Method, device and equipment for determining angle factor of ratio radiometer

Abstract

The invention provides a method, device and equipment for determining an angle factor of a ratio radiometer, and belongs to the technical field of satellite equipment, and the method comprises the steps: determining a first angle factor of a first probe based on an observation information signal value of the first probe; the observation information signal value of the first probe element is acquired from the observation data set of the radiometer at the initial in-orbit stage; based on the first angle factor and the change value of the observation signal in the preset time period, calculating the diffuse plate attenuation rate of at least one target detection element in the preset time period, and obtaining a first estimated value of the diffuse plate attenuation rate of each target detection element; calculating a second angle factor of each target detection element based on the first estimated value of the diffuse plate attenuation rate of each target detection element; and iteratively calculating a second estimated value of the diffuse plate attenuation rate of each target detection element based on the second angle factor, and determining that the second angle factor is the angle factor of the ratio radiometer under the condition that the first estimated value of the target detection element is equal to the second estimated value.

Description

Technical Field

[0001] The present invention relates to the technical field of satellite equipment, and particularly to a method, device and equipment for determining the angular factor of a ratio radiometer. Background Art

[0002] For on-orbit radiometric calibration of the low-light channel, a diffuser plate is configured, and taking the stable sunlight as a reference, the instrument realizes on-orbit absolute radiometric calibration by observing the sunlight transmitted by the diffuser plate. Obtaining the transmittance distribution function BTDF (Bidirectional Transmittance Distribution Function) of the diffuser plate at the calibration moment is the key to realizing on-orbit calibration of the low-light channel on the satellite.

[0003] In the prior art, generally, the BTDF of the diffuser plate is obtained through laboratory and field tests. When determining the angular factor of the radiometer on orbit, it is usually assumed that the BTDF of the diffuser plate does not decay, so that the BTDF of the diffuser plate at the on-orbit moment can be replaced by the measurement value in the laboratory. However, when the satellite is on orbit, affected by ultraviolet radiation, the surface characteristics of the diffuser plate will change, resulting in certain errors in the determination of the angular factor.

[0004] How to improve the accuracy of the angular factor of the ratio radiometer is a technical problem that needs to be urgently solved by those skilled in the art. Summary of the Invention

[0005] In view of the problems existing in the prior art, the present invention provides a method, device and equipment for determining the angular factor of a ratio radiometer.

[0006] The present invention provides a method for determining the angular factor of a ratio radiometer, including:

[0007] Determining a first angular factor of the first detector element based on the observed information signal value of the first detector element; the observed information signal value of the first detector element is obtained from the observation dataset in the initial stage of the radiometer on orbit;

[0008] Calculating the attenuation rate of the diffuser plate of at least one target detector element within the preset time period based on the first angular factor and the change value of the observed signal within the preset time period, to obtain a first estimated value of the diffuser plate attenuation rate of each target detector element;

[0009] Calculating a second angular factor of each target detector element based on the first estimated value of the diffuser plate attenuation rate of each target detector element;

[0010] Based on the second angle factor, iteratively calculate the second estimated value of the diffuser attenuation rate of each target detector element. When the first estimated value of the target detector element is equal to the second estimated value, determine the second angle factor as the angle factor of the ratio radiometer.

[0011] According to a method for determining the angle factor of a ratio radiometer provided by the present invention, determining the first angle factor of the first detector element based on the observed information signal value of the first detector element includes:

[0012] Based on the solar observation signal value and the diffuser observation signal value of the first detector element, use formula (1) to determine the first angle factor:

[0013]

[0014] where, ∧ 1 (α, β) is the first angle factor, is the solar observation signal value of the first detector element, is the diffuser observation signal value of the first detector element.

[0015] According to a method for determining the angle factor of a ratio radiometer provided by the present invention, calculating the diffuser attenuation rate of at least one target detector element within a preset time period based on the first angle factor and the change value of the observed signal within the preset time period to obtain the first estimated value of the diffuser attenuation rate of each target detector element includes:

[0016] Obtain the change value of the solar observation signal of the target detector element within the preset time period;

[0017] Obtain the change value of the diffuser observation signal of the target detector element within the preset time period;

[0018] Based on the first angle factor, the change value of the solar observation signal, and the change value of the diffuser observation signal, calculate the first estimated value of the diffuser attenuation rate of at least one target detector element within the preset time period.

[0019] According to a method for determining the angle factor of a ratio radiometer provided by the present invention, calculating the first estimated value of the diffuser attenuation rate of at least one target detector element within the preset time period based on the first angle factor, the change value of the solar observation signal, and the change value of the diffuser observation signal includes:

[0020] Use formula (2) to calculate the first estimated value of the diffuser attenuation rate of each target detector element within the preset time period:

[0021]

[0022] where, is the first estimated value of the transmissive plate attenuation rate for the i-th target detector element, is the signal of the transmissive plate observation port of the radiometer, is the solar port observation signal of the radiometer.

[0023] According to a method for determining the angular factor of a ratio radiometer provided by the present invention, calculating the second angular factor of each of the target detector elements based on the first estimated value of the transmissive plate attenuation rate of each of the target detector elements includes:

[0024] Based on the first estimated value, calculate the second angular factor of each of the target detector elements using formula (3):

[0025]

[0026] where, ∧ i (α, β) is the second angular factor of the i-th target detector element, ∧ i (α, β) is the angular factor of the i-th detector element of the radiometer, is the value of the transmissive plate observation signal of the i-th detector element of the radiometer, the solar observation signal value of the i-th detector element of the radiometer.

