Full-field instrument magnitude calibration method, device and storage medium

Abstract

The present invention discloses a method, device and storage medium for calibrating the magnitude of a full-field instrument. The method is as follows: taking a star map, detecting and clustering the entire field of view to obtain a large number of bright spots; extracting observed stars, performing photometry and positioning on all bright spots to obtain the position, gray scale, uncertainty and zenith angle; matching the observed stars with a star catalog, and after successful matching, recording the following information, including the stellar magnitude, position, gray scale and uncertainty corresponding to the observed stars; dividing the full field of view into regions, counting all the stars that have been successfully matched in all frames within the region, fitting them by weighted least squares, and recording the zero points of the instrument magnitude obtained in different regions; performing polynomial interpolation on the zero points of the instrument magnitude in different regions of the full field of view to obtain the zero point correction at different fields of view; repeating the above steps at different time periods to obtain an accurate correction method for the on-orbit instrument magnitude of the full time period. The present invention can calibrate the on-orbit instrument magnitude of optoelectronic devices.

Description

Technical Field

[0001] The present invention relates to the field of space optoelectronics, and particularly to a method, device, and storage medium for calibrating the magnitude of a full-field instrument. Background Art

[0002] Space optoelectronic components, such as star sensors, inter-satellite measurement cameras, debris perception cameras, etc., all need to image space targets, accurately measure the magnitude information of (multiple) target stars, and implement faster and more accurate star map matching. More accurate target recognition is of great significance. However, due to the influence of optical system design, development, assembly, and the fact that the detector and optical response are greatly affected by temperature, the image quality of stars or space targets presented on the image plane at different fields of view, different temperatures, and different epochs changes, ultimately affecting the accuracy of target energy measurement and deviating from the calculated value of the instrument magnitude, there are time-varying and space-varying deviations. If the instrument magnitude deviation is too large, the calculated magnitude is used in the star map matching link, and the threshold range is too large, resulting in low matching efficiency and even reducing the matching success rate; if the instrument magnitude deviation is too large, the brightness of space targets cannot be predicted either. When the target brightness changes greatly, it is difficult to distinguish whether the change is the effect brought by the instrument magnitude deviation or the effect brought by the target itself being in a certain maneuvering state, which has a great impact on the accurate recognition of space targets. It can be seen that accurate calibration of the instrument magnitude is a common problem in the field of space optoelectronic measurement and perception. How to use the measured star map data to identify and correct the instrument magnitude deviation caused by space environment, component self-change, etc. is both very necessary and of great significance. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a method, device, and storage medium for calibrating the magnitude of a full-field instrument at all times to achieve accurate correction of the instrument magnitude.

[0004] The technical solution of the present invention is: a method for calibrating the magnitude of a full-field instrument, the method comprising the following steps:

[0005] S1. Use a star sensor to capture a star map, extract the information of multiple observed stars from the star map, calculate the instrument magnitude corresponding to each observed star, and obtain and store the star point information of the observed stars. The star point information includes: position, gray level, instrument magnitude, signal-to-noise ratio, uncertainty, zenith angle;

[0006] S2. Perform a matching operation on the extracted observed stars and the pre-stored star catalog to obtain the information of the star catalog star-observed star pairs that match successfully, and extract and store the star catalog information corresponding to the matched observed stars. The star catalog information includes color difference index and star catalog magnitude;

[0007] S3. Divide the observed star - catalog star pairs into the preset regions of the star sensor's field of view according to the position information, eliminate the unqualified catalog star - observed star pairs, and calculate the average position of all observed stars in each region;

[0008] S4. Change the pointing of the star sensor in space, accumulate more qualified catalog star - observed star pairs for each preset region of the star sensor's field of view, and repeat steps S1 to S4 until the density of qualified catalog star - observed star pairs in each region meets the preset conditions, and then execute step S5 for each region;

[0009] S5. Calculate the zero - point correction term related to the field of view of the regional average position based on the star point information and catalog information of the qualified catalog star - observed star pairs;

[0010] S6. Using the average positions of all matching observed stars in all regions as control points, perform polynomial interpolation on the instrument magnitude zero points at other positions in different regions of the entire field of view to obtain the instrument magnitude zero - point correction term for the entire field of view.

[0011] Preferably, the above - mentioned method for calibrating the instrument magnitude of the entire field of view further includes the following steps:

[0012] S7. Repeat steps S1 to S6 at different time periods to obtain the zero - point correction term of the on - orbit instrument magnitude for the entire time period.

