153 results about "Fiber optical gyroscope" patented technology

An integrated optical circuit for use in a fibre optic gyroscope which senses rotation rates by determining a phase shift due to the Sagnac Effect between light beams travelling around an optical fibre sensing loop (4) in opposite directions, the circuit being provided on a silicon-on-insulator chip comprising a layer of silicon separated from a substrate by an insulating layer, the circuit comprising: rib waveguides (11) formed in the silicon layer for receiving light from a light source (2) and transmitting light to a light detector (3), fibre optic connectors (9) in the form of grooves etched in the silicon layer for receiving the respective ends of the optical fibre sensing loop (4); rib waveguides (11) formed in the silicon layer for transmitting light to and from said fibre optic connectors (9) so as to direct light beams in opposite directions around the sensing loop (4) and receive light beams returning therefrom, phase determining means and (13,17,31) integrated in silicon layer for determining a phase shift between the light beams returning from the sensing loop (4).

The invention discloses a modulation and demodulation circuit of fiber option gyroscope (FOG) open-loop signals. The circuit adopts a monolithic LVDT integrated circuit (IC) for modulating and demodulating an FOG open-loop signal, generating a sinusoidal signal, synchronously detecting and dividing one odd harmonic amplitude and one even harmonic amplitude and acquiring the tangent value of a mobile signal phase by low-pass filtration. The invention uses the monolithic LVDT IC to realize the four functions, i.e., sinusoidal signal generation of a drive phase modulator, synchronous detection, the elimination of light-source light-intensity fluctuation influence and low-pass filtration and greatly simplify a signal-processing circuit; the monolithic LVDT IC outputs the tangent value of a mobile signal phase so that when the phase increases and trends to pi / 2, the tangent value bends upwards, does not trend to saturation and reduces the error of a complementary tangent operation; and a division operation is internally realized by the monolithic LVDT IC so that a digital signal processor at a high price can be replaced by a monolithic computer at a low price for non-linear corrosion.

The invention aims at providing a novel CKF(Crankshaft Fluctuation Sensor)-based SINS (Ship Inertial Navigation System) large misalignment angle initially-aligning method comprising the following steps of: determining an initial position parameter of a carrier by using a GPS (Global Position System); acquiring data output by an optical fiber gyroscope and a quartz accelerometer; finishing the coarse alignment of the system by using an analysis method; preliminarily determining the posture information of the carrier; establishing an initial aligning nonlinear model of a strapdown inertial navigation system; establishing a CKF filtering state equation by taking the speed error as the state variable and a measuring equation by taking the speed error as the measurement quantity under a static base; carrying out filtering estimation by using a CKF filtering method to estimate the misalignment angle of the platform; and obtaining an accurate strapdown initial posture matrix by using a strapdown initial posture matrix of a platform misalignment angle correcting system, thereby finishing the accurate initial alignment. The invention can greatly improve the aligning precision of the strapdown inertial navigation system at the large misalignment angle and provide the accurate strapdown initial posture matrix for the navigation process.

The invention firstly provides a multi-stage control device for the dynamic tension of an optical fiber winding machine. The device comprises a paying-off wheel and a taking-up ring and further comprises a guide wheel A and a guide wheel B. The paying-off wheel, the guide wheel A and the guide wheel B are fixedly arranged in sequence from left to right. The taking-up ring is movably arranged at the tail end of the right side. A tensioning wheel capable of vertically moving is arranged between the guide wheel A and the guide wheel B. The lower portion of the tensioning wheel is sequentially and fixedly connected with a tension and pressure sensor and a micromechanism. The tensioning wheel and the tension and pressure sensor can vertically move at the same time through the micromechannism. The paying-off wheel is connected with a paying-off wheel motor. The micromechanism, the tension and pressure sensor and the paying-off wheel motor are connected with an upper computer. The invention further provides a multi-stage control device for the dynamic tension of the optical fiber winding machine. The multi-stage control technology is adopted, the control precision of the tension of an optical fiber and the quality of an optical fiber loop are improved, it is effectively guaranteed that the optical fiber loop is evenly wound, and the requirement of a high-precision optical fiber gyroscope is met.

