Method for determining matching relationship between active load data and passive load data based on same satellite platform

Abstract

The invention relates to a method for determining a matching relationship between active and passive load data based on the same satellite platform. The method comprises the following steps: S1, determining specific design parameters of active and passive loads; s2, calculating the radiance of laser spots on the sea surface of the laser radar; s3, calculating an image output signal of the sea surface laser spot on the passive load focal plane; and S4, confirming the matching relationship between the active and passive load observation data and the change of the matching relationship along with time. The method can improve the matching precision between the active and passive optical load observation data, effectively monitors the matching relationship between the active and passive observation data of the ocean during the long-term in-orbit operation of the satellite, and lays a foundation for the subsequent fusion processing and application research of the active and passive load data.

Description

Technical Field

[0001] The present invention relates to the field of satellite technology, and in particular to a method for determining a matching relationship between active and passive load data based on the same satellite platform. Background Art

[0002] As an active emission optical remote sensing technology, satellite-borne laser radar technology is an effective method known to achieve vertical profile detection of the upper layer of the global ocean, and is also the most urgently needed optical remote sensing method in the current field of ocean remote sensing. Since satellite-borne laser radar can only receive laser echo signals within the range of the ground laser spot, and then obtain vertical ocean profile information by inverting the observed signals, its observation range is very limited, that is, its observation efficiency is very limited. Therefore, if a laser radar payload is configured on the same satellite platform and a passive optical imaging payload is configured at the same time, the real-time observation range of the satellite in orbit can be effectively expanded, and the observation efficiency of the satellite can be greatly improved, thereby realizing the "three-dimensional detection" of ocean water remote sensing.

[0003] During the on-orbit operation of the spaceborne optical remote sensor, due to the long-term influence of energy particle radiation and external heat flow changes in the external space environment, as well as the changes in the geometric spacing between the optical system and the detector inside the remote sensor, the geometric observation direction of the optical remote sensor will change significantly, especially the geometric matching relationship between the laser emission direction of the lidar and the observation direction of the passive optical imaging payload will change significantly, resulting in a significant change in the matching relationship between the lidar and the passive optical imaging payload observation data, which has a serious impact on the subsequent active and passive data fusion processing and its application research. Therefore, in order to ensure that the observation data of the spaceborne lidar and the passive optical payload can be effectively fused, it is necessary to monitor the matching relationship of the observation data between the lidar and the passive optical imaging payload for a long time. Summary of the invention

[0004] In order to solve the technical problems existing in the above-mentioned prior art, the purpose of the present invention is to provide a method for determining the matching relationship between active and passive payload data based on the same satellite platform, which has the characteristics of high reliability, high stability and high precision.

[0005] To achieve the above-mentioned object of the invention, the present invention provides a method for determining the matching relationship between active and passive payload data based on the same satellite platform, comprising the following steps:

[0006] Step S1, determining specific design parameters of active and passive loads;

[0007] Step S2, calculating the radiance of the laser radar laser spot on the sea surface;

[0008] Step S3, calculating the image output signal of the sea surface laser spot on the passive load focal plane;

[0009] Step S4: confirm the matching relationship between the active and passive load observation data and their changes over time.

[0010] According to a technical solution of the present invention, in step S1, it specifically includes:

[0011] Step S11, determining the satellite orbit arc segment;

[0012] Step S12, confirming the operating parameters of the onboard laser radar, wherein the operating parameters of the laser radar include laser wavelength, laser pulse energy, laser pulse repetition frequency, laser pulse width, laser divergence angle and receiving telescope aperture;

[0013] Step S13, confirming the operating parameters of the passive optical payload; the operating parameters of the passive optical payload include detector type, detector pixel scale, pixel size, optical system F number, optical system transmittance, detector quantum efficiency, and detector exposure time;

[0014] Step S14: confirm that the laser radar and the passive optical payload are turned on at the same time and are working stably.

