Intersatellite link solar transit avoidance and reset tracking method and system

Abstract

Embodiments of the present invention disclose a method and system for solar transit avoidance and resetting tracking for intersatellite links. In one specific implementation, the method includes determining the orientation of a laser terminal; determining whether a solar transit has occurred based on the solar transit angle of a first laser terminal; if a solar transit has occurred, employing different avoidance strategies for different link types to direct the laser terminal away from direct sunlight; and after the solar transit has been avoided, directing the laser terminal to a specified angle to reestablish the intersatellite link. This implementation can be applied to solar transit avoidance and resetting tracking planning for intersatellite laser communications between satellites in a ground control center, and has the advantages of high algorithmic and planning efficiency and ease of engineering implementation.

Description

Technical Field

[0001] The present invention relates to the field of communication satellites, and more particularly to a method and system for avoiding and resetting solar eclipse tracking of an intersatellite link. Background Art

[0002] In large satellite constellations, laser communications between satellites in the same orbital plane or adjacent orbital planes are called intersatellite links (ISLs). A solar eclipse occurs when the direction of an ISL is approximately aligned with the direction of sunlight, causing electromagnetic interference from sunlight, impacting communication quality and shortening the life of laser equipment.

[0003] Satellite constellations typically adopt a Walker-type orbital configuration, which is a uniformly distributed constellation in space. A seed satellite is often selected as the basis for constellation construction according to specific configuration rules. All satellites in the constellation have the same orbital semi-major axis, eccentricity, inclination, and argument of perigee, but different right ascensions and mean anomalies of the ascending node.

[0004] For a constellation with M orbital planes and N satellites on each orbital plane, the number of orbital elements for each satellite is:

[0005] a m，n =a0

[0006] e m，n =e0

[0007] i m，n =i0

[0008] Ω m，n =Ω0+(m-1)ΔΩ

[0009] w m，n =w0

[0010] M m，n =M0+(n-1)ΔM in +(m-1)ΔM out

[0011] Where a, e, i, Ω, w, and M are the Kepler orbit elements of the satellite, m and n represent the nth satellite on the mth orbital plane respectively; 0 represents the seed satellite; ΔΩ is the right ascension deviation of the ascending node between adjacent orbital planes, ΔΩ = Ωs / M, Ωs is the right ascension spread of the ascending node, usually taken as 360°. For polar or near-polar orbital constellations with an orbital inclination close to 90°, the right ascension spread of the ascending node is usually taken as around 180°; M in is the phase difference between adjacent satellites in the same orbital plane, M in =360 / N;M outWhen the first satellite in an orbital plane passes through its ascending node, the phase angle of the satellite in the adjacent orbital plane to the east that has passed through the ascending node is also the difference in the initial phase angles between adjacent satellites. F is the phase factor.

[0012] During the operation of satellite constellations in space, influenced by the perturbations of Earth's gravitational field and the space environment, the actual orbital elements exhibit long-term, short-term, and long-period oscillations and drifts. As the distribution function of Earth's gravitational field changes with latitude and longitude, the satellite orbital plane undergoes a relatively slow precession in the geocentric inertial coordinate system under the influence of perturbations dominated by the J2 term of Earth's non-spherical gravity. Furthermore, as Earth orbits the Sun, the direction of sunlight striking Earth changes. At the summer solstice, the Sun's direct point is near the Tropic of Cancer, while at the winter solstice, it is near the Tropic of Capricorn. Therefore, the angle between the communication links between satellites in large constellations and the direction of sunlight changes over time. This is dependent on the constellation's current spatial configuration, the number of orbital elements, whether the satellite is in Earth's shadow, and the current relative position of the Sun and Earth, resulting in complex temporal and spatial relationships.

[0013] Therefore, for giant constellation satellite communications, if the sun and the optical receiving antenna for laser communications on the satellite are approximately in a straight line, certain avoidance measures must be taken to prevent the laser terminal from being directly exposed to sunlight during solar eclipse. Summary of the Invention

[0014] The object of the present invention is to provide a method and system for avoiding and resetting solar eclipse of an intersatellite link, so as to solve at least one of the problems existing in the prior art.

