A large dynamic high-precision combined fiber-optic gyroscope and a working method thereof

Abstract

The application discloses a large-dynamic high-precision combined optical fiber gyroscope and a working method thereof. The optical fiber gyroscope comprises a first optical fiber and a second optical fiber with a length greater than the first optical fiber, and the first optical fiber and the second optical fiber are coaxially wound. The large-dynamic high-precision combined optical fiber gyroscope further comprises an optical input and output device for inputting light of two different wavelengths to both ends of the first optical fiber and the second optical fiber and outputting interference light output from both ends of the first optical fiber and the second optical fiber. The optical input and output device is connected with a processing device for receiving, processing, outputting and processing interference light output from both ends of the first optical fiber and the second optical fiber. The working method comprises the steps of inputting light of two different wavelengths and generating two kinds of interference light, converting and demodulating the two kinds of interference light to obtain two kinds of rotation speed information, and outputting corresponding rotation speed information according to a comparison result. The application has the advantages of small overall volume and occupied space, simple structure, low cost, good dynamic response performance and the like.

Description

Technical Field

[0001] This invention relates to the field of fiber optic gyroscope technology, specifically to a high dynamic range, high precision combined fiber optic gyroscope and its operating method. Background Technology

[0002] Fiber optic gyroscopes are optical gyroscopes based on the Sagnac effect. They are characterized by their relatively simple structure and low cost, and are currently the fastest-growing type of gyroscope in high-precision applications. The Sagnac effect shows that increasing the fiber length or equivalent diameter of the fiber loop in a fiber optic gyroscope can effectively improve its measurement accuracy. However, higher measurement accuracy leads to a smaller angular velocity measurement range, which limits the use of high-precision fiber optic gyroscopes under high dynamic conditions. To simultaneously meet the needs of high-precision measurement and use under high dynamic conditions, a scheme has been proposed that combines a high-precision fiber optic gyroscope with a low-precision fiber optic gyroscope. The output signals of both gyroscopes are modulated and processed for output. When high-precision measurement is required, the output of the high-precision fiber optic gyroscope's measurement result is used; when high dynamic conditions are required, the output of the low-precision fiber optic gyroscope's result is used. However, existing technologies directly combine a single, complete low-precision fiber optic gyroscope with a single, complete high-precision fiber optic gyroscope. Since both are independent fiber optic gyroscopes, they not only occupy a large space and have high costs, but also have poor consistency in response to environmental temperature, vibration, and shock when the two fiber optic gyroscopes are installed separately, resulting in poor dynamic response performance between the two fiber optic gyroscopes. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the shortcomings of the existing technology and provide a large dynamic high-precision combined fiber optic gyroscope with small overall size and space occupation, simple structure, low cost, good dynamic response performance and its working method.

[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0005] A high dynamic range, high precision combined fiber optic gyroscope includes a first fiber and a second fiber with a length greater than that of the first fiber. The first and second fibers are coaxially wound together. The high dynamic range, high precision combined fiber optic gyroscope also includes a light input / output device for inputting two different wavelengths of light into the two ends of the first and second fibers and outputting interference light from the two ends of the first and second fibers. The light input / output device is connected to a processing device for receiving, processing, and outputting the interference light output from the two ends of the first and second fibers.

[0006] As a further improvement to the aforementioned high dynamic range, high precision combined fiber optic gyroscope:

[0007] The optical input / output device includes a first fiber coupler and a first Y-waveguide connected together. The first fiber coupler is connected to a first wavelength division multiplexer (WDM) for inputting two different wavelengths of light into the first fiber coupler. The first Y-waveguide is connected to a second WDM and a third WDM. One end of the first fiber and the second fiber is connected to the second WDM, and the other end of the first fiber and the second fiber is connected to the third WDM. The second WDM is used to separate the two different wavelengths of light transmitted from the first fiber coupler to the first Y-waveguide and input them into the first fiber and the second fiber respectively. One end of the first optical fiber and the interference light output from one end of the second optical fiber are transmitted to the first optical fiber coupler via the first Y waveguide. The third wavelength division multiplexer is used to separate the two different wavelengths of light transmitted to the first Y waveguide via the first optical fiber coupler and input them to the other end of the first optical fiber and the second optical fiber, and to transmit the interference light output from the other end of the first optical fiber and the second optical fiber via the first Y waveguide to the first optical fiber coupler. A fourth wavelength division multiplexer is connected between the first optical fiber coupler and the processing device to separate the interference light output from the first optical fiber and the second optical fiber transmitted to the first optical fiber coupler via the first Y waveguide and transmit it to the processing device.

