An airborne remote sensing instrument based on a fourier spectrometer

Abstract

This invention relates to the field of optical measurement and discloses an airborne remote sensing instrument based on a Fourier spectrometer. Target radiation enters the front optical path assembly through a scanning mirror, then through a 45° plane mirror and a plane mirror window in the front optical path, and finally through two 45° plane mirrors inside the transmission optical path assembly before entering the interferometer assembly. After passing through a moving mirror, a fixed mirror, and a beam splitter inside the interferometer assembly, it enters the room-temperature optical assembly inside the telescope, and then through the room-temperature optical assembly and the plane mirror window before entering the low-temperature optical assembly inside the Stirling refrigerator. Finally, the detector converts the interference signal generated by the interferometric optics into an electrical signal, which is then processed, amplified, digitized, and transmitted to a computer data storage system.

Description

Technical Field

[0001] This invention relates to the field of optical measurement, and in particular to an airborne remote sensing instrument based on a Fourier spectrometer. Background Technology

[0002] Spectral imaging technology can perform spectral imaging of the same ground target across continuous spectral bands, integrating spatial, radiometric, and spectral information of the ground target.

[0003] Airborne spectral imaging systems are the main means of realizing modern Earth remote sensing applications, playing an irreplaceable role in fields such as mineral identification, disaster monitoring, regional vegetation mapping, and military defense.

[0004] As detection requirements increase, airborne spectral imaging systems need to simultaneously achieve a wide spectral range and high spectral resolution. To achieve this goal, most airborne spectrometers choose to carry multiple spectrometers for spectral imaging data acquisition or sacrifice time to complete the detection. Such solutions will increase the burden on the airborne platform and affect the accuracy of the detection.

[0005] Currently, there is still no further verification of the accuracy of the temperature and humidity atmospheric profile inversion, specifically regarding the comparison of information obtained from simultaneous Earth observations by spaceborne hyperspectral instruments and similar airborne hyperspectral instruments. Furthermore, there has been no airborne flight verification of the optical system used in conjunction with the Fengyun satellite payload, which increases the risks associated with the on-orbit use of spaceborne instruments and hinders the research, further improvement, verification, and optimization of algorithms for the ground system. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides an airborne remote sensing instrument based on a Fourier spectrometer, which aims to reduce the risks associated with the on-orbit use of spaceborne instruments and facilitate algorithm research, further improvement, verification, and optimization of ground systems.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows:

[0008] An airborne remote sensing instrument based on a Fourier spectrometer includes:

[0009] An optical device mounted in the tail section of an aircraft, and an electrical control box assembly that is electrically connected to the internal components of the optical device and located on one side of the optical device;

[0010] The optical device includes a support plate adapted to the tail section of the aircraft, an optical instrument body located on the upper surface of the support plate, and a front optical path assembly located on the lower surface of the support plate and connected to the optical instrument body.

[0011] The main body of the optical instrument includes: a vacuum chamber, a transmission optical path assembly for receiving the beam from the front optical path assembly, an interferometer assembly for receiving the beam from the transmission optical path assembly, a room temperature optical assembly for receiving the beam from the interferometer assembly, and a low temperature optical assembly for receiving the beam from the room temperature optical assembly.

[0012] When the light beam emitted by the target radiation source passes through the pre-optical path component, the transmission optical path component, the interferometer component, the room temperature optical component and the low temperature optical component, the interference signal generated by the interference optics is converted into an electrical signal, which is then processed and amplified, digitized and transmitted to the computer for data storage.

[0013] To achieve the above technical solution, the beam emitted by the target radiation source enters the front optical path assembly, is reflected by a 45° plane mirror, enters the transmission optical path assembly, is reflected by two 45° plane mirrors inside the transmission optical path assembly, and then enters the interferometer assembly. After being formed into coherent light by the interferometer assembly, it enters the room-temperature optical assembly, and after passing through the interior of the room-temperature optics and the plane mirror window on the side of the instrument, it enters the low-temperature optical assembly. The aforementioned interference signal is converted into an electrical signal, which is then processed and amplified, digitized, and transmitted to the computer for data storage.

[0014] As a preferred embodiment of the present invention, the front optical path assembly includes: a support beam connected to the main body of the optical instrument;

[0015] A mounting frame connected to the support beam, wherein an observation space is formed within the mounting frame;

[0016] A first blackbody and a second blackbody are symmetrically arranged on the mounting bracket. The outer surfaces of the first blackbody and the second blackbody are provided with heating elements and heat insulation layers from the inside to the outside.

