Erbium-source-based high-precision light-small three-axis integrated fiber-optic gyroscope

Abstract

Light emitted by an erbium light source assembly is split through a 30 / 70 single-mode optical fiber beam splitter, 30% of the light enters an X-axis optical path, 70% of the light enters a first 50 / 50 single-mode optical fiber beam splitter, and 35% of the light enters a Y-axis optical path and a Z-axis optical path respectively; the light entering the light path of each axis is split by the second 50 / 50 beam splitter and then enters the Y waveguide, the Y waveguide performs polarization processing on the light and then divides the light into two beams, the two beams of light return to the Y waveguide to generate interference after passing through the optical fiber ring, and an interference light signal enters the photoelectric detector through the second 50 / 50 beam splitter and enters the photoelectric detector through the second 50 / 50 beam splitter. The photoelectric detector converts the interference light signal into an electric signal and sends the electric signal to the gyroscope digital circuit; the gyroscope digital circuit is used for carrying out signal conditioning, AD sampling and digital demodulation on the electric signals output by the photoelectric detector; and the light source driving and signal integrated processing circuit is used for converting the output of the three-axis fiber-optic gyroscope circuit into three-axis angular velocity information and respectively carrying out temperature compensation on the three-axis angular velocity information.

Description

Technical Field

[0001] This invention relates to a high-precision, lightweight, and compact three-axis integrated fiber optic gyroscope based on an erbium source ultra-fine diameter optical fiber, which is applied to high-precision remote sensing satellites and high-precision navigation satellites, and belongs to the field of inertial measurement technology. Background Technology

[0002] With the development of integrated navigation technology, inertial measurement technology, with its advantages of low cost and ease of maintenance, is playing an increasingly important role in the fields of high-resolution remote sensing and high-precision integrated navigation, and the requirements for the accuracy and reliability of inertial sensors are also increasing.

[0003] A three-axis integrated fiber optic gyroscope assembly consists of three-axis fiber optic gyroscopes used to measure the angular velocity of an object. Gyroscopes measure the angular velocity of a carrier and have advantages such as low cost, miniaturization, and high precision. They are also easy to integrate with optical path technology, and the signal is stable and reliable, thus they are widely used in the navigation field.

[0004] Traditional gyroscopes suffer from problems such as high power consumption, high price, large size, and numerous internal connecting wires, which cannot meet today's demand for low cost and miniaturization. Summary of the Invention

[0005] The technical problem solved by this invention is to overcome the shortcomings of existing traditional aerospace fiber optic gyroscopes in terms of gyroscope accuracy at the same cost and size, and to provide a low-cost, high-precision, lightweight, and compact triaxial integrated fiber optic gyroscope based on erbium source ultra-fine diameter fiber.

[0006] The technical solution of this invention is: a high-precision, lightweight, and compact three-axis integrated fiber optic gyroscope based on an erbium source. The fiber optic gyroscope includes a hexahedral body, an erbium source assembly, a 30 / 70 single-mode fiber optic beam splitter, a first 50 / 50 single-mode fiber optic beam splitter, a three-axis gyroscope digital circuit, a light source driving and signal integrated processing circuit, and three axes. The three-axis gyroscope digital circuit corresponds one-to-one with the three-axis optical path. Each optical path includes a second 50 / 50 single-mode fiber optic beam splitter, a Y-waveguide, a fiber optic ring, and a photodetector.

[0007] The erbium light source assembly and the 30 / 70 single-mode fiber beam splitter are installed inside the main body. The fiber rings of the three-axis optical paths are respectively installed on the mounting surfaces of the hexahedral structure main body in the X, Y, and Z directions. The light emitted by the erbium light source assembly is split by the 30 / 70 single-mode fiber beam splitter. 30% of the light enters the X-axis optical path, and 70% of the light is split by the first 50 / 50 single-mode fiber beam splitter. 35% of the light from each path enters the Y-axis optical path and the Z-axis optical path, respectively. The light entering each optical path is split by the second 50 / 50 beam splitter and then enters the Y-waveguide. After the Y-waveguide polarizes the light, it splits the light into two beams that propagate counterclockwise and clockwise. The two beams return to the Y-waveguide after passing through the fiber rings and interfere. The interference light signal enters the photodetector through the second 50 / 50 beam splitter. The photodetector converts the interference light signal into an electrical signal and sends it to the corresponding gyroscope digital circuit.