[0015] In order to achieve the above object, the present invention adopts the following technical solutions:

[0016] The first aspect of the present invention provides a method for avoiding and resetting solar eclipse in an intersatellite link, the method comprising:

[0017] Determine the direction of the laser terminal;

[0018] Determining whether a solar eclipse occurs according to the solar eclipse angle of the first laser terminal;

[0019] If a solar eclipse occurs, different avoidance strategies are adopted for different link types to keep the laser terminal away from direct sunlight;

[0020] After avoiding the solar eclipse, the laser terminal is moved to the specified angle to re-establish the intersatellite link.

[0021] Optionally, determining the direction of the laser terminal includes

[0022] Obtaining a first sun vector and a first intersatellite link vector in a first coordinate system;

[0023] A second sun vector and a second inter-satellite link vector in a second coordinate system are obtained by coordinate transformation of the first sun vector and the first inter-satellite link vector.

[0024] Optionally, the determining whether a solar eclipse occurs according to the solar eclipse angle of the first laser terminal includes:

[0025] Calculating a solar transit angle of the first laser terminal according to the second solar vector pitch angle and the second solar vector yaw angle, and the second intersatellite link vector pitch angle and the second intersatellite link vector yaw angle;

[0026] A solar eclipse occurs when the solar eclipse angle of the first laser terminal is less than or equal to the solar eclipse avoidance prediction value.

[0027] Optionally, the solar eclipse avoidance prediction value is in the range of 1-1.5°.

[0028] Optionally, adopting different avoidance strategies for different link types includes:

[0029] For the co-orbital link, a first avoidance yaw angle of the second intersatellite link vector yaw angle is calculated using the second intersatellite link vector yaw angle within the first avoidance time, the sign of the second solar vector yaw angle, and the rotation speed of the second intersatellite link vector yaw angle direction;

[0030] For the off-orbit link, a second avoidance yaw angle of the second intersatellite link vector yaw angle is calculated by using the second intersatellite link vector yaw angle within the second avoidance time, the sign of the change in the yaw angle direction of the second solar vector, and the rotation speed of the yaw angle direction of the second intersatellite link vector.

[0031] Optionally, the second laser terminal sun transit angle is obtained according to the first avoidance yaw angle or the second avoidance yaw angle.

[0032] Optionally, the step of moving the laser terminal to a specified angle to reestablish the intersatellite link includes:

[0033] For the co-orbital link, the first avoidance yaw angle within the first reset tracking time, the first reset tracking time coefficient, and the second inter-satellite link vector yaw angle rotation speed are used to calculate the first reset tracking yaw angle of the second inter-satellite link vector yaw angle;

[0034] For the off-orbit link, the second avoidance yaw angle within the second reset tracking time, the second reset tracking time coefficient and the second inter-satellite link vector yaw angle rotation speed are used to calculate the second reset tracking yaw angle of the second inter-satellite link vector yaw angle.

[0035] Optionally, a third laser terminal sun transit angle is obtained according to the first reset tracking yaw angle or the second reset tracking yaw angle.

[0036] The second aspect of the present invention provides an intersatellite link solar transit avoidance and reset tracking system, the system comprising

[0037] Laser terminal pointing module, used to determine the direction of the laser terminal;

[0038] A solar eclipse determination module, configured to determine whether a solar eclipse occurs based on the solar eclipse angle of the first laser terminal;

[0039] The solar eclipse avoidance module is used to adopt different avoidance strategies for different link types when a solar eclipse occurs, so that the laser terminal avoids direct sunlight;

[0040] The reset tracking module is used to move the laser terminal to a specified angle to re-establish the intersatellite link after avoiding a solar eclipse.

[0041] Optionally, the system further comprises

[0042] Earth shadow module, planetary ephemeris module, general mathematics module, time conversion module, coordinate conversion module, satellite ephemeris module, orbit prediction module and attitude control module.

