Satellite orbit information conversion method and device

Abstract

The invention provides a satellite orbit information conversion method and device. The method comprises the following steps: acquiring orbit information of a satellite in a first coordinate system; and converting the orbit information from the first coordinate system to the second coordinate system by a simplified calculation, where the orbit information includes a position and a velocity of the satellite, and the simplified calculation includes at least one of: simplifying calculation of time each involved in the first coordinate system and the second coordinate system; the calculation of a polar shift conversion matrix is simplified; the calculation of the Greenwich star hour angle is simplified; simplifying the calculation of at least one of a flat aphrodite angle, a yellow meridian nutation, a crossing angle nutation, and an instantaneous aphrodite angle; and the calculation of the age difference angle is simplified.

Description

Technical Field

[0001] The present application relates to the field of satellite orbit calculation, and more specifically, to a method and device for converting satellite orbit information. Background Art

[0002] When a satellite is in orbit, it is necessary to obtain the satellite orbit for the satellite's attitude control, image processing, and positioning of the detection target. Usually, the satellite orbit is obtained by the on-board navigation system obtaining positioning information from positioning systems such as the Global Positioning System (GPS) and the Beidou Navigation Satellite System, and obtaining the satellite orbit based on the positioning information. The satellite orbit may include one or more of a variety of orbital information such as the position and speed of the satellite, the number of six orbits, etc. In addition, these orbital information may have different forms or expressions in different coordinate systems.

[0003] However, satellite attitude control, image processing, and positioning of detection targets often involve the conversion of orbital information between different coordinate systems. Currently, the conversion of orbital information between different coordinate systems is complex and requires high onboard computing resources. Summary of the invention

[0004] The embodiments of the present application provide a method and device for converting satellite orbit information. The following introduces various aspects of the embodiments of the present application.

[0005] In a first aspect, a method for converting satellite orbit information is provided, which may include: acquiring orbit information of a satellite in a first coordinate system; and converting the orbit information from the first coordinate system to a second coordinate system by simplified calculation, wherein the orbit information includes the position and velocity of the satellite, and the simplified calculation may include at least one of the following: simplifying the calculation of time involved in each of the first coordinate system and the second coordinate system; simplifying the calculation of the polar shift conversion matrix; simplifying the calculation of the Greenwich sidereal hour angle; simplifying the calculation of at least one of the mean obliquity, nutation of the ecliptic longitude, nutation of the intersection angle, and instantaneous obliquity; and simplifying the calculation of the precession angle.

[0006] Optionally, simplifying the calculations of the first coordinate system and the second coordinate system respectively related to time may include at least one of the following: unifying the starting points of the first coordinate system and the second coordinate system respectively related to time; and ignoring leap seconds.

[0007] Optionally, simplifying the calculation of the pole shift conversion matrix may include: the pole shift conversion matrix adopts a unit matrix.

[0008] Optionally, simplifying the calculation of the Greenwich sidereal hour angle may include at least one of the following: retaining the polynomial involved in the calculation of the Greenwich sidereal hour angle up to quadratic terms and discarding higher-order terms; and retaining the mean obliquity and nutation of the ecliptic.

[0009] Optionally, simplifying the calculation of at least one of the mean obliquity, nutation of the ecliptic longitude, nutation of the intersection angle and instantaneous obliquity may include: retaining the constant term or the constant term and the linear term in the polynomial involved in the respective calculations of the mean obliquity, nutation of the ecliptic longitude, nutation of the intersection angle and / or instantaneous obliquity.

[0010] Optionally, simplifying the calculation of the ecliptic longitude nutation may include discarding a constant parameter matrix involved in the IAU2000 model.

[0011] Optionally, simplifying the calculation of the precession angle may include: retaining the polynomial involved in the calculation of the precession angle up to first-order terms and discarding higher-order terms.

[0012] Alternatively, the first coordinate system may be one of the WBS84 coordinate system and the J2000 coordinate system, and the second coordinate system may be the other of the WBS84 coordinate system and the J2000 coordinate system.

[0013] In a second aspect, a device for converting satellite orbit information is provided, which may include: an acquisition unit for acquiring orbit information of a satellite in a first coordinate system; and a calculation unit for converting the orbit information from the first coordinate system to a second coordinate system by simplified calculation, wherein the orbit information includes the position and velocity of the satellite, and the simplified calculation includes at least one of the following: simplified calculations of the first coordinate system and the second coordinate system involving time respectively; simplified calculations of the polar shift conversion matrix; simplified calculations of the Greenwich sidereal hour angle; simplified calculations of at least one of the mean obliquity, nutation of the ecliptic longitude, nutation of the intersection angle and instantaneous obliquity; and simplified calculations of the precession angle.

