Autonomous sun avoidance system, method, and medium for low-earth orbit optical remote sensing satellites

Abstract

The application provides a kind of low orbit optical remote sensing satellite autonomous sun avoidance system, method and system, wherein the system includes, the calculation of camera visual axis and the included angle of sun vector, satellite shadow mark for attitude and orbit control computer module;Synthetic electronic computer module is used for multi-condition joint determination, and when the conditions are all satisfied, remote sensing camera is controlled by instruction;Transmission module is used for the transmission of camera visual axis and the included angle of sun vector, satellite shadow mark between synthetic electronic computer module and attitude and orbit control computer module, and the transmission of imaging end instruction between synthetic electronic computer module and optical remote sensing camera module;Optical remote sensing camera module is used to execute imaging end instruction.The application can realize autonomous sun avoidance in the process of attitude turning to the earth when satellite starts to execute imaging task and the process of attitude returning to the sun orientation after imaging task is finished, without ground intervention, the implementation is simple, safety is high, has certain application value and prospect.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of satellite autonomous safety management, and relates to an autonomous sun avoidance system, method and medium for a low-orbit optical remote sensing satellite, in particular, to an autonomous sun avoidance system, method and medium suitable for a steady-state sun-oriented low-orbit optical remote sensing satellite. BACKGROUND

[0002] Compared with sun-synchronous orbits, low-inclination circular orbits can significantly improve the revisit efficiency of medium and low latitude areas. In addition, low-inclination circular orbits can also realize the observation ability of the earth at different phases and under different light conditions. Optical remote sensing satellites operating in low-inclination circular orbits mostly use the fixed installation mode of solar cell arrays, adopt the working mode of steady-state sun-oriented for energy acquisition in non-imaging time and attitude maneuver for pointing to the ground imaging area in imaging time, and mainly have the following advantages:

[0003] 1. The fixed installation mode of the solar cell array has small satellite inertia, and the fundamental frequency of the battery array is high, which is less flexible to attitude control, and is beneficial to rapid attitude maneuver and stability of the satellite.

[0004] 2. Compared with the two-dimensional driving mode of the solar cell array, there is no long-term moving part, high reliability and low cost.

[0005] However, for the optical remote sensing satellite operating in a low-inclination circular orbit in a steady-state sun-oriented manner, frequent attitude maneuver is required during task execution. During the maneuvering process, sunlight directly enters the remote sensing camera field of view, affecting the normal operation of the optical remote sensing camera, and even causing damage to the optical remote sensing camera detector, resulting in serious consequences and impact. Therefore, it is necessary to take measures to prevent the optical remote sensing camera from being directly illuminated by sunlight during the maneuvering process.

[0006] In the Chinese patent document with publication number CN108791955A, a method for a stationary remote sensing satellite to autonomously avoid the sun during on-orbit operation is disclosed. First, the camera line-of-sight vector is calculated according to the structural characteristics of the camera. Second, the positions of the earth and the sun in the satellite body coordinate system are calculated according to the relative positions of the satellite, the earth and the sun and the attitude information of the satellite. Third, appropriate earth contour threshold and sun avoidance threshold are selected, and whether sun avoidance is needed is determined according to the relationship between the camera line-of-sight vector and the positions of the earth and the sun. Finally, after successful sun avoidance determination, a sun avoidance signal is triggered and sun avoidance is executed. This method is of great significance for the safety protection of the camera of a stationary remote sensing satellite during operation. However, the method proposed in this patent document is not suitable for a steady-state sun-oriented low-orbit optical remote sensing satellite.

[0007] In the Chinese patent document with publication number CN108803642A, a sun protection attitude control correlation design method for an optical imaging satellite camera is disclosed, which is suitable for a geostationary orbit large aperture optical imaging satellite, comprising: a yaw guide control method is proposed, and an optimal yaw guide law is obtained by polynomial fitting with the sun elevation angle as a variable and the optimal yaw angle as a variable; for the design constraint that the satellite is only installed with a three-fold plate type sunshade in the-X direction, a yaw large angle maneuver control before and after noon is proposed, an on-board attitude maneuver path planning algorithm is established according to the sun elevation angle of the day to realize seamless connection of the load sun protection; a sun avoidance maneuver control strategy combining the limited area work before and after midnight is proposed to realize the load sun protection at midnight and make the satellite work for the longest time. Finally, an eight-segment attitude control strategy containing three attitude maneuvers per orbit is formed, which meets the task requirements of the geostationary orbit large aperture optical imaging satellite for whole-orbit load sun protection and longest business imaging. However, the method proposed in the patent document is not suitable for a steady-state sun-oriented low-orbit optical remote sensing satellite.

