Satellite yaw attitude regulation and control method based on sun position

Abstract

A satellite yaw attitude regulation and control method based on a sun position comprehensively considers an orbit inclination angle, attitude pointing, a sun irradiation condition, a sunlight avoidance condition and the like, and comprises the following steps: firstly, confirming satellite task information, calculating nominal rolling attitude information and nominal pitching attitude information corresponding to each moment, and calculating a yaw attitude of the satellite; and the obtained attitude information is utilized to calculate the included angle projection at each moment, so that the optimization of the cabin plate illumination condition of the geosynchronous orbit satellite is realized through the average value of the included angle projection, the heat dissipation efficiency is improved, equivalently, the burden and weight of a thermal control system are reduced under the same condition, and the improvement of the comprehensive capability of the whole satellite is facilitated.

Description

Technical Field

[0001] The invention relates to a satellite yaw attitude control method based on the sun's position, belonging to the field of satellite attitude control. Background Art

[0002] Geosynchronous satellites equipped with cameras require a favorable and stable thermal environment during operation. However, due to the obliquity of the ecliptic and the Earth's rotation, the sun's orientation toward the satellite is constantly changing, causing the satellite's heat dissipation efficiency to vary over time. Typically, near the winter and summer solstices, the angle between the normals of the north and south panels of a solar-powered satellite is small, reducing the efficiency of the satellite's heat dissipation, which primarily relies on the panels as the heat dissipation surface. To ensure a stable thermal environment, the satellite must be designed with a larger heat dissipation area or higher heat dissipation efficiency, which increases the burden and weight of the thermal control system.

[0003] One approach to reducing thermal management burden and weight is to adjust the satellite's attitude so that the angle between the sun and the north and south panels is smaller during periods of poor sunlight (e.g., during the summer and winter solstices). However, the missions of satellites equipped with cameras typically require the cameras to be pointed at a fixed area on the ground. Under this constraint, arbitrary roll and pitch adjustments are not possible. Therefore, determining the yaw attitude setting that both meets mission requirements and maximizes heat dissipation efficiency becomes crucial. Summary of the Invention

[0004] The technical problem solved by the present invention is: in view of the problem that there is no universal method to improve the heat dissipation efficiency under the constraints of setting the roll and pitch attitudes on demand in the current existing technology, a satellite yaw attitude control method based on the sun position is proposed.

[0005] The present invention solves the above technical problems by the following technical solutions:

[0006] A method for controlling a satellite's yaw attitude based on the position of the sun, comprising:

[0007] Obtain satellite mission period information, pointing area and satellite orbit position;

[0008] Extract all satellite sampling moments based on satellite mission period information, and calculate the nominal roll attitude information and nominal pitch attitude information of the satellite at each sampling moment using the pointing area and satellite orbital position;

[0009] The nominal roll attitude information, nominal pitch attitude information and 0° yaw angle at each sampling moment are calculated as the reference state of the satellite. During the satellite mission period, the angle projection between the sun and the satellite's north and south panels at each sampling point under the reference state is calculated.

[0010] All angle projections are weighted averaged, and manual decision making is performed based on the weighted average result to obtain the average angle value.

[0011] The time period information of the satellite mission includes the mission start time T0 and the mission end time T1;

[0012] The pointing area is the center coordinate of the area under the ground fixed system [x g ,y g ,z g ] T ;

[0013] The satellite orbital position is the six satellite orbital numbers in the J2000 inertial system, including the semi-major axis o a , eccentricity o e , inclination angle o i , right ascension of ascending node o Ω , the argument of perigee o w , so close to the corner o f ;

[0014] Among them, x g ,y g ,z g It is the three-axis position data of the regional center coordinates under the ground-fixed system.

[0015] The calculation method of the nominal roll attitude information and nominal pitch attitude information of the satellite at each sampling moment is:

[0016] Preset the number of discrete points N, discretize the satellite mission period, and obtain the sampling time t i

[0017] Calculate the coordinates of the satellite in the ground fixed system corresponding to each sampling moment [α i ,β i ,γ i ] T , and calculate the coordinates of the center vector of the satellite's pointing area in the southeast coordinate system;

[0018] The nominal roll attitude information and nominal pitch attitude information at each sampling moment are calculated according to the coordinates of the center vector of the pointing area in the southeast coordinate system.

