Method for reducing air resistance by laying flat a solar panel in a shadow area

Abstract

The application provides a method for reducing air resistance by keeping a sailboard flat in an earth shadow area, which can be applied to a satellite with a solar wing continuously tracking the sun to obtain energy, in particular to a super low orbit satellite pointing to the earth with large air resistance. By recording or calculating the earth shadow area in a current orbit in real time, the method makes the sailboard quickly capture a sailboard rotation angle position with minimum windward surface when entering the earth shadow area, then keeps the sailboard flat, and calculates the latest start-up point in the earth shadow area, so that the sailboard starts to rotate from the start-up point, and the sailboard can face the sun when the satellite enters an illumination area. The method can reduce the air resistance brought by the satellite to the orbit decay, and save fuel without affecting the energy of the satellite.

Description

TECHNICAL FIELD

[0001] The present application relates to a method for reducing air resistance by laying solar panels in the earth shadow area, which can be applied to satellites with solar wings continuously tracking the sun to obtain energy, especially super low orbit satellites with large air resistance, and belongs to the field of satellite control. BACKGROUND

[0002] The configuration of the solar panel is relatively large, which makes the satellite have a large windward area while better accepting sunlight. For satellites in orbits with an earth shadow area, the solar panel in the earth shadow area cannot provide energy for the satellite, but instead continues to bring large air resistance to the satellite, especially for super low orbit satellites with large air density. Therefore, a method for laying solar panels in the earth shadow area is needed to reduce the air resistance caused by the solar panel without affecting the energy of the satellite, thereby reducing the orbit decay caused by the air resistance to the satellite and achieving the purpose of saving fuel. The current method for reducing air resistance caused by solar panels is to use a solar wing fixed laying method, which has the disadvantage of low solar energy utilization rate. In order to ensure the energy of the satellite, a larger solar panel and a heavier power system need to be configured, which increases the weight of the satellite and makes the solar panel more flexible, affecting the stable control of the satellite. SUMMARY

[0003] The technical problem of the present application is to overcome the shortcomings of the prior art and provide a method for reducing air resistance by laying solar panels in the earth shadow area, which realizes the purpose of reducing air resistance in the earth shadow area by laying the solar panel in the earth shadow area at the position of the solar panel corner with the smallest windward area.

[0004] The technical solution of the present application is: in one aspect, a method for reducing air resistance by laying solar panels in the earth shadow area is provided, which comprises the following steps:

[0005] calculating the time T1 required for the solar panel to turn from the reference corner PA at the time of entering the earth shadow area to the reference corner PO corresponding to the laying state of the solar panel according to the last orbit record;

[0006] calculating the reference corner PC of the solar panel corresponding to the control starting point of the solar panel before the earth shadow area;

[0007] calculating the time required for the solar panel to turn from the control starting point PC to the reference corner PB at the time of entering the light area;

[0008] real-time determining the current reference corner of the solar panel, and when the current reference corner of the solar panel is equal to the reference corner PA of the solar panel at the time of entering the earth shadow area recorded in the last orbit period, sending a solar panel driving instruction to make the solar panel rotate at the comprehensive angular velocity ω1 of the solar panel for a time T1 to reach the reference corner PO of the solar panel corresponding to the laying state; when the reference corner of the solar panel is equal to the reference corner PC of the solar panel at the control starting point, sending a solar panel driving instruction to make the solar panel rotate at the comprehensive angular velocity ω1 of the solar panel for a time T3;

[0009] When the satellite enters the Earth's shadow, update the solar panel reference angle PA at the moment the satellite enters the Earth's shadow; when the satellite exits the Earth's shadow, update the solar panel reference angle PB at the moment the satellite enters the illuminated area.

[0010] Preferably, the reference angle of the solar panel is the theoretical angle between the projection of the solar panel normal onto the orbital plane and the projection of the sun onto the orbital plane; when the angle between the solar panel normal and the sun vector is the smallest, the solar panel receives the best solar radiation.

[0011] The reference angle of the solar panel changes continuously with the movement of the sun around the satellite, and its range is 0 to 360°.

[0012] Preferably, the rate of change of the solar panel reference angle during normal solar tracking is the orbital angular velocity ω0. For low Earth orbit satellites, the orbital angular velocity ω0 is between 0.06° / s and 0.07° / s.

[0013] Preferably, T1 is calculated as follows:

[0014]

[0015] Where: mod represents the remainder of Kstate*(PO-PA) divided by 360; Kstate is the satellite's flight state, Kstate=1 when the satellite is flying forward and Kstate=-1 when the satellite is flying backward.