[0043] The beneficial effects of the present invention are as follows:

[0044] The present invention discloses an intersatellite link solar transit avoidance and reset tracking method, which can be used for solar transit avoidance and reset tracking planning during intersatellite laser communication between satellites in a ground control center. It has the advantages of high algorithm efficiency, high planning efficiency and easy engineering implementation. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0046] Figure 1 A schematic diagram of an intersatellite link provided by an embodiment of the present invention is shown.

[0047] Figure 2 A flow chart of an intersatellite link solar transit avoidance and resetting tracking method provided by an embodiment of the present invention is shown.

[0048] Figure 3 A schematic diagram of the solar transit angle of a laser terminal provided by an embodiment of the present invention is shown.

[0049] Figure 4 A schematic diagram of an intersatellite link solar transit avoidance and resetting tracking system provided by an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0050] In order to more clearly illustrate the present invention, the present invention will be further described below in conjunction with the embodiments and drawings. Similar components in the drawings are represented by the same reference numerals. It should be understood by those skilled in the art that the following specific description is illustrative rather than restrictive and should not be used to limit the scope of protection of the present invention.

[0051] Depending on whether the satellites are distributed on the same orbital plane or on different orbital planes during inter-satellite laser communication, laser communication links can be divided into two types, namely, on-orbit links and off-orbit links. Figure 1 FIG2 is a schematic diagram of an intersatellite link provided by an embodiment of the present invention. Figure 1 Satellites A and B are located on the same orbital plane, and satellite C is located on an adjacent prograde orbital plane. The three satellites A, B and C form a typical intersatellite link.

[0052] In the same orbital link, the link direction is defined by the latitude argument of the two satellites on the communication link. If the latitude argument of the laser end satellite is smaller than the latitude argument of the receiving end satellite, it is called a forward link, and the link direction is the same as the satellite's flight direction. Figure 1 The laser link from satellite A to satellite B is referred to as AB link. If the latitude argument of the laser end satellite is greater than the latitude argument of the receiving end satellite, it is called a backward link. At this time, the link direction is opposite to the flight direction of the satellite. Figure 1 The laser link from star B to star A is referred to as BA link.

[0053] According to the constellation configuration design method, the difference in the latitude arguments of satellites on different orbital planes is controlled by the design parameter - phase factor. The communication link between the two satellites closest to each other on adjacent orbital planes is called an inter-orbit link, such as Figure 1 The communication link between satellite A and satellite C is called an AC link when satellite A is the laser end, and is called a CA link when satellite C is the laser end.

[0054] The angle between the communication links between satellites in large constellations and the direction of sunlight changes over time. It is related to the current spatial configuration and number of orbital elements of the constellation, whether the satellite is in the Earth's shadow, and the relative position of the Sun and the Earth at the current moment. The time and space relationship is complex.

[0055] Therefore, for giant constellation satellite communications, if the sun and the optical receiving antenna for laser communications on the satellite are approximately in a straight line, certain avoidance measures must be taken to prevent the laser terminal from being directly exposed to sunlight during solar eclipse.

[0056] In view of this, an embodiment of the present invention provides a method for avoiding and resetting solar eclipse tracking for an intersatellite link, the method comprising determining the direction of a laser terminal; judging whether a solar eclipse occurs based on the solar eclipse angle of a first laser terminal; if a solar eclipse occurs, adopting different avoidance strategies for different link types to enable the laser terminal to avoid direct sunlight; after avoiding the solar eclipse, moving the laser terminal to a specified angle to re-establish the intersatellite link.

[0057] like Figure 2 FIG2 is a flow chart of a method for avoiding a solar eclipse and resetting tracking of an intersatellite link provided by an embodiment of the present invention.

[0058] In one possible implementation, determining the laser terminal pointing includes obtaining a first solar vector and a first intersatellite link vector in a first coordinate system; and obtaining a second solar vector and a second intersatellite link vector in a second coordinate system by coordinate transformation of the first solar vector and the first intersatellite link vector.

[0059] In this embodiment, the first coordinate system is the earth's J2000 inertial coordinate system, and the second coordinate system is the receiving end satellite orbit coordinate system.