[0019] Discretize the satellite operation time to obtain the sampling time t i The method is:

[0020]

[0021] t i =T0+i×τ

[0022] Where (i=0,1,…,N), τ is the step size of the task period discretization, t i is each sampling moment.

[0023] Calculate the coordinates of the satellite in the ground fixed system corresponding to each sampling moment [α i ,β i ,γ i ] T The method for calculating the coordinates of the center vector of the satellite pointing area in the southeast coordinate system is:

[0024] V i f =||[x g -α i ,y g -β i ,z g -γ i ] T ||

[0025]

[0026] Where V i ESD ,V i f They represent the coordinates of the vector pointing to the target area from the satellite in the southeast coordinate system and the ground-fixed system respectively. || || represents the normalization operation. It represents the transformation matrix from the earth-fixed system to the southeast coordinate system, and σ, λ, and ρ are the coordinate values ​​of the vector pointing from the satellite to the target area in the three axes of the southeast coordinate system.

[0027] Calculate the nominal rolling attitude information at each sampling time based on the coordinates of the center vector of the pointing area in the southeast coordinate system Nominal pitch attitude information θ i The method is:

[0028]

[0029] θ i =arcsin(σ i )

[0030] Where, σ i ,λ i ,ρ i For each sampling time t i The corresponding coordinates.

[0031] The calculation method for the projection angle between the sun and the north and south panels of the satellite at each sampling point is:

[0032] Obtain the coordinates of the sun vector corresponding to each sampling point in the earth-fixed system and perform normalization processing. Use the normalized coordinates to calculate the coordinates of the sun vector in the southeast coordinate system.

[0033] Calculate the projection angle between the vector coordinates of the sun in the nominal local system and the north and south panels of the satellite at each sampling point.

[0034] The method for calculating the sun vector coordinates in the southeast coordinate system using the normalized coordinates is:

[0035] Get each t i The coordinates of the sun vector corresponding to the time in the earth-fixed system And calculate the coordinates of the sun vector in the southeast coordinate system

[0036]

[0037] The method for calculating the projection angle between the vector coordinates of the sun in the nominal local system and the north and south panels of the satellite at each sampling point is:

[0038] Calculate the transformation matrix from the southeast system to the nominal local system based on the satellite reference state, use the obtained change matrix to calculate the vector coordinates of the sun in the nominal local system, and calculate the angle projection based on the obtained vector coordinates:

[0039]

[0040] Where, represents the vector coordinate of the sun in the nominal local system, represents the transformation matrix from the southeast system to the nominal local system, ω i Represents the angular projection between the sun vector and the north and south panels of the satellite.

[0041] The manual decision is to set a decision coefficient according to the satellite mission requirements, and use the decision coefficient to process the weighted average result to obtain the average angle value. As the expectation of yaw attitude adjustment for the current mission period.

[0042] The advantages of the present invention compared with the prior art are:

[0043] The present invention provides a satellite yaw attitude control method based on the sun's position. The method optimizes the yaw attitude according to factors such as the satellite orbit, pointing area, and sun angle, comprehensively considering orbital inclination, attitude pointing, solar illumination conditions, and sunlight avoidance conditions. The method can calculate the nominal roll attitude information and nominal pitch attitude information corresponding to each moment based on given satellite mission information, and use the obtained attitude information to calculate the angle projection at each moment. Thus, the cabin panel illumination conditions of the geosynchronous orbit satellite are optimized by taking the average value of the angle projection to improve the heat dissipation efficiency. This is equivalent to reducing the burden and weight of the thermal control system under the same conditions, which is conducive to improving the comprehensive capabilities of the entire satellite. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 A flowchart for implementing the yaw attitude adjustment strategy provided by the invention;

[0045] Figure 2 Schematic diagram of the yaw attitude adjustment results provided by the invention. DETAILED DESCRIPTION

[0046] A satellite yaw attitude control method based on the sun's position comprehensively considers orbital inclination, attitude pointing, solar illumination conditions, and sunlight avoidance conditions. By first confirming satellite mission information, the nominal roll attitude information and nominal pitch attitude information corresponding to each moment are calculated, and the obtained attitude information is used to calculate the angle projection at each moment. Thus, the cabin illumination conditions of the geosynchronous orbit satellite are optimized by taking the average value of the angle projection, thereby improving the heat dissipation efficiency. This is equivalent to reducing the burden and weight of the thermal control system under the same conditions, which is beneficial to improving the comprehensive capabilities of the entire satellite.

