Optical fiber gyroscope with quick starting capability and temperature adaptive capability

Abstract

The invention discloses an optical fiber gyroscope with quick starting capability and temperature adaptation capability. The optical fiber gyroscope comprises a light source, a light source driving and control circuit, a detector I, a beam splitter I, a beam splitter II, a Y waveguide, an optical fiber ring, a detector II and a differential modulation circuit, the method is used for improving the quick starting capability and the temperature performance of the fiber-optic gyroscope and solving the problems of long starting time and poor temperature adaptability of the high-precision fiber-optic gyroscope. The light-operated light path and light source driving control circuit design, the differential modulation circuit design and the heat distribution optimization structure design are mainly broken through. According to the invention, the quick starting capability and the temperature performance of the gyroscope are greatly improved.

Description

Technical Field

[0001] The invention relates to a fiber optic gyroscope with rapid start-up capability and temperature adaptability, belonging to the technical field of fiber optic gyroscopes. Background Art

[0002] The interferometric high-precision fiber optic gyroscope is a fully solid-state inertial instrument with the advantages of high precision, high reliability, and long life. It is widely used in missile guidance, aircraft navigation and other fields. The rapid startup capability and environmental adaptability of the fiber optic gyroscope are particularly important. Therefore, it is urgent to improve the rapid startup capability and temperature adaptability of the fiber optic gyroscope.

[0003] Existing data show that the start-up time of the fiber optic gyroscope is related to the light source, detector, light source drive and temperature control circuit, and the internal thermal design of the fiber optic gyroscope. Since the detector, light source temperature control circuit, digital closed-loop circuit and other components inside the fiber optic gyroscope generate heat after being powered on, the internal thermal balance is broken and rebuilt. In particular, the sensitive component fiber ring is a temperature gradient sensitive device. Due to the existence of the Shupe effect, the positive and negative beams in the fiber ring produce a non-reciprocal phase difference based on the temperature gradient, which eventually causes the zero bias drift of the fiber optic gyroscope. Similarly, when the external temperature changes, the zero bias drift of the fiber optic gyroscope will also be caused. In order to reduce the error introduced by the gyroscope when it is started and when the external temperature changes, the gyroscope can quickly reach its own accuracy and improve the rapid stability of the gyroscope parameters and the adaptability to the temperature environment. Therefore, starting from the stability design of the optical path and circuit, and the optimization design of the structure, the purpose of realizing the rapid start-up capability and temperature adaptability of the fiber optic gyroscope is achieved. Summary of the invention

[0004] The technical problem solved by the present invention is: to overcome the deficiencies of the prior art, and to relate to a fiber optic gyroscope with rapid startup capability and temperature adaptability, so as to realize the rapid startup capability and temperature performance of the gyroscope.

[0005] The technical solution of the present invention is: a fiber optic gyroscope with fast startup capability and temperature adaptability, comprising: a light source, a light source driving and control circuit, a detector I, a beam splitter I, a beam splitter II, a Y waveguide, an optical fiber ring, a detector II and a differential modulation circuit;

[0006] The light source driving control circuit drives the light source to emit a Gaussian spectrum light signal l1, which is divided into two light signals l2 and l3 after entering the beam splitter I; one of the light signals l2 becomes a light signal l4 after passing through the beam splitter II, and the light signal l4 enters the interference optical path composed of the Y waveguide and the optical fiber ring to form an interference signal l5. The interference signal l5 passes through the beam splitter II to form a light signal l6 and is sent to the detector II. The detector II converts the light signal l6 into a voltage signal and sends it to the differential modulation circuit; the differential modulation circuit receives the voltage signal converted from the light signal l6, processes the signal to generate gyroscope angular velocity information and outputs it to the outside, and at the same time generates a differential modulation signal and a feedback signal and sends them to the Y waveguide. The Y waveguide receives the differential modulation signal and the feedback signal sent by the differential modulation circuit to realize the modulation and closed-loop control of the light signal l4; the other light signal l3 reaches the detector I, and the detector I converts the light signal l3 into a voltage signal and sends it to the light source driving control circuit; the light signal l1 is adjusted by the light source driving control circuit to realize the stability of the optical power of the light signal l1.

[0007] The light source adopts a Gaussian spectrum erbium-doped optical fiber light source.