A fiber optic ring interferometer, such as an interferometric fiber optic gyro (IFOG), with a sensing loop doubler. The IFOG device includes a light source, a circulator in optical communication with the light source and a photo diode, an integrated optical chip (IOC) capable of splitting light emitted from the circulator into two paths each of which is capable of being modulated, the IOC further being capable of combining light from each of the two paths when light travels in a direction towards the circulator, a fiber coil, and a polarization maintaining (PM) combiner / splitter disposed in between the IOC and the fiber coil. The PM combiner / splitter operates to send light through the fiber coil a first time in a first polarization state and to subsequently send the same light a second time through the fiber coil in a second orthogonal polarization state, whereby light travels twice the distance compared to a single loop IFOG device and, as such, effectively doubles the LD product.

The invention discloses a method for improving angular displacement measurement accuracy of an optical fiber gyroscope. The method comprises the following steps of: (1) fixing the optical fiber gyroscope on a high-accuracy rotary table to keep a measuring shaft of the optical fiber gyroscope in parallel to a rotating shaft of the high-accuracy rotary table; (2) marking scale factors of the optical fiber gyroscope at different rotary table input angular rates to acquire a correspondence table between the angular rates and the scale factors; (3) taking the optical fiber gyroscope off the high-accuracy rotary table and fixing on a measured rotating device to keep the measuring shaft of the optical fiber gyroscope in parallel to the rotating shaft of the measured rotating device; (4) solving an average value of output values of the optical fiber gyroscope in a testing time under the condition that the measured rotating device is static; (5) rotating the measured rotating device and continuously recording each output value of the optical fiber gyroscope; and (6) calculating a rotation angle, namely the angular displacement of the rotating device by using the correspondence table in thestep (2), the output average value in the step 4 and each output value in the step (5).

The invention discloses a method for restraining speed errors of a single-shaft rotation optical fiber gyro strapdown inertial navigation system. The method comprises the following steps of: 1. acquiring carrier position information through a global positioning system (GPS); 2. acquiring data output by an optical fiber gyro and a quartz accelerometer; 3. driving an inertial component to perform single-shaft forward and backward rotation and stop motion by a rotary mechanism, and adopting a rotation scheme that eight rotation and stop sequences are used as a rotation period; 4. acquiring information of linear velocity and angular velocity of the motion of measurement carriers of the optical fiber gyro and the quartz accelerometer, and performing navigation solution to obtain navigation information; and 5. constructing a Butterworth band elimination filter, and performing Butterworth filter processing on the carrier velocity obtained under a navigation system. According to the method, the Butterworth band elimination filter is designed according to the rotation angular velocity, oscillation error items related to the rotation angular velocity under the navigation system are filtered and removed, and the velocity information accuracy is improved.

The invention discloses a method and a system for measuring frequency characteristics of a high-speed FOG (Fiber Optical Gyroscope). The method comprises the steps of logically generating a pseudorandom sequence test digital signal according to the generation of a pseudorandom sequence; processing and converting the pseudorandom sequence test digital signal into a pseudorandom sequence test analog signal, and inputting the pseudorandom sequence test analog signal to a driving motor of an angular vibration table to be used as a rotary input signal; enabling the angular vibration table to drive a to-be-measured high-speed FOG to run, and obtaining an output signal sequence of the to-be-measured high-speed FOG; collecting an angular speed analog signal of a speed measuring motor, and obtaining a digital signal sequence of the speed measuring motor; computing the output signal sequence of the to-be-measured high-speed FOG and the digital signal sequence of the speed measuring motor, and obtaining a frequency response function of the to-be-measured high-speed FOG, wherein the frequency response function comprises amplitude-frequency characteristics and phase-frequency characteristics; completing the measurement. The method disclosed by the invention can be used for quickly and accurately measuring the frequency characteristics of the high-speed FOG and has the characteristics that the frequency resolution is high, the measured frequency range is large, the amplitude-frequency characteristics and the phase-frequency characteristics of the high-speed FOG can be simultaneously measured, the noise suppression effect is good, the measuring speed is fast, and the like.