[0017] A scanning motor is mounted on the mounting frame and located on the side adjacent to the first blackbody and the second blackbody. The output end of the scanning motor extends into the observation space and is connected to a scanning mirror for Earth observation.

[0018] A folding frame connected to the mounting bracket and opposite to the scanning motor, the folding frame having an optical path space inside, and a first folding mirror connected to the folding frame for receiving the refracted optical path of the scanning mirror;

[0019] A light path protection cover is vertically mounted on the folding frame and connected to the vacuum chamber.

[0020] To achieve the above technical solution, when the target radiation source enters the front optical path assembly, the scanning mirror is rotated to the required angle by controlling the scanning motor and the scanning mirror is aligned with the ground. The radiation from the water surface or the ground is received by the scanning mirror, and the beam is then refracted by the scanning mirror onto the first folding mirror, and finally refracted into the main body of the optical instrument for subsequent processing.

[0021] As a preferred embodiment of the present invention, one end of the first blackbody and the second blackbody extends into the observation space, and a heat insulation pad is provided between the first blackbody and the second blackbody and the mounting frame.

[0022] Both the heat insulation pad and the thermal insulation layer are made of polyimide.

[0023] To achieve the above technical solution, a blackbody is used as the calibration source to correct the radiation response during flight, thereby improving the accuracy of the measurement results. The use of a heat insulation pad isolates heat conduction between the mounting bracket and the blackbody, preventing temperature-related deviations in the radiation response correction. Polyimide possesses excellent thermal stability, superior low-temperature resistance, good dimensional stability and mechanical properties, excellent radiation resistance, good insulation and dielectric properties, and excellent flame retardancy, thus ensuring the optimal operating temperature for the blackbody.

[0024] As a preferred embodiment of the present invention, there are at least six heating elements, which are distributed in a ring at intervals on the surfaces of the first blackbody and the second blackbody.

[0025] To achieve the above technical solution, the heating element placed on the blackbody can be temperature controlled by the components inside the electrical control box assembly to ensure that the blackbody is in the optimal working temperature state, so that the equipment can still operate normally at low temperatures.

[0026] As a preferred embodiment of the present invention, the optical transmission path component includes:

[0027] The frame has a bottom end face and a rear end face respectively provided with an inlet for receiving a light beam from the front optical path component and an outlet for directing a light beam toward the interferometer component.

[0028] The optical path deflector is arranged opposite to each other on both ends of the frame. The optical path deflector includes: a hollow mirror chamber frame embedded in the frame; an annular protrusion extending outward from one end of the mirror chamber frame facing the frame; a first groove on the mirror chamber frame; a blocking edge formed in the first groove; a second deflector mirror that cooperates with the frame and whose one end face abuts against the blocking edge; and an adhesive layer disposed between the contact surfaces of the frame and the second deflector mirror.

[0029] To achieve the above technical solution, during optical path transmission, the light source is transmitted through the front optical path assembly connected to the device, enters the frame through the light inlet, and then shines on the mirror surface of a second folding mirror. After being refracted 90° by this second folding mirror, its propagation path is changed, and it shines on the mirror surface of another second folding mirror. After being refracted 90° by the other second folding mirror, its propagation path is changed again, and it exits from the light outlet of the frame, and then enters the interferometer assembly of the rear optical path for subsequent processing.

[0030] In a preferred embodiment of the present invention, the front end face and the top end face of the frame are both sealed by a sealing plate, and a second groove is provided on the frame to cooperate with the sealing plate.

[0031] To achieve the above technical solution, during installation, the sealing plate is inserted into the second groove and fixed to the frame with screws. Except for the light inlet and light outlet, the frame forms a sealed space, which can protect the transmission of optical signals.

[0032] In a preferred embodiment of the present invention, the second folding mirror and the first groove are in a clearance fit;

[0033] The first groove has an arc-shaped groove to accommodate the corner of the second folding mirror, and colloid is injected into the arc-shaped groove to fix the second folding mirror.

[0034] To achieve the above technical solution, after the second folding mirror is installed, adhesive is applied to the arc-shaped groove. Since the installation of the second folding mirror is a clearance fit, the adhesive can flow into the contact surface between the second folding mirror and the mirror chamber frame to form the adhesive layer, thereby stabilizing the second folding mirror.

[0035] As a preferred embodiment of the present invention, the interferometer assembly includes: a beam splitter for receiving a beam of light from the transmission optical path assembly; the beam splitter transmits one beam of light onto a moving mirror located on one side of the beam splitter; the beam splitter reflects another beam of light onto a fixed mirror located on one side of the beam splitter; the light on the moving mirror and the fixed mirror combines to form coherent light and is directed toward the room temperature optical assembly for processing.