[0008] The processing device includes a first photodetector, a second photodetector, and a digital signal processor. The first and second photodetectors are connected to the fourth wavelength division multiplexer to receive interference light output from the first optical fiber and interference light output from the second optical fiber, respectively. The first photodetector is connected to the digital signal processor through a first AD converter, and the second photodetector is connected to the digital signal processor through a second AD converter.

[0009] The optical input / output device includes a second fiber coupler and a second Y-waveguide connected together, a third fiber coupler and a third Y-waveguide connected together. The two ends of the first optical fiber are connected to the second fiber coupler via the second Y-waveguide. The second Y-waveguide is used to input light input to the second fiber coupler to both ends of the first optical fiber and to transmit interference light output from both ends of the first optical fiber to the second fiber coupler. The second fiber coupler has an optical input terminal for inputting light and an interference light output terminal connected to the processing device for transmitting interference light output from both ends of the first optical fiber to the processing device. The two ends of the second optical fiber are connected to the third fiber coupler via the third Y-waveguide. The third Y-waveguide is used to input light input to the third fiber coupler to both ends of the second optical fiber and to transmit interference light output from both ends of the second optical fiber to the third fiber coupler. The third fiber coupler has an optical input terminal for inputting light and an interference light output terminal connected to the processing device for transmitting interference light output from both ends of the second optical fiber to the processing device.

[0010] The length of the second optical fiber is an integer multiple of the length of the first optical fiber.

[0011] A method for operating the above-mentioned high dynamic range, high precision combined fiber optic gyroscope includes the following steps:

[0012] (S1) The first wavelength light and the second wavelength light are input into the first wavelength division multiplexer. The first wavelength light and the second wavelength light pass through the first wavelength division multiplexer in sequence through the first fiber coupler and the first Y waveguide. The first Y waveguide splits the light into two beams, which enter the second wavelength division multiplexer and the third wavelength division multiplexer respectively. The second wavelength division multiplexer and the third wavelength division multiplexer respectively input the first wavelength light to both ends of the first fiber and converge the first type of interference light output from both ends of the first fiber to the first Y waveguide. The first type of interference light passes through the first Y waveguide, the first fiber coupler and the fourth wavelength division multiplexer in sequence to enter the first photodetector. At the same time, the second wavelength division multiplexer and the third wavelength division multiplexer respectively input the second wavelength light to both ends of the second fiber and converge the second type of interference light output from both ends of the second fiber to the first Y waveguide. The second type of interference light passes through the first Y waveguide, the first fiber coupler and the fourth wavelength division multiplexer in sequence to enter the second photodetector.

[0013] (S2) The first AD converter converts the analog signal converted from the first interference light received by the first photodetector into a first digital signal, and the second AD converter converts the analog signal converted from the second interference light received by the second photodetector into a second digital signal. The digital signal processor receives the first signal and the second signal, demodulates the first signal to obtain the first rotation speed information of the first optical fiber, and demodulates the second signal to obtain the second rotation speed information of the second optical fiber.

[0014] (S3) The digital signal processor compares the second type of rotational speed information with the rotational speed measurement range of the second optical fiber. When the second type of rotational speed information is less than or equal to the rotational speed measurement range of the second optical fiber, the digital signal processor outputs the second type of rotational speed information. When the second type of rotational speed information is greater than the rotational speed measurement range of the second optical fiber, the digital signal processor outputs the first type of rotational speed information.

[0015] Compared with the prior art, the advantages of the present invention are as follows:

[0016] The high-dynamic-range, high-precision combined fiber optic gyroscope of the present invention has a shorter first fiber optic cable for high-dynamic-range measurement and a longer second fiber optic cable for high-precision measurement. This design simultaneously meets the requirements for both high-precision measurement and high-dynamic-range operation. Furthermore, because the first and second fibers are coaxially wound, compared to the traditional approach of directly combining a single low-precision fiber optic gyroscope with a single high-precision fiber optic gyroscope, the overall size and space occupied are significantly reduced, simplifying the structure and lowering costs. Moreover, the coaxial winding of the first and second fibers results in good consistency in response to environmental temperature, vibration, and shock, and excellent dynamic response performance between the two fibers.