The present invention relates to a method for detecting deformation of underwater engineering structure based on fiber-optical gyro technology and its equipment. It is formed from fibre-optical gyroscope, line speed sensor and signal receiving and storing unit which are packaged in a closed container. Said method and its equipment utilize the characteristics of the fiber-optical gyroscope sensingangle speed, said closed container can be pulled and moved along tested object, and the data measured by said gyroscope and line speed sensor can be processed so as to obtain its I-D or 3-D movement trace by means of calculating according to the formula, i.e. I-D or 3-D deflection and deformation of tested object.

A detachable framework used for winding optical fiber coils and a method of producing optical fiber coils with this framework. A framework with a suitable structure is designed considering comprehensively three factors, i.e., the window ratio of an optical fiber coil, the precision of an optical fiber gyro and the easy detachment of the framework from the optical fiber coil. A surface treatment with the framework is performed by coating a layer of thermosol on the surface of the framework so the optical fiber coil can be easily detached from the framework after curing. The required length of optical fiber is winded around the optical fiber coil framework, accompanying with vacuum pressure impregnating with curing adhesive after winding and optical fiber coil curing subsequently. The framework is taken off from the optical fiber coil under the heating circumstances, thereby completing production of the non-framework optical fiber coil.

The invention discloses a method for evaluating the input axis misalignment angle of an optical fiber gyroscope. The optical fiber gyroscope is mounted on a rate rotary table. The method comprises the following steps: Firstly, the OZ axis of the gyroscope is caused to be parallel to the rotation axis of the rotary table, the average value of the gyroscope output is sequentially tested and recorded with a given input angle rate when the rotary table rotates within single-circle time in positive rotation and reverse rotation; then the minus OZ, plus or minus OX and plus or minus OY axes of the optical fiber gyroscope are caused to be parallel to the rotation axis of the rotary table, the testing process above is repeated. By processing all the six groups of data, the value of the input axis misalignment angle of the optical fiber gyroscope is accurately calculated. The method is simple in operation and short in testing time and simultaneously ensures the correctness and accuracy of the test value.

A photonic crystal interferometric optical gyroscope system including a light source for providing a primary beam of light, a photonic crystal sensing coil having a rotational axis, and a beam controlling device configured to split the primary beam into first and second counter-propagating beams in the photonic crystal sensing coil and configured to direct return of the counter-propagating beams wherein the power of the returning counter-propagating beams represents the phase shift between the counter-propagating beams and is indicative of the rate of rotation of the coil about the rotational axis.

The invention discloses a method for reducing temperature sensitivity of optical fiber gyroscope scale factors without a refrigerating light source. The method comprises the following steps of: removing a light source refrigerating circuit from an optical fiber gyroscope, controlling the temperature of the light source of the optical fiber gyroscope via an incubator according to a series of pre-selected temperature points, measuring the average wavelength of the light outputted from the light source with a spectrometer to obtain a table of the average wavelength and the temperature points, and placing the table into a memorizer of a table look-up module in correction step; adding average wavelength correction step, real-time collecting a temperature signal with a thermometer, looking up the table to obtain the average wavelength value under certain temperature according to the temperature signal, and performing average wavelength correction to the original output data of the optical fiber gyroscope according to the value. The corrected data is used as new output data of the optical fiber gyroscope, and the scale factor of the new output data is irrelevant to the average wavelength, so as to reduce the temperature sensitivity of the scale factor of the optical fiber gyroscope without refrigerating light source, thereby simplifying the system, reducing power consumption and heating value, improving the internal thermal environment, and improving the reliability.

The invention provides an integrated attitude determination method without external observed quantity for a modulated strapdown system. The method comprises the steps of: determining initial position parameters of a carrier by a global positioning system (GPS) and binding the parameters to a navigation computer; acquiring data output by a fiber optic gyros and a quartz accelerometer, and processing the data; setting an inertial measurement unit (IMU) single shaft four position rotation stopping scheme; converting the accelerometer output to a carrier semi-fixed coordinate system; designing an infinite impulse response (IIR) digital high-pass filter, and carrying out filtering on the carrier velocity resolved under a navigation system; subtracting the filtered velocity from a velocity calculated by the modulated strapdown system, and using the difference as a system observed quantity; and estimating attitude information of the modulated strapdown inertial navigation system by a Kalman filtering technique. The method provided by the invention does not need external auxiliary equipment to provide observation information, and can effectively solve the problem of mismatching between the frequency of information supply by the auxiliary equipment and the frequency of cultivation of the modulated strapdown system, and realize integrated attitude determination of the modulated strapdown inertial navigation system.