[0016] Preferably, the calculation method for the reference angle PC of the solar panel corresponding to the starting control point of the solar panel before the satellite emerges from the Earth's shadow is as follows:

[0017] PC = mod(PB - Kstate * T3 * ω) f ,360)

[0018] Where mod represents PB-Kstate*T3*ω f Modulo 360; Kstate represents the satellite's flight state, Kstate = 1 when the satellite is flying forward, and Kstate = -1 when the satellite is flying backward; ω f For the specified windshield driving angular velocity, ω f >2ω0, the value is positive.

[0019] Preferably, T3 is calculated as follows:

[0020]

[0021] In the above formula, mod represents the remainder of Kstate*(PB-PA) divided by 360; Kstate is the satellite's flight state, Kstate = 1 when the satellite is flying forward and Kstate = -1 when the satellite is flying backward; ω f For the specified windshield driving angular velocity, ω f> 2ω0.

[0022] Preferably, the comprehensive angular velocity of the sailboard ω1 = Kstate * ω f , wherein:

[0023] Kstate is the flight state of the satellite, Kstate = 1 when the satellite is flying forward, and Kstate = -1 when the satellite is flying backward; ω f is the specified angular velocity of the sailboard drive, ω f > 2ω0.

[0024] Preferably, ω f is the absolute value of the specified angular velocity in the process of rotating the sailboard reference angle PB from the control point PC of the sailboard to the moment of entering the light area.

[0025] In a second aspect, a terminal device is provided, comprising:

[0026] a memory for storing instructions executed by at least one processor;

[0027] a processor for executing instructions stored in the memory to implement the method for reducing air resistance by placing the sailboard flat in the earth shadow area.

[0028] In a third aspect, a computer readable storage medium is provided, the computer readable storage medium stores computer instructions, when the computer instructions run on a computer, the computer instructions make the computer execute the method for reducing air resistance by placing the sailboard flat in the earth shadow area.

[0029] Compared with the prior art, the present application has the following advantages:

[0030] (1) In the earth shadow area, the sailboard windward surface is minimized by adjusting the satellite attitude, thereby reducing the orbit decay caused by the atmospheric resistance in the earth shadow area, saving fuel while not affecting the satellite energy;

[0031] (2) The control strategy is purely algorithmic, without the need for any additional hardware facilities, and has little effect on the stable control of the satellite;

[0032] (3) It has good portability and is suitable for satellites with shadow areas. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 is a flowchart of the method for placing the sailboard flat in the earth shadow area of the present application;

[0034] Figure 2 is a schematic diagram of the control strategy for placing the sailboard flat when the satellite is flying forward of the present application

[0035] Figure 3 is a schematic diagram of the control strategy for placing the sailboard flat when the satellite is flying backward of the present application. DETAILED DESCRIPTION

[0036] The present application provides a method for reducing air resistance of a solar panel in a penumbra area, which reduces air resistance in the penumbra area by placing the solar panel in the penumbra area at a solar panel turning angle with the minimum windward area.

[0037] To achieve the above-mentioned technical effects, the present application is implemented by the following technical process: Figure 1

[0038] Record the solar panel reference turning angle PA at the moment of entering the penumbra area and the solar panel reference turning angle PB at the moment of entering the sunlight area in each orbit as a period.

[0039] Firstly, calculate the time T1 required for driving the solar panel from the solar panel reference turning angle PA at the moment of entering the penumbra area to the solar panel reference turning angle PO corresponding to the minimum windward area of the solar panel.

[0040] The solar panel reference angle means the theoretical angle between the projection of the solar panel normal in the orbit plane and the projection of the sun in the orbit plane.

[0041] The solar panel reference angle is the theoretical angle between the projection of the solar panel normal in the orbit plane and the projection of the sun in the orbit plane. When the actual turning angle of the solar panel is equal to the solar panel reference angle, it can be considered that the angle between the solar panel normal and the sun vector is the smallest, and the solar panel is best illuminated by the sun. The solar panel reference angle continuously changes with the movement of the sun around the satellite, and its change range is 0-360°. When the satellite is normally tracking the sun, the change rate of the solar panel reference angle is the orbit angular velocity ω0. When the satellite is flying forward, the satellite flight state Kstate=1, and when the satellite is flying backward, the satellite flight state Kstate=-1. Therefore, the change rate of the solar panel reference angle is Kstate*ω0. For a low earth orbit satellite, the orbit angular velocity ω0 is between 0.06 and 0.07° / s.

[0042] The state of the solar panel with the minimum windward area is the flat state, and the solar panel reference angle corresponding to the flat state is PO.