[0027] According to a method for determining the angular factor of a ratio radiometer provided by the present invention, the determination of the observation dataset includes:

[0028] Obtain the solar incident angle range within the preset time period;

[0029] Interpolate the solar incident angle range into an interpolation array of a preset size;

[0030] Based on the spline interpolation method and the local smoothing method, fill the angular factors corresponding to each solar incident angle into the interpolation array to determine the observation dataset.

[0031] The present invention also provides a device for determining the angular factor of a ratio radiometer, including:

[0032] A determination module for determining the first angular factor of the first detector element based on the observation information signal value of the first detector element; the observation information signal value of the first detector element is obtained from the observation dataset in the initial stage of the radiometer in orbit;

[0033] A first calculation module for calculating the transmissive plate attenuation rate of at least one target detector element within the preset time period based on the first angular factor and the change value of the observation signal within the preset time period, to obtain the first estimated value of the transmissive plate attenuation rate of each of the target detector elements;

[0034] A second calculation module, configured to calculate a second angular factor for each of the target detection elements based on a first estimated value of the diffuser attenuation rate of each of the target detection elements;

[0035] An iteration module, configured to iteratively calculate a second estimated value of the diffuser attenuation rate of each of the target detection elements based on the second angular factor, and determine the second angular factor as the angular factor of the ratio radiometer when the first estimated value of the target detection element is equal to the second estimated value.

[0036] The present invention further provides an electronic device, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the program, the method for determining the angular factor of the ratio radiometer as described in any one of the above is implemented.

[0037] The present invention further provides a non-transitory computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the method for determining the angular factor of the ratio radiometer as described in any one of the above is implemented.

[0038] The present invention further provides a computer program product, including a computer program. When the computer program is executed by a processor, the method for determining the angular factor of the ratio radiometer as described in any one of the above is implemented.

[0039] The method, device, and equipment for determining the angular factor of the ratio radiometer provided by the present invention obtain the observed information signal value of the first detection element from the observed data set of the ratio radiometer in the initial stage of on-orbit operation based on the observation data set, further determine the first angular factor, and then calculate the first estimated value of the diffuser attenuation rate of at least one target detection element within a preset time period based on the first angular factor and the change value of the observed signal within the preset time period. Then, the second angular factor of the target detection element is calculated through the first estimated value, and further the second estimated value of the target detection element is iteratively calculated through the second angular factor until the first estimated value is equal to the second estimated value, at which point the iteration ends. The second angular factor at the end of the iteration is the angular factor of the ratio radiometer. The method for determining the angular factor of the ratio radiometer of the present invention takes into account the influence of diffuser attenuation on the accuracy of the angular factor of the ratio radiometer, and iteratively calculates to obtain the estimated value of the diffuser attenuation rate and the estimated value of the angular factor simultaneously, solving the problem of poor calculation accuracy of the angular factor of the ratio radiometer due to the failure to consider the diffuser attenuation characteristics during satellite on-orbit operation, and improving the accuracy of determining the angular factor of the ratio radiometer. Description of the Drawings

[0040] To more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0041] Figure 1 It is one of the flow schematic diagrams of the method for determining the angular factor of the ratio radiometer provided by the present invention;

[0042] Figure 2 It is the second of the flow schematic diagrams of the method for determining the angular factor of the ratio radiometer provided by the present invention;

[0043] Figure 3 It is the structural schematic diagram of the device for determining the angular factor of the ratio radiometer provided by the present invention;

[0044] Figure 4 It is the structural schematic diagram of the electronic device provided by the present invention. Detailed implementation manners

[0045] To make the objectives, technical solutions and advantages of the present invention clearer, the following will clearly and completely describe the technical solutions in the present invention in conjunction with the drawings in the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments in the present invention belong to the scope of protection of the present invention.

[0046] To facilitate a better understanding of the method, device and equipment for determining the angular factor of the ratio radiometer of the present invention, the following introduces the relevant background technologies:

[0047] Fengyun-3E satellite is a civil satellite in the dawn-dusk orbit. The Medium Resolution Spectral Imager - Low Light (MERSI-LL) is an important optical instrument carried on the FY-3E satellite. This instrument is equipped with 6 thermal infrared channels and one low light channel, with wavelengths ranging from 500 to 900 nm. For the on-orbit radiometric calibration of the low light channel, a diffuser plate is configured. Taking the stable sunlight as a reference, the instrument realizes the on-orbit absolute radiometric calibration by observing the sunlight transmitted through the diffuser plate. The acquisition of the transmittance distribution function BTDF of the diffuser plate at the calibration moment is the key to realizing the on-satellite calibration of the low light channel.

[0048] Before launch, the bidirectional transmittance distribution function (BTDF) of the diffuser plate was obtained through laboratory and field tests. However, after being in orbit, due to exposure to ultraviolet light, the surface characteristics of the diffuser plate will change to a certain extent. To monitor the change of the BTDF of the diffuser plate in orbit, a solar diffuser stability monitor is configured. This monitor is a ratio radiometer, designed with a solar observation port and a diffuser plate observation port, and determines the attenuation of the BTDF of the diffuser plate by tracking the change of the ratio between the solar observation value and the diffuser plate observation value over time.