[0017] The working method of the high dynamic and high precision combined fiber optic gyroscope of the present invention can simultaneously meet the needs of high precision measurement and use under high dynamic conditions, and the high precision measurement mode and the working mode under high dynamic conditions can be freely switched according to the environment. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of a high-dynamic-range, high-precision combined fiber optic gyroscope.

[0019] Legend:

[0020] 1. First optical fiber; 2. Second optical fiber; 3. First optical fiber coupler; 4. First Y-waveguide; 101. First wavelength division multiplexer; 102. Second wavelength division multiplexer; 103. Third wavelength division multiplexer; 104. Fourth wavelength division multiplexer; 201. First photodetector; 202. Second photodetector; 203. Digital signal processor; 204. First analog-to-digital converter; 205. Second analog-to-digital converter. Detailed Implementation

[0021] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] Example 1:

[0023] like Figure 1As shown, the high dynamic range and high precision combined fiber optic gyroscope of this embodiment includes a first fiber 1 and a second fiber 2 with a length greater than that of the first fiber 1. The first fiber 1 and the second fiber 2 are coaxially wound together, that is, the first fiber 1 and the second fiber 2 are coaxially wound into two fiber loop structures. The high dynamic range and high precision combined fiber optic gyroscope also includes a light input / output device for inputting two different wavelengths of light to the two ends of the first fiber 1 and the second fiber 2 and outputting the interference light output from the two ends of the first fiber 1 and the second fiber 2. The light input / output device is connected to a processing device for receiving, processing and outputting the interference light output from the two ends of the first fiber 1 and the second fiber 2. This high-precision, high-dynamic-range combined fiber optic gyroscope features a shorter first fiber 1 for high-dynamic-range measurements and a longer second fiber 2 for high-precision measurements. This design simultaneously meets the requirements for both high-precision measurement and high-dynamic-range applications. Furthermore, the coaxial winding of the first and second fibers significantly reduces overall size and space requirements compared to the traditional approach of directly combining a single low-precision fiber optic gyroscope with a single high-precision fiber optic gyroscope. This simplifies the structure and lowers costs. Additionally, the coaxial winding of the first and second fibers results in better dynamic response to environmental temperature, vibration, and shock, exhibiting superior dynamic response performance.

[0024] In this embodiment, the optical input / output device includes a first fiber coupler 3 and a first Y-waveguide 4 connected together. The first fiber coupler 3 is connected to a first wavelength division multiplexer 101 for inputting two different wavelengths of light into the first fiber coupler 3. The first Y-waveguide 4 is connected to a second wavelength division multiplexer 102 and a third wavelength division multiplexer 103. One end of the first optical fiber 1 and the second optical fiber 2 are connected to the second wavelength division multiplexer 102, and the other end of the first optical fiber 1 and the second optical fiber 2 are connected to the third wavelength division multiplexer 103. The second wavelength division multiplexer 102 is used to separate the two different wavelengths of light transmitted from the first fiber coupler 3 to the first Y-waveguide 4 and input them to the first optical fiber 1 and the second optical fiber 2. One end of the first optical fiber 1 and the interference light output from one end of the second optical fiber 2 are transmitted to the first optical fiber coupler 3 via the first Y waveguide 4. The third wavelength division multiplexer 103 is used to separate the two different wavelengths of light transmitted to the first Y waveguide 4 via the first optical fiber coupler 3 and input them to the other end of the first optical fiber 1 and the second optical fiber 2, and to transmit the interference light output from the other end of the first optical fiber 1 and the second optical fiber 2 via the first Y waveguide 4 to the first optical fiber coupler 3. The first optical fiber coupler 3 is connected to the processing device by a fourth wavelength division multiplexer 104 for separating the interference light output from the first optical fiber 1 and the second optical fiber 2 and transmitted to the first optical fiber coupler 3 via the first Y waveguide 4 to the processing device.

