Messerschmitt-bolkow-blohm Gmbh

Messerschmitt-boelkow-blohm Gmbh

Siemens Aktiengesellschaft

Deutsche Aerospace Ag

Daimler-benz Aerospace Ag

Lfk-lenkflugkoerpersysteme Gmbh

Daimlerchrysler Aerospace Ag

Deutsche Aerospace Patentabteilung

Deutsch Aerospace

Gert Trommer

Hans Poisel

Reinhard Mueller

Engelbert Hartl

Reinhard Muller

Wolfhardt Buehler

Manfred Borner

Wolfhardt Buhler

Martina Schreiber

Ernst-A Seiffarth

Ulrich Reinhard

Norbert Rothkirch

Manfred Boerner

Peter Jurga

Apparatus for simultaneous calibration of several multi-axis gyro systems, particularly fiber-optical gyro systems, in all measuring axes, uses a single-axle rotary table. A rotary frame is connected with the axis of rotation of the single-axis rotary table, and the gyro systems are arranged thereon in such a manner that corresponding measuring axes of the gyro systems experience an identical component of the rotation of the rotary frame, and none of the components is zero.

Arrangement for calibrating several gyro systems

A rotational rate comparator for a fiber optic gyroscope has a 3.times.3 coupler and an evaluating computer to calculate the rotational rate from photodiode signals generated by the fiber optic gyroscope. An electrical circuit is provided that is independent of the evaluating computer, and embodies an algorithm for producing at least one signal that depends on the rotational rate as a function of the photodiode signals. When the rotational rate dependent signal exceeds at least one presettable limiting value the comparator supplies an output signal.

Rotational rate comparator for a fiber optic gyroscope with a 3.times.3

A method and apparatus for determining a rate of rotation uses a fiber-optic gyro which has a 3.times.3-coupler. A first channel of the coupler is optically connected on one side with a light source and on the other side with a first photo element; and the two other channels are optically connected on one side with a fiber coil and on the other side with a second and third photo element respectively. A depolarizer is arranged at least between the light source and the 3.times.3-coupler or at one end of the fiber coil; alternatively, the fiber coil has a polarization-maintaining fiber. An electronic signal processing system is used to determine a temperature-related value, independent of the rate of rotation, for damping of the fiber coil and of the 3.times.3-coupler, based on the signals of the three photo elements and from temperature-dependent coefficients determined by calibration. Then the rate of rotation is computed based on the signals of the three photo elements, the temperature-dependent coefficients and the computed, temperature-related value for the damping.

Method for determining the rate of rotation

In the case of a fiber optic gyro having a 4.times.4-coupler, the two arms of the coupler which are not connected with the fiber coil are each connected with a monitoring detector. From the output signals of these monitoring detectors, in the case of a desired wavelength, a reference or desired quotient is formed. During the operation of the fiber optic gyro, an actual quotient is in each case formed from these output signals and is compared with the stored desired quotient. The wavelength of a semiconductor laser is controlled by controlling the operating current and/or the temperature of the light source (L) such that the two quotients are identical. The measuring signals will then be error free.

Process and an apparatus for correcting the measuring signals of a fiber

The protective cladding for a mono-mode directional coupler made of at least two incoming and outgoing fiber optic waveguides which are fused to one another along a coupling segment comprises at least two open cladding parts which can be connected to form a tube-shaped cladding. The material of the cladding parts has the same coefficient of expansion as the waveguide material of the mono-mode directional coupler. The protective cladding, being mechanically tightly connected with the incoming and outgoing fiber optic waveguides while leaving open the coupling segment of the mono-mode directional coupler, is closed off in a gas-tight manner such that in the case of temperature changes, there are no mechanical tensions in the coupling segment.

Protective cladding for a mono-mode directional coupler

A fiber optic gyroscope of the type having a 3.times.3 coupler located between a light source and a monomode fiber coil, coupling nonpolarized light into the coil end, and at least one photodetector element associated with the coupler to generate an output signal corresponding to the light intensity transmitted by the coupler. At least one contrast-adjusting element in the form of a rotationally polarizing fiber section is located between the connection on the coil side, of the 3.times.3 coupler in the length of the coil-forming monomode fiber strand. The polarization rotation angle of said fiber section is adjusted so that the output signal of the photodetector element is minimal when the gyroscope is at rest.