[0014] In a third aspect, a satellite orbit information conversion device is provided, which may include: a memory for storing code; and a processor for executing the code stored in the memory to execute the method according to the first aspect or any optional embodiment of the first aspect.

[0015] According to a fourth aspect, a computer-readable storage medium is provided, on which is stored a code for executing the method in the first aspect or any optional embodiment of the first aspect.

[0016] According to a fifth aspect, a computer program is provided, comprising codes for executing the method in the first aspect or any optional embodiment of the first aspect.

[0017] The embodiment of the present application uses a simplified calculation method to achieve the conversion of orbital information between different coordinate systems, thereby reducing the demand for on-board computing resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic flow chart of a satellite orbit information conversion method provided in an embodiment of the present application is shown.

[0019] Figure 2 The orbit information conversion between the WGS84 coordinate system and the J2000 coordinate system is shown.

[0020] Figure 3 A simplified scheme for calculating the parameters involved in converting between coordinate systems is shown.

[0021] Figure 4 The orbit conversion error from WGS84 coordinate system to J2000 coordinate system is shown.

[0022] Figure 5 The orbit conversion error from the J2000 coordinate system to the WGS84 coordinate system is shown.

[0023] Figure 6 A schematic diagram of the structure of a satellite orbit information conversion device provided in one embodiment of the present application is shown.

[0024] Figure 7 A schematic diagram of the structure of a satellite orbit information conversion device provided in one embodiment of the present application is shown. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only embodiments of a part of the present application, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present application should fall within the scope of protection of the present application.

[0026] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0027] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply 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; the terms "first", "second", and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance; in addition, 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 or a detachable connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal connection of 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 specific circumstances.

[0028] When a satellite is in orbit, it is necessary to obtain the satellite orbit for the satellite's attitude control, image processing, and positioning of the detection target. Usually, the satellite orbit is obtained by the onboard navigation system obtaining positioning information from positioning systems such as GPS and Beidou Navigation Satellite System and obtaining the satellite orbit based on the positioning information. The satellite orbit may include one or more of a variety of orbital information such as the satellite's position and speed, and the number of six orbital elements. In addition, these orbital information may have different forms or expressions in different coordinate systems.

[0029] Usually, in order to reduce the consumption of onboard computing resources, the onboard navigation system provides orbital information such as position and velocity with a sampling frequency of 1 Hz or other sampling frequencies customized according to demand. However, in reality, the satellite's attitude control, image processing, and positioning of detection targets often involve different coordinate systems, and their respective requirements for the sampling frequency of the satellite orbit are also different. Therefore, if the onboard navigation system provides satellite orbit information in different coordinate systems with different sampling frequencies, it will place huge hardware resource requirements on the onboard navigation system.

[0030] Taking into account that many satellites have a certain range of requirements for the positioning accuracy of satellite orbits, for example, the positioning accuracy is within 50m, this application proposes a simplified conversion method for satellite orbit information between different coordinate systems, which simplifies the conversion calculation of orbit information by adopting a variety of simplified calculation methods, thereby reducing the demand for on-board computing resources while meeting the accuracy requirements.

[0031] In addition, in response to different orbital positioning accuracy requirements, one or more of the various simplified calculation methods proposed in this article can be adopted to minimize the consumption of on-board computing resources while meeting specific accuracy requirements.

[0032] Combine the following Figure 1 A satellite orbit information conversion method provided in an embodiment of the present application is introduced in detail.

[0033] like Figure 1 As shown, the satellite orbit information conversion method 100 may include: steps S110 to S120.

[0034] In step S110, orbit information of the satellite in the first coordinate system may be acquired.

[0035] The coordinate systems used to describe satellite orbits mainly include geocentric fixed coordinate systems and geocentric inertial coordinate systems. These two types of coordinate systems are suitable for describing different spatial position relationships, and these two types of coordinate systems can be related to each other through complex transformation relationships. For example, a common geocentric fixed coordinate system is the WGS84 coordinate system, which is widely used in GPS and Geographic Information System (GIS). For another example, a common geocentric inertial coordinate system is the J2000 coordinate system, which is suitable for describing the absolute position and velocity of a satellite, and is particularly suitable for orbit calculation and dynamic analysis.

[0036] Orbital information may include one or more of the satellite's position and velocity, six orbital numbers, and other information. For introduction, the six orbital numbers may generally include the following six parameters: semi-major axis a, eccentricity e, orbital inclination i, right ascension of ascending node Ω, argument of perigee ω, and mean anomaly M. These orbital information generally have different forms or expressions in the above-mentioned different coordinate systems, and the conversion between them often involves complex calculations.

[0037] In step S120 , the orbit information may be converted from the first coordinate system to the second coordinate system by simplified calculation.

