Abstract: A method and device for reading out a fiber gyroscope based on the concept of determining, by gating the light signal for particular time intervals, only one particular phase section of the read-out signal of a photodetector of the fiber optic gyroscope modulated with a periodic function. Further phase sections are determined in sequence and cyclically in the same manner so that the entire photodetector signal is detected after one full cycle. Signals associated with individual phase sections are averaged separately and processed to obtain a rotation rate-proportional signal. The read-out signals can also be processed so that a control signal for deviation of the phase modulator is obtained and/or the gyroscope scale factor is stabilized.

Abstract: A fiber optic interferrometer rotation rate sensor is reset by phase ramp via a digital control circuit using as demodulation signal within the control circuit a signal (d) that is statistically independent of all parasitic signals and originates from a modulation signal generator that includes a random number generator. A reversal of the phase modulator signal is provided in a statistically distributed manner to integral values of .pi./2 of the interferometer characteristic. The arrangement avoids deadband and removes scale factor nonlinearities, particularly at low rates of rotation.

Abstract: Optoelectronic positioning tap circuit arrangements of the type in which a beam from a light source irradiates two adjacently arranged diodes connected at their cathode ends and further including an element that is perpendicularly movable with respect to the beam path to partially shade the beam and supply a signal proportional to the difference between the diode currents, such signal characterizing the position of the shading element in the light beam. Sensitivity is increased by utilizing both diode currents to achieve a deflection-proportional output signal by short-circuit current meansurement. Existing current sum points are decoupled as each of the (three) terminals of the series diode circuit is connected to a single current/voltage converter stage. The current sum is directly detected at the input of the voltage converter stage that is connected to the (coupled) cathodes to control the operating point of the light source.

Abstract: In a fiber optic interferometer rotation rate sensor reset by phase ramp via a digital control circuit to undertake the reversal required to obtain the scale factor error information, a reciprocal, alternating phase shift that is not a function of the angle of rotation, but has a fixed timing, is synchronized with gyroscope modulation frequency to avoid lock-in, and scale factor nonlinearities, particularly in the case of low rates of rotation. Even in the case of low rates of rotation, a scale factor error correction is possible and lock-in, caused by variations in bias in the case of the modulation deviation reversal, is avoided.

Abstract: A method for preventing errors in the Doppler radar measurement of velocity in aircraft that result from the radar receiver being locked to backscatter from side lobes of a plurality of main lobes radiated in a fixed radiation geometry. The inertial vertical velocity component (V.sub.IZ) obtained by a baro-inertial control loop is compared with the vertical velocity component (V.sub.DZ) determined from the Doppler frequencies to derive an error detection signal. When the error signal occurs, the inertial vertical velocity component replaces the corresponding velocity component supplied from the Doppler system while the horizontal velocity components are determined, for example, from the last calculated wind and the corresponding airspeed components, for the duration of the error signal.

Abstract: A micromechanical bending spring joint is formed of selectively etched wafer material. The joint includes a pair of leaf springs arranged alongside each other. Each spring is inclined at an oblique angle to the opposed surfaces of the wafer and such springs cross to define a point of intersection. The joint, selectively etched from a single wafer, is characterized by high precision of fulcrum position, bending spring constant and transverse axis rigidity.

Abstract: A method is disclosed for determining the heading of an aircraft which is equipped with both an inertial navigation system and a device capable of receiving navigation satellite signals and computing the aircraft's position, speed and acceleration therefrom. While the aircraft is still on the ground and before flight operations begin, an initial alignment of the inertial navigation system with an earth-fixed coordinate system is performed, and during this alignment, data corresponding to the initial attitude of an aircraft-fixed coordinate system relative to the earth-fixed coordinate system is also determined and stored. Thereafter, during flight operations, the acceleration vector of the aircraft relative to the aircraft-fixed coordinate system is measured by the inertial navigation system and then transposed into a coordinate system which has been horizontally aligned with the earth-fixed system using the initial attitude data.