[0036] The vacuum chamber is equipped with a gas-lock nitrogen cylinder that fixes the moving mirror, which needs to be adjusted, during instrument operation.

[0037] A laser source and a laser detector for controlling the interferometer assembly are provided between the optical transmission path assembly and the room temperature optical assembly.

[0038] To achieve the above technical solution, when the light source enters the interferometer assembly, the moving mirror inside the assembly, which has been adjusted according to actual needs, is unlocked by a nitrogen gas cylinder. A beam of light from the light source is split into two beams after reaching the beam splitter. One beam is transmitted to the moving mirror, and the other beam is reflected to the fixed mirror. The light incident on the room temperature optical assembly is the light reflected from the moving mirror and the fixed mirror, which combine to form coherent light with interference characteristics, so as to generate the required interference signal.

[0039] As a preferred embodiment of the present invention, the room temperature optical component includes: a secondary mirror for receiving a light beam from the interferometer component, the secondary mirror reflecting the light to the third mirror, the primary mirror, and the folding mirror, and the folding mirror directing the light beam through a room temperature window to the low temperature optical component for processing.

[0040] To achieve the above technical solution, the aforementioned room-temperature optical component is placed inside the telescope, and after the coherent light enters the room-temperature optical component, the error caused by the light emitted from the moving mirror and the fixed mirror is eliminated.

[0041] As a preferred embodiment of the present invention, the low-temperature optical component includes: a first dichroic filter for receiving a light beam from the room-temperature optical component; the first dichroic filter reflects optical signals of different wavelengths onto a mirror and a second dichroic filter respectively; the light beam on the second dichroic filter exits through a first medium-wavelength window, one beam passes through a first medium-wavelength filter to a first medium-wavelength immersion lens, and the other beam passes through a long-wavelength filter to a long-wavelength double lens group; the mirror directs the light path through a second medium-wavelength window to a second medium-wavelength immersion lens via a second medium-wavelength filter.

[0042] To achieve the above technical solution, the aforementioned low-temperature optical component is placed in a Stirling refrigerator. The temperature of the optical system is controlled by the Stirling refrigerator, which effectively reduces background noise, improves the signal-to-noise ratio and sensitivity, and can eliminate chromatic aberration to ensure imaging quality.

[0043] In summary, the present invention has the following beneficial effects:

[0044] 1. By comparing information obtained from simultaneous Earth observations by spaceborne hyperspectral instruments and similar airborne hyperspectral instruments, the authenticity of the temperature and humidity atmospheric contour inversion is verified. Furthermore, the optical system consistent with the Fengyun satellite payload is verified by airborne flight. On the one hand, this provides a data foundation for the research of data processing and application methods, greatly reduces the risks of future on-orbit use of spaceborne instruments, and is conducive to the algorithm research, further improvement, verification, and optimization of the ground system. On the other hand, it can also provide effective basis for the performance improvement of infrared hyperspectral instruments under development.

[0045] 2. By controlling the scanning motor to drive the scanning mirror to rotate, multi-angle observation of Earth data can be achieved, ensuring the accuracy of the observation data and increasing its applicability; by controlling the temperature of the blackbody through the insulation layer and heating element, the temperature is kept at the optimal working temperature, so that the equipment can operate normally at low temperatures.

[0046] 3. The installation stability of the second folding mirror is ensured by setting up the optical path folding component, which avoids the deterioration of signal transmission quality. At the same time, only the light inlet and outlet are left to ensure the airtightness of the device and protect the optical path transmission. The main structure of the device is made of titanium alloy, which achieves a lightweight design, ensuring the rigidity of the structure while reducing the weight of the whole machine. Attached Figure Description

[0047] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0048] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0049] Figure 2 This is a schematic diagram of the electrical control box assembly structure of the present invention.

[0050] Figure 3 This is a schematic diagram of the aircraft cabin structure from below, based on the present invention.

[0051] Figure 4 This is a schematic diagram of the main structure of the optical instrument of the present invention.

[0052] Figure 5 This is a schematic diagram of the internal structure of the optical instrument body of the present invention.

[0053] Figure 6 This is a schematic diagram of the optical path of the instrument of the present invention.

[0054] Figure 7 This is a schematic diagram of the front structure of the front optical path component of the present invention.

[0055] Figure 8 This is a schematic diagram of the reverse side structure of the front optical path component of the present invention.

[0056] Figure 9 This is a cross-sectional view of the front optical path assembly of the present invention.

[0057] Figure 10 This is a schematic diagram of the support beam structure of the present invention.

