Space long-life fiber grating temperature measuring demodulator

Abstract

This invention provides a long-life fiber Bragg grating temperature demodulator for space applications, comprising: a secondary power supply assembly, two mutually redundant signal processing and interface circuit boards, two mutually redundant light source drive circuit boards, two main and backup light source modules, two-channel secondary temperature control systems, and one detector circuit board. This invention is a fiber Bragg grating temperature demodulator based on SG-DBR swept-frequency laser demodulation technology. As a new generation of temperature measurement products, fiber Bragg grating temperature demodulators feature wide measurement range, flexible deployment, and light weight, making them ideal for applications requiring large-scale, multi-point temperature measurement of large, precision structures in spacecraft. To achieve multi-point temperature measurement on satellites, fiber Bragg grating temperature sensor networks can be deployed inside the satellite cabin and on antenna panels to monitor temperature changes in various parts of the satellite structure.

Description

Technical Field

[0001] This invention belongs to the field of fiber optic grating temperature measurement technology, and specifically relates to a long-life fiber optic grating temperature demodulator for space use, which is mainly used to monitor the temperature field of instruments and equipment during satellite operation. Background Technology

[0002] With the development and transformation of the aerospace field, the demand for multi-point temperature measurement is increasing. Temperature detection of key satellite equipment can help to detect problems in a timely manner, provide early warnings, effectively prevent and reduce the occurrence of failures, and at the same time help us understand the operating status of the equipment, providing assistance for equipment maintenance and fault diagnosis.

[0003] Since 1989, fiber Bragg grating (FBG) sensors have received widespread attention and continuous development worldwide. FBGs possess strong resistance to electromagnetic interference, and their wavelength exhibits a good linear relationship with temperature over a wide range. The reflection spectrum of a FBG shifts laterally with changes in external physical parameters (such as temperature), but its spectral shape remains unchanged. Therefore, when the external temperature changes, the temperature change can be indirectly measured by measuring the change in the center wavelength of the FBG reflection spectrum. Thus, to achieve multi-point temperature measurement on satellites, FBG temperature sensing networks can be deployed inside the satellite cabin and on antenna panels to monitor temperature changes in various parts of the satellite structure. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, the inventors have conducted intensive research and provided a space-use long-life fiber optic grating temperature demodulator, and in particular a space-use long-life fiber optic grating temperature demodulator. This fiber optic grating temperature demodulator has a wide measurement range, flexible deployment and light weight, and is very suitable for use in large-scale and multi-point temperature measurement of large precision structures in spacecraft.

[0005] The technical solution provided by this invention is as follows:

[0006] A space-use long-life fiber Bragg grating temperature demodulator includes: a secondary power supply assembly, two signal processing and interface circuit boards that serve as cold backups for each other, two light source driving circuit boards that serve as cold backups for each other, two main backup light source modules, two secondary temperature control systems, and one detector circuit board.

[0007] The secondary power supply component is used to convert the system operating power supply voltage into a secondary voltage.

[0008] The two signal processing and interface circuit boards, which serve as cold backups for each other, are used for the acquisition and control of photoelectric and temperature data, output voltage control signals to the light source driver circuit board, and provide an external communication interface.

[0009] The two light source driver circuit boards, which serve as cold backups for each other, are used to provide a stable driving current to the light source;

[0010] The main backup light source module is used to emit light of different wavelengths to illuminate the fiber optic grating under the drive of the driving current.

[0011] The two-channel secondary temperature control system is used to control the heating of the light source module and control the temperature of the light source chip.

[0012] The detector circuit board performs photoelectric conversion on the reflected light. The strength of the electrical signal output by the detector indicates the strength of the reflected light. After calculation, the center wavelength of the fiber optic grating reflection spectrum data is output, and the current temperature is determined based on the center wavelength.