[0049] The angle of sunlight will change at the on-orbit calibration time, which will cause the signal detected by the radiometer to change. This characteristic is called the angular factor of the radiometer. The angular factor includes the geometric factor of solar observation, the BTDF in the direction of observing the diffuser plate, and the cosine factor of sunlight irradiating the diffuser plate. The angular factor can be measured separately in the laboratory. Given that the measurement state in the laboratory is different from the on-orbit usage state, and there are differences in the light source spectra, it is necessary to test the reliability of the angular factor measured in the laboratory before use.

[0050] The difficulty in determining the angular factor of the radiometer in orbit lies in the determination of the BTDF of the diffuser plate at different on-orbit observation times. Therefore, when determining the angular factor of the radiometer in orbit, it is usually assumed that the BTDF of the diffuser plate has not decayed. In this way, the BTDF of the diffuser plate at the on-orbit time can be replaced by the measured value in the laboratory. Currently, there are mainly two methods for determining the geometric factor of the solar observation port of the radiometer in orbit.

[0051] Using the observation data of the radiometer in the initial stage of orbit, assuming that the diffuser plate does not decay, and based on the observations of the radiometer at different solar incidence angles, the angular factor of the radiometer is calculated by regression. Assuming that the radiation characteristics of the diffuser plate do not decay within one year, for shorter wavelengths, certain errors may be introduced, which will affect the calculation accuracy of the subsequent angular factor.

[0052] Therefore, the embodiment of the invention provides a method for determining the angular factor of a ratio radiometer, which takes into account the attenuation of the diffuser plate and improves the calculation accuracy of the angular factor.

[0053] The following combines Figures 1 - 4 to describe the method, device, and equipment for determining the angular factor of the ratio radiometer of the present invention.

[0054] Figure 1 is one of the flow diagrams of the method for determining the angular factor of the ratio radiometer provided by the present invention. As Figure 1 shown, the method for determining the angular factor of the ratio radiometer according to the embodiment of the present invention includes:

[0055] Step 110: Determine the first angle factor of the first detector element based on the observed information signal value of the first detector element; the observed information signal value of the first detector element is obtained from the observation dataset at the initial stage of the on-orbit operation of the radiometer.

[0056] Specifically, the detection wavelengths of different detector elements are different. In this step, the first detector element refers to the detector element with a detection wavelength of 865 nm in the near-infrared range, which is referred to as the first detector element. Due to the characteristic that the attenuation of the radiation characteristics of the diffuse transmission plate decreases as the detection wavelength increases, the BTDF attenuation of the diffuse transmission plate at the detector element with the longest detection wavelength can be ignored. Therefore, based on the observed signal value at the first detector element, the angle factor of the ratio radiometer at the 865 nm detector element is established.

[0057] Furthermore, the observed information signal value at the first detector element is obtained from the observation dataset. The time period of the observation dataset can be from one year to three years after the satellite is on orbit. Collect the observation data of the ratio radiometer from one year to three years after the satellite is on orbit at the initial stage. The observation data includes the solar observation signal value at the solar observation port, the diffuse transmission plate observation signal value at the diffuse transmission plate observation port, and the solar incidence angle at different times. Generally, one cycle is when the satellite orbits the Earth once. At the calibration moment of each cycle, the observation data is measured and obtained.

[0058] Furthermore, in order to improve the calculation accuracy of the first angle factor, it is necessary to further process the historical observation data to refine the solar incidence angle, which will be specifically elaborated later.

[0059] Step 120: Calculate the diffuse transmission plate attenuation rate of at least one target detector element within the preset time period based on the first angle factor and the change value of the observed signal within the preset time period, and obtain the first estimated value of the diffuse plate attenuation rate of each target detector element.

[0060] Specifically, in this step, the first angle factor is a preliminary estimated value because the attenuation of the BTDF of the diffuse transmission plate is not considered. Based on the first angle factor and the change value of the observed signal within the preset time period, the first estimated value of the diffuse transmission plate attenuation rate of a certain detector element within the preset time period is calculated.

[0061] Furthermore, the preset time period can be regarded as from one year to three years, which is an observation time period. In the embodiment of the present invention, there are a total of five detector elements. Except for the first detector element with the longest detection wavelength in the above steps, the detection wavelengths of the remaining detector elements are 555 nm, 670 nm, 700 nm, and 709 nm respectively. These detector elements are all target detector elements.

[0062] First, obtain the solar observation signal value of a certain target detector element within a preset time period, and the change value of the diffuse transmission plate observation signal value at the diffuse transmission plate observation port, that is, the observation signal change value. Then, combine the first angle factor and calculate the first estimated value of the diffuse transmission plate attenuation rate of the target detector element within the preset time period. Since the first angle factor is a pre-estimated value that ignores the attenuation of the diffuse transmission plate BTDF, the first estimated value of the diffuse transmission plate attenuation rate calculated based on it is also inaccurate. Therefore, it is the first estimated value of the target detector element.

[0063] It should also be noted that the change value of the observation signal is the observation sequence of the radiometer at 865 nm.

[0064] Step 130: Calculate the second angle factor of each target detector element based on the first estimated value of the diffuse transmission plate attenuation rate of each target detector element.