[0015] According to a technical solution of the present invention, in step S11, based on satellite orbit parameters, an orbital arc segment when the satellite operates in the shadow area of ​​the earth and the ground observation target is an ocean water body is selected as the satellite orbital arc segment.

[0016] According to a technical solution of the present invention, in the step S14, it specifically includes:

[0017] Step S141, the laser radar is turned on before entering the predetermined arc segment, and the advance startup time is 10 minutes to confirm that the laser radar has reached a stable working state;

[0018] Step S142: The passive optical load is powered on before entering the predetermined arc segment, and the advance power-on time is 5 minutes to confirm that the passive optical load has reached a stable working state.

[0019] According to a technical solution of the present invention, in the step S2, it specifically includes:

[0020] Step S21: Calculate the number of photons N emitted by the laser radar according to the operating parameters of the laser radar. S , expressed as

[0021]

[0022] Among them, E laserrepresents the laser single pulse energy of the laser radar, h represents the Planck constant, c represents the value of the speed of light, and λ represents the laser wavelength emitted by the laser radar;

[0023] Step S22: according to the atmospheric transmittance t between the satellite and the ground atom , calculate the number of photons N emitted by the laser radar that reach the sea surface G , expressed as

[0024] N G =t atom ·N S (2)

[0025] Step S23: According to the random state law of the ocean surface in all directions under the action of the sea breeze, assuming that the sea surface is a Lambertian radiator, the radiance L of the laser spot on the sea surface is calculated. G .

[0026] According to a technical solution of the present invention, in the step S23, it specifically includes:

[0027] Step S231: The number of photons emitted by the laser radar to the sea surface forms a laser spot on the sea surface. The area of ​​the laser spot is S. G , according to the satellite-to-ground distance H and the laser divergence angle θ of the laser radar, the area of ​​the laser spot is calculated and expressed as

[0028]

[0029] Step S232: according to the laser single pulse energy E of the laser radar Laser and the laser pulse width T laser , atmospheric transmittance t atom and the area size S of the laser spot G , calculate the radiance E of the laser spot G , expressed as

[0030]

[0031] Step S233: According to the random state law of the sea surface in all directions under the action of the sea breeze, assuming that the sea surface is a Lambertian radiator, the laser energy reflection caused by the sea surface obeys the Lambert radiation law, and according to the radiant illumination E of the laser spot G and sea surface reflectivity ρ sea , calculate the radiance L of the laser spot on the sea surface during satellite observation G , expressed as

[0032] L G =ρ sea ·E G / π (5).

[0033] According to a technical solution of the present invention, in step S3, it specifically includes:

[0034] Step S31: Radiance L of the laser spot formed by reflection from the sea surface G and atmospheric transmittance t atom , calculate and obtain the radiance L of the laser spot at the entrance pupil of the optical system of the passive optical load S , expressed as

[0035] L S =t atom ·L G (6);

[0036] Step S32: according to the operating data of the passive optical load and the radiance L of the laser spot at the entrance pupil of the optical system of the passive optical load, S , calculate the focal plane image output signal N of the laser spot on the passive optical load E , expressed as

[0037]

[0038] Among them, A det is the area of ​​the detector pixel of the passive optical load; T is the detector exposure time of the passive optical load; η is the detector quantum efficiency of the passive optical load, that is, the average number of photoelectrons that can be generated per incident photon number; τ is the optical system transmittance of the passive optical load; The F number designed for the optical system of the passive optical load.

