise reference data. Measurement uncertainties can be corrected through calibration subsequently to the measurement process. For the measurement of spatial angles a three-axis gyro measurement package comprising a computer and the possibility of feeding or automaticly reading-in of reference data characterizing the reference directions. The reference data can be a number, a marker of the measurement point or in the case of positional measurements a terrestrial aiming point. When measuring angular characteristics, i.e. the interdependence of angles and external forces or moments, the latter are considered as references.