[0058] Figure 11 This is a schematic diagram of the mounting bracket mating structure of the present invention.

[0059] Figure 12 This is a schematic diagram of the overall structure of the optical transmission path component of the present invention.

[0060] Figure 13 This is a schematic diagram of the optical transmission path component assembly structure of the present invention.

[0061] Figure 14 This is a cross-sectional view of the optical transmission path component of the present invention.

[0062] Figure 15 This is a schematic diagram of the mirror chamber frame structure of the present invention.

[0063] The numbers and letters in the diagram represent the names of the corresponding components:

[0064] 1. Aircraft tail section; 2. Electrical control box assembly; 201. Mounting bracket; 202. Vacuum pump assembly; 203. Instrument electrical control box; 204. Interferometer electrical control box; 205. Data acquisition unit; 206. Refrigeration unit power supply; 207. Temperature control box; 208. Scanning motor electrical control box; 209. POS510; 2010. POS electrical control box; 2011. Inverter; 3. Optical device; 4. Main body of optical instrument; 5. Support plate; 6. Vacuum chamber;

[0065] 7. Front optical path assembly; 701. Support beam; 701a. Base plate; 701b. First hollow frame; 701c. Middle plate; 701d. Second hollow frame; 701e. Top plate; 701f. First reinforcing plate; 701g. Second reinforcing plate; 702. Mounting bracket; 702a. Blackbody mounting bracket; 702b. Motor mounting bracket; 703. First blackbody; 704. Second blackbody; 705. Thermal insulation Layer; 706, Heating element; 707, Scanning motor; 708, Optical path protective cover; 709, Cover; 7010, Optical correction hole; 7011, Mounting frame; 7012, First folding mirror; 7013, Adjustment shim; 7014, Folding frame; 7015, Optical path space; 7016, Scanning mirror; 7017, Engaging end; 7018, Protective baffle; 7019, Protrusion; 7020, Slot;

[0066] 8. Nitrogen cylinder with gas lock; 9. Optical path assembly; 901. Frame; 902. Mirror chamber frame; 903. Second folding mirror; 904. Sealing plate; 905. Front end face; 906. Top end face; 907. Rear end face; 908. Bottom end face; 909. Light inlet; 9010. Light outlet; 9011. First groove; 9012. Arc-shaped groove; 9013. Second groove; 9014. Annular ridge;

[0067] 10. Interferometer assembly; 1001. Beam splitter; 1002. Fixed mirror; 1003. Moving mirror;

[0068] 11. Room temperature optical components; 1101. Secondary mirror; 1102. Tertiary mirror; 1103. Primary mirror; 1104. Folding mirror; 1105. Room temperature window;

[0069] 12. Laser detector; 13. Low-temperature optical components; 1301. First dichroic filter; 1302. First mid-wavelength window; 1303. Second dichroic filter; 1304. First mid-wavelength filter; 1305. First mid-wavelength immersion lens; 1306. Long-wavelength filter; 1307. Long-wavelength double lens group; 1308. Mirror; 1309. Second mid-wavelength window; 1310. Second mid-wavelength filter; 1311. Second mid-wavelength immersion lens. Detailed Implementation

[0070] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0071] Example

[0072] The main technical specifications of this invention are as follows:

[0073] The operating wavelength of the instrument of this invention is 3.92μm-15.38μm.

[0074] The spectral resolution of the instrument in this invention is 0.625 cm⁻¹. -1 .

[0075] The working altitude of the instrument of this invention is 4-10km.

[0076] like Figures 1 to 15 As shown, the present invention is an airborne remote sensing instrument based on a Fourier spectrometer, comprising: an optical device 3 mounted on the tail section 1 of an aircraft, and an electrical control box assembly 2 that is electrically connected to the internal components of the optical device 3 and located on one side of the optical device 3.

[0077] The electrical control box assembly 2 includes: a mounting bracket 201, which is divided into three layers: a vacuum assembly 202 located at the bottom layer of the mounting bracket 201; a data acquisition unit 205, an interferometer electrical control box 204, and an instrument electrical control box 203 located in the middle layer of the mounting bracket 201; and a refrigerator power supply 206, a temperature control box 207, a scanning motor 707 electrical control box 208, a POS 510 209, a POS electrical control box 2010, and an inverter 2011 located at the top layer of the mounting bracket 201.

[0078] The optical device 3 includes a support plate 5 adapted to the tail section 1 of the aircraft, an optical instrument body 4 located on the upper surface of the support plate 5, and a front optical path assembly 7 located on the lower surface of the support plate 5 and connected to the optical instrument body 4.