[0008] In the article "Sun Avoidance Design for Camera of Geostationary Orbit Remote Sensing Satellite" published by Pengzhou, Li Zhen Song, Qiao Guodong, Liu Xinyan, an improved rolling axis maneuver sun avoidance method is mentioned, which has good engineering application value for sun avoidance protection of a geostationary orbit remote sensing satellite camera. However, the method proposed in the article is not suitable for a steady-state sun-oriented low-orbit optical remote sensing satellite. SUMMARY

[0009] In view of the defects in the prior art, the purpose of the present application is to provide an autonomous sun avoidance system, method and medium for a low-orbit optical remote sensing satellite.

[0010] The autonomous sun avoidance system for a low-orbit optical remote sensing satellite provided by the present application comprises:

[0011] An attitude and orbit control computer module is used for calculating the angle between the camera visual axis and the sun vector and the satellite shadow mark;

[0012] A comprehensive electronic computer module is used for multi-condition joint judgment, and when all conditions are met, the remote sensing camera is controlled by an instruction; the multi-condition joint judgment comprises joint judgment of any one or more of the following conditions: the angle between the camera visual axis and the sun vector, the satellite shadow mark, the satellite working mode, and the control mode;

[0013] A transmission module is used for data transmission between modules;

[0014] An optical remote sensing camera module is used for executing an imaging end instruction.

[0015] Preferably, the optical remote sensing camera module comprises any one or more of the following modules: a space visible light camera module, an infrared camera module, and a hyperspectral camera module.

[0016] Preferably, the integrated electronic computer module comprises any computer with data management function.

[0017] Preferably, the transmission module comprises a serial data bus; the inter-module data transmission path comprises transmission of the angle between the camera visual axis and the sun vector and the satellite shadow flag from the orbit control computer module to the integrated electronic computer module, and transmission of the imaging end instruction from the integrated electronic computer module to the optical remote sensing camera module.

[0018] Preferably, the serial data bus can be configured in any form of single or double or multiple redundant bus.

[0019] An autonomous sun-avoiding method for a low-orbit optical remote sensing satellite, comprising:

[0020] Step S1: the orbit control computer calculates the angle between the camera visual axis and the sun vector in real time according to the satellite position information and attitude information;

[0021] Step S2: the orbit control computer calculates the satellite shadow flag according to the relative position relationship between the satellite, the earth and the sun;

[0022] Step S3: the integrated electronic computer judges whether the angle θ between the camera visual axis and the sun vector is less than a set threshold value, and if yes, step S4 is executed, and if no, step S3 is continued;

[0023] Step S4: the integrated electronic computer judges whether the satellite shadow flag F sun is a lighted area, and if yes, step S5 is executed, and if no, step S3 is returned;

[0024] Step S5: the integrated electronic computer judges whether the satellite working mode is non-spectral calibration or non-solar radiation calibration, and if yes, step S6 is executed, and if no, step S3 is returned;

[0025] Step S6: the integrated electronic computer judges whether the control mode is a task mode, and if yes, step S7 is executed, and if no, step S3 is returned;

[0026] Step S7: when the conditions of S3 to S6 are all satisfied, the integrated electronic computer autonomously sends an imaging end instruction through the serial data bus.