[0025] The first optical fiber 1 and the second optical fiber 2 share a first optical fiber coupler 3 and a first Y-waveguide 4. Four wavelength division multiplexers, namely the first wavelength division multiplexer 101, the second wavelength division multiplexer 102, the third wavelength division multiplexer 103 and the fourth wavelength division multiplexer 104, are used to realize the transmission requirements of input light and interference light. This satisfies the functions of high-precision measurement and independent use under large dynamic conditions, which can reduce the overall cost of large dynamic high-precision combined fiber optic gyroscopes. Moreover, it is stable and reliable in operation and can reduce wiring.

[0026] In other embodiments, the optical input / output device may also include a connected second fiber coupler and a second Y-waveguide, and a connected third fiber coupler and a third Y-waveguide. The two ends of the first fiber 1 are connected to the second fiber coupler via the second Y-waveguide. The second Y-waveguide is used to input light input to the second fiber coupler to both ends of the first fiber 1 and to transmit the interference light output from both ends of the first fiber 1 to the second fiber coupler. The second fiber coupler has an optical input end for inputting light and an interference light output end connected to a processing device for transmitting the interference light output from both ends of the first fiber 1 to the processing device. The two ends of the second fiber 2 are connected to the third fiber coupler via the third Y-waveguide. The third Y-waveguide is used to input light input to the third fiber coupler to both ends of the second fiber 2 and to transmit the interference light output from both ends of the second fiber 2 to the third fiber coupler. The third fiber coupler has an optical input end for inputting light and an interference light output end connected to a processing device for transmitting the interference light output from both ends of the second fiber 2 to the processing device. That is, the first fiber 1 and the second fiber 2 each use independent fiber couplers and Y-waveguides.

[0027] In this embodiment, the processing device includes a first photodetector 201, a second photodetector 202, and a digital signal processor 203. The first photodetector 201 and the second photodetector 202 are connected to a fourth wavelength division multiplexer 104 to receive interference light output from the first optical fiber 1 and the second optical fiber 2, respectively. The first photodetector 201 is connected to the digital signal processor 203 via a first analog-to-digital converter 204, and the second photodetector 202 is connected to the digital signal processor 203 via a second analog-to-digital converter 205. The first analog-to-digital converter 204 and the second analog-to-digital converter 205 can respectively convert the analog signals received by the first photodetector 201 and the second photodetector 202 into digital signals and transmit them to the digital signal processor 203. The digital signal processor 203 processes the digital signals and demodulates them to obtain the rotational speed information of the first optical fiber 1 and the second optical fiber 2. The interference light signals from the first optical fiber 1 and the second optical fiber 2 are converted by the first AD converter 204 and the second AD converter 205, respectively, and then processed by the same digital signal processor 203. This improves the synchronization and real-time performance of the fiber optic gyroscope in signal demodulation and shortens the response time of the fiber optic gyroscope to dynamic changes.

[0028] In this embodiment, the length of the second optical fiber 2 is an integer multiple of the length of the first optical fiber 1, so that the first optical fiber 1 and the second optical fiber 2 are exactly in a frequency multiple relationship with the modulation frequency, which is beneficial to the modulation and demodulation of the fiber optic gyroscope signal.

[0029] Example 2:

[0030] A method for operating a high-dynamic-range, high-precision combined fiber optic gyroscope according to Embodiment 1 includes the following steps:

[0031] (S1) The first wavelength light and the second wavelength light are input into the first wavelength division multiplexer 101. After passing through the first wavelength division multiplexer 101, the first wavelength light and the second wavelength light pass through the first fiber coupler 3 and the first Y-waveguide 4 in sequence. The first Y-waveguide 4 splits the light into two beams, which enter the second wavelength division multiplexer 102 and the third wavelength division multiplexer 103 respectively. The second wavelength division multiplexer 102 and the third wavelength division multiplexer 103 respectively input the first wavelength light to both ends of the first optical fiber 1 and converge the first type of interference light output from both ends of the first optical fiber 1. The first Y-waveguide 4, the first type of interference light sequentially passes through the first Y-waveguide 4, the first fiber coupler 3 and the fourth wavelength division multiplexer 104 and enters the first photodetector 201. At the same time, the second wavelength division multiplexer 102 and the third wavelength division multiplexer 103 respectively input the second wavelength light to both ends of the second fiber 2 and converge the second type of interference light output from both ends of the second fiber 2 to the first Y-waveguide 4. The second interference light sequentially passes through the first Y-waveguide 4, the first fiber coupler 3 and the fourth wavelength division multiplexer 104 and enters the second photodetector 202.