[0039] According to a technical solution of the present invention, in step S4, it specifically includes:

[0040] Step S41: Outputting a signal N according to the focal plane image of the laser spot on the passive optical load E , the image centroid position coordinates (x0, y0) of the laser spot are calculated using the grayscale centroid method, expressed as

[0041]

[0042] The image signal of the laser spot is M×N pixels, (x1, y1) is the pixel coordinate of the upper left corner of the image, (x M ,y N ) is the pixel coordinate of the lower right corner of the image, f(i,j) is the gray value of the pixel in the i-th row and j-th column of the image;

[0043] Step S42, repeating step S41 to calculate the image centroid position coordinates of the laser spot at any different time;

[0044] Step S43, compare the calculation results of the image centroid position coordinates at different times, obtain the matching relationship between the active and passive load observation data and its change over time, expressed as:

[0045]

[0046] Among them, (x0', y0') is the coordinate of the center of mass position of the laser spot image at different times calculated according to the grayscale centroid method; (Δx, Δy) is the change in the center of mass position of the laser spot, which indicates the change in the matching relationship between the observation data of the lidar and the passive optical imaging payload.

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] (1) The method provided by the present invention is technically feasible. The method provided by the present invention is based on the basic observation principle of the satellite-borne optical remote sensor. By selecting the orbital arc segment when the satellite is operating in the shadow area of ​​the earth and the ground is ocean water, the passive optical payload of the same satellite platform performs imaging observation of the laser spot target on the sea surface, and obtains the calculation result of the focal plane output signal of the passive optical payload detector, thereby directly obtaining the matching accuracy between the active and passive payload observation data. The method of the present invention is simple and easy to implement, does not increase the design complexity of the satellite working mode, and does not require the additional configuration of other monitoring equipment. It has few engineering resource constraints and is technically feasible.

[0049] (2) The method provided by the present invention ensures high matching accuracy between the observation data of active and passive payloads. During the on-orbit operation of the satellite, the laser radar and the passive optical imaging payload are located on the same satellite platform, which not only avoids the inconsistency error of the spatial geometric observation orientation caused by factors such as the satellite orbit, platform attitude stability, and attitude pointing accuracy when the two optical payloads are located on different satellite platforms, but also avoids the large error caused by the difference in transit time when the two optical payloads pass through the same target area, thereby effectively ensuring high-precision matching between the observation data of the two active and passive payloads.

[0050] (3) The method provided by the present invention has a wide range of applications. The method of the present invention proposes a working mode, test method, test process for obtaining the matching relationship between the active and passive payload observation data of the same satellite platform, as well as a calculation method for the basic radiation amount of the laser spot target. It is suitable for the subsequent design of the active and passive joint detection satellite for the ocean, and is also suitable for long-term monitoring of the matching relationship of the observation data between the two active and passive payloads and their changes over time during the satellite on-orbit application stage. The method of the present invention is mature and reliable, and is conducive to engineering application. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0052] Figure 1 A flowchart schematically showing a method for determining a matching relationship between active and passive payload data based on the same satellite platform according to an embodiment of the present invention;

[0053] Figure 2 A schematic diagram schematically shows the layout of active and passive loads on the same satellite platform according to an embodiment of the present invention;

[0054] Figure 3 A schematic diagram showing the geometry of a satellite-borne passive payload observing a laser spot on the sea surface according to one embodiment of the present invention;

[0055] Figure 4 A schematic diagram schematically shows a satellite in orbit flying in the shadow area of ​​the earth according to one embodiment of the present invention;

[0056] Figure 5 A schematic diagram schematically showing a laser spot image output result of a focal plane of a passive load at time T1 according to an embodiment of the present invention;

[0057] Figure 6 A schematic diagram schematically shows the output result of the laser spot image of the focal plane of the passive load at time T2 according to one embodiment of the present invention. DETAILED DESCRIPTION

[0058] The description of the embodiments of this specification should be combined with the corresponding drawings, which should be considered as part of the complete specification. In the drawings, the shape or thickness of the embodiments may be enlarged and indicated for simplification or convenience. Furthermore, the parts of each structure in the drawings will be described separately. It is worth noting that the elements not shown in the drawings or not described in words are in a form known to ordinary technicians in the relevant technical field.

[0059] The description of the embodiments herein and any reference to directions and orientations are only for the convenience of description and are not to be construed as any limitation on the scope of protection of the present invention. The following description of the preferred embodiments may involve combinations of features, which may exist independently or in combination, and the present invention is not particularly limited to the preferred embodiments. The scope of the present invention is defined by the claims.