[0047] The satellite yaw attitude control method based on the sun position includes the following steps:

[0048] Obtain satellite mission period information, pointing area and satellite orbit position;

[0049] Extract all satellite sampling moments based on satellite mission period information, and calculate the nominal roll attitude information and nominal pitch attitude information of the satellite at each sampling moment using the pointing area and satellite orbital position;

[0050] The nominal roll attitude information, nominal pitch attitude information and 0° yaw angle at each sampling time are calculated as the satellite's reference state. During the satellite mission period, the projection angle between the sun and the satellite's north and south panels at each sampling point is calculated.

[0051] All angle projections are weighted averaged, and manual decision making is performed based on the weighted average result to obtain the average angle value.

[0052] The satellite mission period information includes the mission start time T0 and the mission end time T1;

[0053] The pointing area is the center coordinate of the area under the ground fixed system [x g ,y g ,z g ] T ;

[0054] The satellite orbital position is the six satellite orbital numbers in the J2000 inertial system, including the semi-major axis o a , eccentricity o e , inclination angle o i , right ascension of ascending node o Ω , the argument of perigee o w , so close to the corner o f ;

[0055] Among them, x g ,yg ,z g It is the three-axis position data of the regional center coordinates under the ground-fixed system.

[0056] The calculation method of the nominal roll attitude information and nominal pitch attitude information of the satellite at each sampling moment is:

[0057] Preset the number of discrete points N, discretize the satellite mission period, and obtain the sampling time t i

[0058] Calculate the coordinates of the satellite in the ground fixed system corresponding to each sampling moment [α i ,β i ,γ i ] T , and calculate the coordinates of the center vector of the satellite's pointing area in the southeast coordinate system;

[0059] The nominal roll attitude information and nominal pitch attitude information at each sampling moment are calculated according to the coordinates of the center vector of the pointing area in the southeast coordinate system.

[0060] The calculation method for the projection angle between the sun and the north and south panels of the satellite at each sampling point is:

[0061] Obtain the coordinates of the sun vector corresponding to each sampling point in the earth-fixed system and perform normalization processing. Use the normalized coordinates to calculate the coordinates of the sun vector in the southeast coordinate system.

[0062] Calculate the angle projection between the vector coordinates of the sun in the nominal local system and the north and south panels of the satellite at each sampling point in the reference state.

[0063] The calculation method of the angle projection is as follows: calculate the transformation matrix from the southeast system to the nominal local system based on the satellite reference state, use the obtained change matrix to calculate the vector coordinates of the sun in the nominal local system, and calculate the angle projection based on the obtained vector coordinates:

[0064] Manual decision-making is to set the decision coefficient according to the satellite mission requirements, and use the decision coefficient to process the weighted average result to obtain the average angle value. As the expectation of yaw attitude adjustment for the current mission period.

[0065] The following is further described in conjunction with the accompanying drawings and preferred embodiments:

[0066] In the current embodiment, if Figure 1 The specific implementation steps are as follows:

[0067] 4.1 Determine the input conditions for the task, including:

[0068] Focus on the task period: specifically the task start time T0 and the task end time T1

[0069] Mission pointing area: Specifically, the regional center coordinates [x g ,y g ,z g ] T

[0070] Satellite orbital position: Specifically, the six numbers in the J2000 inertial system can be used: semi-major axis o a , eccentricity o e , inclination angle o i , right ascension of ascending node o Ω , the argument of perigee o w , so close to the corner o f