[0013] The long-life fiber Bragg grating temperature demodulator for space applications provided by the present invention has the following beneficial effects:

[0014] (1) The present invention meets the installation and fixing requirements of each component in its structural design, ensuring that the signal processing and interface circuit, light source module, power supply module, etc. are securely installed, while isolating the optical module and light source driving circuit from the power supply, which helps to reduce the impact of power supply heat on the light source driving circuit;

[0015] (2) In the design of the light source driving circuit, the present invention adopts the “D / A+I / V+V / I” method, which can realize the tuning of the light power and the tuning of the light wavelength of the light source; on the other hand, in the selection of components, all domestic and imported plug-in replacement packages are adopted, which can be used in high reliability space models, and can also be replaced in place with low cost devices, which can be promoted to more models and reduce design costs.

[0016] (3) The light source secondary temperature control of the present invention adopts a digital temperature control method with solid and relay combined with heating element. Compared with the previous analog temperature control, the control is more flexible and more accurate. It can also incorporate fuzzy and PID algorithms, making the temperature control more adaptable. It greatly narrows the external temperature range of the light source and effectively improves the stability of the output wavelength of the light source.

[0017] (4) In terms of system composition, the present invention adopts a cold backup mode for important circuits and important modules, which reduces the probability of single point failure, greatly improves product reliability, and is more suitable for high-requirement and long-life occasions.

[0018] (5) In the power supply system design, the present invention adopts a main power supply to supply power to the signal processing and interface circuit and the main light source driving circuit, and adds a Schottky diode for isolation before the main power supply; the backup power supply to supply power to the backup signal processing and interface circuit and the backup light source driving circuit, and adds a Schottky diode for isolation before the backup power supply; the main and backup are interconnected after being isolated by diodes and simultaneously supply power to the detector circuit board. The main and backup diode isolation design effectively avoids the occurrence of hidden paths.

[0019] (6) In the signal processing and interface circuit design, the present invention adopts a dual memory mode, namely PROM+FLASH. The algorithm segment and data segment in the DSP program are stored in PROM and FLASH respectively. The data segment is copied three times and stored in three different addresses inside FLASH. After power-on, the consistency of the data segment program at the three addresses of FLASH is continuously compared through program control. The purpose is to prevent the FLASH chip from being knocked over by particles, causing the data segment program to be permanently lost. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of a fiber Bragg grating temperature measurement system.

[0021] Figure 2 This is a schematic diagram of the structural composition of the present invention;

[0022] Figure 3 This is a block diagram of the composition logic of the present invention;

[0023] Figure 4 This is a power supply block diagram of the present invention;

[0024] Figure 5 This is a schematic diagram of the signal processing and interface circuit of the present invention;

[0025] Figure 6 This is a schematic diagram of the light source driving circuit of the present invention;

[0026] Figure 7 This is a schematic diagram of the light source temperature control circuit of the present invention;

[0027] Figure 8 This is a schematic diagram of the detector circuit of the present invention. Detailed Implementation

[0028] The features and advantages of the present invention will become clearer and more explicit from the following detailed description.

[0029] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments. Although various aspects of embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless specifically indicated otherwise.

[0030] This invention provides a long-life fiber Bragg grating temperature demodulator for space applications. The fiber Bragg grating temperature demodulator and the fiber Bragg grating temperature sensor array constitute a fiber Bragg grating temperature measurement system. See [link to documentation]. Figure 1The fiber Bragg grating temperature sensor is installed on the surface of the object to be measured. The fiber Bragg grating temperature demodulator is the core of the fiber Bragg grating temperature measurement system, which mainly performs functions such as signal acquisition, processing and transmission of the fiber Bragg temperature sensor.

[0031] The fiber Bragg grating temperature demodulator is based on SG-DBR swept-frequency laser demodulation technology. After receiving DSP instructions, the FPGA (A54SX72A-CQ208B) sends a digital voltage signal to the D / A conversion circuit. The voltage signal is converted into a current signal by the light source driving circuit to drive the laser to sweep the frequency. Different current combinations correspond to different laser output wavelengths. The swept light sequentially illuminates the fiber optic temperature sensor, and the reflected light sequentially passes through a circulator and is photoelectrically converted by the detector circuit. The strength of the electrical signal output by the detector indicates the strength of the reflected light. The electrical signal is acquired by the A / D acquisition circuit and sent to the DSP (FT-C6701V-A) for algorithm fitting to determine the center wavelength of the discrete fiber Bragg grating reflection spectrum data. Then, the current temperature is determined based on the center wavelength.