[0027] Preferably, the calculation formula of the angle θ between the camera visual axis and the sun vector is as follows:

[0028] T=t / 86400 / 36525

[0029] e sun= 0.01670862 - 0.00004204 x T

[0030] i sun = 23.439291 - 0.01300417 x T

[0031] ω sun = 282.937347 + 0.32256206 x T

[0032] M sun = 357.5291 + 35999.0502888889 x T

[0033] u sun = ω sun + M sun + 2e sun sin M sun + 1.25e sun 2 sin(2M sun )

[0034]

[0035]

[0036]

[0037] In the formula, T is the Julian century number, t is the current time in seconds since 8:00:00 on January 1, 2000 in Beijing time, e sun is the eccentricity of the sun's orbit, i sun is the inclination of the sun's orbit, ω sun is the argument of perihelion of the sun's orbit, M sun is the mean anomaly of the sun's orbit, u sun is the amplitude of the sun's orbital latitude, is the projection of the sun's position in the inertial system, P b is the projection of the star-sun pointing vector in the body system, is the projection of the satellite's current position in the inertial system, is the satellite's current attitude angle in the body system relative to the inertial system (1-2-3 rotation order), l b is the projection of the camera's visual axis in the satellite's body system.

[0038] Preferably, the calculation formula of the satellite shadow flag F sun is as follows:

[0039]

[0040]

[0041]

[0042] In the formula, ψ is the geostationary-satellite-earth angle, ψ0 is the satellite cutting earth edge angle, R is the earth radius. e

[0043] Preferably, the step S3 camera view axis and the sun vector angle θ threshold, ground modification.

[0044] A computer readable storage medium storing a computer program, the computer program is executed by the processor to realize the steps of the low-orbit optical remote sensing satellite autonomous sun avoidance method.

[0045] Compared with the prior art, the present application has the beneficial effects as follows:

[0046] 1. The present application adopts a steady-state sun-oriented low-orbit optical remote sensing satellite, which realizes autonomous sun avoidance during the attitude turning-to-earth process when starting to perform an imaging task and the attitude returning-to-sun orientation process after the imaging task is completed.

[0047] 2. The present application adopts comprehensive electronic computer autonomous management, relies on on-board autonomous switching, and does not need ground intervention, so that the implementation is simple.

[0048] 3. The present application adopts a simple, reliable and fast system scheme, which effectively ensures the safety of the optical remote sensing camera detector during the satellite attitude maneuvering process, and has certain application value and prospect. BRIEF DESCRIPTION OF DRAWINGS

[0049] Other features, objects and advantages of the present application will become more apparent from the following detailed description of non-limiting embodiments, made with reference to the accompanying drawings:

[0050] Figure 1 It is a low-orbit optical remote sensing satellite autonomous sun avoidance system module schematic diagram;

[0051] Figure 2 It is a low-orbit optical remote sensing satellite autonomous sun avoidance method flow chart. DETAILED DESCRIPTION

[0052] The present application will be described in detail below with specific embodiments. The following embodiments will help those skilled in the art to further understand the present application, but do not limit the present application in any form. It should be pointed out that, for those skilled in the art, without departing from the concept of the present application, a number of changes and improvements can be made. These all belong to the protection scope of the present application.

[0053] The present application introduces a low-orbit optical remote sensing satellite autonomous sun avoidance system, which is described with reference to Figure 1 ​As shown, the system comprises an orbit control computer module, an integrated electronic computer module, an optical remote sensing camera module and a transmission module.

[0054] The orbit control computer module is mainly used for calculating the angle between the camera visual axis and the sun vector and the satellite shadow mark.

[0055] The satellite integrated electronic computer module is mainly used for jointly judging the angle between the camera visual axis and the sun vector, the satellite shadow mark, the satellite working mode, the control mode and the like, and performing instruction control on the remote sensing camera when all the conditions are met.

[0056] The optical remote sensing camera module is used for executing the imaging end instruction to realize the protection of the camera detector.

[0057] The transmission module is used for data transmission, including the transmission of the angle between the camera visual axis and the sun vector and the satellite shadow mark between the integrated electronic computer module and the orbit control computer module, and the transmission of the imaging end instruction between the integrated electronic computer module and the optical remote sensing camera module.

[0058] The optical remote sensing camera module comprises any one or more of the following modules: a space visible light camera module, an infrared camera module or a hyperspectral camera module.

[0059] Specifically, in the system module, the integrated electronic computer module periodically receives the angle between the camera visual axis and the sun vector and the satellite shadow mark sent by the orbit control computer module through the transmission module, combines the satellite working mode and the control mode, and the integrated electronic computer module performs autonomous judgment, and sends the remote sensing camera imaging end instruction autonomously through the transmission module after meeting certain conditions.