[0008] The gyroscope digital circuit conditions the electrical signal output by the photodetector, performs AD sampling, and demodulates the digital signal, directly outputting the demodulated phase information; at the same time, it converts the phase information into a digital phase step wave, sends it to the DA converter, amplifies the signal, and applies it to the Y waveguide of the corresponding axis, so that the gyroscope always works at zero phase, realizing closed-loop operation.

[0009] The light source driving and signal integrated processing circuit is used to drive the erbium light source component to output optical signals and to control the temperature of the erbium light source component; it converts the output of the three-axis fiber optic gyroscope circuit into three-axis angular velocity information, performs temperature compensation processing on the three-axis angular velocity information, and outputs the compensated three-axis angular velocity information.

[0010] Preferably, the fiber ring is wound with ultra-fine diameter polarization-maintaining fiber with a wavelength of 1550nm and a specification of 60 / 100μm.

[0011] Preferably, the photodetector is a single-power differential output photodetector.

[0012] Preferably, the above-mentioned three-axis integrated fiber optic gyroscope also includes four temperature sensors, three of which are placed inside the three fiber optic rings respectively to measure the temperature inside the fiber optic rings; the fourth temperature sensor is used to monitor the temperature of the erbium light source assembly.

[0013] Preferably, the temperature compensation processing method is as follows: the temperature inside the fiber optic ring measured by the temperature sensor is used as the ambient temperature of the single-axis fiber optic gyroscope, and the corresponding zero bias is obtained by indexing according to the relationship between temperature and zero bias, and the zero bias parameter is compensated into the single-axis angular velocity information.

[0014] Preferably, the digital circuit of the three-axis gyroscope is connected to the light source drive and signal integrated processing circuit using flexible printed lines.

[0015] Preferably, the gyroscope digital circuit is installed within the structure of the fiber optic ring.

[0016] Preferably, the light source driving and signal integrated processing circuit includes a signal processing module, a combined power supply circuit, a power-on reset circuit, an external interface circuit, a gyroscope interface circuit, a light source driving circuit, and a cooling control circuit;

[0017] The power-on reset circuit is used to reset and initialize the signal processing module.

[0018] A combined power supply circuit is used to power the signal processing module, external interface circuit, and gyroscope interface circuit.

[0019] External interface circuitry is used to receive external commands and send them to the signal processing circuitry, and to send the processing results of the signal processing circuitry to the outside.

[0020] The gyroscope interface circuit is used to receive the output data from the digital circuit of the three-axis gyroscope and forward it to the signal processing circuit.

[0021] The signal processing circuit converts the output of the three-axis fiber optic gyroscope circuit into three-axis angular velocity information, performs temperature compensation processing on the three-axis angular velocity information, and outputs the compensated three-axis angular velocity information.

[0022] Light source driving circuit, used to drive the erbium light source component to output light signals;

[0023] The cooling control circuit controls the temperature of the erbium light source assembly, thus offsetting the impact of temperature changes in the space environment on the light source output.

[0024] Preferably, the signal processing module is implemented using an FPGA.

[0025] Preferably, the outer envelope dimensions of the fiber optic gyroscope assembly are 106mm × 105.5mm × 91mm, and the weight is 1.1Kg.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) The light source of the three-axis fiber optic gyroscope of the present invention is an erbium light source. Compared with the SLD light source, the 1550nm erbium light source has a larger output optical power under the same driving current, which can achieve better gyroscope performance.

[0028] (2) The three-axis integrated fiber optic gyroscope assembly of the present invention has only two types of circuits: gyroscope digital circuit and light source drive and signal integrated processing circuit, which greatly reduces the size and weight, and reduces the production cost and assembly process of the product.

[0029] (3) In the three-axis integrated fiber optic gyroscope assembly of the present invention, the gyroscope digital circuits are independent of each other, and the optical paths are also independent except for the shared light source of the three axes, which improves the reliability of the product.