[0013] Preferably, in step S1, the instrument magnitude of the observed star is calculated using the method for calculating the energy and magnitude of the observed star that has been calibrated on the ground.

[0014] Preferably, the unqualified catalog star - observed star pairs are catalog star - observed star pairs that meet one of the following conditions:

[0015] a. Stars in the star catalog with a color - difference index greater than 1;

[0016] b. The observed star belongs to a multiple - star system; the multiple - star system refers to a system where the star spacing of the observed star is less than twice the distance of the half - width of the PSF;

[0017] c. There are many faint stars or galaxies in the background of the observed star; the "faint" stars or galaxies are stars with a magnitude 1 - 3 magnitudes lower than the instrument sensitivity;

[0018] d. Stars with an observed star signal - to - noise ratio less than 5;

[0019] e. The observed star is a saturated star.

[0020] Preferably, step S3 determines the function f to be corrected i (c0, c1, c2, c3, c4, Z) such that the function satisfies the following conditions to determine the zero - point correction term c0 related to the field of view of the regional average position:

[0021]

[0022] f i = M cat,i + c0 + c1×Z i + c2×(color i ) + c3×(color i ) 2 + c4×(color i ) 3

[0023] where, m inst,i is the instrumental magnitude corresponding to the observed star i, f i (c0, c1, c2, c3, c4, Z i ) is the function to be corrected, M cat,i is the catalog magnitude corresponding to the observed star i, c0 is the zero-point correction term related to the regional average position and the field of view, Z i is the zenith angle function corresponding to the atmospheric extinction term of the observed star i, color i is the color difference index of the observed star i, is the energy uncertainty of the observed star i; c0 can be expressed as a function of zone j zone j is the average position of all observed star points in region j.

[0024] Another technical solution of the present invention is: a full-time and full-field on-orbit instrumental magnitude calibration device, the device includes:

[0025] An image preprocessing module, which is used to extract and store the star point information of multiple observed stars from the star map obtained by imaging the entire field of view, calculate the instrumental magnitude corresponding to the observed stars, and obtain and store the star point information of the observed stars, the star point information includes: position, gray scale, instrumental magnitude, signal-to-noise ratio, uncertainty, zenith angle;

[0026] A star pair matching module, which performs a matching operation on the extracted observed stars and the pre-stored star catalog to obtain the star catalog star-observed star pair information with successful matching, and extracts and stores the star catalog information corresponding to the matched observed stars, the star catalog information includes color difference index, catalog magnitude;

[0027] A star network matching module, which divides the observed star - catalog star pairs into the preset regions of the star sensor field of view according to the position information, eliminates the unqualified star catalog star-observed star pairs, and calculates the average position of all observed stars in the region;

[0028] Star pair collection module, which changes the pointing of the star sensor in space, accumulates more qualified star catalog star-observation star pairs for each area preset in the field of view of the star sensor until the density of qualified star catalog star-observation star pairs in each area meets the preset conditions;

[0029] Magnitude distortion fitting module, which calculates the zero-point correction term related to the field of view of the average position of this area according to the star point information and star catalog information of the qualified star catalog star-observation star pairs;

[0030] Magnitude interpolation module, which uses the average positions of all matching observed stars in all areas as control points to perform polynomial interpolation on the instrument magnitude zero points at other positions in different areas of the entire field of view to obtain the instrument magnitude zero-point correction term for the entire field of view.

[0031] Preferably, in step S1, the instrument magnitude of the observed star is calculated by using the method for calculating the energy and magnitude of the observed star that has been calibrated on the ground.

[0032] Preferably, the unqualified star catalog star-observation star pairs are star catalog star-observation star pairs that meet one of the following conditions:

[0033] a. Stars in the star catalog with a color difference index greater than 1;

[0034] b. The observed star belongs to a multiple star system; the multiple star system refers to a system where the star spacing of the observed star is less than twice the PSF half-width distance;

[0035] c. There are many faint stars or galaxies in the background of the observed star; "faint" stars or galaxies are stars with a magnitude 1 to 3 magnitudes lower than the instrument sensitivity;

[0036] d. Stars with an observed star signal-to-noise ratio less than 5;

[0037] e. The observed star is a saturated star.