[0060] The working principle of the present invention is as follows:

[0061] The space-borne laser radar actively emits laser pulses to the ground, forming a laser spot target on the sea surface. If the passive optical imaging payload can directly observe the laser spot target, then the matching relationship between the laser radar and the passive optical imaging payload observation data can be obtained.

[0062] When the passive optical imaging payload observes the laser spot target generated by the laser radar on the ground, the output signal (number of electrons) generated by the laser spot target signal at the focal plane of the passive optical imaging payload is calculated as follows:

[0063]

[0064] In the above formula, L S A is the radiance at the entrance pupil of the passive load optical system; det is the area of ​​the passive optical payload detector pixel; T is the exposure time of the passive optical payload detector. Considering that the laser radar is a pulsed light source, that is, the laser radar is an intermittent light source rather than a continuous light source, T is taken here as T = T laser ; η is the quantum efficiency of the passive optical payload detector, that is, the average number of photoelectrons generated per incident photon number; τ is the optical system transmittance of the passive optical payload; is the F number designed for the optical system of the passive optical payload; λ is the wavelength of the laser emitted by the lidar; h is Planck's constant, and c is the speed of light.

[0065] From the above calculation formula of the passive optical imaging payload output signal (number of electrons), it can be known that if the satellite is in the shadow area of ​​the earth, the stray light signal interference caused by the background light of the sun can be ignored. Then the target signal detected by the passive optical imaging payload is the light radiation signal generated by the laser spot target of the laser radar. Therefore, the present invention proposes a method for determining the matching relationship between active and passive payload data based on the same satellite platform based on the basic observation principles of satellite-borne laser radar and passive optical imaging payload. When the satellite is operating in the shadow area, the satellite-borne laser radar emits laser pulses to the sea surface to generate a laser spot, and then the passive optical payload performs imaging observation of the ground laser spot target, thereby determining the matching relationship between the laser radar and the passive optical payload observation data.

[0066] like Figure 1 As shown, a method for determining the matching relationship between active and passive load data based on the same satellite platform of the present invention comprises the following steps:

[0067] Step S1, determining specific design parameters of active and passive loads;

[0068] Step S2, calculating the radiance of the laser radar laser spot on the sea surface;

[0069] Step S3, calculating the image output signal of the sea surface laser spot on the passive load focal plane;

[0070] Step S4: confirm the matching relationship between the active and passive load observation data and their changes over time.

[0071] In the present invention, when the satellite operates in the shadow area, the on-board laser radar emits laser pulses to the sea surface to generate a laser spot, and the passive optical payload directly performs imaging observation on the laser spot target, and determines the matching relationship between the laser radar and the passive optical payload observation data, thereby realizing the long-term monitoring of the matching relationship of observation data between the active and passive payloads on the same satellite platform that operates in orbit for a long time and their changes over time, thereby effectively providing the matching accuracy between the active and passive optical payload observation data, and effectively monitoring the matching relationship of the active and passive observation data of the ocean when the satellite is in orbit for a long time, laying a foundation for the subsequent fusion processing and application research of the active and passive payload data.

[0072] In the present invention, during the on-orbit operation of the satellite, the laser radar and the passive optical imaging payload are located on the same satellite platform, which not only avoids the inconsistency error in the spatial geometric observation orientation caused by factors such as the satellite orbit, platform attitude stability, and attitude pointing accuracy when the two optical payloads are located on different satellite platforms, but also avoids the large error caused by the difference in transit time when the two optical payloads pass through the same target area, thereby effectively ensuring high-precision matching between the observation data of the two active and passive payloads.

[0073] Taking an ocean remote sensing satellite equipped with a laser radar and a passive optical imaging payload on the same satellite platform in orbit as an example, the method for determining the matching relationship between active and passive payload data based on the same satellite platform provided by the present invention is described in detail below.