[0032] Figure 2 This is a schematic diagram of the structure of a fiber Bragg grating temperature demodulator. The structural design meets the installation and fixing requirements of each component, ensuring that the signal processing and interface circuit, light source module, power supply module, etc. are securely installed. At the same time, the optical module and light source driving circuit are isolated from the power supply, which helps to reduce the impact of power supply heat on the light source driving circuit.

[0033] Figure 3 This is a block diagram of the fiber Bragg grating temperature demodulator. To improve system reliability, this invention incorporates a primary / backup design for the secondary power supply assembly, signal processing and interface circuit board, and light source and its driving circuit board. Specifically, the fiber Bragg grating temperature demodulator includes: a secondary power supply assembly, two mutually redundant signal processing and interface circuit boards, two mutually redundant light source driving circuit boards, two light source modules (primary and backup), two-channel secondary temperature control systems, one detector circuit board, one optical coupler, two electrical connectors, eight optical connectors, a signal processing and interface circuit support board, a fiber optic heat shrink tubing support board, the demodulator body, and upper and lower cover plates.

[0034] Secondary power supply components

[0035] The secondary power supply assembly includes one secondary power supply circuit board (containing a main unit and a backup), two sets of EMI filters installed independently of the secondary power supply circuit board, two sets of DC / DC power modules (both containing a main unit and a backup), and eight Schottky diodes. The secondary power supply circuit board is equipped with a main and backup "overcurrent protection circuit", "surge suppression and power-on / off control circuit" and "main and backup power switch control circuit". After the primary power supply is converted into the secondary power supply required by the demodulator through overcurrent protection, surge suppression, EMI filtering and DC / DC power module conversion, it responds to the main and backup power supply power-on and power-off commands.

[0036] like Figure 4 As shown, the secondary power supply component has two types of power supply: one is a 30V system working power supply voltage, and the other is a 30V remote control power supply voltage. On one hand, the 30V system operating voltage enters the secondary power supply assembly and is divided into two paths. One path passes through the main "overcurrent protection circuit" and then enters the main "surge suppression and power-on / off control circuit," while the other path passes through the backup "overcurrent protection circuit" and then enters the backup "surge suppression and power-on / off control circuit." On the other hand, the 30V remote control power supply and external power-on / off commands pass through the "main and backup power-on / off control circuits" and simultaneously affect the main and backup "surge suppression and power-on / off control circuits." The "main and backup power switch control circuits" control whether the main and backup "surge suppression and power-on / off control circuits" are turned on or off to realize the system's power-on / off function. When the power-on command is valid, the 30V system operating voltage, after passing through overcurrent protection and surge suppression, enters the "filtering circuit" of the EMI filter for filtering. Then, it enters the "secondary power conversion circuit" of the DC / DC power module to convert the primary 30V voltage into secondary +5V and -5V voltages respectively. Finally, it is isolated by eight Schottky diodes before supplying power to other circuit boards in the subsequent stages.

[0037] Two signal processing and interface circuit boards that serve as cold backups for each other.

[0038] like Figure 3 and Figure 5 As shown, the two signal processing and interface circuit boards that serve as cold backups for each other include: a watchdog and power-on reset module, a level conversion module, an RS422 communication module, an A / D acquisition module, a 5-channel D / A conversion and conditioning module, a DSP+FPGA+FLAH+PROM minimum system module, and a temperature control module.

[0039] Watchdog and power-on reset module, used to implement watchdog and power-on reset;

[0040] The level conversion module is used to convert the secondary 5V voltage output from the secondary power supply component into the voltage required by the signal processing and interface circuit board.

[0041] The RS422 communication module is used to implement one-channel RS-422 standard serial communication.

[0042] The A / D acquisition module is used to acquire data from multiple detectors, such as 20 detectors, and from multiple channels, such as 2 channels, of temperature signals.