[0079] The main body of the optical instrument 4 includes: a vacuum chamber 6, a transmission optical path assembly 9 for receiving the beam from the front optical path assembly 7, an interferometer assembly 10 for receiving the beam from the transmission optical path assembly 9, a room temperature optical assembly 11 for receiving the beam from the interferometer assembly 10, and a low temperature optical assembly 13 for receiving the beam from the room temperature optical assembly 11.

[0080] When the light beam emitted by the target radiation source passes through the pre-optical path component 7, the transmission optical path component 9, the interferometer component 10, the room temperature optical component 11 and the low temperature optical component 13, the interference signal generated by the interference optics is converted into an electrical signal, which is then processed and amplified, digitized and transmitted to the computer for data storage.

[0081] The front optical path assembly 7 includes: a support beam 701 connected to the main body 4 of the optical instrument; a mounting frame 702 connected to the support beam 701; an observation space formed within the mounting frame 702; a first blackbody 703 and a second blackbody 704 symmetrically arranged on the mounting frame 702; a heating element 706 and a heat insulation layer 705 sequentially arranged from the inside to the outside on the outer surfaces of the first blackbody 703 and the second blackbody 704; and a heating element 706 and a heat insulation layer 705 disposed on the mounting frame 702 and adjacent to the first blackbody 703 and the second blackbody 704. A scanning motor 707 is mounted on one side. The output end of the scanning motor 707 extends into the observation space and is connected to a scanning mirror 7016 for Earth observation. A folding frame 7014 is connected to the mounting frame 702 and is opposite to the scanning motor 707. An optical path space 7015 is provided inside the folding frame 7014. A first folding mirror 7012 is connected to the folding frame 7014 to receive the refracted light path of the scanning mirror 7016. An optical path protective cover 708 is vertically mounted on the folding frame 7014 and connected to the vacuum chamber 6.

[0082] When the light beam emitted by the target radiation source enters the front optical path assembly 7, the scanning motor 707 is controlled to drive the scanning mirror 7016 to rotate to the required angle and the scanning mirror 7016 is aligned with the ground. The radiation from the water surface or the ground is received by the scanning mirror 7016, and the light beam is then refracted by the scanning mirror onto the first folding mirror 7012, and finally refracted into the optical instrument body 4 for subsequent processing.

[0083] One end of the first blackbody 703 and the second blackbody 704 extends into the observation space. A heat insulation pad is provided between the first blackbody 703 and the second blackbody 704 and the mounting bracket 702. Both the heat insulation pad and the heat insulation layer 705 are made of polyimide.

[0084] By employing a blackbody as a calibration source, on-flight radiation response correction is achieved, thereby improving the accuracy of measurement results. The use of a heat insulation pad isolates heat conduction between the mounting bracket 702 and the blackbody, preventing temperature-related deviations in radiation response correction. Polyimide possesses excellent thermal stability, superior low-temperature resistance, good dimensional stability and mechanical properties, excellent radiation resistance, good insulation and dielectric properties, and excellent flame retardancy, thus ensuring the optimal operating temperature for the blackbody.

[0085] There are at least six heating elements 706, which are arranged in a ring at intervals on the surfaces of the first blackbody 703 and the second blackbody 704. The heating elements 706 placed on the blackbody can be temperature controlled by the devices inside the electrical control box assembly 2 to ensure that the blackbody is in the optimal operating temperature state, so that the equipment can still operate normally at low temperatures.

[0086] The support beam 701 includes a base plate 701a, a first hollow frame 701b vertically mounted on the base plate 701a, a middle plate 701c mounted on the top of the first hollow frame 701b, a second hollow frame 701d vertically mounted on the middle plate 701c, a top plate 701e mounted on the top of the second hollow frame 701d, and a first reinforcing plate 701f and a second reinforcing plate 701g mounted on the adjacent end faces of the first hollow frame 701b and the second hollow frame 701d.

[0087] The support beam 701 adopts a lightweight structural design, which can effectively reduce the weight of the device while ensuring its high rigidity, and at the same time improve the overall performance of the device and extend its service life. Furthermore, the support beam 701 can be modularly modified to meet the needs of different installation environments.

[0088] Mounting bracket 702 includes a blackbody mounting bracket 702a201 and a motor mounting bracket 702b201 mounted on the blackbody mounting bracket 702a201. One end face of the motor mounting bracket 702b201 is provided with a locking end 7017. A protective baffle 7018 is provided on one side of the locking end 7017. A groove 7020 is provided on the protective baffle 7018. A protrusion 7019 that mates with the groove 7020 extends outward from the blackbody mounting bracket 702a201.