[0071] 4.2 Calculating the satellite's roll and pitch attitude includes the following steps:

[0072] 4.2.1 Given the number of discrete points N, discretize time and obtain each sampling moment t i (i=0,1,…,N)

[0073]

[0074] t i =T0+i×τ

[0075] 4.2.2 Calculate each t i The coordinates of the satellite in the ground-fixed system corresponding to the time [α i ,β i ,γ i ] T , further calculate the coordinate representation of the vector pointing to the center of the mission area in the southeast coordinate system

[0076] V i f =||[x g -α i ,y g -β i ,z g -γ i ] T ||

[0077]

[0078] Here V i ESD ,V i fThe coordinates of the vector pointing from the satellite to the target area are expressed in the southeast coordinate system and the earth-fixed coordinate system, respectively. || || represents the normalization operation. The calculation method of the transformation matrix from the earth-fixed system to the southeast coordinate system is common knowledge in the field and will not be repeated here.

[0079] 4.2.3 Calculate each t i The nominal roll and pitch attitude of the satellite corresponding to the moment, specifically using the 123 sequence

[0080]

[0081] θ i =arcsin(σ i )

[0082] θ i The nominal roll and pitch attitudes at each sampling moment

[0083] 4.3 Calculate the projection angle between the sun and the satellite panel at each sampling moment, specifically including:

[0084] 4.3.1 Get each t i The coordinate representation of the sun vector corresponding to the moment in the earth-fixed system (after normalization), and then calculate the solar vector coordinates in the southeast system

[0085]

[0086] It is the solar vector coordinate representation in the southeast system. Its calculation method is common knowledge in the field and will not be repeated here.

[0087] 4.3.2 Calculate each t i The vector coordinate angle projection of the sun in the nominal system at this moment

[0088]

[0089] here represents the vector coordinate of the sun in the nominal local system, Represents the transformation matrix from the southeast system to the nominal local system. ω i Represents the angular projection of the sun vector

[0090] 4.3.3 Calculate all angle projections ω i The weighted average of (i=0,1,2,...,N) is a typical example of directly calculating the arithmetic mean and making manual decisions (for example, multiplying the arithmetic mean by a coefficient of 0.9). The angle value obtained is That is, the expected yaw attitude adjustment during the current mission period.

[0091] like Figure 2 As shown, this is the result of the yaw attitude adjustment. Compared with before the adjustment, the angles between the satellite's north and south panels and the sun are reduced, which is conducive to providing a better thermal environment for the payload.

[0092] The yaw attitude adjustment strategy proposed in this embodiment can determine the optimal angle between the heat dissipation surfaces of the satellite's north and south panels and the sun during the mission period, thereby improving the heat dissipation efficiency. This is equivalent to reducing the burden and weight of the thermal control system under the same conditions, which is beneficial to improving the comprehensive capabilities of the entire satellite.

[0093] Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modification to the above embodiments made according to the technical essence of the present invention without departing from the content of the technical solution of the present invention is not limited to the present invention.

[0094] Equivalent changes and modifications all fall within the protection scope of the technical solution of the present invention.

[0095] The contents not described in detail in the specification of the present invention belong to the common knowledge of those skilled in the art.

Claims

1. A satellite yaw attitude control method based on the sun's position, characterized in that include: Obtain satellite mission period information, pointing area and satellite orbit position; Extract all satellite sampling moments based on satellite mission period information, and calculate the nominal roll attitude information and nominal pitch attitude information of the satellite at each sampling moment using the pointing area and satellite orbital position; The nominal roll attitude information, nominal pitch attitude information and 0° yaw angle at each sampling moment are calculated as the reference state of the satellite. During the satellite mission period, the angle projection between the sun and the satellite's north and south panels at each sampling point under the reference state is calculated. All angle projections are weighted averaged, and manual decision making is performed based on the weighted average result to obtain the average angle value.