[0065] Specifically, in this step, re-estimate the angle factor of the target detector element. Based on the first estimated value of the diffuse transmission plate attenuation rate of the target detector element obtained in the above step 120, revise the diffuse transmission plate attenuation rate of the target detector element and calculate the second angle factor of the target detector element.

[0066] Step 140: Iteratively calculate the second estimated value of the diffuse transmission plate attenuation rate of each target detector element based on the second angle factor. When the first estimated value of the target detector element is equal to the second estimated value, determine the second angle factor as the angle factor of the ratio radiometer.

[0067] Specifically, in this step, based on the second angle factor of the target detector element obtained above, recalculate the value of the diffuse transmission plate attenuation rate of the target detector element, regarded as the second estimated value. Then, continuously perform the above iterative process. Based on the obtained second estimated value, obtain a new round of angle factors, and further recalculate the value of the diffuse transmission plate attenuation rate of the target detector element until the first estimated value and the second estimated value, which are the two consecutive estimated values, are equal. Then stop the iteration. In this case, the current second angle factor is the angle factor of the ratio radiometer.

[0068] The method for determining the angular factor of the ratio radiometer provided by the embodiment of the present invention determines the first angular factor by obtaining the observed information signal value of the first detector element from the observation dataset, and then calculates the first estimated value of the diffuse transmission plate attenuation rate of at least one target detector element within a preset time period based on the first angular factor and the change value of the observed signal within the preset time period. Subsequently, the second angular factor of the target detector element is calculated through the first estimated value, and further, the second estimated value of the target detector element is iteratively calculated through the second angular factor until the first estimated value and the second estimated value are equal, at which point the iteration ends. The angular factor of the ratio radiometer at the end of the iteration is the angular factor of the ratio radiometer. The method for determining the angular factor of the ratio radiometer of the present invention takes into account the influence of diffuse transmission plate attenuation on the accuracy of the angular factor of the ratio radiometer, and simultaneously obtains the estimated value of the diffuse transmission plate attenuation rate and the estimated value of the angular factor through iterative calculation, solving the problem of poor calculation accuracy of the angular factor of the ratio radiometer due to the neglect of the diffuse transmission plate attenuation characteristics during satellite on-orbit operation, and improving the accuracy of determining the angular factor of the ratio radiometer.

[0069] Optionally, according to a method for determining the angular factor of a ratio radiometer provided by an embodiment of the present invention, the determining the first angular factor of the first detector element based on the observed information signal value of the first detector element includes:

[0070] Based on the solar observation signal value and the diffuse transmission plate observation signal value of the first detector element, the first angular factor is determined using formula (1):

[0071]

[0072] where, ∧ 1 (α, β) is the first angular factor, is the solar observation signal value of the first detector element, is the diffuse transmission plate observation signal value of the first detector element.

[0073] Specifically, the first angular factor is an estimated value.

[0074] ∧ 1 (α, β) refers to the signal ratio of the radiometer observing the sun and observing the diffuse plate when the incident elevation angle of the sun is α and the incident horizontal angle of the sun is β at the calibration moment. In fact, based on the above discussion, the first angular factor is determined based on the solar observation signal value and the diffuse transmission plate observation signal value of the first detector element, and the first detector element selects a detector element with a detection wavelength of 865 nm.

[0075] Furthermore, in order to improve the estimation accuracy of the initial angle factor, it is necessary to refine the incident angle of the sun. The incident angle of the sun is divided into the incident pitch angle of the sun and the incident horizontal angle of the sun. During a preset time period, the value range of the incident pitch angle of the sun is generally 0 to 36 degrees, and the value range of the incident horizontal angle of the sun is generally -4 degrees to 4 degrees. Based on the incident angle of the sun, an interpolation array of 500 * 500 is interpolated. For the angle factor at the incident angle of the sun that is consistent with the actual observation, it is filled by the actual observation method. For the incident angle of the sun without actual observation values, based on the adjacent observation values, the interpolation array is filled by using the method of spline interpolation and local smoothing, and a two-dimensional array corresponding to the sun incident angle and the angle factor is obtained. Based on this array, a closer angle factor can be determined at a certain calibration moment.

[0076] The method for determining the angle factor of the ratio radiometer provided by the embodiment of the present invention determines the first angle factor by further obtaining the observation information signal value of the first detection element from the observation data set, then calculates the first estimated value of the attenuation rate of the diffuser plate of at least one target detection element during the preset time period based on the first angle factor and the change value of the observation signal during the preset time period, and then calculates the second angle factor of the target detection element through the first estimated value. Further, the second estimated value of the target detection element is iteratively calculated through the second angle factor until the iteration ends when the first estimated value and the second estimated value are equal. The second angle factor at the end of the iteration is the angle factor of the ratio radiometer. The method for determining the angle factor of the ratio radiometer of the present invention considers the influence of the diffuser plate attenuation on the accuracy of the angle factor of the ratio radiometer, and simultaneously obtains the estimated value of the diffuser plate attenuation rate and the estimated value of the angle factor through iterative calculation, solves the problem that the calculation accuracy of the angle factor of the ratio radiometer is poor due to the failure to consider the attenuation characteristics of the diffuser plate during satellite on-orbit operation, and improves the accuracy of determining the angle factor of the ratio radiometer.