[0032] (S2) The first AD converter 204 converts the analog signal received by the first photodetector 201 after receiving the first type of interference light into a first type of digital signal. The second AD converter 205 converts the analog signal received by the second photodetector 202 after receiving the second type of interference light into a second type of digital signal. The digital signal processor 203 receives the first signal and the second signal, demodulates the first signal to obtain the first rotation speed information of the first optical fiber 1, and demodulates the second signal to obtain the second rotation speed information of the second optical fiber 2. Among them, the rotation speed signal generated by the first optical fiber 1 has high dynamic characteristics and a large rotation speed measurement range, and the rotation speed signal generated by the second optical fiber 2 has high resolution and high measurement accuracy.

[0033] (S3) The digital signal processor 203 compares the second type of rotational speed information with the rotational speed measurement range of the second optical fiber 2. When the second type of rotational speed information is less than or equal to the rotational speed measurement range of the second optical fiber 2, the digital signal processor 203 outputs the second type of rotational speed information. When the second type of rotational speed information is greater than the rotational speed measurement range of the second optical fiber 2, the digital signal processor 203 outputs the first type of rotational speed information.

[0034] The working method of this high-precision combined fiber optic gyroscope with large dynamic range can simultaneously meet the needs of high-precision measurement and use under large dynamic conditions, and the high-precision measurement mode and the working mode under large dynamic conditions can be freely switched according to the environment.

[0035] The above description is merely a preferred embodiment of the present invention, and the scope of protection of the present invention is not limited to the above embodiments. For those skilled in the art, improvements and modifications obtained without departing from the inventive concept should also be considered within the scope of protection of the present invention.

Claims

1. A high-dynamic-range, high-precision combined fiber optic gyroscope, characterized in that: The gyroscope includes a first optical fiber (1) and a second optical fiber (2) with a length greater than that of the first optical fiber (1). The first optical fiber (1) and the second optical fiber (2) are coaxially wound together. The high dynamic high precision combined fiber optic gyroscope also includes an optical input / output device for inputting two different wavelengths of light to the two ends of the first optical fiber (1) and the second optical fiber (2) and outputting the interference light output from the two ends of the first optical fiber (1) and the second optical fiber (2). The optical input / output device is connected to a processing device for receiving, processing and outputting the interference light output from the two ends of the first optical fiber (1) and the second optical fiber (2).

2. The high dynamic range, high precision combined fiber optic gyroscope according to claim 1, characterized in that: The optical input / output device includes a first optical fiber coupler (3) and a first Y-waveguide (4) connected together. The first optical fiber coupler (3) is connected to a first wavelength division multiplexer (101) for inputting two different wavelengths of light into the first optical fiber coupler (3). The first Y-waveguide (4) is connected to a second wavelength division multiplexer (102) and a third wavelength division multiplexer (103). One end of the first optical fiber (1) and the second optical fiber (2) is connected to the second wavelength division multiplexer (102), and the other end of the first optical fiber (1) and the second optical fiber (2) is connected to the third wavelength division multiplexer (103). The second wavelength division multiplexer (102) is used to separate the two different wavelengths of light transmitted from the first optical fiber coupler (3) to the first Y-waveguide (4) and input them to the first optical fiber (1) and the second optical fiber (2). The interference light output from one end of the first fiber (1) and the second fiber (2) is transmitted to the first fiber coupler (3) via the first Y waveguide (4). The third wavelength division multiplexer (103) is used to separate the two different wavelengths of light transmitted to the first Y waveguide (4) via the first fiber coupler (3) and input them to the other end of the first fiber (1) and the second fiber (2), and to transmit the interference light output from the other end of the first fiber (1) and the second fiber (2) via the first Y waveguide (4) to the first fiber coupler (3). A fourth wavelength division multiplexer (104) is connected between the first fiber coupler (3) and the processing device to separate the interference light output from the first fiber (1) and the second fiber (2) transmitted to the first fiber coupler (3) via the first Y waveguide (4) and transmit it to the processing device.