[0038] Preferably, the magnitude distortion fitting module determines the function f to be corrected i (c0, c1, c2, c3, c4, Z), such that this function satisfies the following conditions to determine the zero-point correction term c0 related to the average position of the area:

[0039]

[0040] f i = M cat,i + c0 + c1×Z i + c2×(color i ) + c3×(color i ) 2 + c4×(color i ) 3

[0041] where m inst,i is the instrumental magnitude corresponding to the observed star i, and f i (c0, c1, c2, c3, c4, Z i ) is the function to be corrected, M cat,i is the catalog magnitude corresponding to the observed star i, c0 is the zero-point correction term related to the regional average position and the field of view, and Z i is the zenith angle function corresponding to the atmospheric extinction term of the observed star i, and color i is the color difference index of the observed star i. is the energy uncertainty of the observed star i; c0 can be expressed as a function of zone j where zone j is the average position of all observed star points in region j.

[0042] One technical solution of the present invention is to provide a non-volatile storage medium for storing a software program, and when the software program is executed, it is used to execute the above method.

[0043] The beneficial effects of the present invention compared with the prior art are as follows:

[0044] (1), The present invention continuously changes the pointing of the star sensor in space, collects qualified catalog star-observed star pairs, and can reduce the influence of observation errors, sky background noise, etc. on the zero point of the instrumental magnitude as much as possible;

[0045] (2), The present invention calculates the zero point of the instrumental magnitude of each field of view region separately by dividing into several regions, and can fully characterize the inconsistency of the zero point of the instrumental magnitude caused by optical system distortion, non-uniform detector response, etc.;

[0046] (3), Still processing in the aforementioned manner for different time periods, the change of the zero point of the instrumental magnitude with time or temperature parameters can be obtained, and the time domain error can be further reduced.

[0047] (4), Using the technical solution of the present invention, the correction value of the instrumental magnitude of the entire field of view can be calculated by collecting and accumulating the information of observed stars in different fields of view. The camera can be calibrated both on the ground and in orbit, improving the calibration accuracy of the camera.

[0048] (5), Collecting and correcting the zero point of the instrumental magnitude by statistical means, compared with the prior art, can characterize the change of the zero point of the instrumental magnitude with the field of view, with time or environmental parameters, that is, fully considering the spatial and temporal variation characteristics of the zero point of the instrumental magnitude. After compensation, the zero point error of the instrumental magnitude of each star will be further reduced, ensuring the instrumental magnitude accuracy of the product. Description of the Drawings

[0049] Figure 1Schematic flow chart of a method for calibrating the instrument magnitude for the whole time period and the whole field of view according to an embodiment of the present invention;

[0050] Figure 2(a) is a schematic diagram of the residual instrument magnitude after the zenith angle function correction according to an embodiment of the present invention;

[0051] Figure 2(b) is a schematic diagram of the residual instrument magnitude after the chromatic aberration correction according to an embodiment of the present invention;

[0052] Figure 3 Schematic diagram of the residual instrument magnitude after the chromatic aberration function correction according to another embodiment of the present invention;

[0053] Figure 4 Results of the residual zero point of the instrument magnitude at different fields of view after the chromatic aberration function correction according to the embodiment of the present invention;

[0054] Figure 5 Schematic structural diagram of a device for calibrating the instrument magnitude for the whole time period and the whole field of view provided by the embodiment of the present invention. Detailed implementation manners

[0055] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0056] Due to the influence of various factors, the instrument magnitude shows a complex change pattern. Different optical image qualities, detector responses, temperature changes, etc. have a great impact on the "zero point" of the instrument magnitude. Therefore, it is necessary to compensate for the errors caused by the above factors. In the compensation process, there are differences between ground calibration and on-orbit calibration. There is an atmospheric extinction effect in ground calibration, which does not exist in space-based systems. Space-based systems have problems such as aging of instrument equipment and changes in installation orientation, which do not exist on the ground, while the temperature effect is common. Therefore, a unified calibration method is needed to accurately correct the above effects. Based on this, a method, device, and storage medium for calibrating the instrument magnitude for the whole time period and the whole field of view are provided, and the specific solutions are as follows.