[0077] Optionally, according to a method for determining the angle factor of a ratio radiometer provided by an embodiment of the present invention, the specific implementation steps of the above step 120 are as follows Figure 2 is the second flowchart of the method for determining the angle factor of the ratio radiometer provided by the present invention, as Figure 2 shown, calculating the first estimated value of the attenuation rate of the diffuser plate of at least one target detection element during the preset time period based on the first angle factor and the change value of the observation signal during the preset time period includes:

[0078] Step 210, obtain the change value of the sun observation signal of the target detection element during the preset time period;

[0079] Specifically, in this step, obtain the change value of the solar observation signal of a target detector other than the first detector within a preset time period, that is, the solar observation signal values at different calibration times within the preset time period, and their difference is the change value of the solar observation signal within the preset time period.

[0080] Step 220: Obtain the change value of the diffuser observation signal of the target detector within the preset time period;

[0081] Specifically, in this step, obtain the diffuser observation signal values of a target detector other than the first detector within a preset time period, that is, the diffuser observation signal values at different calibration times within the preset time period, and their difference is the change value of the diffuser observation signal within the preset time period.

[0082] Step 230: Calculate a first estimated value of the diffuser attenuation rate of at least one target detector within the preset time period based on the first angle factor, the change value of the solar observation signal, and the change value of the diffuser observation signal.

[0083] Specifically, in this step, calculate the first estimated value of the diffuser attenuation rate of the selected target detector within the preset time period. Since the angle factor of this target detector is unknown, use the first angle factor to substitute for the calculation of the first estimated value. That is, at the initial stage of iterative calculation, for the angle factor at the target detector, use the first angle factor of the first detector with a detection wavelength of 865 nm to replace it.

[0084] The method for determining the angle factor of the ratio radiometer provided by the embodiment of the present invention, by obtaining the observation information signal value of the first detector from the observation dataset, further determining the first angle factor, then based on the first angle factor and the change value of the observation signal within the preset time period, calculating the first estimated value of the diffuser attenuation rate of at least one target detector within the preset time period, and then calculating the second angle factor of this target detector through the first estimated value, and further iteratively calculating the second estimated value of this target detector through the second angle factor until the first estimated value and the second estimated value are equal, the iteration ends, and the second angle factor at the end of the iteration is the angle factor of the ratio radiometer. The method for determining the angle factor of the ratio radiometer of the present invention considers the influence of diffuser attenuation on the accuracy of the angle factor of the ratio radiometer, and through iterative calculation, simultaneously obtains the estimated value of the diffuser attenuation rate and the estimated value of the angle factor, solves the problem that the calculation accuracy of the angle factor of the ratio radiometer is poor due to the neglect of the diffuser attenuation characteristics during satellite on-orbit operation, and improves the accuracy of determining the angle factor of the ratio radiometer.

[0085] Optionally, according to a method for determining the angle factor of a ratio radiometer provided by an embodiment of the present invention, the specific implementation manner of the above step 230 is as follows:

[0086] Based on the first angle factor, the change value of the solar observation signal, and the change value of the observation signal of the diffuser plate, use formula (2) to calculate the first estimated value of the diffuser plate attenuation rate of at least one target detector element within the preset time period:

[0087]

[0088] Wherein, is the first estimated value of the diffuser plate attenuation rate of the i-th target detector element, is the observation signal value of the diffuser plate, is the solar observation signal value.

[0089] Specifically, when initially calculating the first estimated value of the diffuser plate attenuation rate of the i-th target detector element, since the angle factor is unknown within the preset time period, first use the first angle factor at the first detector element for calculation.

[0090] The method for determining the angle factor of the ratio radiometer provided by the embodiment of the present invention determines the first angle factor by further obtaining the observation information signal value of the first detector element from the observation dataset, then calculates the first estimated value of the diffuser plate attenuation rate of at least one target detector element within the preset time period based on the first angle factor and the change value of the observation signal within the preset time period, then calculates the second angle factor of the target detector element through the first estimated value, and further iteratively calculates the second estimated value of the target detector element through the second angle factor until the first estimated value and the second estimated value are equal, at which point the iteration ends, and the second angle factor at the end of the iteration is the angle factor of the ratio radiometer. The method for determining the angle factor of the ratio radiometer of the present invention takes into account the influence of diffuser plate attenuation on the accuracy of the angle factor of the ratio radiometer, and simultaneously obtains the estimated value of the diffuser plate attenuation rate and the estimated value of the angle factor through iterative calculation, solving the problem of poor calculation accuracy of the angle factor of the ratio radiometer due to the failure to consider the diffuser plate attenuation characteristics when the satellite is in orbit, and improving the accuracy of determining the angle factor of the ratio radiometer.

[0091] Optionally, according to a method for determining the angle factor of a ratio radiometer provided by an embodiment of the present invention, calculating the second angle factor of each target detector element based on the first estimated value of the diffuser plate attenuation rate of each target detector element among the target detector elements includes:

[0092] Based on the first estimated value, use formula (3) to calculate the second angle factor of each target detector element:

[0093]

[0094] Wherein, ∧ i (α, β) is the second angle factor of the i-th target detector element, The solar observation signal value of the i-th detector element The observation signal value of the diffuser plate of the i-th detector element.