Abstract: A method and apparatus for stabilizing relatively high-dynamics devices (e.g. a sight) mounted on a low-dynamics support such as a tank. Movement of the low-dynamics support is determined by means of an inertial central sensor block that may comprise a strapdown set of gyros or gyros and accelerometers. Stabilization is achieved by a two-step process in which the individual high-dynamics devices are stabilized with respect to the support by means of large bandwidth control loops. The much slower support movement is applied to a superposed loop of appropriately smaller band-width. Compensation thereby takes place by specifying a reference value for the control loops of the higher-dynamics devices.

Abstract: A method for determining the flight altitude h above ground of an aircraft equipped with a radar altimeter and an additional (baro-inertial) altitude measuring device or a course and position reference system capable of determining altitude. The method relies upon restriction of high-frequency emissions from the radar altimeter to very short periods of time. The radar altimeter measures h.sub.RO within the high-frequency intermission intervals to calibrate the altitude value supplied by the other altitude-measuring device. The method permits the omission of any radar altimeter from aircraft-launched missiles without degrading system performance.

Abstract: Apparatus, suitable for a laser ring resonator, for superposing of two light beams that interfere at an angle of divergence and form a pattern of interference fringes at an observation location. The apparatus consists of two prism parts that are cemented to one another at a common internal connecting surface. The prism parts have slightly differing base angles. A partial region of the internal connecting surface between the two partial prisms is provided with a partially-transmitting mirror coating. A non-totally-reflecting partial coating on both outer surfaces of the prism parts has a greater refractive index than the internal medium of the prism parts and covers regions of the possible first light incidence points of light beams passing through the partial prisms from specified light entrance points at the base. The two partial prisms cemented to one another are connected, on the base side, to the glass substrate of a mirror for coupling-out light.

Abstract: A method for the determining route angle and for automatically calibrating course accuracy with a three-axis magnetometer fixed to an aircraft despite the presence of interfering vehicle magnetic fields and instrumentation errors. The method is accomplished in flight and includes numerous computations to compensate the magnetometer's principal error sources. A calibration flight includes specified flight maneuvers (without change of position). The method is particularly suitable for helicopters equipped with three-axis magnetometers.

Abstract: Apparatus for stabilization and control of an aircraft includes a pair of strapdown devices that are rigidly fixed in space relative to one another. Each device includes two two-axis gyroscopes, permitting the generation of triple redundancy. The measurement axes (M.sub.11, M.sub.12 and M.sub.21, M.sub.22) have different arrangements in the horizontal plane. The redundant axis of each strapdown device is arranged in such a way (preferably at 45 degrees) that an allocation to the two horizontal measurement axes is provided by computational transformation.

Abstract: A synchronous demodulation system with digital signal output contains a summation circuit receiving an input signal to be demodulated and a control signal. The output of the summation circuit is applied to a synchronous demodulator which feeds into a controller. The controller comprises an integrator, which precedes an A/D converter and a processor that acquires the output pulses of the A/D converter. The processor drives a D/A converter supplying the control signal to the summation circuit so that the summation of the input signal and the output of the D/A converter, averaged over time, leads to an (approximately) zero signal in the synchronous demodulator. Due to digital control the circuit is distinguished by a large dynamic range and high accuracy with simultaneous insensitivity.

Abstract: A rotation rate readout method employing a passive optical resonator. The ring resonator is operated at approximate resonance in reflection and rotation rate-dependent phase shifts are detected, in particular as first harmonics, in the resonator. Two partial light beams are first frequency shifted by equal and opposite amounts, such frequency shift being modulated. Light components coupled out of the resonator pass through a mode filter in the opposite direction and are detected as an interference signal by an opto-electronic converter. The latter signal is demodulated with respect to the modulation frequency or its harmonics and the rotation rate signal obtained therefrom. Self-compensation of the optical and electronic readout systems may be attained by periodic brief and strong damping of the ring resonator.