[0043] A 5-channel D / A conversion and conditioning module is used to generate 5 voltage control signals for the light source drive circuit;

[0044] The analog switch control module is used to generate 8 analog switch switching signals to the detector circuit to enable the selection of multiple detectors, such as 20 detectors, and multiple temperature signals, such as 2 channels.

[0045] The temperature control module is used to output one temperature control signal to the heating element of the two-stage temperature control system to realize two-stage temperature control of the light source;

[0046] The minimum system module is DSP+FPGA+FLAH+PROM. The PROM and FLAH are used to store the algorithm segment and data segment of the DSP. The algorithm segment is used to demodulate the temperature of the fiber Bragg grating, and the data segment contains the parameters of the fiber Bragg grating sensor.

[0047] The FPGA receives DSP instructions and sends digital voltage signals to the 5-channel D / A conversion and conditioning module. The voltage signals are converted into current signals by the light source driving circuit to drive the laser to perform frequency sweeping. Different current combinations correspond to different laser output wavelengths. The swept light sequentially illuminates the fiber optic temperature sensor, and the reflected light sequentially passes through the circulator and is photoelectrically converted by the detector circuit. The strength of the electrical signal output by the detector indicates the strength of the reflected light. The electrical signal is acquired by the A / D acquisition module and sent to the DSP (FT-C6701V-A) for algorithm fitting to determine the center wavelength of the discrete fiber optic grating reflection spectrum data. The current temperature is then determined based on the center wavelength.

[0048] The power supply for the signal processing and interface circuit board comes from the secondary power supply component. The signal from the A / D acquisition module comes from the detector circuit, the signal from the RS422 communication module comes from the external power connector, the 5-channel D / A conversion and conditioning module goes to the light source drive circuit, the 8-channel analog switch switching signal goes to the detector circuit, and the 1-channel temperature control signal goes to the heating element of the secondary temperature control system.

[0049] The DSP uses the FT-C6701V-A, with the XF0 pin for dog feeding. This chip has a maximum clock frequency of 167MHz, and its 32-bit floating-point computing capability meets the high-speed calculation requirements of temperature demodulation algorithms for multiple temperature sensors. The FPGA is an imported A54SX72A-CQ208B. The FPGA is a crucial component of the signal processing and interface circuitry, used for A / D data acquisition and analog switch channel switching, external D / A output control, external serial communication interface, interface with the DSP, external memory read / write control, and outputting temperature control signals. The memory uses a PROM + FLASH combination. The PROM has a capacity of 32K×8bit, and the FLASH has a capacity of 16Mbit. The algorithm and data segments of the DSP program are stored in the PROM and FLASH respectively. The data segment is copied three times and stored at three different addresses within the FLASH. After power-on, the program continuously compares the consistency of the data segment program at the three addresses in the FLASH, preventing permanent loss of the data segment program due to particle knocking.

[0050] Light source driver circuit board and light source module

[0051] like Figure 3 and Figure 6 As shown, the light source driver circuit board and the light source module together form a complete functional module. The light source driver circuit board includes 5 voltage-controlled current source circuits and 1 light source die temperature control circuit. The 5-channel D / A conversion and conditioning module on the signal processing and interface circuit board includes 5 D / A conversion circuits and 5 I / V conditioning amplifier circuits. The D / A conversion circuits receive the digital output from the signal processing and interface circuits, convert it to current, and output the corresponding current to the I / V conditioning amplifier circuit. After processing by the I / V conditioning amplifier circuit, the current is sent to the voltage-controlled current source circuit, which converts the voltage into current, providing a stable drive current to the light source module. The 5-channel D / A conversion circuit-I / V conditioning amplifier circuit-voltage-controlled current source circuit respectively control the 5 current sources in the semiconductor optical amplifier, gain region, phase region, left grating region, and right grating region, realizing optical power tuning and optical wavelength tuning.