[0095] Specifically, since the angular factor of the i-th target detector element is uncertain, the backstepping method is used. Based on the first estimated value of the attenuation rate of the diffuser plate of the target detector element obtained above, the observation signal value of the ratio radiometer is corrected to obtain a new second angular factor of the i-th target detector element.

[0096] Furthermore, in a specific implementation, the obtained second angular factor needs to be substituted into the above formula (2) to obtain a new second estimated value, that is, iterative calculation is performed. Then, the first estimated value and the second estimated value are compared. When the first estimated value and the second estimated value are very close and it is determined that the first estimated value and the second estimated value are equal, the iterative calculation is stopped, indicating that the second angular factor at this time is the best estimated value, and it is considered that the second angular factor is the angular factor of the ratio radiometer.

[0097] Optionally, according to a method for determining the angular factor of a ratio radiometer provided by an embodiment of the present invention, the determination of the observation data set includes:

[0098] Obtain the solar incidence angle range within the preset time period;

[0099] Interpolate the solar incidence angle range into an interpolation array of a preset size;

[0100] Based on the spline interpolation method and the local smoothing method, fill the angular factors corresponding to each solar incidence angle into the interpolation array to determine the observation data set.

[0101] Specifically, in order to improve the estimation accuracy of the initial angular factor, it is necessary to refine the solar incidence angle. The solar incidence angle is divided into the solar incidence pitch angle and the solar incidence horizontal angle. Within the preset time period, the value range of the solar incidence pitch angle is generally 0 to 36 degrees, and the value range of the solar incidence horizontal angle is generally -4 degrees to 4 degrees. Based on the solar incidence angle, an interpolation array of 500*500 is interpolated. For the angular factor at the solar incidence angle consistent with the actual observation, the actual observation method is used for filling. For the solar incidence angle without actual observation values, based on the adjacent observation values, the interpolation array is filled using the spline interpolation and local smoothing methods, obtaining a two-dimensional array corresponding to the solar incidence angle and the angular factor. Based on this array, a closer angular factor can be determined at a certain calibration moment.

[0102] Next, a device for determining the angular factor of a ratio radiometer provided by the present invention will be described. The device for determining the angular factor of a ratio radiometer described below can be correspondingly referred to the method for determining the angular factor of a ratio radiometer described above.

[0103] Figure 3 This is a schematic structural diagram of a device for determining the angular factor of a ratio radiometer provided by the present invention. As Figure 3 shown, the device for determining the angular factor of the ratio radiometer provided by the embodiments of the present invention includes

[0104] a determination module 310, configured to determine a first angular factor of the first detector element based on the observed information signal value of the first detector element; the observed information signal value of the first detector element is obtained from the observation dataset in the initial stage of the on-orbit operation of the radiometer;

[0105] Specifically, the first detector element refers to the detector element with a detection wavelength of 865 nm, which is referred to as the first detector element. Since as the detection wavelength increases, the attenuation of the radiation characteristics of the diffusive transmission plate decreases, the BTDF attenuation of the diffusive transmission plate at the detector element with the longest detection wavelength can be ignored. Therefore, based on the observed signal value at the first detector element, the angular factor of the ratio radiometer at the 865-nm detector element is established.

[0106] Furthermore, the observed information signal value at the first detector element is obtained from the observation dataset. The time period of the observation dataset can be from one year to three years after the satellite is on orbit. Collect the observation data of the ratio radiometer from one year to three years after the satellite is on orbit in the initial stage. The observation data includes the solar observation signal value at the solar observation port, the diffusive transmission plate observation signal value at the diffusive transmission plate observation port, and the solar incidence angle at different times. Generally, one cycle is defined as the satellite orbiting the Earth once. At the calibration moment of each cycle, the observation data is measured and obtained.

[0107] a first calculation module 320, configured to calculate the diffusive transmission plate attenuation rate of at least one target detector element within the preset time period based on the first angular factor and the change value of the observed signal within the preset time period, and obtain a first estimated value of the diffusive plate attenuation rate of each target detector element;

[0108] Specifically, the first angular factor is a preliminary estimated value because the attenuation of the BTDF of the diffusive transmission plate is not considered. Based on the first angular factor and the change value of the observed signal within the preset time period, the first estimated value of the diffusive transmission plate attenuation rate of a certain detector element within the preset time period is calculated.

[0109] Furthermore, the preset time period can be regarded as from one year to three years, which is an observation time period. In the embodiments of the present invention, there are a total of five detector elements. Except for the first detector element with the longest detection wavelength in the above steps, the detection wavelengths of the remaining detector elements are 555 nm, 670 nm, 700 nm, and 709 nm respectively. These detector elements are all target detector elements.

[0110] First, obtain the solar observation signal value of a certain target detection element within a preset time period, and the change value of the diffuse transmission plate observation signal value at the observation port of the diffuse transmission plate, that is, the observation signal change value. Then, combine the first angle factor and calculate the first estimate of the diffuse transmission plate attenuation rate of the target detection element within the preset time period. Since the first angle factor is a pre-estimated value that ignores the attenuation of the diffuse transmission plate BTDF, the first estimate of the diffuse transmission plate attenuation rate calculated based on it is also inaccurate. Therefore, it is the first estimate of the target detection element.

[0111] The second calculation module 330 is configured to calculate the second angle factor of each target detection element based on the first estimate of the diffuse transmission plate attenuation rate of each target detection element.