[0060] The integrated electronic computer can be other computers with data management function, the transmission module comprises a serial data bus, the serial data bus can be a data communication bus for executing any standard protocol such as 1553B or CAN, and the bus form can be configured as single or double or multiple redundant buses.

[0061] The application also introduces an autonomous sun avoidance method of a low-orbit optical remote sensing satellite, as shown in the formula (1). Figure 2 The method comprises the following steps:

[0062] Step S1: The orbit control computer calculates the angle between the camera visual axis and the sun vector according to the satellite position information and the attitude information in real time.

[0063] The calculation formula of the angle between the camera visual axis and the sun vector θ is as follows:

[0064] T=t / 86400 / 36525

[0065] e sun= 0.01670862 - 0.00004204 x T

[0066] i sun = 23.439291 - 0.01300417 x T

[0067] ω sun = 282.937347 + 0.32256206 x T

[0068] M sun = 357.5291 + 35999.0502888889 x T

[0069] u sun = ω sun + M sun + 2e sun sin M sun + 1.25e sun 2 sin(2M sun )

[0070]

[0071]

[0072]

[0073] In the formula, T is a Julian century number, t is a second count of the current time from Beijing time 8:00:00 on January 1, 2000, e sun is an orbital eccentricity of the sun, i sun is an orbital inclination of the sun, ω sun is an orbital argument of perihelion of the sun, M sun is an orbital mean anomaly of the sun, u sun is an orbital amplitude of the sun, is a projection of the sun position in an inertial system, P b is a projection of a star-sun pointing vector in a body system, is a projection of a current position of a satellite in an inertial system, is an attitude angle (1-2-3 rotation sequence) of a body system of the satellite relative to the inertial system at the current time of the satellite, l b is a projection of a camera visual axis in the body system of the satellite.

[0074] Step S2: The attitude and orbit control computer calculates a satellite shadow mark according to satellite position information, relative positions of the earth and the sun;

[0075] The calculation formula of the satellite shadow mark F sun is as follows:

[0076]

[0077]

[0078]

[0079] In the formula, ψ is the angle between Earth, the satellite, and the sun, ψ0 is the angle at which the satellite is tangent to the Earth's adjacent edge, and R... e The radius is the Earth's radius.

[0080] Step S3: The computer determines whether the angle θ between the camera's line of sight and the solar vector is less than a set threshold. The threshold can be modified on the ground. If it is "yes", proceed to step S4; if it is "no", continue to step S3.

[0081] Step S4: Use a computer to determine the satellite shadow marker F sun Is it a lit area? If it is "yes", proceed to step S5; if it is "no", return to step S3.

[0082] Step S5: The integrated computer determines whether the satellite's working mode is non-spectral calibration or non-solar radiation calibration. If it is "yes", proceed to step S6; if it is "no", return to step S3.

[0083] Step S6: The integrated electronic computer determines whether the control mode is task mode. If it is "yes", proceed to step S7; if it is "no", return to step S3.

[0084] Step S7: When the integrated computer determines that all conditions S3 to S6 are satisfied as "yes", the integrated computer autonomously sends a remote sensing camera imaging end command through serial data thread control.

[0085] The present invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of an autonomous solar avoidance method for low-orbit optical remote sensing satellites.

[0086] Those skilled in the art will understand that, besides implementing the system and its various devices, modules, and units provided by this invention in the form of purely computer-readable program code, the same functions can be achieved entirely through logical programming of the method steps, making the system and its various devices, modules, and units of this invention function in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers. Therefore, the system and its various devices, modules, and units provided by this invention can be considered as a hardware component, and the devices, modules, and units included therein for implementing various functions can also be considered as structures within the hardware component; alternatively, the devices, modules, and units for implementing various functions can be considered as both software modules implementing the method and structures within the hardware component.

[0087] The specific embodiments of the present application are described above. It needs to be understood that the present application is not limited to the specific embodiments described above, and various changes or modifications can be made by those skilled in the art within the scope of the claims, which does not affect the essential content of the present application. The embodiments of the present application and the features in the embodiments can be combined with each other at will without conflict.