[0060] Orbit prediction is performed based on the orbital elements at the start of the mission to obtain the orbital data (position and velocity in the J2000 coordinate system) of the two FX-2 satellites during the mission planning period;

[0061] The position data of the sun in the Earth's J2000 inertial coordinate system during the mission planning period is obtained based on the planetary ephemeris model;

[0062] The coordinate transformation matrix from the Earth's J2000 inertial coordinate system to the satellite's orbital coordinate system is calculated at each moment during the mission planning period based on the position and velocity vector of the receiving satellite.

[0063] The inter-satellite link vector in the earth's J2000 inertial coordinate system is calculated and converted to the receiving end satellite orbit coordinate system; that is, the first inter-satellite link vector is obtained by coordinate transformation as the first inter-satellite link vector in the second coordinate system.

[0064] Calculate the yaw and pitch angles of the intersatellite link vector in the receiving satellite orbit coordinate system;

[0065] The solar vector of the receiving satellite is calculated and converted into the orbital coordinate system of the satellite; that is, the first solar vector in the first coordinate system is converted into the second solar vector in the second coordinate system through coordinate transformation.

[0066] Calculate the yaw and pitch angles of the sun vector in the receiver satellite orbit coordinate system.

[0067] Specifically, the on-orbit positions of satellites in a giant satellite constellation during mission planning are predicted using a high-precision orbital dynamics model with a time step of 1 s. The link vector direction can be obtained by vector subtraction on the ground. The inter-satellite laser link vector from satellite i to satellite j can be expressed as

[0068]

[0069] Where r i and r j are the position vectors of the two satellites in the Earth's inertial J2000 coordinate system.

[0070] The definitions of the links in different directions, i-star and j-star are shown in Table 1.

[0071] Table 1 Definition of intersatellite links

[0072] Link direction i star J Star Link Category Forward Link A B Same track Backward Link B A Same track Right front link A C Deviant Left rear link C A Deviant

[0073] The vector d ij Projecting the Earth's J2000 inertial coordinate system onto the receiving satellite's orbital coordinate system yields

[0074]

[0075] Where, the superscript l represents the quantity in the Earth's J2000 inertial coordinate system, the superscript o represents the quantity in the receiving satellite orbit coordinate system, and M lo is the coordinate transformation matrix from the J2000 inertial coordinate system to the orbital coordinate system.

[0076]

[0077] Where x o ,y o and z 。 Represent the first, second and third columns of the coordinate transformation matrix respectively; and They are the position and velocity vectors of the receiving satellite j in the Earth’s J2000 inertial coordinate system respectively; ||·|| is the vector modulus operation, which is as follows

[0078]

[0079] Vector The unit vector of

[0080]

[0081] The vector of sunlight incident on the receiving satellite, the solar vector i s In the J2000 inertial coordinate system, it can be expressed as

[0082]

[0083] Where, is the position vector of the sun.

[0084] Converted to the satellite's orbital coordinate system, we get

[0085]

[0086] According to the pitch angle and yaw angle of the sun direction and the intersatellite link vector in the receiver orbit coordinate system during the mission planning period, the sun direction vector can be expressed as

[0087]

[0088] Where, and are the yaw and pitch angles of the sun direction vector in the receiver orbit coordinate system.

[0089]

[0090]

[0091] Where i s，x ,i s，y and i s，z are the x, y, and z components of the sun direction vector in the orbital coordinate system.

[0092] The intersatellite link vector can be expressed as

[0093]

[0094] Where, φ AZ and φ EL It is the yaw angle and pitch angle of the intersatellite link vector in the receiving satellite orbit coordinate system.

[0095]

[0096]

[0097] Where i d，x ,i d，y and i d，z are the x, y and z coordinate components of the intersatellite link vector in the orbital coordinate system.

[0098] The transit angle of the laser terminal is obtained according to the pitch angle and yaw angle of the intersatellite link vector and the sun vector in the receiving satellite orbit coordinate system during mission planning, and whether avoidance is needed is determined according to the avoidance threshold.