[0052] In terms of light source temperature control design, a "first-level analog temperature control + second-level digital temperature control" approach is adopted. The light source chip temperature control circuit is a first-level analog temperature control system used to control the temperature of the light source chip. See Figure 7The light source chip temperature control circuit includes a temperature sampling bridge circuit, an operational amplifier conditioning circuit, a PID feedback circuit, a Peltier driver circuit, and a sampling circuit. The thermistor in the power module is connected to the operational amplifier conditioning circuit via the temperature sampling bridge circuit. The output of the operational amplifier conditioning circuit is connected to two Peltier driver circuits and the Peltier in the power module. The sampling circuit collects the voltage of the Peltier and transmits it to the operational amplifier conditioning circuit through the PID feedback circuit to achieve closed-loop temperature feedback. In other words, the main function of the light source driver circuit is to achieve first-level analog temperature control of the light source chip temperature and provide five stable drive currents for the light source, enabling optical power tuning and optical wavelength tuning.

[0053] Two-stage temperature control system

[0054] The two-channel secondary temperature control system is a digital temperature control system, including a primary light source secondary temperature control system and a backup light source secondary temperature control system. Its function is to reduce the ambient temperature of the light source, making the output wavelength of the light source more stable. Each secondary temperature control system includes one temperature-sensing resistor, two heating elements connected in series, and a temperature control circuit. The primary and backup temperature-sensing resistors and heating elements are respectively installed on the structural components of the light source module. The temperature-sensing circuit of the temperature control circuit is on the detector circuit board, and the temperature control module is on the signal processing and interface circuit board. The two signal lines of the temperature-sensing resistor are twisted together and connected to the "temperature-sensing circuit" on the detector circuit board. After passing through the analog switch and voltage follower circuit, the output is sent to the "A / D acquisition module" of the signal processing and interface circuit board. The DSP reads the A / D data and converts it into temperature. After temperature control algorithm, it controls whether the heating elements are heated.

[0055] Detector circuit board

[0056] like Figure 8 As shown, the detector circuit board includes multiple PIN-FET photodetectors (e.g., 20), two 16-to-1 analog switches, two temperature acquisition circuits for secondary temperature control, a reserved signal acquisition circuit, and a voltage follower circuit. The PIN-FET photodetectors, temperature acquisition circuit, and reserved signal acquisition circuit are connected to the two 16-to-1 analog switches. After the two 16-to-1 analog switches are activated, the voltage signal is transmitted to the voltage follower circuit and output to the "A / D acquisition module" on the signal processing and interface circuit board to determine the current temperature.

[0057] Fiber Bragg gratings can reflect light of specific wavelengths. The reflected light passes through a circulator and enters a corresponding photodetector. The photodetector converts the optical signal into an electrical signal, which is then sent to the signal processing and interface circuit for demodulation. The detector circuit board is powered by a secondary power supply assembly. Eight analog switch signals originate from the signal processing and interface circuit board, and temperature signals come from two temperature sampling circuits. Twenty detector fiber optic connections connect to the optical signals returned by 200 gratings. The analog switch output signals are then processed and output to the A / D acquisition module on the signal processing and interface circuit board.

[0058] Optical coupler

[0059] The main function of the optical coupler module is to connect two light sources and multiple strings of fiber Bragg gratings (e.g., 20 strings) and multiple photodetectors (e.g., 20 channels). The fiber Bragg grating demodulator needs to measure 20 channels, with 10 sensors per channel. The light source is split into 20 beams by a 2×20 coupler, which then pass through a circulator and enter the corresponding measurement channel.

[0060] Electrical connectors and optical connectors

[0061] The electrical and optical connectors include two electrical connectors and five optical connectors. The electrical connectors are used for external power supply, as well as the transmission of signals such as remote control commands, external communication, and telemetry voltage; the optical connectors are used to connect 20 strings of fiber Bragg grating temperature sensors.

[0062] The signal processing and interface circuit support board, the fiber optic heat shrink tubing support board, the demodulator's outer frame, and the upper and lower cover plates together constitute the structural support of the demodulator. In terms of component selection, all circuit boards use domestically produced and imported plug-in replacement packages, which are suitable for high-reliability, space-constrained models, and can also be replaced in situ with low-cost components, allowing for wider application and reducing design costs.

[0063] The present invention has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.