[0008] The light source, detector I and light source driving and control circuit are installed in the same space, and the differential modulation circuit and detector II are installed in another space, and are respectively connected to the passive device part consisting of beam splitter I, beam splitter II, Y waveguide and optical fiber ring through a heat insulation plate to reduce the influence of the internal temperature change of the gyroscope on the optical signal.

[0009] The light-controlled light source driving control circuit drives the light source to generate the light signal l1 and performs real-time control according to the electrical signal light signal l1 generated by the detector I, so as to realize that the light source outputs a stable light signal.

[0010] The differential modulation circuit includes a front-end signal processing circuit, an FPGA logic circuit and a Y-waveguide control modulation circuit; the detector signal with angular velocity information is converted into an electrical signal digital quantity with angular velocity information by the front-end signal processing circuit, and the FPGA logic circuit modulates and demodulates the electrical signal digital quantity to form three signals, namely, an angular velocity signal e1, a modulation signal e2, and a gain error signal e3; wherein, the angular velocity signal e1 is directly output to the outside as a gyroscope signal; the modulation signal e2 and the gain error signal e3 are simultaneously sent to the Y-waveguide control modulation circuit to generate a feedback analog signal, and the feedback analog signal is sent to the Y-waveguide by generating a modulation and feedback signal through a switching switch, and the phase of the Y-waveguide is electro-optically modulated, so as to realize high-sensitivity modulation and closed-loop control of the polarized light signal, and complete a closed-loop control loop.

[0011] The output Gaussian spectrum light signal is super fluorescence in the 1.56±0.02 μm band.

[0012] The advantages of the present invention compared with the prior art are:

[0013] (1) The present invention proposes a light source drive control circuit. The detector I collects the light signal l3 of the light source, monitors the fluctuation of the light power of l3 when the gyro is started and when the temperature changes, and adjusts the strength of the light source drive signal through the light source drive control circuit, so that the light power of the light signal l3 converges faster when the gyro is started and when the external temperature changes, thereby achieving the control of the light power stability of the light source light signal l1. Avoid large fluctuations in the gyro light power when it is started or when the external temperature changes, thereby achieving the purpose of improving the gyro's rapid start-up and temperature performance.

[0014] (2) The present invention proposes a differential modulation circuit, which effectively reduces the error introduced into the control loop by the gyroscope at startup and when the external temperature changes by controlling the polarity conversion of the Y waveguide, so that the gyroscope can quickly reach its own accuracy. At the same time, it can suppress the decrease in the zero bias stability of the gyroscope caused by the common mode drift of key parameters of electronic components, and improve the rapid stabilization of gyroscope parameters and the adaptability to temperature environments.

[0015] (3) The present invention designs the light source and the light source driving control circuit as a whole according to the heating characteristics of the light source, the detector and the electronic components, and places them at one end of the passive components such as the optical fiber ring. The other end is the differential modulation circuit and the detector connected to it through the heat insulation board, and heat transfer and heat insulation measures are taken to reduce the influence of the internal heating of the gyroscope on the temperature sensitive parts of the optical path such as the optical fiber ring. When the gyroscope is started and working, the optical path components are in a good thermal environment, thereby achieving rapid startup and stable temperature performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the overall design of the fiber optic gyroscope of the present invention;

[0017] Figure 2 It is a schematic diagram of the differential circuit design of the fiber optic gyroscope of the present invention;

[0018] Figure 3 Schematic diagram of polarity conversion of differential modulation Y-waveguide of the present invention; DETAILED DESCRIPTION

[0019] like Figure 1 As shown, the present invention discloses a fiber optic gyroscope with fast startup capability and temperature adaptability, including a light-controlled optical path and a light-controlled light source drive control circuit, a differential modulation circuit, and a heat distribution optimization structure.

[0020] The light source emits a light signal l1, which becomes two light signals l2 and l3 after entering beam splitter I. Light signal l2 becomes light signal l4 after passing through beam splitter II. Light signal l4 enters the interference optical path composed of Y waveguide and optical fiber ring to form interference signal l5. Interference signal l5 passes through beam splitter II to form light signal l6 which is sent to detector II. At the same time, light signal l3 reaches detector I.

[0021] Light source drive control circuit: The light source drive control circuit sends a drive signal to make the light source generate a light signal. The output Gaussian spectrum light signal is a superfluorescence in the 1.56±0.02μm band. The light signal enters the beam splitter I. At the same time, the light signal l3 reaches the detector I, which is converted into a voltage signal by the detector I and sent to the light source drive control circuit to realize the control of the output light signal.