[0074] The analysis and calculation tool involved in the following embodiments is MATLAB software. All the specific design parameters of the laser radar, the parameter index of the passive optical imaging load, and the calculation of the basic physical quantities (radiance, radiance, etc.) are performed by MATLAB.

[0075] like Figure 2 As shown, the active optical payload and the passive optical payload are located on the same satellite platform, and the active payload is a lidar.

[0076] The method for determining the matching relationship between active and passive payload data based on the same satellite platform provided in this embodiment specifically includes the following steps:

[0077] Step S1, determining specific design parameters of active and passive payloads; the design parameters of active and passive payloads include: satellite orbit arc, operating parameters of onboard laser radar, operating parameters of passive optical payload, and operating status of laser radar and passive optical payload;

[0078] In step S1, it specifically includes:

[0079] Step S11, determining the satellite orbit arc segment;

[0080] According to the satellite orbit parameters, the orbital arc segment when the satellite operates in the shadow area of ​​the earth and the ground observation target is the ocean water body is selected as the satellite operation orbital arc segment.

[0081] According to the satellite orbit parameters, as shown in Table 1 below, select the orbit arc segment when the satellite is operating in the shadow area of ​​the earth and the ground observation target is the ocean water body, such as Figure 4 As shown, taking the case where the Earth's shadow area is selected and the ground observation target is the Pacific Ocean water body as an example, the observation mission of the onboard lidar and passive optical imaging payload is performed.

[0082] Table 1 Satellite orbit parameters

[0083] Project Name Orbital parameters Orbital altitude (km) 417.76 Descending Node Time 10:30AM Semi-major axis (km) 6788.76 Orbital inclination (°) 97.09 Orbital period (min) 92.78 Number of laps per day 15+1 / 2

[0084] Step S12: confirm the operating parameters of the onboard laser radar.

[0085] The operating parameters of the lidar include laser wavelength, laser pulse energy, laser pulse repetition frequency, laser pulse width, laser divergence angle and receiving telescope aperture. The specific indicators are shown in Table 2.

[0086] Table 2 Index parameters of onboard laser radar

[0087] Project Name parameter Laser wavelength (nm) 486 Laser pulse energy (mJ) 100 Laser pulse repetition frequency (Hz) 100 Laser pulse width (ns) 20 Laser divergence angle (mrad) 0.1 Receiving telescope aperture (m) 1

[0088] Step S13, confirming the operating parameters of the passive optical load;

[0089] The operating parameters of the passive optical payload include detector type, detector pixel scale, pixel size, optical system F number, optical system transmittance, detector quantum efficiency, and detector exposure time. The specific indicators are shown in Table 3.

[0090] Table 3 Index parameters of passive optical payload

[0091]

[0092]

[0093] Step S14, confirming that the laser radar and the passive optical payload are turned on and working stably at the same time;

[0094] The calculation of LiDAR parameters and specific imaging data can only be carried out after confirming that the LiDAR and passive optical payload are turned on and have reached a stable working state.

[0095] In step S14, it specifically includes:

[0096] Step S141, the laser radar is turned on before entering the predetermined arc segment, and the advance startup time is 10 minutes to confirm that the laser radar has reached a stable working state;

[0097] Step S142: The passive optical load is powered on before entering the predetermined arc segment, and the advance power-on time is 5 minutes to confirm that the passive optical load reaches a stable working state.

[0098] Step S2, calculating the radiance of the laser radar laser spot on the sea surface;

[0099] In step S2, it specifically includes:

[0100] Step S21: Calculate the number of photons N emitted by the laser radar according to the operating parameters of the laser radar. S , expressed as

[0101]

[0102] Among them, E laser represents the laser single pulse energy of the laser radar, which is 100mJ; h represents the Planck constant, which is 6.626E-34J·s; c represents the speed of light, which is 3E+8m / s; λ represents the laser wavelength emitted by the laser radar, which is 486nm;

[0103] Step S22: according to the atmospheric transmittance t between the satellite and the ground atom , calculate the number of photons N emitted by the lidar that reach the sea surface G , expressed as

[0104] N G =t atom ·N S (2)

[0105] Among them, the atmospheric transmittance between the satellite and the ground is t atom The value is 0.8; the number of photons emitted by the laser radar is N S The calculated value is 2.445E+17.