[0030] (4) In the three-axis integrated fiber optic gyroscope assembly, this invention uses flexible printed lines instead of wires to achieve electrical interconnection, which simplifies the assembly process and improves reliability. At the same time, compared with traditional wires, flexible printed lines have more certain spatial positions between signals, prevent errors, and can better ensure assembly consistency during mass production, which is conducive to improving product manufacturability.

[0031] (5) The present invention adopts a shared light source for three-axis fiber optic gyroscopes, which reduces the power consumption of fiber optic gyroscope components and improves the reliability of the system. The fiber optic gyroscope can achieve a continuous on-orbit working life of not less than 8 years and realizes a three-axis integrated design. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the external structure of an embodiment of the present invention;

[0033] Figure 2 This is a schematic diagram of the internal structure of an embodiment of the present invention;

[0034] Figure 3 This is a schematic diagram of an embodiment of the present invention;

[0035] Figure 4 This is a functional block diagram of the light source driving and signal integrated processing circuit according to an embodiment of the present invention;

[0036] Figure 5 This is a schematic diagram of the optical path structure according to an embodiment of the present invention. Detailed Implementation

[0037] The present invention will now be described in detail with reference to the accompanying drawings.

[0038] like Figure 5 As shown, this invention provides a high-precision, lightweight, integrated three-axis fiber optic gyroscope based on an erbium source. The integrated three-axis fiber optic gyroscope includes a hexahedral body 1, an erbium source assembly 2, a 30 / 70 single-mode fiber optic beam splitter 3, a first 50 / 50 single-mode fiber optic beam splitter, a three-axis gyroscope digital circuit 6, a light source driving and signal integrated processing circuit 7, and three axes. The three-axis gyroscope digital circuit 6 corresponds one-to-one with the three-axis optical paths. Each optical path includes a second 50 / 50 single-mode fiber optic beam splitter, a Y-waveguide, a fiber optic ring, and a photodetector.

[0039] The light emitted by the erbium light source assembly is split by a 30 / 70 single-mode fiber beam splitter. 30% of the light enters the X-axis optical path, and 70% of the light is split by a first 50 / 50 single-mode fiber beam splitter. 35% of the light from each path enters the Y-axis optical path and the Z-axis optical path, respectively. The light entering each optical path is split by a second 50 / 50 beam splitter and then enters the Y-waveguide. The Y-waveguide polarizes the light and splits it into two beams that propagate counterclockwise and clockwise. The two beams return to the Y-waveguide after passing through a fiber optic loop and interfere. The interference light signal enters the photodetector through the second 50 / 50 beam splitter. The photodetector converts the interference light signal into an electrical signal and sends it to the corresponding gyroscope digital circuit 6.

[0040] The gyroscope digital circuit (6) performs signal conditioning, AD sampling, and digital signal demodulation on the electrical signal output by the photodetector, and directly outputs the phase information obtained from the demodulation; at the same time, it converts the phase information into a digital phase ladder wave and sends it to the DA after signal amplification and applies it to the Y waveguide of the corresponding axis, so that the gyroscope always works at zero phase and realizes closed-loop operation.

[0041] The light source driving and signal integrated processing circuit 7 is used to drive the erbium light source component to output the light signal 2 and to control the temperature of the erbium light source component 2; it converts the output of the three-axis fiber optic gyroscope circuit into three-axis angular velocity information, performs temperature compensation processing on the three-axis angular velocity information, and outputs the compensated three-axis angular velocity information.

[0042] like Figure 1 and Figure 2 , Figure 3 As shown, a high-precision, lightweight, triaxial integrated fiber optic gyroscope structure based on an erbium source includes a body 1, an erbium light source assembly 2, a 30 / 70 single-mode fiber optic bundle splitter 3, a first 50 / 50 single-mode fiber optic bundle splitter 4, three Y-waveguides 5, three gyroscope digital circuit boards, a light source driving and signal integrated processing circuit board, a J30J-25ZK electrical connector 8, two side covers 9, three fiber optic ring assemblies 10, two gyroscope circuit covers 11, a bottom cover 12, a top cover 13, an electrical connector bracket 14, and a reference mirror 15. The three axially orthogonal fiber optic ring assemblies are mounted on the sides of the body and below the top cover.