[0043] The flat state of the solar panel has two types. One type is that the satellite is between the earth and the sun, and the satellite is in the sunlight area and the solar panel is illuminated. The other type is that the earth is between the satellite and the sun, and the satellite is in the penumbra area and the solar panel is not illuminated. The present application selects the flat state of the solar panel when the satellite is in the penumbra area.

[0044] Let the orbit angular velocity be ω0, and the specified solar panel driving angular velocity be ω f The time T1 required for driving the solar panel from the solar panel reference turning angle PA at the current moment to PO is:

[0045]

[0046] Wherein, mod represents the remainder of Kstate*(PO-PA) divided by 360. ​

[0047] Second step, calculate the sailboard reference angle PC corresponding to the pre-eclipse area sailboard control point. The pre-eclipse area sailboard control point refers to the time point when the sailboard starts to rotate from the flat state to the sailboard reference angle PB when entering the light area. It is the latest time point when the satellite controls the sailboard to rotate around the rotation axis to make the sailboard face the sun when entering the light area. It aims to make the sailboard remain in the flat state for as long as possible in the eclipse area, and at the same time, the sailboard captures the sailboard reference angle when entering the light area to obtain sunlight, thereby realizing the purpose of not affecting the whole satellite energy.

[0048] Specifically, the sailboard reference angle is in the interval [PA, PC], the sailboard is in the flat state with the smallest windward area, and the purpose of reducing atmospheric resistance in the eclipse area is realized, and the sunlight can be immediately obtained when entering the light area. The calculation method of PC is:

[0049] PC = mod(PB - Kstate * T3 * ω f , 360)

[0050] Third step, calculate the time T3 required for the sailboard to drive to the sailboard reference angle PB from the pre-eclipse area control point PC to enter the light area. The calculation method of T3 is:

[0051]

[0052] Fourth step, execute the sailboard flat control strategy: Real-time judge the current sailboard reference angle, when the current sailboard reference angle is equal to the sailboard reference angle PA recorded in the last orbit period when entering the eclipse, send the sailboard driving instruction, make the sailboard reach the flat angle PO with the comprehensive angular velocity ω1 for time T1; When the sailboard reference angle is equal to the sailboard control point PC, send the sailboard driving instruction, make the sailboard drive at the specified angular velocity for time T3; The mathematical expression of the sailboard comprehensive angular velocity ω1 is Kstate * ω f . The sailboard flat control strategy when the satellite is flying forward is shown in Figure 2 , and the sailboard flat control strategy when the satellite is flying backward is shown in Figure 3 .

[0053] Fifth step, real-time update the sailboard reference angle PA when entering the eclipse in the current period, and the sailboard reference angle PB when entering the light area from the eclipse, complete the control of the sailboard flat in the eclipse area to reduce the air resistance in one orbit period.

[0054] Second aspect, provide a terminal device, comprising:

[0055] Memory, used for storing instructions executed by at least one processor;

[0056] Processor, used for executing instructions stored in the memory, realizing the above-mentioned method of reducing air resistance by flat sailboard in eclipse area.

[0057] In a third aspect, a computer readable storage medium is provided, which stores computer instructions, when the computer instructions are run on a computer, the computer is caused to execute the method for reducing air resistance by flatly placing a solar panel in a shadow area.

[0058] Embodiment:

[0059] 1. Calculate the time T1 required for the solar panel to rotate from the reference angle PA at the time of entering the shadow to the reference angle PO of the minimum windward surface of the solar panel;

[0060] Taking a satellite flying vertically at an altitude of 407KM as an example, the corresponding orbital angular velocity is 0.0647° / s, the specified angular velocity when driving to the flat angle position is 0.6° / s, and the corresponding flat angle PO is 180° with respect to the flight direction of the satellite.

[0061]

[0062] 2. Calculate the time T3 required for the solar panel to capture the reference angle PB from the control point PC to the time of entering the light area;

[0063]

[0064] 3. Calculate the control point PC of the solar panel in the shadow area, so that the solar panel captures the reference angle at the time of entering the light, obtains solar light, and further realizes the purpose of not affecting the energy of the whole satellite, so that the reference angle is in the interval [PA, PC], the solar panel is in a 180° flat state, at this time the windward area of the solar panel is the smallest, and the purpose of reducing air resistance is achieved;

[0065] PC = PB-T3*0.6

[0066] 4. Execute the flat control strategy of the solar panel, and determine whether the reference angle of the solar panel reaches the reference angle PA at the time of entering the shadow recorded last time, if yes, execute the flat strategy, otherwise continue to determine;

[0067] 5. Real-time update the reference angle PA of the solar panel at the time of entering the shadow, and the reference angle PB of the solar panel at the time of entering the light from the shadow.