[0022] like Figure 2 As shown, the differential modulation circuit receives the voltage signal of detector II, performs signal processing on the voltage signal of detector II to generate gyroscope angular velocity information, generates a differential modulation signal and a feedback signal at the same time, outputs the gyroscope angular velocity information to the outside, and sends the differential modulation signal and the feedback signal to the Y waveguide part.

[0023] The optical signal output by the light source is split by beam splitter I to form two beams of light, which pass through beam splitter II, Y waveguide, optical fiber ring and Y waveguide in sequence to generate an optical signal with angular velocity information, which reaches detector II through beam splitter II, and is converted into an electrical signal with angular velocity information through photoelectric conversion and output to the differential modulation circuit. The electrical signal is modulated and demodulated to form three signals: angular velocity signal e1, modulation signal e2, and gain error signal e3. The angular velocity signal e1 is directly output as a gyroscope signal. The modulation signal e2 and the gain error signal e3 are both sent to the digital-to-analog converter I of the differential modulation circuit to generate a feedback analog signal. The feedback analog signal passes through the amplifier circuit I and then passes through the following: Figure 3 The switching switch shown generates the modulation and feedback signals and sends them to the Y waveguide of the optical path part, performs electro-optical modulation on the phase of the Y waveguide, realizes high-sensitivity modulation and closed-loop control of the polarized light signal, and completes the closed-loop control loop.

[0024] The heat distribution optimization structure is that the fiber optic gyroscope is installed separately according to the heating characteristics of each device. The light source, detector I and the light source drive and control circuit are installed in the same space, and the differential modulation circuit and detector II are installed in another space. They are connected to the passive device part composed of beam splitter I, beam splitter II, Y waveguide and optical fiber ring through heat insulation plates respectively. The optical path part is separated from the circuit part and is relatively independent. When the gyroscope is started, the heat generated by the light source, detector and circuit can be evenly distributed around the optical fiber ring to achieve rapid start-up of the gyroscope. At the same time, the impact of changes in external environmental temperature is effectively reduced to improve the temperature environment adaptability of the gyroscope.

[0025] In the fiber optic gyroscope of the present invention, the light source driving control circuit works as follows:

[0026] The light signal L3 is collected through the light source drive control circuit and the detector I, and the fluctuation of the light power of L3 is monitored when the gyro is started and when the temperature changes. The strength of the light source drive signal is adjusted through the light source drive control circuit, so that the light power of the light signal L3 converges faster when the gyro is started and when the external temperature changes, thereby achieving the control of the light power of the light source light signal L1 to be stable. Avoid large fluctuations in the gyro light power when it is started or when the external temperature changes, thereby achieving the purpose of improving the gyro's rapid start-up and temperature performance.

[0027] The working principle of the differential modulation circuit of the present invention is:

[0028] The electrical signal e2 of the modulation channel is applied to the positive and negative electrodes of the Y waveguide of the fiber optic gyroscope. When the polarity of the voltage applied to the two electrodes of the Y waveguide changes, the scale factor of the fiber optic gyroscope changes symmetrically in positive and negative directions, which is equivalent to the forward and reverse rotation of the fiber optic gyroscope. The differential output controls the polarity conversion of the Y waveguide to reduce the error introduced into the control loop when the gyroscope is started and when the external temperature changes.

[0029] By controlling the Y-waveguide polarity conversion, the gyroscope can quickly reach its own accuracy. At the same time, it can suppress the decrease in gyroscope zero bias stability caused by the common mode drift of key parameters of electronic components, and improve the rapid stabilization of gyroscope parameters and temperature environment adaptability. Figure 3 shown.

[0030] The heat distribution optimization structure of the present invention adopts corresponding heat transfer and heat insulation measures for three ways of heat transfer: heat conduction, heat convection and heat radiation, so as to reduce the influence of the internal heating of the gyroscope on the sensitive parts of the optical path such as the optical fiber ring. On the one hand, the light source and the light control circuit are designed as a whole and placed at one end of the passive device such as the optical fiber ring, and the other end is the differential modulation circuit and the detector connected to it through the heat insulation board, so that the optical path components of the gyroscope are in a good thermal environment during the startup and operation of the gyroscope, thereby achieving rapid startup and stable temperature performance. On the other hand, the fiber optic gyroscope light source drive control circuit part, the optical path part and the differential circuit part are separated and relatively independent, without contact conduction or installing heat insulation material parts on the contact surface to reduce heat conduction, and at the same time, the heat convection and heat radiation heat transfer are blocked in the structure, so as to avoid the influence of the internal heating of the gyroscope on the optical path components of the fiber optic gyroscope.