[0043] The erbium light source assembly 2 and the 30 / 70 single-mode fiber beam splitter 3 are installed inside the hexahedral body 1. Three orthogonally distributed fiber ring assemblies 10 are respectively installed on the mounting platforms in the X, Y, and Z axes of the body 1. The gyroscope digital circuit 6, the Y-waveguide 5, and the second 50 / 50 single-mode fiber beam splitter 4 are installed inside the fiber ring structure, and the gyroscope circuit cover 11 is installed outside the fiber ring structure. The light source drive and signal integration processing circuit 7 is installed at the top of the back of the Z-axis mounting platform, below the upper cover 13. Side covers and bottom covers achieve side and bottom closure. The electrical connector 8 is installed on the electrical connector bracket 14. The electrical connector bracket 14 is installed on the top of the body 1, the upper cover 13 is installed on the top of the body 1, the reference mirror 15 is installed on the top of the body 1, the side covers 9 cover the viewing windows on both sides of the body 1, and the bottom cover 12 is installed on the bottom of the body 1. One electrical connector enables external power input and signal input / output.

[0044] The aforementioned integrated fiber optic gyroscope achieves closed-loop control through an erbium light source assembly, beam splitter, Y-waveguide, fiber optic ring, AD module, and DA module, which greatly improves measurement accuracy. Furthermore, the optical path and circuit structure are simple and small in size.

[0045] Preferably, the fiber ring is wound with ultra-fine diameter polarization-maintaining fiber with a wavelength of 1550nm and a specification of 60 / 100μm (60μm is the fiber core diameter and 100μm is the cladding diameter). Ultra-fine diameter polarization-maintaining fiber allows for the winding of longer fibers while maintaining a smaller overall fiber ring size, ensuring higher accuracy for the gyroscope.

[0046] Preferably, the photodetector is a single-power differential output photodetector. The single-power design results in low power consumption and minimal temperature rise, mitigating the impact of temperature rise in miniaturized fiber optic gyroscopes. Simultaneously, the differential output design reduces ground plane fluctuations and noise, enhancing the detector's anti-interference capability.

[0047] Preferably, the above-mentioned three-axis integrated fiber optic gyroscope also includes four temperature sensors, three of which are placed inside the three fiber optic rings respectively to measure the temperature inside the fiber optic rings; the fourth temperature sensor is used to monitor the temperature of the erbium light source assembly 2.

[0048] The temperature compensation processing method is as follows: the temperature inside the fiber optic ring measured by the temperature sensor is used as the ambient temperature of the single-axis fiber optic gyroscope. Then, based on the relationship between temperature and zero bias, the corresponding zero bias is obtained by indexing, and the zero bias parameter is compensated into the single-axis angular velocity information.

[0049] The relationship between temperature and zero bias can be calibrated in advance, typically within a range of -30℃ to 70℃. The calibration method usually employs traditional polynomial fitting. However, a dynamic compensation scheme optimized using the temperature change rate combined with neural network algorithms can further enhance the model's generalization ability. This dynamic compensation scheme can effectively reduce errors in variable-temperature scenarios in space environments.

[0050] The digital circuit 6 of the three-axis gyroscope is connected to the light source driver and signal integrated processing circuit 7 via flexible printed lines. A single J30J-25ZK electrical connector is connected to the light source driver and signal integrated processing circuit via flexible printed lines.

[0051] When the fiber optic gyroscope assembly is running in orbit, under normal conditions, the FPGA receives the default command 0xEb900000 sent from the ground and performs routine data processing. In case of an anomaly, the ground can reset the fiber optic gyroscope as needed via a reset command, thereby improving reliability.

[0052] The gyroscope digital circuit 6 is installed inside the structure of the fiber optic ring.

[0053] The light source drive and signal integrated processing circuit 7 integrates the functions of signal processing circuit, external interface circuit, light source drive and cooling circuit. It has the functions of primary bus overcurrent protection, primary bus surge current suppression, light source drive and cooling, gyroscope signal processing and compensation, and RS422 external signal communication.