[0112] The iteration module 340 is configured to iteratively calculate the second estimate of the diffuse transmission plate attenuation rate of each target detection element based on the second angle factor. When the first estimate of the target detection element is equal to the second estimate, determine the second angle factor as the angle factor of the ratio radiometer.

[0113] Specifically, in the iteration module, based on the second angle factor of the target detection element obtained above, recalculate the value of the diffuse transmission plate attenuation rate of the target detection element, regarded as the second estimate. Then, continuously perform the above iterative process. Based on the obtained second estimate, obtain a new round of angle factors, and further recalculate the value of the diffuse transmission plate attenuation rate of the target detection element until the first estimate and the second estimate, that is, the two consecutive estimates are equal, then stop the iteration. In this case, the current second angle factor is the angle factor of the ratio radiometer.

[0114] The device for determining the angle factor of the ratio radiometer provided by the embodiments of the present invention improves the accuracy of determining the angle factor of the ratio radiometer through the mutual cooperation of each module. By obtaining the observation information signal value of the first detection element from the observation dataset, further determining the first angle factor, and then based on the first angle factor and the change value of the observation signal within the preset time period, calculating the first estimate of the diffuse transmission plate attenuation rate of at least one target detection element within the preset time period. Then, calculate the second angle factor of the target detection element through the first estimate, and further iteratively calculate the second estimate of the target detection element through the second angle factor until the first estimate and the second estimate are equal, then the iteration ends. The second angle factor at the end of the iteration is the angle factor of the ratio radiometer. The method for determining the angle factor of the ratio radiometer of the present invention considers the influence of the diffuse transmission plate attenuation on the accuracy of the angle factor of the ratio radiometer. By iteratively calculating, the estimated value of the diffuse transmission plate attenuation rate and the estimated value of the angle factor are obtained simultaneously, solving the problem of poor calculation accuracy of the angle factor of the ratio radiometer due to the lack of consideration of the diffuse transmission plate attenuation characteristics when the satellite is in orbit, and improving the accuracy of determining the angle factor of the ratio radiometer.

[0115] Figure 4 It is a schematic structural diagram of the electronic device provided by the present invention. Figure 4 An example of a schematic physical structure diagram of an electronic device is shown as Figure 4 shown. The electronic device may include: a processor 410, a communications interface 420, a memory 430, and a communication bus 440. Among them, the processor 410, the communications interface 420, and the memory 430 complete mutual communication through the communication bus 440. The processor 410 may call the logical instructions in the memory 430 to execute the method for determining the angular factor of the ratio radiometer. The method includes:

[0116] Based on the observed information signal value of the first detector element, determine the first angular factor of the first detector element; the observed information signal value of the first detector element is obtained from the observation data set in the initial stage of the on-orbit operation of the radiometer;

[0117] Based on the first angular factor and the change value of the observed signal within a preset time period, calculate the diffuse transmission plate attenuation rate of at least one target detector element within the preset time period, and obtain the first estimated value of the diffuse plate attenuation rate of each target detector element;

[0118] Based on the first estimated value of the diffuse transmission plate attenuation rate of each target detector element, calculate the second angular factor of each target detector element;

[0119] Based on the second angular factor, iteratively calculate the second estimated value of the diffuse transmission plate attenuation rate of each target detector element. When the first estimated value of the target detector element is equal to the second estimated value, determine the second angular factor as the angular factor of the ratio radiometer.

[0120] In addition, when the logical instructions in the above-mentioned memory 430 are implemented in the form of software functional units and sold or used as independent products, they may be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or a part of this technical solution, may be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in various embodiments of the present invention. The foregoing storage medium includes: various media such as USB flash drives, mobile hard disks, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), magnetic disks, or optical discs that can store program codes.

[0121] On the other hand, the present invention also provides a computer program product, which includes a computer program. The computer program can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the method for determining the angular factor of the ratio radiometer provided by each of the above methods. The method includes:

[0122] Based on the observed information signal value of the first detector element, determine the first angular factor of the first detector element; the observed information signal value of the first detector element is obtained from the observation dataset in the initial stage of the on-orbit operation of the radiometer;

[0123] Based on the first angular factor and the change value of the observed signal within a preset time period, calculate the attenuation rate of the diffuser plate of at least one target detector element within the preset time period, and obtain the first estimated value of the diffuser plate attenuation rate of each target detector element;

[0124] Based on the first estimated value of the diffuser plate attenuation rate of each target detector element, calculate the second angular factor of each target detector element;

[0125] Based on the second angular factor, iteratively calculate the second estimated value of the diffuser plate attenuation rate of each target detector element. When the first estimated value of the target detector element is equal to the second estimated value, determine the second angular factor as the angular factor of the ratio radiometer.

[0126] On another aspect, the present invention also provides a non-transitory computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, it is implemented to execute the method for determining the angular factor of the ratio radiometer provided by each of the above methods. The method includes:

[0127] Based on the observed information signal value of the first detector element, determine the first angular factor of the first detector element; the observed information signal value of the first detector element is obtained from the observation dataset in the initial stage of the on-orbit operation of the radiometer;

[0128] Based on the first angular factor and the change value of the observed signal within a preset time period, calculate the attenuation rate of the diffuser plate of at least one target detector element within the preset time period, and obtain the first estimated value of the diffuser plate attenuation rate of each target detector element;

[0129] Based on the first estimated value of the diffuser plate attenuation rate of each target detector element, calculate the second angular factor of each target detector element;

[0130] Based on the second angular factor, iteratively calculate the second estimated value of the diffuser plate attenuation rate of each target detector element. When the first estimated value of the target detector element is equal to the second estimated value, determine the second angular factor as the angular factor of the ratio radiometer.