3. The high dynamic range, high precision combined fiber optic gyroscope according to claim 2, characterized in that: The processing device includes a first photodetector (201), a second photodetector (202), and a digital signal processor (203). The first photodetector (201) and the second photodetector (202) are connected to the fourth wavelength division multiplexer (104) to receive interference light output from the first optical fiber (1) and interference light output from the second optical fiber (2), respectively. The first photodetector (201) is connected to the digital signal processor (203) through a first AD converter (204), and the second photodetector (202) is connected to the digital signal processor (203) through a second AD converter (205).

4. The high dynamic range, high precision combined fiber optic gyroscope according to claim 1, characterized in that: The optical input / output device includes a second fiber coupler and a second Y-waveguide connected together, a third fiber coupler and a third Y-waveguide connected together. The two ends of the first fiber (1) are connected to the second fiber coupler through the second Y-waveguide. The second Y-waveguide is used to input the light input to the second fiber coupler to the two ends of the first fiber (1) respectively and to transmit the interference light output from the two ends of the first fiber (1) to the second fiber coupler. The second fiber coupler has an optical input end for inputting light and an interference light output end connected to the processing device for transmitting the interference light output from the two ends of the first fiber (1) to the processing device. The two ends of the second fiber (2) are connected to the third fiber coupler through the third Y-waveguide. The third Y-waveguide is used to input the light input to the third fiber coupler to the two ends of the second fiber (2) respectively and to transmit the interference light output from the two ends of the second fiber (2) to the third fiber coupler. The third fiber coupler has an optical input end for inputting light and an interference light output end connected to the processing device for transmitting the interference light output from the two ends of the second fiber (2) to the processing device.

5. The high dynamic range, high precision combined fiber optic gyroscope according to any one of claims 1 to 4, characterized in that: The length of the second optical fiber (2) is an integer multiple of the length of the first optical fiber (1).

6. A method for operating the high dynamic range, high precision combined fiber optic gyroscope as described in claim 3, characterized in that: Includes the following steps: (S1) The first wavelength light and the second wavelength light are input into the first wavelength division multiplexer (101). The first wavelength light and the second wavelength light pass through the first wavelength division multiplexer (101) and then through the first fiber coupler (3) and the first Y waveguide (4) in sequence. The first Y waveguide (4) splits the light into two beams, which enter the second wavelength division multiplexer (102) and the third wavelength division multiplexer (103) respectively. The second wavelength division multiplexer (102) and the third wavelength division multiplexer (103) respectively input the first wavelength light to both ends of the first fiber (1) and converge the first interference light output from both ends of the first fiber (1) to the first Y waveguide (103). Waveguide (4), the first type of interference light passes through the first Y waveguide (4), the first fiber coupler (3) and the fourth wavelength division multiplexer (104) in sequence and enters the first photodetector (201). At the same time, the second wavelength division multiplexer (102) and the third wavelength division multiplexer (103) respectively input the second wavelength light to both ends of the second fiber (2) and converge the second type of interference light output from both ends of the second fiber (2) to the first Y waveguide (4). The second type of interference light passes through the first Y waveguide (4), the first fiber coupler (3) and the fourth wavelength division multiplexer (104) in sequence and enters the second photodetector (202). (S2) The first AD converter (204) converts the analog signal converted by the first photodetector (201) after receiving the first interference light into the first digital signal. The second AD converter (205) converts the analog signal converted by the second photodetector (202) after receiving the second interference light into the second digital signal. The digital signal processor (203) receives the first signal and the second signal, demodulates the first signal to obtain the first rotation speed information of the first optical fiber (1), and demodulates the second signal to obtain the second rotation speed information of the second optical fiber (2). (S3) The digital signal processor (203) compares the second type of rotational speed information with the rotational speed measurement range of the second optical fiber (2). When the second type of rotational speed information is less than or equal to the rotational speed measurement range of the second optical fiber (2), the digital signal processor (203) outputs the second type of rotational speed information. When the second type of rotational speed information is greater than the rotational speed measurement range of the second optical fiber (2), the digital signal processor (203) outputs the first type of rotational speed information.

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