[0064] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A space-use long-life fiber Bragg grating temperature demodulator, characterized in that, include: The system includes a secondary power supply assembly, two signal processing and interface circuit boards that serve as cold backups for each other, two light source drive circuit boards that serve as cold backups for each other, two main backup light source modules, two secondary temperature control systems, and one detector circuit board. The secondary power supply component is used to convert the system operating power supply voltage into a secondary voltage. The two signal processing and interface circuit boards, which serve as cold backups for each other, are used for the acquisition and control of photoelectric and temperature data, output voltage control signals to the light source driver circuit board, and provide an external communication interface. The two light source driver circuit boards, which serve as cold backups for each other, are used to provide a stable driving current to the light source; The main backup light source module is used to emit light of different wavelengths to illuminate the fiber optic grating under the drive of the driving current. The two-channel secondary temperature control system is used to control the heating of the light source module and control the temperature of the light source chip. The detector circuit board performs photoelectric conversion on the reflected light. The strength of the electrical signal output by the detector indicates the strength of the reflected light. After calculation, the center wavelength of the fiber optic grating reflection spectrum data is output, and the current temperature is determined based on the center wavelength. The two signal processing and interface circuit boards that serve as cold backups for each other include: a watchdog and power-on reset module, a level conversion module, an RS422 communication module, an A / D acquisition module, a 5-channel D / A conversion and conditioning module, a DSP+FPGA+FLAH+PROM minimum system module, and a temperature control module; Watchdog and power-on reset module, used to implement watchdog and power-on reset; The level conversion module is used to convert the secondary 5V voltage output from the secondary power supply component into the voltage required by the signal processing and interface circuit board. The RS422 communication module is used to implement one-channel RS-422 standard serial communication. The A / D acquisition module is used to acquire data from multiple detectors and multiple temperature signals. A 5-channel D / A conversion and conditioning module is used to generate 5 voltage control signals for the light source drive circuit; The analog switch control module is used to generate 8 analog switch switching signals to the detector circuit to enable the selection of multiple detectors and multiple temperature signals; The temperature control module is used to output one temperature control signal to the heating element of the two-stage temperature control system to realize two-stage temperature control of the light source; The minimum system module consists of a DSP, FPGA, FLAH, and PROM. The PROM and FLAH store the DSP's algorithm and data segments. The algorithm segment demodulates the temperature of the fiber Bragg grating, and the data segment stores the parameters of the fiber Bragg grating. The FPGA receives DSP commands and sends digital voltage signals to a 5-channel D / A conversion and conditioning module. The voltage signals are converted into current signals by a light source driving circuit to drive a laser for frequency sweeping. Different current combinations correspond to different laser output wavelengths. The swept light sequentially illuminates the fiber Bragg grating, and the reflected light sequentially passes through a circulator and is converted into photoelectric signals by a photodetector circuit. The strength of the electrical signal output by the photodetector indicates the strength of the reflected light. The electrical signal is acquired by an A / D acquisition module and sent to the DSP for algorithm fitting to determine the center wavelength of the discrete fiber Bragg grating reflection spectrum data. The current temperature is then determined based on the center wavelength. The light source driving circuit board includes five voltage-controlled current source circuits; the five-channel D / A conversion and conditioning module on the signal processing and interface circuit board includes five D / A conversion circuits and five I / V conditioning amplifier circuits. The D / A conversion circuit receives the digital quantity output from the signal processing and interface circuit, and outputs a corresponding current to the I / V conditioning amplifier circuit after D / A conversion. After processing by the I / V conditioning amplifier circuit, the current is sent to the voltage-controlled current source circuit, which converts the voltage into current to provide a stable driving current to the light source module. The five-channel D / A conversion circuit-I / V conditioning amplifier circuit-voltage-controlled current source circuit respectively control the five current sources in the semiconductor optical amplifier, gain region, phase region, left grating region, and right grating region to achieve optical power tuning and optical wavelength tuning. The light source driver circuit board also includes a light source chip temperature control circuit for controlling the temperature of the light source chip. The light source chip temperature control circuit includes a temperature sampling bridge circuit, an operational amplifier conditioning circuit, a PID feedback circuit, a Peltier driver circuit, and a sampling circuit. The thermistor in the power module is connected to the operational amplifier conditioning circuit after passing through the temperature sampling bridge circuit. The output of the operational amplifier conditioning circuit is connected to two Peltier driver circuits and the Peltier in the power module. The sampling circuit collects the voltage of the Peltier and transmits it to the operational amplifier conditioning circuit through the PID feedback circuit to achieve closed-loop temperature feedback.