[0057] Figure 1 Schematic flow chart of a method for calibrating the instrument magnitude for the whole time period and the whole field of view provided by the embodiment of the present invention. As Figure 1 shown, the method includes the following steps:

[0058] S1. Use a star sensor to capture a star map, extract the information of multiple observed stars from the star map, calculate the corresponding instrument magnitude of each observed star, and obtain and store the star point information of the observed stars. The star point information includes: position, gray scale, instrument magnitude, signal-to-noise ratio, uncertainty, and zenith angle;

[0059] In this step, the star sensor images the entire field of view to obtain a star map of the whole field of view, extracts multiple bright points from the star map, uses a photometry method to extract the information of multiple observed stars, and then uses the observed star energy and magnitude calculation method that has been calibrated on the ground to calculate the instrument magnitude of the observed stars.

[0060] S2. Match the extracted observed stars with the pre-stored star catalog to obtain the information of the star catalog star-observed star pairs with successful matches, and extract and store the star catalog information corresponding to the matched observed stars. The star catalog information includes the color difference index and the star catalog magnitude.

[0061] S3. Divide the observed star-star catalog star pairs into the preset regions of the star sensor's field of view according to the position information, eliminate the unqualified star catalog star-observed star pairs, and calculate the average position of all the observed stars in each region.

[0062] The unqualified star catalog star-observed star pairs are the star catalog star-observed star pairs that meet one of the following conditions:

[0063] 1) Stars in the star catalog with a color difference index greater than 1;

[0064] 2) The observed star belongs to a multiple-star system. The multiple-star system refers to a system where the star separation of the observed star is less than twice the PSF half-width distance;

[0065] 3) There are many faint stars or galaxies in the background of the observed star. The "faint" stars or galaxies are stars with a magnitude 1 - 3 magnitudes lower than the instrument sensitivity;

[0066] 4) The signal-to-noise ratio of the observed star is less than 5;

[0067] 5) The observed star is a saturated star.

[0068] The calculation formula for the average position of all the observed star points in the region is:

[0069]

[0070] where zone j is the average position of region j, (u i,j , v i,j ) are the coordinates of the observed star i in the image plane of region j; N j is the number of observed stars in region j, j ∈ [1, N], and N is the number of regions.

[0071] S4. Change the pointing of the star sensor in space, and for each region preset in the star sensor's field of view, accumulate more qualified star catalog star-observed star pairs. Repeat steps S1 - S4 until the density of the qualified star catalog star-observed star pairs in each region meets the preset condition, and then execute step S5 for each region;

[0072] The preset condition is: the density of the star catalog star-observed star pairs in each region is not less than 10 per square degree.

[0073] S5. Calculate the zero-point correction term related to the field of view for the average position of this area based on the star point information and star catalog information of the qualified star catalog star-observed star pairs; specifically, use the weighted least squares method: determine the function f to be corrected i (c0, c1, c2, c3, c4, Z) such that this function satisfies the following conditions, and at this time, the corresponding c0(zone j ) is the zero-point correction term related to the field of view for the average position of the area.

[0074]

[0075] f i = M cat,i + c0 + c1×Z i + c2×(color i ) + c3×(color i ) 2 + c4×(color i ) 3

[0076] where, m inst,i is the instrumental magnitude corresponding to the observed star i, f i (c0, c1, c2, c3, c4, Z i ) is the function to be corrected, M cat,i is the catalog magnitude corresponding to the observed star i, c0 is the zero-point correction term related to the field of view for the average position of the area, Z i is the zenith angle function corresponding to the atmospheric extinction term of the observed star i, color i is the color difference index of the observed star i, is the energy uncertainty of the observed star i; c0 can be expressed as a function of zone j , and zone j is the average position of all observed star points in area j.

[0077] S6. Using the average positions of all matching observed stars in all areas as control points, perform polynomial interpolation on the instrumental magnitude zeros at other positions in different areas of the entire field of view to obtain the instrumental magnitude zero-point correction term for the entire field of view.

[0078] S7. Repeat steps S1 to S6 at different time periods to obtain the instrumental magnitude zero-point correction term for the entire on-orbit period.

[0079] The above-mentioned method for precisely correcting the instrumental magnitude for the entire time period, that is, while the external environment changes, repeat the above steps to obtain the instrumental magnitude correction function corresponding to different external environments. For the changes between different external environments, the exact value can be further obtained by interpolation.