[0031] The startup time of the high-precision gyroscope without the improvement of the present invention is 10 minutes, while the startup time of the high-precision gyroscope using the present invention is no more than 30 seconds. Under the same temperature change conditions, the temperature performance is improved by 20%. It can be seen that the design of the present invention can improve the startup ability and temperature performance of the high-precision gyroscope. The contents not described in detail in the specification of the present invention belong to the known technology of professional and technical personnel in this field.

Claims

1. A fiber optic gyroscope with fast startup capability and temperature adaptability, characterized in that: include: Light source, light source driving and control circuit, detector I, beam splitter I, beam splitter II, Y waveguide, optical fiber ring, detector II and differential modulation circuit; The light source driving control circuit drives the light source to emit a Gaussian spectrum light signal l1, which enters the beam splitter I and is divided into two light signals l2 and l3; One of the optical signals l2 becomes optical signal l4 after passing through beam splitter II. Optical signal l4 enters the interference optical path composed of Y waveguide and optical fiber ring to form interference signal l5. Interference signal l5 passes through beam splitter II to form optical signal l6 which is sent to detector II. Detector II converts optical signal l6 into a voltage signal which is sent to the differential modulation circuit. The differential modulation circuit receives the voltage signal converted from the optical signal l6, processes the signal to generate gyroscope angular velocity information and outputs it externally, and simultaneously generates a differential modulation signal and a feedback signal and sends them to the Y waveguide. The Y waveguide receives the differential modulation signal and the feedback signal sent by the differential modulation circuit to realize the modulation and closed-loop control of the optical signal l4; another optical signal l3 reaches the detector I, and the detector I converts the optical signal l3 into a voltage signal and sends it to the light source drive control circuit; the light signal l1 is adjusted by the light source drive control circuit to realize the stability of the optical power of the control optical signal l1.

2. The fiber optic gyroscope with fast startup capability and temperature adaptability according to claim 1, characterized in that: The light source adopts a Gaussian spectrum erbium-doped optical fiber light source.

3. The fiber optic gyroscope with fast startup capability and temperature adaptability according to claim 1, characterized in that: The light source, detector I and light source driving and control circuit are installed in the same space, and the differential modulation circuit and detector II are installed in another space, and are respectively connected to the passive device part consisting of beam splitter I, beam splitter II, Y waveguide and optical fiber ring through a heat insulation plate to reduce the influence of the internal temperature change of the gyroscope on the optical signal.

4. The fiber optic gyroscope with fast startup capability and temperature adaptability according to claim 1, characterized in that: The light-controlled light source driving control circuit drives the light source to generate the light signal l1 and performs real-time control according to the electrical signal light signal l1 generated by the detector I, so as to realize that the light source outputs a stable light signal.

5. The fiber optic gyroscope with rapid startup capability and temperature adaptability according to claim 1, characterized in that: The differential modulation circuit includes a front-end signal processing circuit, an FPGA logic circuit and a Y-waveguide control modulation circuit; the detector signal with angular velocity information is converted into an electrical signal digital quantity with angular velocity information by the front-end signal processing circuit, and the FPGA logic circuit modulates and demodulates the electrical signal digital quantity to form three signals, namely, an angular velocity signal e1, a modulation signal e2, and a gain error signal e3; wherein, the angular velocity signal e1 is directly output to the outside as a gyroscope signal; the modulation signal e2 and the gain error signal e3 are simultaneously sent to the Y-waveguide control modulation circuit to generate a feedback analog signal, and the feedback analog signal is sent to the Y-waveguide by generating a modulation and feedback signal through a switching switch, and the phase of the Y-waveguide is electro-optically modulated, so as to realize high-sensitivity modulation and closed-loop control of the polarized light signal, and complete a closed-loop control loop.

6. The fiber optic gyroscope with fast startup capability and temperature adaptability according to claim 1, characterized in that: The Gaussian spectrum light signal is superfluorescence in the 1.56±0.02 μm band.

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