[0099] In one possible implementation, determining whether a solar eclipse occurs based on the solar eclipse angle of the first laser terminal includes calculating the solar eclipse angle of the first laser terminal based on the second solar vector pitch angle and the second solar vector yaw angle, as well as the second intersatellite link vector pitch angle and the second intersatellite link vector yaw angle; a solar eclipse occurs when the solar eclipse angle of the first laser terminal is less than or equal to the solar eclipse avoidance prediction value.

[0100] In a possible implementation, the solar eclipse avoidance prediction value is in the range of 1-1.5°.

[0101] In this embodiment, the laser terminal transit angle is calculated during mission planning;

[0102] Determine whether the laser terminal transit angle is less than or equal to the transit avoidance prediction value during the mission planning period. If so, set the transit avoidance flag to F = 1, and record the number of consecutive transit avoidance time points corresponding to the moment less than the transit avoidance prediction value, with a time step of 1s; if not, set the transit avoidance flag to F = 0, index = 0;

[0103] Returns the laser terminal's transit angle, the transit avoidance flag F, and the time vector of the transit avoidance start time.

[0104] Specifically, such as Figure 3 The figure shows a schematic diagram of the solar transit angle of the laser terminal provided by an embodiment of the present invention. In order to avoid direct sunlight, the laser terminal should be rotated to a certain angle for avoidance. The angle between the laser terminal and the sun, the solar transit angle, is defined as the angle between the intersatellite link vector and the sun direction vector that is always less than 180°, that is, the solar transit angle of the first laser terminal is calculated based on the second solar vector pitch angle and the second solar vector yaw angle, as well as the second intersatellite link vector pitch angle and the second intersatellite link vector yaw angle. The formula for calculating the solar transit angle is:

[0105]

[0106] Solar angle θ≤θ * When the intersatellite link experiences a solar eclipse, θ * This is the day's avoidance value.

[0107] According to the laser terminal design indicators, the solar eclipse avoidance value is 1°. Considering the laser terminal rotation speed and execution delay, a certain design margin is reserved, and the solar eclipse avoidance prediction value is Set to 1.5°.

[0108] In a possible implementation, adopting different avoidance strategies for different link types includes, for a co-orbital link, using the second inter-satellite link vector yaw angle within the first avoidance time, the sign of the second solar vector yaw angle, and the rotation speed of the second inter-satellite link vector yaw angle, to calculate a first avoidance yaw angle of the second inter-satellite link vector yaw angle;

[0109] For the off-orbit link, a second avoidance yaw angle of the second intersatellite link vector yaw angle is calculated by using the second intersatellite link vector yaw angle within the second avoidance time, the sign of the change in the yaw angle direction of the second solar vector, and the rotation speed of the yaw angle direction of the second intersatellite link vector.

[0110] In a possible implementation, the second laser terminal sun transit angle is obtained according to the first avoidance yaw angle or the second avoidance yaw angle.

[0111] In this embodiment, for continuous avoidance periods, the laser terminal transit angle is obtained;

[0112] Determine whether the laser terminal transit angle during the period is less than the solar transit avoidance angle. If so, extract the pitch angle, yaw angle, laser terminal pitch angle of the solar vector during the avoidance period, and the laser terminal yaw angle at the initial moment of the period in sequence;

[0113] Calculate the laser terminal yaw avoidance angle according to the link type;

[0114] The laser terminal transit angle during the avoidance period is calculated from the pitch angle, yaw angle of the solar vector during the avoidance period, the laser terminal pitch angle and the yaw avoidance angle;

[0115] Determine whether the laser terminal solar transit angle is greater than the intersatellite link solar transit avoidance angle during the avoidance period. If so, the avoidance success flag G = 1, otherwise G = 0;

[0116] Returns the laser terminal transit angle after avoidance, yaw avoidance angle and avoidance success flag G.