2. The method for controlling satellite yaw attitude based on the sun's position according to claim 1, characterized in that: The time period information of the satellite mission includes the mission start time T0 and the mission end time T1; The pointing area is the center coordinate of the area under the ground fixed system [x g ,y g ,z g ] T ; The satellite orbital position is the six numbers of the satellite orbit in the J2000 inertial system, including the semi-major axis o a , eccentricity o e , inclination angle o i , right ascension of ascending node o Ω , the argument of perigee o w , so close to the corner o f ; Among them, x g ,y g ,z g It is the three-axis position data of the regional center coordinates under the ground-fixed system.

3. The method for controlling satellite yaw attitude based on the sun's position according to claim 1, characterized in that: The calculation method of the nominal roll attitude information and nominal pitch attitude information of the satellite at each sampling moment is: Preset the number of discrete points N, discretize the satellite mission period, and obtain the sampling time t i Calculate the coordinates of the satellite in the ground fixed system corresponding to each sampling moment [α i ,β i ,γ i ] T , and calculate the coordinates of the center vector of the satellite's pointing area in the southeast coordinate system; The nominal roll attitude information and nominal pitch attitude information at each sampling moment are calculated according to the coordinates of the center vector of the pointing area in the southeast coordinate system.

4. The method for controlling satellite yaw attitude based on the sun's position according to claim 3, characterized in that: Discretize the satellite operation time to obtain each sampling time t i The method is: t i =T0+i×τ Where (i=0,1,…,N), τ is the step size of the task period discretization, t i is each sampling moment.

5. The method for controlling satellite yaw attitude based on the sun's position according to claim 4, characterized in that: Calculate the coordinates of the satellite in the ground fixed system corresponding to each sampling moment [α i ,β i ,γ i ] T , and the method for calculating the coordinates of the satellite pointing area center vector in the southeast coordinate system is: Where, They represent the coordinates of the vector pointing to the target area from the satellite in the southeast coordinate system and the ground-fixed system respectively. |||| represents the normalization operation. It represents the transformation matrix from the earth-fixed system to the southeast coordinate system, and σ, λ, and ρ are the coordinate values ​​of the vector pointing from the satellite to the target area in the three axes of the southeast coordinate system.

6. The method for controlling satellite yaw attitude based on the sun's position according to claim 5, characterized in that: Calculate the nominal rolling attitude information at each sampling time based on the coordinates of the center vector of the pointing area in the southeast coordinate system Nominal pitch attitude information θ i The method is: i i =arcsin(σ i ) Where, σ i ,λ i ,ρ i For each sampling time t i The corresponding coordinates.

7. The method for controlling satellite yaw attitude based on the sun's position according to claim 6, characterized in that: The calculation method for the projection angle between the sun and the north and south panels of the satellite at each sampling point is: Obtain the coordinates of the sun vector corresponding to each sampling point in the earth-fixed system and perform normalization processing. Use the normalized coordinates to calculate the coordinates of the sun vector in the southeast coordinate system. Calculate the projection angle between the vector coordinates of the sun in the nominal local system and the north and south panels of the satellite at each sampling point.

8. The method for controlling satellite yaw attitude based on the sun's position according to claim 7, characterized in that: The method for calculating the sun vector coordinates in the southeast coordinate system using the normalized coordinates is: Get each t i The coordinates of the sun vector corresponding to the time in the earth-fixed system And calculate the coordinates of the sun vector in the southeast coordinate system 9. The method for controlling satellite yaw attitude based on the sun's position according to claim 7, characterized in that: The method for calculating the projection angle between the vector coordinates of the sun in the nominal local system and the north and south panels of the satellite at each sampling point is: Calculate the transformation matrix from the southeast system to the nominal local system based on the satellite reference state, use the obtained change matrix to calculate the vector coordinates of the sun in the nominal local system, and calculate the angle projection based on the obtained vector coordinates: Where, represents the vector coordinate of the sun in the nominal local system, represents the transformation matrix from the southeast system to the nominal local system, ω i Represents the angular projection between the sun vector and the north and south panels of the satellite.

10. The method for controlling satellite yaw attitude based on the sun's position according to claim 7, characterized in that: The manual decision is to set a decision coefficient according to the satellite mission requirements, and use the decision coefficient to process the weighted average result to obtain the average angle value. As the expectation of yaw attitude adjustment for the current mission period.

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