The invention aims to provide a high-precision interference type optical fiber gyroscope temperature drift error model optimizing method. According to the method, optical fiber ring temperature product quantity T*delta T, optical fiber ring temperature T and optical fiber ring temperature variable quantity delta T jointly serve as optimal input quantities of an interference type optical fiber gyroscope temperature drift error basic model, and an interference type optical fiber gyroscope temperature drift error optimization model is realized by adopting RBF-ANN; a temperature drift error measured value is obtained by a temperature increasing and reducing test, a temperature drift error estimated value is obtained by estimating an optimization model, and the precision of the optimized model is verified by comparing the temperature drift error measured value and the estimated valve. According to the method, the adopted optimal input quantities are more integral, the temperature drift error model is described more precisely, the accuracy, the real-time property and the universality of interference type optical fiber gyroscope temperature drift error estimation are improved, and the stability and the reliability of output data of the interference type optical fiber gyroscope are guaranteed.

The invention discloses an optical fiber strapdown inertial navigation high-precision positioning system and method for an underwater bathyscaph. The optical fiber strapdown inertial navigation high-precision positioning system comprises a navigation solution module, a global positioning system module, a strapdown inertial navigation receiving module, a Doppler speed-measuring module and an information fusion filtering module. An optical fiber gyroscope, an accelerometer and a magnetometer in the strapdown inertial navigation receiving module output the navigation attitude, the speed and position initial information, data output by the optical fiber gyroscope are subjected to error processing and correction through a dynamic Allan variance method, the processed data pass through the navigation solution module to obtain the velocity, position and attitude information of a carrier, finally the velocity information of the carrier is subjected to fusion and filtering error correction through the information fusion filtering module, and thus the underwater bathyscaph is precisely positioned. High-precision, high-reliability and high-real-time-property positioning and navigation of the underwater bathyscaph are achieved, and the deficiency of accuracy of position information of a traditional navigation system is overcome.

The invention provides a method and equipment for calibrating a fighter weapon system by a fiber-optic gyroscope. The equipment comprises an azimuth and posture determining instrument and fighter vertical axis azimuth determining equipment, wherein the azimuth and posture determining instrument comprises an azimuth and posture regulator, a second fiber-optic gyroscope module is mounted on the azimuth and posture regulator, a computer for analyzing azimuth angle data is embedded into the second fiber-optic gyroscope module, an electronic optical aligner and a display are mounted on the second fiber-optic gyroscope module, both an integral solving module of the second fiber-optic gyroscope module and the display are connected with the computer through data transmission interfaces, the computer is connected with an integral solving module of a first fiber-optic gyroscope module through a data transmission interface, and the fighter vertical axis azimuth determining equipment can measure the current vertical axis direction of the fighter and indicate the direction through a cross line of sight, displayed in a level eyepiece. The method and the equipment have the advantages that steps in the process for calibrating fighter weapons can be effectively simplified, the calibrating efficiency can be effectively improved and the affect of natural factors can be prevented.

The invention provides a fiber optic acoustic wave sensing cross-dipole acoustic wave well-logging system and a measurement method thereof. The fiber optic acoustic wave sensing cross-dipole acousticwave well-logging system comprises an in-well fiber optic acoustic wave sensing cross-dipole acoustic wave well-logging device, the in-well fiber optic acoustic wave sensing cross-dipole acoustic wavewell-logging device comprises a cylindrical structure instrument shell and a fiber optic acoustic wave dipole sensor; and a fiber optic gyroscope, a sound insulation body short section and a dipole acoustic source generator are perpendicularly and sequentially mounted on the lower part of the fiber optic acoustic wave dipole sensor. A ground wellhead well-logging vehicle controls going down intoa well and rising from the well of the in-well fiber optic acoustic wave sensing cross-dipole acoustic wave well-logging device, provides a power supply for the in-well fiber optic acoustic wave sensing cross-dipole acoustic wave well-logging device, and drives the dipole acoustic source generator to continuously and repeatedly emit a dipole acoustic wave signal during operation; and a ground DASmodulation and demodulation instrument emits a laser pulse into the fiber optic acoustic wave dipole sensor, and collects a backscattering rayleigh wave inside the fiber optic acoustic wave dipole sensor. The fiber optic acoustic wave sensing cross-dipole acoustic wave well-logging system can work for a long time at the high temperature and realize the function of high-speed upward-transmission ofdata.