[0117] For the co-orbit link, the first avoidance yaw angle of the second inter-satellite link vector yaw angle is calculated using the second inter-satellite link vector yaw angle, the sign of the second solar vector yaw angle and the rotation speed of the second inter-satellite link vector yaw angle within the first avoidance time. Specifically, for the co-orbit link, the sign of the solar yaw angle to avoid the solar transit at the initial moment is determined, and the yaw angle corresponding to the receiving end is adjusted in the opposite direction. The yaw angle avoidance value is

[0118]

[0119] Among them, the value range of the avoidance time t of the co-orbit link for the i-th solar eclipse is t i+1 and represents the first and last sampling points of the discrete sampling moments corresponding to this solar eclipse; c j is the sign of the current sun direction yaw angle, is the yaw angle toward the sun; φ AZ (t i+1) is the laser terminal yaw angle; is the rotation speed of the laser terminal in the yaw direction.

[0120] For the off-orbit link, the second avoidance yaw angle of the second inter-satellite link vector yaw angle is calculated by using the second inter-satellite link vector yaw angle, the sign of the change in the direction of the second solar vector yaw angle and the rotation speed of the second inter-satellite link vector yaw angle within the second avoidance time. Specifically, for the off-orbit link, the yaw angle of the laser terminal is adjusted in the opposite direction, and the yaw angle avoidance value is

[0121]

[0122] Among them, the value range of the time t of avoiding the different orbit link during the i-th solar eclipse is t i+1 and represents the first and last sampling points of the discrete sampling moments corresponding to this solar eclipse; φ AZ (t i ) is the yaw angle of the laser terminal; c l In order to avoid the change direction of the sun's yaw angle between the end time and the initial time, is the rotation speed of the laser terminal in the yaw direction.

[0123] According to the yaw angle avoidance value, the laser terminal transit angle after avoidance is calculated, that is, the second laser terminal transit angle is obtained according to the first avoidance yaw angle or the second avoidance yaw angle. The calculation formula is:

[0124]

[0125] In one possible implementation, causing the laser terminal to re-establish the intersatellite link at the specified angle includes, for a co-orbital link, calculating a first reset tracking yaw angle of a second intersatellite link vector yaw angle using a first avoidance yaw angle within a first reset tracking time, a first reset tracking time coefficient, and a second intersatellite link vector yaw angle rotation speed;

[0126] For the off-orbit link, the second avoidance yaw angle within the second reset tracking time, the second reset tracking time coefficient and the second inter-satellite link vector yaw angle rotation speed are used to calculate the second reset tracking yaw angle of the second inter-satellite link vector yaw angle.

[0127] In a possible implementation, the third laser terminal sun transit angle is obtained according to the first reset tracking yaw angle or the second reset tracking yaw angle.

[0128] In this embodiment, the avoidance end time is obtained;

[0129] Calculate the yaw angle during the laser terminal reset and tracking period according to the link type;

[0130] The laser terminal transit angle during the avoidance period is calculated from the pitch angle, yaw angle of the sun vector during the reset tracking period, and the laser terminal pitch angle and yaw angle;

[0131] Determine whether the laser terminal solar transit angle is greater than the intersatellite link solar transit avoidance angle during the avoidance period. If so, the avoidance success flag H=1, otherwise H=0;

[0132] Returns the laser terminal transit angle after avoidance, the laser terminal yaw avoidance angle and the avoidance success flag H.

[0133] For co-orbital links, the first avoidance yaw angle within the first reset tracking time, the first reset tracking duration coefficient, and the rotational velocity of the second inter-satellite link vector yaw angle are used to calculate the first reset tracking yaw angle of the second inter-satellite link vector yaw angle. Specifically, because the two satellites communicating in a co-orbital inter-satellite link always remain in the same nominal orbital plane, the inter-satellite phase angle remains stable, and the pitch and yaw angles of the co-orbital inter-satellite link receiving satellite laser terminal remain unchanged. After performing an avoidance maneuver during a solar eclipse, the receiving satellite laser terminal's yaw angle is simply reset to 0.

[0134] The laser terminal resets the tracking yaw angle to

[0135]

[0136] Where, It is the time for the co-track link to reset and track.