2. The space-use long-life fiber Bragg grating temperature demodulator according to claim 1, characterized in that, The secondary power supply assembly includes one secondary power supply circuit board, two sets of main backup EMI filters installed independently of the secondary power supply circuit board, two sets of main backup DC / DC power modules, and eight Schottky diodes; the secondary power supply circuit board is equipped with a main backup overcurrent protection circuit, a surge suppression and power-on / off control circuit, and a main backup power switch control circuit. After entering the secondary power supply assembly, the system operating voltage is divided into two paths. One path passes through the main overcurrent protection circuit and then enters the main surge suppression and power-on / off control circuit. The other path passes through the backup overcurrent protection circuit and then enters the backup surge suppression and power-on / off control circuit. Remote power supply and external power-on / off commands pass through the main and backup power-on / off control circuits and simultaneously affect the surge suppression and power-on / off control circuits of both the main and backup circuits. The main and backup power switch control circuits control whether the surge suppression and power-on / off control circuits of the main and backup circuits are turned on or off to realize the system's power-on / off function. When the power-on command is valid, the system operating voltage after passing through the overcurrent protection and surge suppression enters the EMI filter circuit for filtering. Then, it enters the secondary power conversion circuit of the DC / DC power module to convert the primary system operating voltage into secondary +5V and -5V voltages respectively. Finally, it is isolated by eight Schottky diodes before supplying power to other circuit boards in the subsequent stages.

3. The space-use long-life fiber Bragg grating temperature demodulator according to claim 1, characterized in that, The FPGA is selected from the A54SX72A-CQ208B chip; and / or The DSP uses the FT-C6701V-A chip.

4. The space-use long-life fiber Bragg grating temperature demodulator according to claim 1, characterized in that, The two-channel secondary temperature control system is a digital temperature control system, including a primary light source secondary temperature control system and a backup light source secondary temperature control system. Each secondary temperature control system includes one temperature-sensing resistor, two heating elements connected in series, and a temperature control circuit. The primary and backup temperature-sensing resistors and heating elements are respectively installed on the structural components of the light source module. The temperature-sensing circuit of the temperature control circuit is on the detector circuit board, and the temperature control module is on the signal processing and interface circuit board. The two signal lines of the temperature-sensing resistor are twisted together and connected to the temperature-sensing circuit on the detector circuit board. After passing through an analog switch and a voltage follower circuit, the signal is output to the A / D acquisition module of the signal processing and interface circuit board. The DSP reads the A / D data and converts it into temperature. After temperature control algorithm, it controls whether the heating elements are heated.

5. The space-use long-life fiber Bragg grating temperature demodulator according to claim 1, characterized in that, The detector circuit board includes multiple PIN-FET photodetectors, two 16-to-1 analog switches, two temperature acquisition circuits for secondary temperature control, a reserved signal acquisition circuit, and a voltage follower circuit. The PIN-FET photodetectors, temperature acquisition circuit, and reserved signal acquisition circuit are connected to the two 16-to-1 analog switches. After the two 16-to-1 analog switches are turned on, the voltage signal is transmitted to the voltage follower circuit and output to the signal processing and interface circuit board to determine the current temperature.

6. The space-use long-life fiber Bragg grating temperature demodulator according to claim 1, characterized in that, The fiber optic grating temperature demodulator also includes an optical coupler module for connecting a light source, multiple fiber optic gratings, and multiple photodetectors.

7. The space-use long-life fiber Bragg grating temperature demodulator according to claim 1, characterized in that, The fiber Bragg grating temperature demodulator also includes two electrical connectors and five optical connectors. The electrical connectors are used for external power supply, as well as for transmitting remote control commands, external communication, and telemetry voltage signals. The optical connectors are used to connect multiple strings of fiber Bragg gratings.

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