The present invention provides a novel detection method of an optical fiber gyroscope, wherein the detection ports are a reciprocal port (I port) and a nonreciprocal port (II port) of an interferometric depolarization fiber optic gyroscope, and the signal processing adopts the differential signal processing manner. The method comprises that: the optical structure of the interferometric depolarization fiber optic gyroscope for testing requires that lyot depolarizers are respectively added between the light source and the light source coupler, the light source coupler and the optical fiber ring coupler, and the optical fiber ring coupler and the optical fiber ring, the phase modulation adopts the sine signal having optical fiber gyroscope eigenfrequency, the amplitude of the sine signal is correspondingly adjusted so as to make the modulation depth value be stabilized to near 1.841, a dual-channel photoelectrically balanced detector is utilized to concurrently detect the reciprocal port (I port) and the nonreciprocal port (II port) of the interferometric depolarization fiber optic gyroscope, the two electrical signals being subjected to photoelectric conversion are subjected to normalization and then are subjected to a differential treatment, and the differential result is utilized to demodulate the gyroscope signal. With the method of the present invention, the random walk of the optical fiber gyroscope can be effectively reduced, and the zero-bias stability of the optical fiber gyroscope can be improved.

The invention provides an error suppressing method of a fiber strap-down inertial navigation system based on three-axis rotation. The error suppressing method comprises the following steps: determining an initial position parameter of a carrier by using a GPS (global positioning system); collecting data output by a fiber-optic gyroscope and a quartz accelerometer; determining attitude information of the carrier according to relationship of output of the accelerometer and gravity acceleration as well as relationship of output of the gyroscope and the rotational angular velocity of the earth, and accomplishing initial alignment of the system; employing an indexing scheme of a rotational period of twelve rotation-stop orders by IMU (inertial measurement unit); converting data generated by the fiber-optic gyroscope and the quartz accelerometer after rotation of the IMU to be in navigation coordinate system to obtain a modulation format of constant deviation of an inertial unit; updating a strap-down matrix by utilizing an output value of the fiber-optic gyroscope; and calculating position information of the carrier after the IMU is rotated and modulated. With the adoption of the error suppressing method disclosed by the invention, constant deviation of the inertial unit in three-axis direction can be modulated, thereby navigation positioning precision is improved.

A resonator fiber optic gyroscope (RFOG) is provided. The RFOG includes a gyroscope resonator having a clockwise input port and a counter-clockwise input port; a first laser configured to couple a clockwise optical beam into to the clockwise input port; a clockwise Pound-Drever-Hall modulation generator to modulate the clockwise optical beam with a resonance tracking modulation before the clockwise optical beam is coupled into the clockwise input port; bias correction electronics; FSR-detection-and-servo electronics including a switch communicatively coupled to the clockwise Pound-Drever-Hall modulation generator; a clockwise transmission detector configured to receive an optical beam output from the counter-clockwise input port and output signals to the bias correction electronics and the FSR-detection-and-servo electronics; and a second laser configured to couple a counter-clockwise optical beam into to the counter-clockwise input port, wherein the FSR of the gyroscope resonator is measured based on the Pound-Drever-Hall modulation of the clockwise optical beam.