[0137] For off-orbit links, the second avoidance yaw angle within the second reset tracking time, the second reset tracking time coefficient, and the second inter-satellite link vector yaw angle rotation speed are used to calculate the second reset tracking yaw angle of the second inter-satellite link vector yaw angle. Specifically, the pitch angle and yaw angle of the off-orbit link laser terminal vary greatly during inter-satellite communication. Therefore, when resetting the tracking, it is necessary to obtain the change trend of the terminal yaw rotation speed and the off-orbit link yaw angle. Usually the off-orbit link yaw angle changes linearly, and the slope can be obtained by taking the difference at the corresponding time.

[0138]

[0139] Where, and The yaw angles of the intersatellite link in the orbital coordinate system correspond to the start and end times of the i-th extraorbital solar transit, respectively.

[0140] Reset tracking time is

[0141]

[0142] Where c is the reset tracking time coefficient, which is determined by the constellation orbit parameters.

[0143] Laser terminal resets tracking yaw angle

[0144]

[0145] Where, It is the time for resetting and tracking the off-track link. To round down.

[0146] Calculate the laser terminal transit angle during the reset tracking period, that is, obtain the third laser terminal transit angle according to the first reset tracking yaw angle or the second reset tracking yaw angle. The calculation formula is:

[0147]

[0148] The present invention discloses an intersatellite link solar transit avoidance and reset tracking method, which can be used for solar transit avoidance and reset tracking planning during intersatellite laser communication between satellites in a ground control center, and has the advantages of high algorithm efficiency and easy engineering implementation.

[0149] Another embodiment of the present invention provides an intersatellite link solar eclipse avoidance and reset tracking system, which includes a laser terminal pointing module for determining the direction of the laser terminal; a solar eclipse judgment module for judging whether a solar eclipse occurs based on the solar eclipse angle of the first laser terminal; a solar eclipse avoidance module for adopting different avoidance strategies for different link types to enable the laser terminal to avoid direct sunlight when a solar eclipse occurs; and a reset tracking module for causing the laser terminal to re-establish the intersatellite link at a specified angle after avoiding the solar eclipse.

[0150] In one possible implementation, the system further includes an earth shadow module, a planetary ephemeris module, a general mathematics module, a time conversion module, a coordinate conversion module, a satellite ephemeris module, an orbit prediction module, and an attitude control module.

[0151] like Figure 4 Figure 1 shows a schematic diagram of an intersatellite link solar transit avoidance and re-tracking system provided by an embodiment of the present invention. Solar transit avoidance strategies can be pre-planned and transmitted to satellites by the ground control system, or the satellite's onboard computer can autonomously generate them based on autonomous planning and orbit prediction models. This embodiment provides a solar transit avoidance strategy for the ground control system. Figure 4 The ground operation and control system includes a mission planning model architecture, which includes a general model and a special model.

[0152] The intersatellite link solar transit avoidance and reset tracking system disclosed in this embodiment can be used for solar transit avoidance and reset tracking planning during intersatellite laser communication in a ground control center, and has the advantages of high algorithm efficiency and easy engineering implementation.

[0153] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper" and "lower" is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be internal communication between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0154] It should also be noted that, in the description of the present invention, relational terms such as first and second, etc., are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variants thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a..." does not exclude the presence of additional identical elements in the process, method, article, or device comprising the element.

[0155] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in this field, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the scope of protection of the present invention.

Claims

1. A method for avoiding and resetting solar eclipse in an intersatellite link, characterized in that: The method includes Determine the direction of the laser terminal; Determining whether a solar eclipse occurs according to the solar eclipse angle of the first laser terminal; If a solar eclipse occurs, different avoidance strategies are adopted for different link types to keep the laser terminal away from direct sunlight; After avoiding the solar eclipse, the laser terminal is moved to the specified angle to re-establish the intersatellite link; The different avoidance strategies adopted for different link types include: For the co-orbital link, a first avoidance yaw angle of the second intersatellite link vector yaw angle is calculated using the second intersatellite link vector yaw angle within the first avoidance time, the sign of the second solar vector yaw angle, and the rotation speed of the second intersatellite link vector yaw angle direction; For the off-orbit link, a second avoidance yaw angle of the second intersatellite link vector yaw angle is calculated by using the second intersatellite link vector yaw angle within the second avoidance time, the sign of the change in the yaw angle direction of the second solar vector, and the rotation speed of the yaw angle direction of the second intersatellite link vector.

