An infrared star detection system and method

Abstract

The present application provides an infrared star detection system and method, which combines ground-based and space-based detection technologies, continuously observes infrared stars and accumulates data, reduces the observation condition limit of ground-based observation, improves the timeliness and accuracy of infrared star observation, and reduces the influence of atmosphere and geographical position on observation results. ‑15 The detection sensitivity of 5*10 ‑15 @SNR=6 stars, which can realize the star reference calibration of the to-be-calibrated device at any position in the world, and meets the on-orbit observation requirements.

Description

Technical Field

[0001] This invention relates to the field of infrared star calibration technology, specifically to an infrared star detection system and method. Background Technology

[0002] Stars that radiate infrared light are called infrared stars. Current technology relies on ground-based measurement equipment to observe infrared stars.

[0003] Patent 202010535424.3 discloses a method and device for relative measurement of stellar irradiance, which uses ground-based measurement equipment to observe infrared stars and calculates irradiance based on the observation data. The device includes: (1) a standard star grayscale calculation unit, used to acquire images of standard stars, calculate the sum of the grayscale of pixels in the star region of the image after removing the background as the grayscale of the current standard star, calculate the atmospheric transmittance based on the angle of the current standard star from the zenith, and calculate the grayscale of the current standard star outside the atmosphere based on the grayscale of the current standard star and the atmospheric transmittance; (2) a relationship fitting unit, used to obtain the grayscale of multiple standard stars outside the atmosphere, and obtain the irradiance of the corresponding standard star outside the atmosphere based on the star catalog data, and obtain the fitting formula between irradiance and grayscale; (3) an irradiance calculation unit, used to acquire images of the star to be measured, calculate the grayscale of the star to be measured outside the atmosphere, and obtain the irradiance based on the fitting formula.

[0004] In addition, patent 202011259894.8 discloses a method and apparatus for measuring the irradiance of an airborne point target using infrared bands, including: (1) an irradiance calculation module for calculating the irradiance in the long-wave infrared image of the airborne point target in order to acquire the long-wave infrared image of the airborne point target; (2) a transmittance calculation module for calculating the atmospheric transmittance from the airborne point target to the measuring device; (3) an extra-atmospheric irradiance calculation module for calculating the irradiance outside the atmosphere of the airborne point target by means of atmospheric transmittance; and (4) a correction module for correcting the irradiance outside the atmosphere of the airborne point target using a correction coefficient.

[0005] While the above two methods can achieve infrared star detection and calculate irradiance based on the detection data, their detection accuracy is significantly affected by the atmosphere and geographical location, and they can only observe a portion of infrared stars, failing to meet current measurement needs. Therefore, there is an urgent need for an infrared star observation method that can overcome the limitations of ground-based detection and improve the accuracy of observations. Summary of the Invention

[0006] In view of this, the present invention provides an infrared star detection system and method that can improve observation accuracy and avoid the limitations of observation conditions.

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

[0008] An infrared satellite detection system includes a ground planning module, an on-board measurement module, an on-board processing module, and a ground computing module.

[0009] The ground planning module determines the satellite's orientation and uploads the information to the onboard measurement module.

[0010] The onboard measurement module includes an optical imaging unit, a filter unit, and a detector, and is mounted on the satellite turntable.

[0011] The satellite turntable adjusts its attitude according to the satellite's orientation, aligning the optical imaging unit with the infrared star. The detector drives the optical imaging unit to acquire an infrared star image and transmits it to the filtering unit. The filtering unit filters the infrared star image and transmits it to the detector. The detector converts the filtered infrared star image into infrared star grayscale and transmits it to the onboard processing module.

[0012] The onboard processing module calculates grayscale based on infrared radiation data and transmits it to the ground-based calculation module.

[0013] The ground-based calculation module calculates the irradiance of the infrared satellite based on grayscale values.

[0014] Furthermore, the onboard measurement module ceases operation when the angle between it and the sun is between -15° and +15°.