[0080] Based on the above method, the present invention also provides a full-time and full-field on-orbit instrument magnitude calibration device, which includes:

[0081] An image preprocessing module, configured to extract and store the star point information of multiple observed stars from the star map obtained by imaging the entire field of view, calculate the instrument magnitude corresponding to the observed stars, and obtain and store the star point information of the observed stars. The star point information includes: position, grayscale, instrument magnitude, signal-to-noise ratio, uncertainty, zenith angle;

[0082] A star pair matching module, which performs a matching operation on the extracted observed stars and the pre-stored star catalog to obtain the star catalog star-observed star pair information with successful matching, and extracts and stores the star catalog information corresponding to the matched observed stars. The star catalog information includes color difference index and star catalog magnitude;

[0083] A star network matching module, which divides the observed star-star catalog star pairs into preset regions of the star sensor's field of view according to the position information, eliminates unqualified star catalog star-observed star pairs, and calculates the average position of all observed stars in the region; preferably, the grid method can be used to divide the field of view of the star sensor into several regions.

[0084] A star pair collection module, which changes the pointing of the star sensor in space, accumulates more qualified star catalog star-observed star pairs for each preset region of the star sensor's field of view until the density of qualified star catalog star-observed star pairs in each region meets the preset conditions;

[0085] A magnitude distortion fitting module, which calculates the zero-point correction term related to the field of view of the average position of the region according to the star point information and star catalog information of the qualified star catalog star-observed star pairs;

[0086] A magnitude interpolation module, which uses the average positions of all matched observed stars in all regions as control points, and performs polynomial interpolation on the instrument magnitude zero points at other positions in different regions of the full field of view to obtain the instrument magnitude zero-point correction term for the full field of view.

[0087] A full-time interpolation module, which repeats the above steps for different epochs, records the environmental parameters, estimates the environmental parameters for other epochs, and interpolates the f i (c0, c1, c2, c3, c4, Z) results as the magnitude correction amounts for different fields of view and different stars under the environmental parameters of this epoch.

[0088] In the embodiment of the present invention, by continuously adjusting the camera pointing, accumulating different types of star information in different field of view regions, the instrument magnitude correction amounts at different fields of view are obtained through the weighted least squares fitting method. Since the formula used is a general formula, it can be used for both ground calibration and on-orbit calibration.

[0089] Example 1:

[0090] Step 101: Extract the bright spots in the entire star map. Use the photometry method to extract the information of multiple observed stars with a signal-to-noise ratio greater than 5. Utilize the calculation method of the energy and magnitude of the observed stars that has been calibrated on the ground to calculate the instrumental magnitude corresponding to the observed star, and save the star point information of the observed star. The star point information includes: position, gray scale, instrumental magnitude, signal-to-noise ratio and uncertainty, zenith angle; Use the Tycho star catalog for matching. After successful matching, record the corresponding star catalog information. The star catalog information includes color index and catalog magnitude.

[0091] Step 102: Divide the image plane into m×m regions (m≥3) using the rectangular grid method. Change the pointing in a rotational manner, process all frame star point data, count the qualified star points into the corresponding regions, and delete the unqualified observed star pairs. Unqualified stars include: 1) Multiple-star systems; 3) There are many faint stars or galaxies in the background; 4) Stars with a signal-to-noise ratio less than 5; 5) Saturated stars and affected stars;

[0092] Step 103: Stop collecting when the number of stars in each region is greater than 100. Calculate the average position of all stars. The calculation method is:

[0093] where, zone j is the average position of region j, (u i,j , v i,j ) are the coordinates of the observed star i in the image plane within region j; N j is the number of observed stars in region j, j∈[1,N], and N is the number of regions.

[0094] Fit it using the weighted least squares method, record the instrumental magnitude correction parameters obtained for this region, and the average position of all observed stars within the region;

[0095] The formula for the weighted least squares method is:

[0096]

[0097] color i =(B-V) T , representing the color index defined by Tycho, B is the B-band index, and V is the V-band index;

[0098] where, m inst,i is the instrumental magnitude corresponding to the observed star i, f i (c0,c1,c2,c3,c4,Z i ) is the function to be corrected, M cat,i is the catalog magnitude corresponding to the observed star i, c0 is the zero-point correction term related to the average position of the region and the field of view, Z i is the zenith angle function corresponding to the atmospheric extinction term of the observed star i, colori The color difference index of the observed star i is the energy uncertainty of the observed star i; c0 can be expressed as a function of zone j , where zone j is the average position of all observed star points in region j.