[0106] Step S23: According to the random state law of the ocean surface in all directions under the action of the sea breeze, it can be assumed that the sea surface is a Lambertian radiator, and the radiance L of the laser spot on the sea surface is calculated. G .

[0107] Step S231: The number of photons emitted by the laser radar to the sea surface forms a laser spot on the sea surface. The area of ​​the laser spot is S. G , according to the satellite-to-ground distance H (i.e., the orbital height of the satellite) and the laser divergence angle θ of the laser radar, the area of ​​the laser spot is calculated and expressed as

[0108]

[0109] Among them, the satellite-to-earth distance H is 417km; the laser divergence angle θ of the lidar is 0.1mrad.

[0110] Step S232: according to the laser single pulse energy E of the laser radar Laser and the laser pulse width T laser , atmospheric transmittance t atom and the laser spot size S G , calculate the radiance E of the laser spot G , expressed as

[0111]

[0112] The values ​​of each parameter are as follows:

[0113] Atmospheric transmittance t atom , the value is 0.8;

[0114] Laser radar single pulse energy E Laser , the value is 100mJ;

[0115] Laser radar laser pulse width T laser , the value is 20ns;

[0116] The size of the laser spot S G , the calculated value is 1365.72m 2 .

[0117] Step S233: According to the random state law of the sea surface in all directions under the action of sea breeze, assuming that the sea surface is a Lambertian radiator, the laser energy reflection caused by the sea surface obeys the Lambert radiation law, and according to the radiant illumination E of the laser spot G and sea surface reflectivity ρ sea , calculate the radiance L of the laser spot on the sea surface during satellite observation G , expressed as

[0118] L G =ρ sea ·E G / π (5).

[0119] The values ​​of each parameter are as follows:

[0120] Sea surface reflectivity ρ sea , the value is 0.04;

[0121] Laser radar single pulse energy E Laser , the value is 100mJ;

[0122] Laser radar laser pulse width T laser , the value is 20ns;

[0123] The area of ​​the laser spot S G , the calculated value is 1365.72m 2 .

[0124] Step S3, calculating the image output signal of the sea surface laser spot on the passive load focal plane;

[0125] In step S3, it specifically includes:

[0126] Step S31: Radiance L of the laser spot formed by reflection from the sea surface G and atmospheric transmittance t atom , calculate and obtain the radiance L of the laser spot at the entrance pupil of the optical system of the passive optical load S , expressed as

[0127] L S =t atom ·L G (6);

[0128] The values ​​of each parameter are as follows:

[0129] The radiance L of the laser spot formed by the reflection on the sea surface G The calculated value is 37.29 W·m -2 ·sr -1 ;

[0130] Atmospheric transmittance t atom , the value is 0.8.

[0131] Step S32: according to the operation data of the passive optical load and the radiance L of the laser spot at the entrance pupil of the optical system of the passive optical load, S , calculate the laser spot on the focal plane image output signal N of the passive optical load E , expressed as

[0132]

[0133] Among them, L S is the radiance of the laser spot at the entrance pupil of the optical system of the passive optical load, and the calculated value is 29.83 W·m -2 ·sr -1 ; Adet is the area of ​​the detector pixel of the passive optical load, and the calculated value is 9E-10m 2 ; T is the exposure time of the passive optical payload detector. Considering that the laser radar is a pulsed light source rather than a continuous light source, T = T laser , with a value of 20ns; η is the detector quantum efficiency of the passive optical load, that is, the average number of photoelectrons that can be generated per incident photon number, with a value of 0.7; τ is the optical system transmittance of the passive optical load, with a value of 0.6; The F number designed for the optical system of the passive optical load is 2.5; h is Planck's constant, which is 6.626E-34J·s; c is the speed of light, which is 3E+8m / s.