Fiber optic gyroscope including a 3.times.3 coupler and a contrast

A sagnac-type fiber optic gyroscope in which depolarizers are connected to both ends of the fiber coil and are then connected with the outputs of a 3.times.3 directional coupler.

Sagnac-type optical fiber gyroscope having depolarizers of differing

An optical sensor head for the directional detecting of optical radiation has an arrangement of individual optical systems that are differently sloped with their optical axes, are convergently aligned in the viewing direction and each have conical, partially overlapping viewing areas. To provide an exact bounding of the observation sector assigned to the sensor head without any impairment of the operatability, at least one outer-edge-side individual optical system of the sensor head is provided with a beam diaphragm which partially shades the assigned viewing cone. At least one of the neighboring optical systems, which is situated closer to a sensor center, is arranged with its light entrance opening approximately at the level of the diaphragm-bounded edge beams of the outer-edge-side individual optical system.

Optical sensor head with sloped, convergent optical systems and beam

A Sagnac-type fiber optic gyro having a control and analysis unit which controls the intensity and the center wave length of the light emitted from the light source in such a manner that the ratio of the output signal of the light detector to the output signal of its monitoring detector is constant.

Sagnac-type fiber-optic gyro with 3.times.coupler arrangement for

A Sagnac-type fiber-optic gyroscope having a light source, a fiber coil consisting of an optical fiber, and a receiver arrangement which are all connected with a directional coupler in such a manner that wide-band light of the light source is fed into the two ends of the fiber coil and passes through it in opposite directions, the light emerging from the ends of the fiber coil and forming an interference signal in the directional coupler which is detected. An auxiliary coil is also connected with the directional coupler into which light from the single light source is also coupled, the dimensions of the auxiliary coil and of the main coil with respect to their length and their diameter being such that a measuring range is obtained that is expanded by the auxiliary coil and in which, for the whole measuring range, unambiguous measuring values may be determined for the rate of rotation of the fiber-optic gyroscope.

Sagnac-type fiber-optic gyroscope with auxiliary fiber coil

The damping of the fiber coil of a fiber gyroscope is automatically corrected or newly determined in a microprocessor by repeating a calculation program in which a previously known damping factor of the fiber coil is replaced by a more recently determined damping factor. The calculation program is repeated until the calculated damping factor converges toward a fixed value. In this way, changes in the damping factor, e.g. due to aging of the fiber coil, due to splicings in the fiber coil, are ascertained and automatically corrected.

Method for self-correction of a fiber gyroscope with a 3.times.3-coupler

An analog-digital converter having an analog integrator which integrates the difference between the analog input signal and a signal from, for example, a digital-analog converter controlled by a microprocessor, whereby a high resolution and a very high operating speed are rendered possible with a relatively low degree of complexity and minimal noise.

Apparatus for converting analog signals into digital signals

The light mixing device for the uniform spectral and intensity-related distribution of light coming in from n.times.n optical fibers to n.times.n outgoing optical fibers. The incoming and the outgoing optical fibers are distributed into n groups of n each respectively, each group of optical fibers being optically connected with a first front face of a mixer lamina. The n mixer laminae of the incoming optical fibers are stacked and arranged to form a first stack, and the n mixer laminae of the outgoing optical fibers are stacked and arranged to form a second stack, in each case congruently and above one another in such a manner that the free second front faces of the mixer laminae of both stacks form one surface respectively. The surfaces of both stacks are directed against one another and arranged in a manner in which they are rotated by 90.degree. with respect to one another, and are subsequently optically connected with one another.

Light mixing device

A Sagnac-type fiber-optic gyroscope having a light source, a fiber coil consisting of an optical fiber, a receiver arrangement which are all connected with gates of a directional coupler, in which the light fed into the fiber coil interferes with the light emerging from the fiber coil in a coupling area and the rate of rotation of the fiber-optic gyroscope is determined from the interference signals. In order to achieve a working point which is situated in or close to the quadrature point, the directional coupler is developed as a 4.times.4 coupler between the arms of which fixed phase relations are provided in the coupling area.

Sagnac-type fiber-optic gyroscope

A method and system for evaluating signals from a fiber optical gyro employs a 3.times.3-coupler which makes it possible to ascertain a precise Sagnac-Signal in spite of the fact that the fluctuations of the optical characteristics of the fiber coil are unknown. Thus, a high precision is assured, while simultaneously reducing the quality requirments for the optical components of the system.

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Munich, Germany

Gert Trommer