[0015] Furthermore, the ground planning module determines the satellite's orientation for the next moment based on the detected infrared satellite position, and uploads it to the onboard measurement module in the form of right ascension and declination coordinates.

[0016] Furthermore, the detector monitors and adjusts the temperature of the onboard measurement module to its operating temperature.

[0017] An infrared star detection method, used in any of the above-mentioned infrared star detection systems, includes the following steps:

[0018] Step 1: The ground planning module plans the infrared satellite measurement sequence and uploads the right ascension and declination coordinates pointed to by the satellite to the on-board measurement module.

[0019] Step 2: The onboard measurement module acquires infrared star images and extracts infrared radiation data.

[0020] Step 3: The on-board processing module calculates the grayscale based on the infrared radiation data and transmits it to the ground calculation module.

[0021] Step 4: The ground calculation module calculates the irradiance of the infrared star based on the grayscale.

[0022] Beneficial effects:

[0023] 1. This invention proposes an infrared star detection system that combines ground-based and space-based detection for continuous observation and data accumulation of infrared stars. This reduces the limitations of ground-based observation on observation conditions, improves the timeliness and accuracy of infrared stellar observation, reduces the influence of the atmosphere and geographical location, and can achieve 5×10 -15 With an SNR of 6 and a measurement uncertainty of 13.5%, the detection performance is significantly improved compared to ground-based measurement devices.

[0024] 2. In this invention, the temperature of the on-board measurement module is adjusted in real time by the detector to ensure normal operation.

[0025] 3. In this invention, the on-board measurement module stops working when the angle between it and the sun is between -15° and +15°, thus providing a protective function.

[0026] 4. This invention proposes an infrared star detection method, which, through observation mission design, can comprehensively ensure the detection sensitivity of multiple stars across the entire sky at 5×10⁻⁶. -15 The observation of stars with an SNR of 6 enables the calibration of stellar references for calibration instruments at any location globally, meeting the requirements for on-orbit observation. Attached Figure Description

[0027] Figure 1 This is a system composition diagram of the present invention.

[0028] Figure 2 This is a flowchart of the method of the present invention. Detailed Implementation

[0029] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0030] like Figure 1 As shown, this invention provides an infrared satellite irradiance detection system, including a ground planning module, an on-board measurement module, an on-board processing module, and a ground computing module. The on-board measurement module and the on-board processing module are both mounted on a satellite platform.

[0031] This invention, through optimized design, can achieve 5×10 -15 With an SNR of 6 and a measurement uncertainty of 13.5%, the detection performance is significantly improved compared to ground-based measurement devices.

[0032] The ground planning module determines the satellite's orientation based on the location of the infrared satellite to be detected and uploads it to the onboard measurement module in the form of right ascension and declination coordinates.

[0033] The onboard measurement module includes an optical imaging unit, a filter unit, and a detector, and is mounted on the satellite turntable.

[0034] The satellite turntable adjusts its attitude according to the satellite's pointing direction, aligning the optical imaging unit with the infrared star. The detector drives the optical imaging unit to acquire an infrared star image, which is then transmitted to the filtering unit. The filtering unit filters the infrared star image and transmits it back to the detector. The detector converts the filtered infrared star image into infrared star grayscale and transmits it to the onboard processing module. Furthermore, the detector monitors and adjusts the temperature of the onboard measurement module to its operating temperature. Considering the high sensitivity of stellar observations to solar stray light, this embodiment uses a solar avoidance angle of 30°. This means that the onboard measurement module stops operating when the angle between the onboard measurement module and the sun is between -15° and +15°, serving a protective function.

[0035] In this embodiment, the optical imaging unit adopts a compact coaxial reflective system with a field of view of 2°×1.74°, which is a large field of view reflective system to ensure imaging quality. The filtering unit uses a low-temperature filter wheel to solve the cooling and switching of multiple filters required by the onboard measurement module, enabling time-division multiplexing of long-wave infrared data in three bands: 7.7–10μm, 8–12μm, and 7.7–12μm. The detector is a long-wave infrared detector that converts the infrared radiation data of the infrared star map into electrical signals and sends them to the onboard processing module. Simultaneously, the detector is also responsible for imaging drive, image non-uniformity correction, and temperature control. The optical imaging unit needs to operate at a preset temperature (below ambient temperature) to function properly; therefore, the detector also adjusts the temperature in real time.