The invention discloses an off-line wavelet denoising fast initial alignment method which has the advantages that the initial coarse alignment time of a high-precision strapdown inertial system is further reduced, and the accuracy is further improved. The method comprises the following steps of (1) acquiring sensor data comprising data of an optical fiber gyroscope and a quartz flexible accelerometer; (2) establishing initial alignment coordinate systems comprising an initial carrier coordinate system, an initial navigation coordinate system, an initial earth coordinate system, a carrier coordinate system, a navigation coordinate system, an earth coordinate system and an inertial coordinate system; (3) establishing a gravity apparent motion vector model, and constructing an off-line wavelet denoising algorithm; (4) utilizing a gravity apparent motion vector subjected to denoising and filtering for calculating an optimum initial attitude; (5) utilizing the calculated optimum initial attitude quaternion and using an attitude matrix chain rule to realize a fast initial alignment process. According to the off-line wavelet denoising fast initial alignment method provided by the invention, the calculation accuracy and the efficiency of an initial alignmentalgorithm are effectively improved, and the application range is wide.

The present invention discloses a spraying demonstration device of adopting the machine vision and a fiber optic gyroscope to position cooperatively. The spraying demonstration device comprises a demonstration powder room on which a spray gun device is arranged, a first camera is arranged on the side wall of the demonstration powder room, and a second camera is arranged at the top of the demonstration powder room. The spray gun device is equipped with the fiber optic gyroscope used for acquiring the poses of a demonstration spray gun, and the fiber optic gyroscope is connected with an external multi-shaft controller. According to the present invention, by utilizing the first camera and the second camera to substitute for the complicated mechanical mechanisms in the prior art to obtain the coordinate parameters of the spray gun device, and utilizing the fiber optic gyroscope to obtain the pose parameters of the spray gun device, and using the multi-shaft controller to obtain the coordinate parameters and the pose parameters and then drive a manipulator to reappear the operation process of a demonstration mechanism, the defects that a conventional multi-shaft manipulator is complicated in demonstration mode, the technical requirements are high, etc., can be solved, the flexibility of a multi-shaft manipulator spraying working mode is improved, and the purposes of simplifying the structure of the demonstration device, reducing the production cost, improving the flexibility of the demonstration device and expanding the working range are achieved.

The invention belongs to the technical fields of optical fiber sensing and inertial navigation, and relates to a closed loop fiber-optical gyroscope temperature compensating method. The closed loop fiber-optical gyroscope temperature compensating method is characterized in that a Y waveguide half-wave voltage substitutes temperature information to carry out temperature compensation on a closed loop fiber-optical gyroscope by using the approximate linear relationship between the Y waveguide half-wave voltage change and the temperature change of the closed loop fiber-optical gyroscope, and a four state modulation-based double-loop closed loop fiber-optical gyroscope is used to extract the change information of the waveguide half-wave voltage with the temperature in real time in order to realize the temperature sensor-free closed loop fiber-optical gyroscope temperature compensation. The method simplifies the design of software and hardware of a circuit, further reduces the size of the gyroscope, increases the compensation precision, has the characteristics of simple realization method, low cost and high reliability, and is of great significance to increase the temperature change precision of the fiber-optical gyroscope and further expand the application field of the fiber-optical gyroscope.

Disclosed is a method and apparatus for modulating the phase difference between a pair of optical waves that exit a Sagnac interferometer, and, more particularly, one that is commonly employed as a fiber gyro, and includes a detector responsive to phase difference between the pair of waves that exit the interferometer, and a phase modulator that forms part of two control loops that are instrumental in deriving an accurate measurement of rotation rate. As disclosed herein, phase modulation applied equally to the pair of waves as they counter-propagate through the phase modulator induces modulation of the phase-difference between the two waves as they exit the interferometer. This phase difference modulation includes (i) a bias phase-difference modulation component having a selected frequency, amplitude, and waveform, (ii) a rotation-rate feedback phase-difference component that is equal in magnitude to, and opposite in sign of, the Sagnac phase difference, so that the sum thereof is controlled to be substantially zero, and (iii) a calibration feedback phase-difference modulation component that is characterized by a predetermined phase difference magnitude having substantially alternating positive and negative sign values.