Abstract: A process for producing a laser cathode by vacuum coating provides well-controlled, slow layer growth in the presence of the laser gas at a total pressure of up to 5.times.10.sup.-4 mbar. Such process includes laser gas atoms in the cathode layer. Without interruption of the vacuum, the coated cathode is moved into a (second) position and laser gas is introduced under slight pressue against the cathode coating by means of a nozzle. At the same time, a number of discharge cycles are initiated via the electrically conductive base of the cathode basic element and an electrode, arranged concentrically with respect to the nozzle, having the effect of premature sputtering-off to cause a levelling of the current density and a further inclusion of inert gas atoms in the Al coating. After a number of discharge cycles, a small amount of oxygen may be added to form an Al.sub.2 O.sub.3 passivation layer before flooding of the recipient.

Abstract: A navigation method for independently determining direction and for determining course for aircraft with low quality gyros and an external, calibrated magnetic course sensor. The method, which functions in the event of failure of the magnetic course sensor, is based upon the concept of determining, from the magnetic course last determined prior to failure as corrected by the local declination, and the true course as determined by the quotient of the two gyro horizontal axes distorted by the gyro drift, a "synthetic magnetic course" for course support.

Abstract: A method for determining the horizontal airspeed of a helicopter in the high speed (v.sub.e >20 m/s) range. Pitch angle and the longitudinal control signals are recorded by sensors such as an inertial navigation system and a potentiometer connected to the pilot's control lever. Equivalent speed signals are calculated from the measured pitch angle and longitudinal control signals by means of calibration equations. These signals are then filtered and weighted. The horizontal airspeed is then derived from the sum of the weighted signals divided by the sum of weighting factors k.sub..theta. and k.sub..delta.x determined in accordance with the sensed pitch angle and longitudinal control signals. The horizontal velocity signal may be filtered, if necessary.

Abstract: Method and apparatus for angular rate measurement and digital angular rate readout by means of a fiber interferometer using the Sagnac effect. Three component light beams are generated by means of an acousto-optical modulator which is operated in the Raman-Nath region. One component light beam is introduced unmodulated in a first direction into a fiber coil while the second and third component light beams are introduced with raised and lowered frequencies, respectively in the opposite direction. After passing through the coil, the component light beams are received by a photodetector and fed to controllers for generating the differential frequencies. Weighted, the differential frequencies are subtracted from each other or summed and evaluated as the angular rate and/or measures of the temperature of the fiber coil.

Abstract: A method and apparatus for reading out angular rates by means of a passive optical resonator provides for the generation of three component light beams individually tuned to distinct resonator modes. One component light beam is radiated into the resonator in the opposite direction to the two other component light beams. By means of an evaluating logic, differences are formed between the counterrotating light beams and the differences weighted and subtracted from each other to provide angular rate. The optical length of the resonator, and, thus, temperature are available as a weighted sum of the differences. Temperature drift may be eliminated from angular rate measurements by compensation according to the invention.

Abstract: A method is disclosed for determining the horizontal airspeed of helicopters in low speed ranges. At least three control functions, .theta..sub.o,i (collective pitch), .theta..sub.s,i (longitudinal control) and .theta..sub.c,i (lateral control) are measured. The magnitude of the horizontal airspeed, V.sub.H,i, is determined from its known relationship to .theta..sub.o,i. This magnitude is included in non-linear calibration equations .theta..sub.s (V.sub.H, .psi.) and .theta..sub.c (V.sub.H, .psi.) and control profiles .theta..sub.s (V.sub.H,i, .psi.) and .theta..sub.c (V.sub.H,i, .psi.) are derived therefrom. The measured values .theta..sub.s,i and .theta..sub.c,i are applied to the respective control profiles and corresponding phase pairs .psi..sub.s,1, .psi..sub.s,2 and .psi..sub.c,1, and .psi..sub.c,2 located. The pairs are compared and the incident flow angle .psi..sub.i is determined as the value common to the two pairs.