[0089] The engaging end 7017 on the motor mounting bracket 702b is fitted into the blackbody mounting bracket 702a, and the engaging end 7017 can support the blackbody mounting bracket 702a. At the same time, the protrusion 7019 of the blackbody mounting bracket 702a cooperates with the groove 7020 to limit and reduce the positional offset of the motor mounting bracket 702b during operation.

[0090] The mounting bracket 702 has an optical calibration hole 7010 located on one side of the first blackbody 703 and the second blackbody 704, and a cover 709 is provided on the optical calibration hole 7010. Through the optical calibration hole 7010, the blackbody and the scanning mirror 7016 can be optically calibrated, thereby ensuring the accuracy of subsequent information and the installation precision.

[0091] The folding frame 7014 is connected to the mounting frame 7011. The first folding mirror 7012 is placed inside the mounting frame 7011 and is tilted at 45° to facilitate the transmission of light.

[0092] An adjustment shim 7013 is provided between the mounting frame 7011 and the folding frame 7014. By adding the adjustment shim 7013, the position can be finely adjusted to cope with various usage environments and ensure the accuracy of the measured information.

[0093] The optical path component 9 includes a frame 901, with a bottom end face 908 and a rear end face 907 respectively provided with an inlet 909 for receiving the light beam from the front optical path component 7 and an outlet 9010 for directing the light beam to the interferometer component 10. The optical path folding components are arranged opposite to each other on the two ends of the frame 901. The optical path folding components include a mirror chamber frame 902 embedded in the frame 901 and having a hollow shape, an annular protrusion 9014 extending outward from one end of the mirror chamber frame 902 facing the frame 901, a first groove 9011 formed on the mirror chamber frame 902, a blocking edge formed in the first groove 9011, a second folding mirror 903 that cooperates with the frame 901 and has one end face abutting against the blocking edge, and an adhesive layer disposed between the contact surfaces of the frame 901 and the second folding mirror 903.

[0094] During optical path transmission, the light source is transmitted through the pre-optical path assembly 7 connected to the device and enters the interior of the frame 901 through the light inlet 909. Then, the light source shines on the mirror surface of a second refracting mirror 903. After being refracted by 90° by this second refracting mirror 903, its propagation path is changed, and it shines on the mirror surface of another second refracting mirror 903. After being refracted by 90° by the other second refracting mirror 903, its propagation path is changed again and it exits from the light outlet 9010 of the frame 901. Then, it enters the interferometer assembly 10 of the rear optical path for subsequent processing.

[0095] The front end face 905 and the top end face 906 of the frame 901 are both sealed by the sealing plate 904, and a second groove 9013 is provided on the frame 901 to cooperate with the sealing plate 904.

[0096] During installation, the sealing plate 904 is inserted into the second groove 9013 and fixed to the frame 901 with screws. Except for the light inlet 909 and the light outlet 9010, the frame 901 forms a sealed space, which can protect the transmission of optical signals.

[0097] The second folding mirror 903 and the first groove 9011 are fitted with a clearance. An arc-shaped groove 9012 is provided at the first groove 9011 to accommodate the corner of the second folding mirror 903, and colloid is injected into the arc-shaped groove 9012 to fix the second folding mirror 903.

[0098] After the second folding mirror 903 is installed, glue is applied to the arc-shaped groove 9012. Since the installation of the second folding mirror 903 is a clearance fit, the glue can flow into the contact surface between the second folding mirror 903 and the mirror chamber frame 902 to form the aforementioned glue layer, thereby stabilizing the second folding mirror 903.

[0099] The interferometer assembly 10 includes: a beam splitter 1001 for receiving a beam from the optical transmission path assembly 9; the beam splitter 1001 transmits one beam of light onto a moving mirror 1003 located on one side of the beam splitter 1001; the beam splitter 1001 reflects another beam of light onto a fixed mirror 1002 located on one side of the beam splitter 1001; the light from the moving mirror 1003 and the fixed mirror 1002 combines to form coherent light, which is then directed to the room-temperature optical assembly 11 for processing.

[0100] The vacuum chamber 6 is equipped with a gas-lock nitrogen cylinder 8 that secures the movable mirror 1003, which needs to be adjusted, during instrument operation.

[0101] A laser source and a laser detector 12 for controlling the interferometer assembly 10 are provided between the optical transmission path assembly 9 and the room temperature optical assembly 11.