[0099] Step 104, calculate all zones j and the corresponding instrumental magnitude zero points, forming an interpolation queue [zone j , c0(zone j ), and perform two-dimensional fifth-order polynomial interpolation on the instrumental magnitude zero points of other regions to obtain the zero point correction c0(zone j ), j = 1 to N j .

[0100] Step 105, repeat Steps 101 - 104 within different orbital periods T(epoch) and the life cycle t of the star sensor, and replace the earlier part of the information stored in Step 4 to ensure that there are no less than 100 samples stored in each region of the field of view, and the total number of samples stored in the entire field of view does not exceed the on-board memory limit. Then calculate the magnitude correction using the one-dimensional fifth-order polynomial interpolation method;

[0101] From Steps 101 - 104, the instrumental magnitude correction of the entire field of view can be obtained. From Steps 101 - 105, the instrumental magnitude corrections within different orbital periods and the satellite life cycle can be obtained. After compensating the least squares fitting results, the obtained results are shown in Figures 2(a) and 2(b). Figures 2(a) and 2(b) are schematic diagrams of the instrumental magnitude zero point residuals at different fields of view after atmospheric extinction and color difference correction in the embodiments of the present invention. In the figures, the RMS of the instrumental magnitude residuals is 0.02 mag.

[0102] Example 2:

[0103] The method is basically the same as that in Step of Example 1. The difference is that in Step 101, the Gaia star catalog is used, and in Step 3, color i =(Bp - Rp), which represents the color difference index defined by Gaia. Bp is the Bp band index, and Rp is the Rp band index.

[0104] Example 3:

[0105] The difference between this example and Example 1 is that in Step 104, Lagrange polynomial fitting is used for fitting, and the order is L times, where L is greater than or equal to 3.

[0106] Example 4:

[0107] The difference between this embodiment and Embodiment 1 is that in steps 101 - 105, standard stars across the entire celestial sphere are used as the observed stars for collection, fitting, zero - point calculation, and correction.

[0108] Embodiment 5:

[0109] The difference between this embodiment and Embodiment 1 is that the fitting formula in step 103 is:

[0110]

[0111] That is, the result without considering the extinction effect of size is used for the magnitude correction of on - orbit instruments. For the obtained result, see Figure 3 and Figure 4 , Figure 3 Figure Figure 4 is the schematic diagram of the instrument magnitude residual after chromatic aberration correction in the embodiments of the present invention. In the figure, the RMS of the instrument magnitude residual is 0.02 mag.

[0112] Embodiment 6:

[0113] The difference between this embodiment and Embodiment 1 is that in step 104, spline polynomial fitting is used for fitting, and in step 105, the radial basis function interpolation method is used to calculate the magnitude correction amount.

[0114] Embodiment 7:

[0115] The method is basically the same as that in step 101 of Embodiment 1. The difference is that in step 101, the SDSS star catalog is used, and in step 3, color=(B - V)=f(u,g,r,i,z) or color=(V - I)=g(u,g,r,i,z). Here,

[0116] Figure 5 Figure Figure 5 shows the schematic diagram of the modules included in a device for realizing the instrument magnitude calibration of the entire field of view at all times provided by the embodiments of the present invention. As

[0117] The image pre - processing module 401 is used to extract and store the star point information of multiple observed stars from the star map obtained by imaging the entire field of view, calculate the instrument magnitude corresponding to the observed star, and save the star point information, including: position, gray scale, instrument magnitude, signal - to - noise ratio and uncertainty, and zenith angle;

[0118] The star pair matching module 402 performs a matching operation on the extracted multiple first observed stars with the pre - stored star catalog. For those that match successfully with the star catalog, an observed star - star catalog constant star pair is established, and the star catalog star information is incorporated into the observed star, including the chromatic aberration index and the star catalog magnitude;

[0119] The star grid matching module 403 divides the field of view into a number of regions using a grid method, divides the observed star-catalog star pairs into a predetermined number of grid regions according to their position information, removes unqualified star pairs, and calculates the average position of all observed stars in the region;

[0120] The star pair collection module 404 is used to change the direction of the star sensor in space after matching the star grid, and repeatedly extract the star point information of multiple observed stars until a certain density of stars is placed in the corresponding grid. After the collection is completed, the density is not less than 100 / square degree.