[0054] like Figure 4 As shown, the light source driving and signal integrated processing circuit 7 includes a signal processing module, a combined power supply circuit, a power-on reset circuit, an external interface circuit, a gyroscope interface circuit, a light source driving circuit, and a cooling control circuit.

[0055] The power-on reset circuit is used to reset and initialize the signal processing module.

[0056] The combined power supply circuit is used to provide the +5V primary power required by the fiber optic gyroscope to the signal processing module, external interface circuit, and gyroscope interface circuit.

[0057] The external interface circuit is used to receive external commands and send them to the signal processing circuit, and to send the processing results of the signal processing circuit to the outside. The external interface circuit is used to receive RS422 external commands and send them to the FPGA, and to send the processing results of the FPGA to the outside using RS422 signals.

[0058] The gyroscope interface circuit is used to receive the output data of the three-axis gyroscope digital circuit and forward it to the signal processing circuit; in this embodiment of the invention, the output data of the three-axis gyroscope digital circuit is transmitted via serial port.

[0059] The signal processing circuit converts the output of the three-axis fiber optic gyroscope circuit into three-axis angular velocity information, performs temperature compensation processing on the three-axis angular velocity information, outputs the compensated three-axis angular velocity information, and responds to various external commands.

[0060] A light source driving circuit is used to drive the erbium light source assembly to output optical signal 2;

[0061] The cooling control circuit controls the temperature of the erbium light source component 2 to counteract the effect of temperature changes in the space environment on the light source output.

[0062] The signal processing module is implemented using an FPGA, specifically an A3P1000 FPGA. The FPGA program and compensation parameters of the three-axis integrated fiber optic gyroscope are uploaded to the light source driver and signal integrated processing circuit via a simulator to achieve FPGA program update and full-temperature parameter compensation functions.

[0063] The fiber optic gyroscope assembly is a three-axis integrated fiber optic gyroscope assembly with an outer envelope size of 106mm×105.5mm×91mm and a weight of 1.1Kg.

[0064] In summary, this invention significantly reduces cost and size through optical path miniaturization technology, three-axis integrated fiber optic gyroscope technology, and circuit integration technology. Furthermore, by continuously maturing and reliable low-cost optical and electronic components, it helps the fiber optic gyroscope meet the requirements of a ground storage life of no less than 5 years, an on-orbit life of no less than 8 years, and a reliability of no less than 0.9 at the end of its 8-year lifespan.

[0065] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. A high-precision, lightweight, three-axis integrated fiber optic gyroscope based on an erbium source, characterized in that... It includes a hexahedral structure body (1), an erbium light source assembly (2), a 30 / 70 single-mode fiber beam splitter (3), a first 50 / 50 single-mode fiber beam splitter, a three-axis gyroscope digital circuit (6), a light source driving and signal integrated processing circuit (7), and three axes; the three-axis gyroscope digital circuit (6) corresponds one-to-one with the three-axis optical path; each optical path includes a second 50 / 50 single-mode fiber beam splitter, a Y-waveguide, a fiber optic ring, and a photodetector; Erbium light source assembly (2) and 30 / 70 single-mode fiber beam splitter (3) are installed inside the body (1). The fiber rings of the three-axis optical path are respectively installed on the mounting surfaces of the hexahedral structure body (1) in the X, Y, and Z directions. The light emitted by the erbium light source assembly is split by the 30 / 70 single-mode fiber beam splitter. 30% of the light enters the X-axis optical path, and 70% of the light is split by the first 50 / 50 single-mode fiber beam splitter. 35% of the light enters the Y-axis optical path and the Z-axis optical path respectively. The light entering each optical path is split by the second 50 / 50 beam splitter and then enters the Y waveguide. After the Y waveguide polarizes the light, it splits the light into two beams that propagate counterclockwise and clockwise. The two beams return to the Y waveguide after passing through the fiber ring and interfere. The interference light signal enters the photodetector through the second 50 / 50 beam splitter. The photodetector converts the interference light signal into an electrical signal and sends it to the corresponding gyroscope digital circuit (6). The gyroscope digital circuit (6) performs signal conditioning, AD sampling, and digital signal demodulation on the electrical signal output by the photodetector, and directly outputs the phase information obtained from the demodulation; at the same time, it converts the phase information into a digital phase ladder wave and sends it to the DA after signal amplification and applies it to the Y waveguide of the corresponding axis, so that the gyroscope always works at zero phase and realizes closed-loop operation. The light source driving and signal integrated processing circuit (7) is used to drive the erbium light source component to output light signal (2) and to perform temperature control on the erbium light source component (2); The output of the three-axis fiber optic gyroscope circuit is converted into three-axis angular velocity information. Temperature compensation is then applied to the three-axis angular velocity information, and the compensated three-axis angular velocity information is output.