[0134] Step S4: confirm the matching relationship between the active and passive load observation data and their changes over time.

[0135] In step S4, it specifically includes:

[0136] Step S41, the focal plane image output signal of the passive optical load at time T1 is as follows: Figure 6 As shown, according to the focal plane image output signal N of the passive optical load E , the image centroid position coordinates (x0, y0) of the laser spot are calculated using the grayscale centroid method, expressed as

[0137]

[0138] Among them, the image signal of the laser spot is M×N pixels, 8×7 is taken; (x1, y1) is the pixel coordinate of the upper left corner of the image, (x8, y7) is the pixel coordinate of the lower right corner of the image, and f(i, j) is the gray value of the pixel in the i-th row and j-th column in the image;

[0139] Step S42, repeating step S41, calculating the image centroid position coordinates of the laser spot at any different time;

[0140] Repeat step S41 to calculate the centroid position coordinates of the laser spot image at time T2 as (x0', y0').

[0141] Repeat step S41 to calculate the centroid position coordinates (x0", y0") of the laser spot image at any moment.

[0142] Step S43, compare the calculation results of the image centroid position coordinates at different times, obtain the matching relationship between the active and passive load observation data and its change over time, expressed as:

[0143]

[0144] Among them, (x0', y0') is the coordinate of the center of mass position of the laser spot image at different times calculated according to the grayscale centroid method; (Δx, Δy) is the change in the center of mass position of the laser spot, which indicates the change in the matching relationship between the observation data of the lidar and the passive optical imaging payload.

[0145] It should be noted that the above is a preferred embodiment of the present invention. It should be pointed out that although the preferred embodiment of the present invention has been described, once the basic creative concept of the present invention is known, a number of improvements and modifications can be made by a person skilled in the art without departing from the principles of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention. Therefore, the attached claims are intended to be interpreted as including the preferred embodiment and all changes and modifications that fall within the scope of the embodiments of the present invention.

Claims

1. A method for determining the matching relationship between active and passive payload data based on the same satellite platform, characterized in that: The following steps are involved: Step S1, determining specific design parameters of active and passive loads; Step S2, calculating the radiance of the laser radar laser spot on the sea surface; Step S3, calculating the image output signal of the sea surface laser spot on the passive load focal plane; Step S4: confirm the matching relationship between the active and passive load observation data and their changes over time.

2. The method for determining the matching relationship between active and passive load data based on the same satellite platform according to claim 1, characterized in that: In the step S1, it specifically includes: Step S11, determining the satellite orbit arc segment; Step S12, confirming the operating parameters of the onboard laser radar, wherein the operating parameters of the laser radar include laser wavelength, laser pulse energy, laser pulse repetition frequency, laser pulse width, laser divergence angle and receiving telescope aperture; Step S13, confirming the operating parameters of the passive optical payload; the operating parameters of the passive optical payload include detector type, detector pixel scale, pixel size, optical system F number, optical system transmittance, detector quantum efficiency, and detector exposure time; Step S14: confirm that the laser radar and the passive optical payload are turned on at the same time and are working stably.

3. The method for determining the matching relationship between active and passive load data based on the same satellite platform according to claim 2, characterized in that: In step S11, according to the satellite orbit parameters, an orbit arc segment when the satellite operates in the shadow area of ​​the earth and the ground observation target is an ocean water body is selected as the satellite operation orbit arc segment.

4. The method for determining the matching relationship between active and passive load data based on the same satellite platform according to claim 2, characterized in that: In the step S14, it specifically includes: Step S141, the laser radar is turned on before entering the predetermined arc segment, and the advance startup time is 10 minutes to confirm that the laser radar has reached a stable working state; Step S142: The passive optical load is powered on before entering the predetermined arc segment, and the advance power-on time is 5 minutes to confirm that the passive optical load has reached a stable working state.