[0121] The magnitude distortion fitting module 405 fits it according to the weighted least square method, and records the area to obtain the instrument magnitude correction parameters. The weighted least square method formula is:

[0122]

[0123] Among them, m inst,i is the instrument magnitude corresponding to the observed star i, f i (c0,c1,c2,c3,c4,Z i ) is the function to be corrected, M cat,i is the catalog magnitude of the observed star i, c0 is the zero-point correction term related to the regional average position and the field of view, Z i is the zenith angle function corresponding to the atmospheric extinction term of the observed star i, color i The chromatic aberration index of the observed star i, is the energy uncertainty of the observed star i; c0 can be expressed as zone j Function, zone j is the average position of all observed star points in region j.

[0124] The magnitude zero point interpolation module 406 performs polynomial interpolation on the instrument magnitude c0(zone) according to the average position of the observed star points in the region and the instrument magnitude zero point to obtain zero point correction at different fields of view.

[0125] The full-time interpolation module 407 records the environmental parameters of different epochs and obtains the magnitude zero point interpolation module 406 to obtain the f of different epochs. i (c0, c1, c2, c3, c4, Z), then for other epochs, the interpolation method can be used to obtain the instrumental magnitude corrections for different fields of view and different stars under other epoch environmental parameters.

[0126] An embodiment of the present invention provides a non-volatile storage medium for storing a software program, wherein the software program is used to perform the above Figure 1 The method described.

[0127] The present invention realizes real-time correction of factors such as temperature alternation and CCD response degradation by collecting field-of-view distortion data in different temperature ranges, different orbital segments, and different life segments, and fusing and correlating the data in different temperature ranges and different life segments.

[0128] The present invention can calibrate the magnitude of on-orbit instruments for optoelectronic devices with an accuracy better than 0.01 mag, providing an accurate reference for more precise star matching and target recognition.

[0129] Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention without departing from the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

[0130] The content not detailedly described in the specification of the present invention belongs to the well-known technology of those skilled in the art.

Claims

1. A method for calibrating the magnitude of a full-field instrument, characterized in that It includes the following steps: S1. Use a star sensor to capture a star map, extract the information of multiple observed stars from the star map, calculate the instrumental magnitude corresponding to each observed star, and obtain and store the star point information of the observed stars. The star point information includes: position, gray scale, instrumental magnitude, signal-to-noise ratio, uncertainty, zenith angle; S2. Perform a matching operation on the extracted observed stars and the pre-stored star catalog to obtain the information of the successfully matched star catalog star-observed star pairs, extract and store the star catalog information corresponding to the matched observed stars. The star catalog information includes color difference index and catalog magnitude; S3. Divide the observed star-catalog star pairs into preset regions of the star sensor's field of view according to the position information, eliminate the unqualified star catalog star-observed star pairs, and calculate the average position of all observed stars in each region; The step S3 determines the function f to be corrected i (c0, c1, c2, c3, c4, Z) such that the function satisfies the following conditions, thereby determining the zero correction term c0 related to the regional average position and the field of view: f i = M cat,i + c0 + c1 × Z i + c2 × (color i ) + c3 × (color i ) 2 + c4 × (color i ) 3 where m inst,i is the instrumental magnitude corresponding to the observed star i, f i (c0, c1, c2, c3, c4, Z i ) is the function to be corrected, M cat,i is the catalog magnitude corresponding to the observed star i, c0 is the zero-point correction term related to the regional average position and the field of view, Z i is the zenith angle function corresponding to the atmospheric extinction term of the observed star i, color i is the color difference index of the observed star i, is the energy uncertainty of the observed star i; c0 is expressed as a function of zone j where zone j is the average position of all observed star points in region j; S4. Change the pointing of the star sensor in space, accumulate more qualified star catalog star-observed star pairs for each preset region of the star sensor's field of view, and repeat steps S1 to S4 until the density of qualified star catalog star-observed star pairs in each region meets the preset conditions, and perform step S5 on each region; S5. Calculate the zero-point correction term related to the field of view of the regional average position according to the star point information and star catalog information of the qualified star catalog star-observed star pairs; S6. Use the average position of all matched observed stars in all regions as control points to perform polynomial interpolation on the instrumental magnitude zero points at other positions in different regions of the entire field of view to obtain the instrumental magnitude zero-point correction term of the entire field of view.

2. The method for calibrating the magnitude of a full-field instrument according to claim 1, characterized in that It also includes the following steps: S7. Repeat steps S1 to S6 at different time periods to obtain the on-orbit instrumental magnitude zero-point correction term for the entire period.