Claims

1. An autonomous sun-avoidance method for a low-orbit optical remote sensing satellite, characterized in that, Comprising: Step S1: The attitude and orbit control computer calculates the angle between the camera visual axis and the sun vector according to the satellite position information and attitude information in real time; Step S2: The attitude and orbit control computer calculates the satellite shadow mark according to the satellite position information and the relative position relationship between the Earth and the sun; Step S3: The electronic computer judges whether the angle between the camera's visual axis and the sun vector is less than a set threshold value. If the answer is "Yes", step S4 is executed. If the answer is "No", step S3 is continued. Step S4: The electronic computer judges whether the angle between the camera's visual axis and the sun vector is less than a set threshold value. If the answer is "Yes", step S5 is executed. If the answer is "No", step S3 is continued. Step S4: The electronic computer judges the satellite shadow mark whether it is an illumination area, if "Yes", step S5 is executed, if "No", step S3 is returned; Step S5: The integrated electronic computer judges whether the satellite working mode is non-spectral calibration or non-solar radiation calibration, if "yes", step S6 is executed, if "no", step S3 is returned; Step S6: The integrated electronic computer judges whether the control mode is the task mode, if "yes", step S7 is executed, if "no", step S3 is returned; Step S7: When the integrated electronic computer judges that the conditions of S3 to S6 are all "yes", the integrated electronic computer sends the imaging end instruction through the serial data bus.

2. The autonomous sun avoidance method of the low-orbit optical remote sensing satellite according to claim 1, characterized in that, Camera boresight angle with respect to the sun vector The formula for calculating the angle is as follows: wherein is the Julian century number, is the current time in seconds since 8:00:00 on January 1, 2000 in Beijing time, is the eccentricity of the sun's orbit, is the inclination of the sun's orbit, is the argument of perihelion of the sun's orbit, is the mean anomaly of the sun's orbit, is the argument of latitude of the sun's orbit, is the projection of the sun's position in the inertial system, is the projection of the star-sun direction vector in the body system, is the projection of the satellite's current position in the inertial system, is the satellite's current attitude angle in the body system relative to the inertial system, using the 1-2-3 rotation sequence, is the projection of the camera boresight in the satellite's body system.

3. The autonomous sun avoidance method of the low-orbit optical remote sensing satellite according to claim 2, characterized in that, Satellite shadow flag The calculation formula is as follows: wherein is the geostationary-satellite-earth angle, is the satellite cut earth limb angle, is the earth radius.

4. The autonomous sun-avoidance method of low-earth optical remote sensing satellites of claim 1, wherein, The step S3 camera boresight angle with the sun vector Threshold, ground-based injection modification.

5. A system for implementing the autonomous sun-avoidance method of the low- orbit optical remote-sensing satellite of claim 1, characterized in that, Comprising: An attitude and orbit control computer module for calculating the angle between the camera visual axis and the sun vector and the satellite shadow mark; An integrated electronic computer module for multi-condition joint judgment, and for instructing the remote sensing camera when the conditions are all met; the multi-condition joint judgment includes joint judgment of any one or more of the following conditions: the angle between the camera visual axis and the sun vector, the satellite shadow mark, the satellite working mode, and the control mode; A transmission module for data transmission between modules; An optical remote sensing camera module for executing the imaging end instruction.

6. The system of claim 5, wherein, The optical remote sensing camera module includes any one or more of the following modules: a space visible light camera module, an infrared camera module, and a hyperspectral camera module.

7. The system of claim 5, wherein, The integrated electronic computer module includes any computer with data management function.

8. The system of claim 5, wherein, The transmission module includes a serial data bus, and the data transmission path between modules includes: the attitude and orbit control computer module transmitting the angle between the camera visual axis and the sun vector and the satellite shadow mark to the integrated electronic computer module, and the integrated electronic computer module transmitting the imaging end instruction to the optical remote sensing camera module.

9. The system of claim 8, wherein, The serial data bus is configured in the form of single or double or multiple redundant bus.

10. A computer readable storage medium storing a computer program, characterized in that, The computer program is executed by the processor to realize the steps of the autonomous sun avoidance method of the low-orbit optical remote sensing satellite according to any one of claims 1 to 4.

Images