[0102] When the light source enters the interferometer assembly 10, the movable mirror 1003, adjusted according to actual needs, is unlocked via the nitrogen gas cylinder 8. A beam of light from the light source is split into two beams by the beam splitter 1001. One beam is transmitted to the movable mirror 1003, and the other is reflected to the fixed mirror 1002. The light incident on the room-temperature optical assembly 11 is formed by the convergence of the light reflected from the movable mirror 1003 and the fixed mirror 1002, creating coherent light with interference characteristics to generate the desired interference signal. In other words, the interferometer assembly 10 employs a dual-beam interference beam splitting method to meet the requirements of a wide spectral channel range and high spectral resolution.

[0103] The room temperature optical component 11 includes a secondary mirror 1101 for receiving the light beam from the interferometer component 10. The secondary mirror 1101 reflects the light to the third mirror 1102, the primary mirror 1103, and the folding mirror 1104. The folding mirror 1104 then directs the light beam through the room temperature window 1105 to the low temperature optical component 13 for processing.

[0104] After the coherent light enters the room temperature optical component 11, it ensures that the errors caused by the light emitted from the driven mirror 1003 and the fixed mirror 1002 are eliminated.

[0105] The low-temperature optical component 13 includes: a first dichroic filter 1301 for receiving light beams from the room-temperature optical component 11; the first dichroic filter 1301 reflects optical signals of different wavelengths onto a mirror 1308 and a second dichroic filter 1303 respectively; the light beam on the second dichroic filter 1303 is emitted through a first medium-wavelength window 1302, one beam passes through a first medium-wavelength filter 1304 to a first medium-wavelength immersion lens 1305, and the other beam passes through a long-wavelength filter 1306 to a long-wavelength dual-lens group 1307; the mirror 1308 emits light through a second medium-wavelength window 1309, and through a second medium-wavelength filter 1310 to a second medium-wavelength immersion lens 1311.

[0106] The aforementioned low-temperature optical component 13 is placed in a Stirling refrigerator, which controls the temperature of the optical system. The controlled temperature is 75K, or -198℃, which effectively reduces background noise, improves the signal-to-noise ratio and sensitivity, and can eliminate chromatic aberration to ensure image quality.

[0107] In this invention, the light beam emitted by the target radiation source enters the front optical path assembly 7, is reflected by a 45° plane mirror, enters the transmission optical path assembly 9, is reflected by two 45° plane mirrors inside the transmission optical path assembly 9, and then enters the interferometer assembly 10. After coherent light is formed by the interferometer assembly 10, it enters the room temperature optical assembly 11, and after passing through the interior of the room temperature optical assembly and the plane mirror window on the side of the instrument, it enters the low temperature optical assembly 13. The aforementioned interference signal is converted into an electrical signal, which is then processed and amplified, digitized, and transmitted to the computer for data storage.

[0108] By comparing information obtained from simultaneous Earth observations by spaceborne hyperspectral instruments and similar airborne hyperspectral instruments, the authenticity of the temperature and humidity atmospheric contour inversion is verified. Furthermore, the optical system consistent with the Fengyun satellite payload is verified by airborne flight. On the one hand, this provides a data foundation for the research of data processing and application methods, greatly reduces the risks of future on-orbit use of spaceborne instruments, and is conducive to the algorithm research, further improvement, verification, and optimization of the ground system. On the other hand, it can also provide effective basis for the performance improvement of infrared hyperspectral instruments under development.

[0109] By controlling the scanning motor 707 to drive the scanning mirror 7016 to rotate, multi-angle observation of Earth data can be achieved, ensuring the accuracy of the observation data and increasing its applicability. The temperature of the blackbody is controlled by the insulation layer 705 and the heating element 706 to ensure that the temperature is controlled at the optimal working temperature, so that the equipment can operate normally at low temperatures.

[0110] The optical path folding component ensures the installation stability of the second folding mirror 903 and prevents signal transmission quality from deteriorating. At the same time, the device is sealed by leaving only the light inlet and outlet ports, which can protect the optical path transmission. The main structure of the device is made of titanium alloy, which achieves a lightweight design, ensuring structural rigidity while reducing the overall weight of the device.