3. The method for calibrating the magnitude of a full-field instrument according to claim 1, characterized in that In step S1, the instrumental magnitude of the observed stars is calculated by using the method for calculating the energy and magnitude of the observed stars that has been calibrated on the ground.

4. The method for calibrating the magnitude of a full-field instrument according to claim 1, characterized in that The unqualified star catalog star-observed star pairs are star catalog star-observed star pairs that meet one of the following conditions: a. Stars in the star catalog with a color difference index greater than 1; b. The observed stars belong to a multiple-star system. The multiple-star system refers to a system where the star spacing of the observed stars is less than twice the distance of the half-width of the PSF; c. There are many faint stars or galaxies in the background of the observed stars. "Faint" stars or galaxies are stars with a magnitude 1 to 3 magnitudes lower than the instrument sensitivity; d. Observed stars with a signal-to-noise ratio less than 5; e. Observed stars that are saturated stars.

5. A device for calibrating the magnitude of an on-orbit instrument with full-time and full-field, characterized in that It includes: An image preprocessing module for extracting and storing the star point information of multiple observed stars from the star map obtained by imaging the entire field of view, calculating the instrumental magnitude corresponding to the observed stars, and obtaining and storing the star point information of the observed stars. The star point information includes: position, gray scale, instrumental magnitude, signal-to-noise ratio, uncertainty, zenith angle; A star pair matching module for performing a matching operation on the extracted observed stars and the pre-stored star catalog to obtain the information of the successfully matched star catalog star-observed star pairs, and extracting and storing the star catalog information corresponding to the matched observed stars. The star catalog information includes color difference index and catalog magnitude; A star network matching module for dividing the observed star-catalog star pairs into preset regions of the star sensor's field of view according to the position information, eliminating the unqualified star catalog star-observed star pairs, and calculating the average position of all observed stars in the region; A star pair collection module changes the pointing of the star sensor in space and accumulates more qualified star catalog star-observation star pairs for each area preset in the star sensor's field of view until the density of qualified star catalog star-observation star pairs in each area meets the preset conditions. A magnitude distortion fitting module calculates a zero-point correction term related to the average position of the area and the field of view based on the star point information and star catalog information of the qualified star catalog star-observation star pairs. A magnitude interpolation module performs polynomial interpolation on the instrument magnitude zero points at other positions in different areas of the entire field of view with the average positions of all matching observed stars in all areas as control points to obtain the instrument magnitude zero-point correction term for the entire field of view. The magnitude distortion fitting module determines the function f to be corrected i (c0, c1, c2, c3, c4, Z) such that the function satisfies the following conditions, thereby determining the zero-point correction term c0 related to the regional average position and the field of view: f i = M cat,i + c0 + c1 × Z i + c2 × (color i ) + c3 × (color i ) 2 + c4 × (color i ) 3 where m inst,i is the instrumental magnitude corresponding to the observed star i, f i (c0, c1, c2, c3, c4, Z i ) is the function to be corrected, M cat,i is the catalog magnitude corresponding to the observed star i, c0 is the zero-point correction term related to the regional average position and the field of view, Z i is the zenith angle function corresponding to the atmospheric extinction term of the observed star i, color i is the color index of the observed star i, is the energy uncertainty of the observed star i; c0 is expressed as a function of zone j , zone j is the average position of all observed star points in region j.

6. The device for calibrating the magnitude of an on-orbit instrument with full-time and full-field according to claim 5, characterized in thatAn image preprocessing module calculates the instrument magnitude of the observed star using the method for calculating the energy and magnitude of the observed star that has been corrected on the ground.

7. A full-time and full-field on-orbit instrument magnitude calibration device according to claim 5, characterized in that The unqualified star catalog star-observation star pairs are star catalog star-observation star pairs that meet one of the following conditions: a. Stars in the star catalog with a color difference index greater than 1; b. The observed star belongs to a multiple star system; the multiple star system refers to a system where the star spacing of the observed star is less than twice the distance of the half-width of the PSF; c. There are many faint stars or galaxies in the background of the observed star; "faint" stars or galaxies are stars with magnitudes 1 to 3 magnitudes lower than the instrument sensitivity; d. Stars with an observed star signal-to-noise ratio less than 5; e. The observed star is a saturated star.

8. A non-volatile storage medium, characterized in that A software program storage is used to store a software program which, when executed, is used to execute the method described in any one of claims 1 to 4 above.

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