5. The method for determining the matching relationship between active and passive load data based on the same satellite platform according to claim 1, characterized in that: In the step S2, it specifically includes: Step S21: Calculate the number of photons N emitted by the laser radar according to the operating parameters of the laser radar. S , expressed as Among them, E laser represents the laser single pulse energy of the laser radar, h represents the Planck constant, c represents the value of the speed of light, and λ represents the laser wavelength emitted by the laser radar; Step S22: according to the atmospheric transmittance t between the satellite and the ground atom , calculate the number of photons N emitted by the laser radar that reach the sea surface G , expressed as N G =t atom ·N S (2) Step S23: According to the random state law of the ocean surface in all directions under the action of the sea breeze, assuming that the sea surface is a Lambertian radiator, the radiance L of the laser spot on the sea surface is calculated. G .

6. The method for determining the matching relationship between active and passive load data based on the same satellite platform according to claim 5, characterized in that: In the step S23, it specifically includes: Step S231: The number of photons emitted by the laser radar to the sea surface forms a laser spot on the sea surface. The area of ​​the laser spot is S. G , according to the satellite-to-ground distance H and the laser divergence angle θ of the laser radar, the area of ​​the laser spot is calculated and expressed as Step S232: according to the laser single pulse energy E of the laser radar Laser and the laser pulse width T laser , atmospheric transmittance t atom and the area size S of the laser spot G , calculate the radiance E of the laser spot G , expressed as Step S233: According to the random state law of the sea surface in all directions under the action of the sea breeze, assuming that the sea surface is a Lambertian radiator, the laser energy reflection caused by the sea surface obeys the Lambert radiation law, and according to the radiant illumination E of the laser spot G and sea surface reflectivity ρ sea , calculate the radiance L of the laser spot on the sea surface during satellite observation G , expressed as L G =ρ sea ·E G / π (5).

7. The method for determining the matching relationship between active and passive load data based on the same satellite platform according to claim 6, characterized in that: In the step S3, it specifically includes: Step S31: Radiance L of the laser spot formed by reflection from the sea surface G and atmospheric transmittance t atom , calculate and obtain the radiance L of the laser spot at the entrance pupil of the optical system of the passive optical load S , expressed as L S =t atom ·L G (6); Step S32: according to the operating data of the passive optical load and the radiance L of the laser spot at the entrance pupil of the optical system of the passive optical load, S , calculate the focal plane image output signal N of the laser spot on the passive optical load E , expressed as Among them, A det is the area of ​​the detector pixel of the passive optical load; T is the detector exposure time of the passive optical load; η is the detector quantum efficiency of the passive optical load, that is, the average number of photoelectrons that can be generated per incident photon number; τ is the optical system transmittance of the passive optical load; The F number designed for the optical system of the passive optical load.

8. The method for determining the matching relationship between active and passive load data based on the same satellite platform according to claim 7, characterized in that: In the step S4, it specifically includes: Step S41: Outputting a signal N according to the focal plane image of the laser spot on the passive optical load E , the image centroid position coordinates (x0, y0) of the laser spot are calculated using the grayscale centroid method, expressed as The image signal of the laser spot is M×N pixels, (x1, y1) is the pixel coordinate of the upper left corner of the image, (x M ,y N ) is the pixel coordinate of the lower right corner of the image, f(i,j) is the gray value of the pixel in the i-th row and j-th column of the image; Step S42, repeating step S41 to calculate the image centroid position coordinates of the laser spot at any different time; Step S43, compare the calculation results of the image centroid position coordinates at different times, obtain the matching relationship between the active and passive load observation data and its change over time, expressed as: Among them, (x0', y0') is the coordinate of the center of mass position of the laser spot image at different times calculated according to the grayscale centroid method; (Δx, Δy) is the change in the center of mass position of the laser spot, which indicates the change in the matching relationship between the observation data of the lidar and the passive optical imaging payload.

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