[0111] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An airborne remote sensing instrument based on a Fourier spectrometer, characterized in that, include: An optical device mounted in the tail section of an aircraft, and an electrical control box assembly that is electrically connected to the internal components of the optical device and located on one side of the optical device; The optical device includes a support plate adapted to the tail section of the aircraft, an optical instrument body located on the upper surface of the support plate, and a front optical path assembly located on the lower surface of the support plate and connected to the optical instrument body. The main body of the optical instrument includes: a vacuum chamber, a transmission optical path assembly for receiving the beam from the front optical path assembly, an interferometer assembly for receiving the beam from the transmission optical path assembly, a room temperature optical assembly for receiving the beam from the interferometer assembly, and a low temperature optical assembly for receiving the beam from the room temperature optical assembly. When the light beam emitted by the target radiation source passes through the pre-optical path component, the transmission optical path component, the interferometer component, the room temperature optical component and the low temperature optical component, the interference signal generated by the interference optics is converted into an electrical signal, which is then processed and amplified, digitized and transmitted to the computer for data storage. The optical transmission path component includes: The frame has a bottom end face and a rear end face respectively provided with an inlet for receiving a light beam from the front optical path component and an outlet for directing a light beam toward the interferometer component. The optical path deflector is arranged opposite to the two ends of the frame. The optical path deflector includes: a hollow mirror chamber frame embedded in the frame; an annular protrusion extending outward from one end of the mirror chamber frame facing the frame; a first groove on the mirror chamber frame; a blocking edge formed in the first groove; a second deflector mirror that cooperates with the frame and whose one end face abuts against the blocking edge; and an adhesive layer disposed between the contact surfaces of the frame and the second deflector mirror. The front and top surfaces of the frame are sealed by a sealing plate, and a second groove is provided on the frame to cooperate with the sealing plate. The second folding mirror and the first groove are in a clearance fit; The first groove has an arc-shaped groove to accommodate the corner of the second folding mirror, and colloid is injected into the arc-shaped groove to fix the second folding mirror.

2. The airborne remote sensing instrument based on a Fourier spectrometer according to claim 1, characterized in that, The front optical path assembly includes: a support beam connected to the main body of the optical instrument; A mounting frame connected to the support beam, wherein an observation space is formed within the mounting frame; A first blackbody and a second blackbody are symmetrically arranged on the mounting bracket. The outer surfaces of the first blackbody and the second blackbody are provided with heating elements and heat insulation layers from the inside to the outside. A scanning motor is mounted on the mounting frame and located on the side adjacent to the first blackbody and the second blackbody. The output end of the scanning motor extends into the observation space and is connected to a scanning mirror for Earth observation. A folding frame connected to the mounting bracket and opposite to the scanning motor, the folding frame having an optical path space inside, and a first folding mirror connected to the folding frame for receiving the refracted optical path of the scanning mirror; A light path protection cover is vertically mounted on the folding frame and connected to the vacuum chamber.

3. The airborne remote sensing instrument based on a Fourier spectrometer according to claim 2, characterized in that, One end of the first blackbody and the second blackbody extends into the observation space, and a heat insulation pad is provided between the first blackbody, the second blackbody, and the mounting frame; Both the heat insulation pad and the thermal insulation layer are made of polyimide.

4. The airborne remote sensing instrument based on a Fourier spectrometer according to claim 2, characterized in that, The heating element comprises at least six elements, which are arranged in a ring at intervals on the surfaces of the first and second black bodies.

5. The airborne remote sensing instrument based on a Fourier spectrometer according to claim 1, characterized in that, The interferometer assembly includes: a beam splitter for receiving a beam from the transmission optical path assembly; the beam splitter transmits one beam of light onto a moving mirror located on one side of the beam splitter; the beam splitter reflects another beam of light onto a fixed mirror located on one side of the beam splitter; the light on the moving mirror and the fixed mirror combines to form coherent light and is directed toward the room temperature optical assembly for processing. The vacuum chamber is equipped with a gas-lock nitrogen cylinder that fixes the moving mirror, which needs to be adjusted, during instrument operation. A laser source and a laser detector for controlling the interferometer assembly are provided between the optical transmission path assembly and the room temperature optical assembly.

6. The airborne remote sensing instrument based on a Fourier spectrometer according to claim 1, characterized in that, The ambient temperature optical component includes: a secondary mirror for receiving the light beam from the interferometer component; the secondary mirror reflects the light to the third mirror, the primary mirror, and the folding mirror; and the folding mirror directs the light beam through the ambient temperature window to the low temperature optical component for processing.

7. The airborne remote sensing instrument based on a Fourier spectrometer according to claim 1, characterized in that, The low-temperature optical component includes: a first dichroic filter for receiving a light beam from the room-temperature optical component; the first dichroic filter reflects optical signals of different wavelengths onto a mirror and a second dichroic filter respectively; the light beam on the second dichroic filter exits through a first medium-wavelength window, one beam passes through a first medium-wavelength filter to a first medium-wavelength immersion lens, and the other beam passes through a long-wavelength filter to a long-wavelength double lens group; the mirror directs the light path through a second medium-wavelength window to a second medium-wavelength immersion lens via a second medium-wavelength filter.

Images