The invention discloses an angular displacement optical fiber gyroscope, which comprises an optical path part and a circuit part. The optical path part consists of an optical fiber ring, a Y waveguide, a coupler, an optical source and a detector; in the optical path part, an optical signal generates phase shifting through a Sagnac effect; the phase-shifting signal parasitizes in interference optical intensity and is converted and output as a detector signal (electric signal) by the detector; in the circuit part, the detector signal output by the detector is subjected to signal amplification and conversion through a preliminary amplifier and an analog-to-digital conversion circuit; and the circuit part also comprises a circuit resolving unit logic circuit; the circuit resolving unit logic circuit resolves the rotation angle information of the optical fiber gyroscope through carrying out digital signal demodulation, digital filtering and integral treatment on the amplified and converted detector signal, judges and outputs an angle direction. The angular displacement optical fiber gyroscope has the advantages that a program, logic and the like for processing the signal in the circuit part are innovated and improved, so that the optical fiber gyroscope has an angular displacement output function.

An integrated biplane optical sensing core chip has a non-linear optical substrate, a first waveguide structure, a second waveguide structure and a waveguide coupled fiber. The non-linear optical substrate, the first waveguide structure and the second waveguide structure are made of the same nonlinear optical material. The first waveguide structure is connected to the second waveguide structure via a waveguide coupled fiber is outside and independent to the non-linear optical substrate. Therefore, the first waveguide structure and the second waveguide structure can overlap in the vertical direction, and can be set close to each other in the horizontal and vertical directions, so the integrated biplane optical sensing core chip can be miniaturized and can meet reciprocity. The integrated biplane optical sensing core chip is suitable for an optical fiber sensor, and the optical fiber sensor can be a fiber-optic gyroscope or a fiber-optic current sensor.

The invention provides a quick recovery method of a remote sensing image based on vibration detection of a gyroscope and coding exposure. A vibration process of a satellite platform can be detected in real time by adopting a double-shaft fiber-optical gyroscope, the remote sensing image can be simultaneously obtained as an imaging camera is in coding exposure, an image degradation point spread function can be calculated and obtained by a processing system according to vibration data obtained through the measurement of the fiber-optic gyroscope and a time coding value of an exposure process of the imaging camera, the platform vibration influence can be then removed by deconvolution of the remote sensing image, and the clear remote sensing image can be quickly obtained. Since the coding exposure is adopted and the fiber-optic gyroscope is adopted for measuring the platform vibration, the quick recovery method is suitable for obtaining the clear remote sensing image by the satellite platform with complicated vibration.

An automatic gain control system for a fiber optic gyroscope control loop includes an adjustable gain applied to the gyro output signal. A pilot signal is injected into the fiber optic gyroscope control loop. A compensation loop receives signals output from the control loop and also receives pilot signals. The compensation loop processes the pilot signal to produce a compensation signal that is combined with signals output from the control loop to provide a compensated fiber optic gyroscope output signal. An automatic gain control loop is connected between the compensation loop and the adjustable gain applied to the fiber optic gyroscope output signal. The automatic gain control loop includes a gain error demodulator that multiplies the compensated fiber optic gyroscope output signal and the compensation signal together to produce a gain error signal used to control the adjustable gain in order to stabilize the gain of the gyro control loop.

The invention relates to a self-adaptive initial alignment method of a ship strapdown inertial navigation system. The self-adaptive initial alignment method comprises the following steps: enabling a ship SINS(Ship Inertial Navigation System) to begin to work, and acquiring measured information of a fiber-optical gyroscope and an accelerometer; providing an initial location of a ship according to aglobal positioning system carried by the ship as well as the acquired fiber-optical gyroscope and accelerometer information, primarily determining attitude information of the ship by utilizing a parsing-type coarse alignment algorithm, and completing the coarse alignment of the ship SINS; establishing a nonlinear error model of the ship SINS in a high-dynamic environment; establishing a nonlinearfilter equation in the high-dynamic environment of the ship; estimating the system noise by utilizing a VCE-based self-adaptive CKF algorithm in real time, and estimating a misalignment angle of thesystem; and correcting an initial strapdown attitude matrix of the system by utilizing the misalignment angle estimated in step 5, obtaining a precise initial strapdown matrix, and completing a precise alignment process under a movable foundation bed. By adopting the method, the nonlinear problem and uncertain noise problem in the initial alignment of the inertial navigation system can be solved,and the alignment comprehensive performance can be effectively improved.