[0131] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art can understand and implement it without creative efforts.

[0132] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on this understanding, the essence of the above technical solutions or the part that contributes to the prior art can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0133] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments or perform equivalent replacements for some of the technical features. And these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of each embodiment of the present invention.

Claims

1. A method for determining the angular factor of a ratio radiometer, characterized in that, Including: Determine a first angle factor of the first sounding element based on the observed information signal value of the first sounding element; The observed information signal value of the first sounding element is obtained from the observation dataset in the initial stage of the radiometer in orbit; Based on the first angle factor and the change value of the observed signal within a preset time period, calculate the transmissive plate attenuation rate of at least one target sounding element within the preset time period, and obtain a first estimated value of the transmissive plate attenuation rate of each target sounding element; Based on the first estimated value of the transmissive plate attenuation rate of each target sounding element, calculate a second angle factor of each target sounding element; Based on the second angle factor, iteratively calculate a second estimated value of the transmissive plate attenuation rate of each target sounding element. When the first estimated value of the target sounding element is equal to the second estimated value, determine the second angle factor as the angle factor of the ratio radiometer.

2. The method for determining the angular factor of the ratio radiometer according to claim 1, characterized in that, The determining the first angle factor of the first sounding element based on the observed information signal value of the first sounding element includes: Based on the solar observation signal value and the transmissive plate observation signal value of the first sounding element, determine the first angle factor using formula (1): Among them, ∧ 1 (α, β) is the first angle factor, is the solar observation signal value of the first detection element, is the diffuse plate observation signal value of the first detection element.

3. The method for determining the angular factor of the ratio radiometer according to claim 1, characterized in that, The calculating the transmissive plate attenuation rate of at least one target sounding element within the preset time period based on the first angle factor and the change value of the observed signal within the preset time period, and obtaining a first estimated value of the transmissive plate attenuation rate of each target sounding element includes: Obtain the change value of the solar observation signal of the target sounding element within the preset time period; Obtain the change value of the transmissive plate observation signal of the target sounding element within the preset time period; Based on the first angle factor, the change value of the solar observation signal, and the change value of the transmissive plate observation signal, calculate a first estimated value of the transmissive plate attenuation rate of each target sounding element within the preset time period.

4. The method for determining the angular factor of the ratio radiometer according to claim 3, characterized in that The calculating a first estimated value of the transmissive plate attenuation rate of each target sounding element within the preset time period based on the first angle factor, the change value of the solar observation signal, and the change value of the transmissive plate observation signal includes: Calculate a first estimated value of the transmissive plate attenuation rate of at least one target sounding element within the preset time period using formula (2): wherein, is the first estimated value of the attenuation rate of the diffusion plate of the i-th target exploration element, is the signal of the diffusion plate observation port of the radiometer, is the diffusion plate observation signal of the solar port of the radiometer.

5. The method for determining the angular factor of the ratio radiometer according to claim 4, characterized in that The calculating the second angle factor of each target sounding element based on the first estimated value of the transmissive plate attenuation rate of each target sounding element includes: Based on the first estimated value, calculate the second angle factor of each target sounding element using formula (3): wherein, ∧ i (α, β) is the second angle factor of the i-th target detector element, ∧ i (α, β) is the angle factor of the i-th detector element of the radiometer, is the solar observation signal value of the i-th detector element of the radiometer.

6. The method for determining the angular factor of the ratio radiometer according to claim 1, characterized in that, The determination of the observation dataset includes: Obtain the solar incident angle range within the preset time period; Interpolate the solar incident angle range into an interpolation array of a preset size; Based on the spline interpolation method and the local smoothing method, fill the angle factor corresponding to each solar incident angle into the interpolation array to determine the observation dataset.

7. An apparatus for determining the angular factor of a ratio radiometer, characterized in that, Including: A determination module for determining a first angle factor of the first sounding element based on the observed information signal value of the first sounding element; The observed information signal value of the first sounding element is obtained from the observation dataset in the initial stage of the radiometer in orbit; The first calculation module is configured to calculate the attenuation rate of the diffusion plate of at least one target detector element within the preset time period based on the first angle factor and the change value of the observation signal within the preset time period, so as to obtain the first estimated value of the attenuation rate of the diffusion plate of each target detector element; The second calculation module is configured to calculate the second angle factor of each target detector element based on the first estimated value of the attenuation rate of the diffusion plate of each target detector element; The iteration module is configured to iteratively calculate the second estimated value of the attenuation rate of the diffusion plate of each target detector element based on the second angle factor, and determine the second angle factor as the angle factor of the ratio radiometer when the first estimated value of the target detector element is equal to the second estimated value.

8. An electronic device, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the method for determining the angle factor of the ratio radiometer according to any one of claims 1 to 6.

9. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the method for determining the angle factor of the ratio radiometer according to any one of claims 1 to 6.

10. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the method for determining the angle factor of the ratio radiometer according to any one of claims 1 to 6.

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