2. The high-precision, lightweight, and compact three-axis integrated fiber optic gyroscope based on an erbium source according to claim 1, characterized in that, The fiber ring is wound with ultra-fine diameter polarization-maintaining fiber with a wavelength of 1550nm and a specification of 60 / 100μm.

3. A high-precision, lightweight, three-axis integrated fiber optic gyroscope based on an erbium source according to claim 1, characterized in that... The photodetector is a single-power differential output photodetector.

4. The high-precision, lightweight, and compact three-axis integrated fiber optic gyroscope based on an erbium source according to claim 1, characterized in that, It also includes four temperature sensors, three of which are placed inside the three fiber optic rings to measure the temperature inside the fiber optic rings; and a fourth temperature sensor to monitor the temperature of the erbium light source assembly (2).

5. A high-precision, lightweight, three-axis integrated fiber optic gyroscope based on an erbium source according to claim 1, characterized in that, The temperature compensation processing method is as follows: the temperature inside the fiber optic ring measured by the temperature sensor is used as the ambient temperature of the single-axis fiber optic gyroscope. Then, based on the relationship between temperature and zero bias, the corresponding zero bias is obtained by indexing, and the zero bias parameter is compensated into the single-axis angular velocity information.

6. A high-precision, lightweight, three-axis integrated fiber optic gyroscope based on an erbium source according to claim 1, characterized in that, The three-axis gyroscope digital circuit (6) is connected to the light source drive and signal integrated processing circuit (7) using flexible printed lines.

7. A high-precision, lightweight, three-axis integrated fiber optic gyroscope based on an erbium source according to claim 1, characterized in that, The gyroscope digital circuit (6) is installed inside the structure of the fiber optic ring.

8. A high-precision, lightweight, three-axis integrated fiber optic gyroscope based on an erbium source according to claim 1, characterized in that, The light source driving and signal integrated processing circuit (7) includes a signal processing module, a combined power supply circuit, a power-on reset circuit, an external interface circuit, a gyroscope interface circuit, a light source driving circuit, and a cooling control circuit. The power-on reset circuit is used to reset and initialize the signal processing module. A combined power supply circuit is used to power the signal processing module, external interface circuit, and gyroscope interface circuit. External interface circuitry is used to receive external commands and send them to the signal processing circuitry, and to send the processing results of the signal processing circuitry to the outside. The gyroscope interface circuit is used to receive the output data from the digital circuit of the three-axis gyroscope and forward it to the signal processing circuit. The signal processing circuit converts the output of the three-axis fiber optic gyroscope circuit into three-axis angular velocity information, performs temperature compensation processing on the three-axis angular velocity information, and outputs the compensated three-axis angular velocity information. A light source driving circuit is used to drive the erbium light source assembly to output optical signals (2); The cooling control circuit controls the temperature of the erbium light source assembly (2) to counteract the effect of temperature changes in the space environment on the light source output.

9. A high-precision, lightweight, three-axis integrated fiber optic gyroscope based on an erbium source according to claim 8, characterized in that, The signal processing module is implemented using an FPGA.

10. A high-precision, lightweight, three-axis integrated fiber optic gyroscope based on an erbium source according to claim 1, characterized in that, The outer envelope dimensions of the fiber optic gyroscope assembly are 106mm × 105.5mm × 91mm, and its weight is 1.1Kg.

Images