2. The intersatellite link solar eclipse avoidance and resetting tracking method according to claim 1, characterized in that: Determining the direction of the laser terminal includes Obtaining a first sun vector and a first intersatellite link vector in a first coordinate system; A second sun vector and a second inter-satellite link vector in a second coordinate system are obtained by coordinate transformation of the first sun vector and the first inter-satellite link vector.

3. The intersatellite link solar eclipse avoidance and resetting tracking method according to claim 1, characterized in that: The step of determining whether a solar eclipse occurs according to the solar eclipse angle of the first laser terminal includes: Calculating a solar transit angle of the first laser terminal according to the second solar vector pitch angle and the second solar vector yaw angle, and the second intersatellite link vector pitch angle and the second intersatellite link vector yaw angle; A solar eclipse occurs when the solar eclipse angle of the first laser terminal is less than or equal to the solar eclipse avoidance prediction value.

4. The intersatellite link solar eclipse avoidance and resetting tracking method according to claim 3, characterized in that: The solar eclipse avoidance prediction value ranges from 1 to 1.5°.

5. The intersatellite link solar eclipse avoidance and resetting tracking method according to claim 1, wherein: A second laser terminal sun eclipse angle is obtained according to the first avoidance yaw angle or the second avoidance yaw angle.

6. The intersatellite link solar eclipse avoidance and resetting tracking method according to claim 1, characterized in that: The step of moving the laser terminal to a specified angle to re-establish the intersatellite link includes: For the co-orbital link, the first avoidance yaw angle within the first reset tracking time, the first reset tracking time coefficient, and the second inter-satellite link vector yaw angle rotation speed are used to calculate the first reset tracking yaw angle of the second inter-satellite link vector yaw angle; For the off-orbit link, the second avoidance yaw angle within the second reset tracking time, the second reset tracking time coefficient and the second inter-satellite link vector yaw angle rotation speed are used to calculate the second reset tracking yaw angle of the second inter-satellite link vector yaw angle.

7. The intersatellite link solar eclipse avoidance and resetting tracking method according to claim 6, characterized in that: The third laser terminal sun eclipse angle is obtained according to the first reset tracking yaw angle or the second reset tracking yaw angle.

8. An intersatellite link solar transit avoidance and reset tracking system, characterized in that: The system includes Laser terminal pointing module, used to determine the direction of the laser terminal; A solar eclipse determination module, configured to determine whether a solar eclipse occurs based on the solar eclipse angle of the first laser terminal; A solar eclipse avoidance module is used to adopt different avoidance strategies for different link types to avoid direct sunlight for the laser terminal when a solar eclipse occurs. This includes, for a co-orbital link, calculating a first avoidance yaw angle of the second intersatellite link vector yaw angle using the yaw angle of the second intersatellite link vector within a first avoidance time, the sign of the second solar vector yaw angle, and the rotation speed of the second intersatellite link vector yaw angle; For the off-orbit link, a second avoidance yaw angle of the second intersatellite link vector yaw angle is calculated using the sign of the change in the second intersatellite link vector yaw angle, the second solar vector yaw angle direction, and the rotation speed of the second intersatellite link vector yaw angle within the second avoidance time. The reset tracking module is used to move the laser terminal to a specified angle to re-establish the intersatellite link after avoiding a solar eclipse.

9. The intersatellite link solar transit avoidance and resetting tracking system according to claim 8, characterized in that: The system further includes Earth shadow module, planetary ephemeris module, general mathematics module, time conversion module, coordinate conversion module, satellite ephemeris module, orbit prediction module and attitude control module.

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