[0036] The onboard processing module converts the infrared radiation data into the grayscale of the infrared satellite and transmits it to the ground-based computing module.

[0037] The ground-based computing module calculates the irradiance of the infrared satellite based on its grayscale value.

[0038] like Figure 2 As shown, this invention proposes an infrared satellite observation method. Through observation mission design, it can comprehensively ensure the detection sensitivity of multiple satellites across the entire sky at 5×10⁻⁶. -15 The observation of stars with an SNR of 6 enables stellar reference calibration of instruments to be calibrated at any location globally, meeting the requirements for on-orbit observation. The method of this invention is used in the aforementioned infrared star observation system, and the specific steps include:

[0039] Step 1: The ground planning module plans the infrared satellite measurement sequence and uploads the right ascension and declination coordinates pointed to by the satellite to the onboard measurement module. Without affecting system functionality and main missions, the ground planning module initiates stellar observation missions within a suitable time window. The ground planning module determines the stellar measurement sequence and number, and the ground command computer uploads the right ascension and declination information of the stars pointed to by the satellite to the platform.

[0040] Step 2: The onboard measurement module adjusts its attitude, acquires infrared star images, and extracts infrared radiation data.

[0041] The standard for proper attitude adjustment is: adjust the satellite attitude according to the position of stars in the infrared star catalog, and the attitude meets the preset deviation range.

[0042] The standard for completing target acquisition is: based on the acquisition time, the time to complete one imaging session is 2-3 seconds.

[0043] Step 3: The on-board processing module calculates the grayscale based on the infrared radiation data and transmits it to the ground calculation module.

[0044] Step 4: The ground calculation module calculates the irradiance of the infrared star based on the grayscale.

[0045] In summary, the above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An infrared star detection system, characterized in that, It includes a ground planning module, an on-board measurement module, an on-board processing module, and a ground computing module; The ground planning module determines the satellite's orientation and uploads the information to the onboard measurement module. The onboard measurement module includes an optical imaging unit, a filter unit, and a detector, and is mounted on a satellite turntable; The satellite turntable adjusts its attitude according to the satellite's orientation, aligning the optical imaging unit with the infrared star; the detector drives the optical imaging unit to acquire an infrared star image and transmits it to the filtering unit. The filtering unit filters the infrared star image and transmits it to the detector; the detector converts the filtered infrared star image into infrared star grayscale and transmits it to the on-board processing module. The on-board processing module calculates grayscale based on infrared radiation data and transmits it to the ground-based calculation module. The ground-based calculation module calculates the irradiance of the infrared satellite based on grayscale values.

2. The infrared star detection system as described in claim 1, characterized in that, The on-board measurement module stops working when the angle between it and the sun is between -15° and +15°.

3. The infrared star detection system as described in claim 1, characterized in that, The ground planning module determines the satellite's orientation for the next moment based on the detected infrared satellite position, and uploads it to the onboard measurement module in the form of right ascension and declination coordinates.

4. The infrared star detection system as described in claim 1 or 2, characterized in that, The detector monitors and adjusts the temperature of the onboard measurement module to its operating temperature.

5. An infrared star detection method, used in any of the infrared star detection systems described in claims 1-4, characterized in that, The specific steps include: Step 1: The ground planning module plans the infrared satellite measurement sequence and uploads the right ascension and declination coordinates pointed to by the satellite to the on-board measurement module; Step 2: The onboard measurement module acquires infrared star images and extracts infrared radiation data; Step 3: The on-board processing module calculates the grayscale based on the infrared radiation data and transmits it to the ground calculation module. Step 4: The ground calculation module calculates the irradiance of the infrared star based on the grayscale.

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