[0068] The contents not described in detail in the specification of the present application belong to the prior art known to those skilled in the art.

Claims

1. A method for reducing air resistance by placing a horizontally mounted solar panel in a ground shadow area, characterized in that... include: Within each orbital period: Using the reference angle PA of the sail at the moment of entering the shadow recorded in the previous orbit cycle, calculate the time T1 required for the sail to turn from PA to the flat state, corresponding to the reference angle PO of the sail; the flat state is the state when the windward area of ​​the sail is the smallest when it is in the shadow area. Calculate the reference angle PC of the windsurfing control point in the shadow area; Calculate the time required for the windsurf reference angle PC to rotate from the windsurf start point to the windsurf reference angle PB at the moment of entering the illuminated area; The system continuously determines the current reference angle of the solar panel, which is the theoretical angle between the projection of the solar panel normal onto the orbital plane and the projection of the sun onto the orbital plane. When the current reference angle is equal to the reference angle PA recorded at the moment of entering the Earth's shadow in the previous orbital cycle, a solar panel drive command is sent to make the solar panel rotate at a combined angular velocity ω1 for a time T1 to reach the reference angle PO corresponding to the horizontal position. When the reference angle is equal to the reference angle PC at the solar panel starting control point, a solar panel drive command is sent to make the solar panel rotate at a combined angular velocity ω1 for a time T3. When the satellite enters the shadow region, update the solar panel reference angle PA at the time the satellite enters the shadow region; when the satellite exits the shadow region, update the solar panel reference angle PB at the time the satellite enters the illuminated region.

2. The method for reducing air resistance by horizontally placing a windshield in a ground shadow area according to claim 1, characterized in that: The solar radiation conditions are best when the angle between the normal to the solar panel and the solar vector is the smallest. The reference angle of the solar panel changes continuously with the movement of the sun around the satellite, and its range is 0 to 360°.

3. The method for reducing air resistance by horizontally placing a windshield in a ground shadow area according to claim 2, characterized in that: The rate of change of the solar panel reference angle during normal solar tracking is the orbital angular velocity ω0. For low Earth orbit satellites, the orbital angular velocity ω0 is between 0.06° / s and 0.07° / s.

4. The method for reducing air resistance by horizontally placing a windshield in a ground shadow area according to claim 1, characterized in that: The method for calculating T1 is as follows: Where: mod represents the remainder of Kstate*(PO-PA) divided by 360; Kstate is the satellite's flight state, Kstate=1 when the satellite is flying forward and Kstate=-1 when the satellite is flying backward.

5. The method for reducing air resistance by horizontally placing a windshield in a ground shadow area according to claim 3, characterized in that: The calculation method for the reference rotation angle PC of the solar panel corresponding to the control point of the solar panel before the satellite leaves the Earth's shadow is as follows: PC=mod(PB-Kstate*T3*ω f ,360) Where mod represents PB-Kstate*T3*ω f Modulo 360; Kstate represents the satellite's flight state, Kstate = 1 when the satellite is flying forward, and Kstate = -1 when the satellite is flying backward; ω f For the specified windshield driving angular velocity, ω f >2ω0, the value is positive.

6. The method for reducing air resistance by horizontally placing a windshield in a ground shadow area according to claim 3, characterized in that: The calculation method for T3 is as follows: In the above formula, mod represents the remainder of Kstate*(PB-PA) divided by 360; Kstate is the satellite's flight state, Kstate = 1 when the satellite is flying forward and Kstate = -1 when the satellite is flying backward; ω f For the specified windshield driving angular velocity, ω f >2ω0.

7. The method for reducing air resistance by placing a horizontally mounted sail in a ground shadow area according to claim 1, characterized in that: The combined angular velocity of the windsurfing board ω1=Kstate*ω f ,in: Kstate represents the satellite's flight state; Kstate = 1 when the satellite is flying normally, and Kstate = -1 when the satellite is flying backwards; ω f For the specified magnitude of the windshield driving angular velocity, ω f >2ω0.

8. A method for reducing air resistance by horizontally placing a windshield in a ground shadow area according to any one of claims 5-7, characterized in that: ω f It is the absolute value of the specified angular velocity during the process of the windsurfing system rotating from its starting control point PC to the reference angle PB at the moment of entering the illuminated area.

9. A terminal device, characterized in that, include: Memory, used to store at least one instruction executed by a processor; A processor for executing instructions stored in memory to implement the method as described in any one of claims 1-8.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions that, when executed on a computer, cause the computer to perform the method as described in any one of claims 1-8.

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