[0038] In some embodiments, the orbital information may include the position and velocity of the satellite, and the simplified calculation may include at least one of the following: simplifying the calculation of the first coordinate system and the second coordinate system respectively involving time; simplifying the calculation of the polar shift transformation matrix; simplifying the calculation of the Greenwich sidereal time angle; simplifying the calculation of at least one of the mean obliquity, nutation of the ecliptic longitude, nutation of the intersection angle and the instantaneous obliquity; and simplifying the calculation of the precession angle.

[0039] Different coordinate systems often involve their own time variables t, such as Coordinated Universal Time (UTC), Universal Time 1 (UT1), International Atomic Time (TAI), Terrestrial Time (TT), Terrestrial Dynamical Time (TDT), Barycentric Dynamical Time (TDB), and so on.

[0040] In some embodiments, simplifying the calculation of the time involved in the first coordinate system and the second coordinate system may include: unifying the starting point of the time involved in the first coordinate system and the second coordinate system. For example, unifying the starting point of various time involved as 12:0:00 on January 1, 2000, thereby simplifying the calculation of various time to seconds accumulated from the starting point.

[0041] By unifying the starting points of various types of time involved in different coordinate systems, it is no longer necessary to distinguish the time variable t between the coordinate systems, thereby reducing the confusion caused by calculating various types of time, simplifying the calculation, and reducing the demand for on-board computing resources.

[0042] In some embodiments, additionally or alternatively, simplifying the calculations of the first coordinate system and the second coordinate system related to time may include: ignoring leap seconds. Leap seconds are a time adjustment mechanism introduced for consistency between UTC and UT1. By ignoring leap seconds, the calculation of time variables can be simplified when converting between coordinate systems of orbit information, thereby reducing the amount of calculation.

[0043] The polar shift transfer matrix is ​​a mathematical tool used to describe the tiny movement of the Earth's rotation axis on the Earth's surface. It is usually expressed as a 3×3 rotation matrix and needs to be taken into account when accurately calculating the satellite orbit. Specifically, the polar shift transfer matrix can include 7 days of observations and forecast values ​​for the next 365 days. For real-time calculations of satellites on orbit, the observations are historical data and are not used; the forecast values ​​for the next 365 days are too large.

[0044] In some embodiments, considering that the change of the Earth's polar motion is relatively small, after simulation verification, the polar motion conversion matrix can be directly replaced by the unit matrix, that is, replaced by the 3×3 unit matrix. Therefore, the calculation can be simplified when performing the conversion between coordinate systems of orbit information.

[0045] Greenwich sidereal hour angle S g It is a parameter that describes the rotation state of the Earth and indicates the angular position of the Greenwich meridian relative to the vernal equinox. gIt can be used for coordinate system transformation in satellite orbit calculations to take into account the effects of the Earth's rotation.

[0046] Greenwich sidereal hour angle S g It involves various types of time such as UT1, TT, TDB, etc. In some embodiments, the calculation of the simplified Greenwich sidereal hour angle may include the operations included in simplifying the time involved in the first coordinate system and the second coordinate system in the above embodiments.

[0047] In the calculation of the Greenwich sidereal hour angle, a high-order polynomial calculation of a time variable may also be involved. In some embodiments, considering that the coefficients of the high-order terms in these high-order polynomials are small, after simulation verification, simplifying the calculation of the Greenwich sidereal hour angle may additionally or alternatively include: retaining the polynomial involved in the calculation of the Greenwich sidereal hour angle up to the quadratic term and discarding the higher-order terms.

[0048] In the calculation of Greenwich sidereal hour angle, the mean obliquity ε is also involved. A After simulation, in some embodiments, simplifying the calculation of the Greenwich sidereal hour angle may additionally or alternatively include: in the calculation of the Greenwich sidereal hour angle, retaining the mean ecliptic obliquity ε A And the ecliptic longitude movement Δψ.

[0049] Pinghuang equatorial angle ε A It can represent the average angle between the Earth's rotation axis and the ecliptic plane. The instantaneous obliquity ρ can represent the actual angle between the Earth's rotation axis and the ecliptic plane at a specific moment. The nutation of the ecliptic longitude Δψ can represent the small swing of the Earth's rotation axis in a short period. The nutation of the angle Δε can represent the small change of the angle between the Earth's rotation axis and the ecliptic plane in a short period. These four angles are often used in the coordinate system conversion of orbital information.

[0050] When calculating these angles, it is usually necessary to calculate the mean longitude Ω of the ascending node of the moon and the mean obliquity ε. A 、Sun's mean anomaly S o , lunar latitude argument F1, sun-moon mean angle F2, ecliptic longitude nutation Δψ, intersection angle nutation Δε, instantaneous ecliptic obliquity ρ, etc. In some embodiments, simplifying the calculation of at least one of the mean ecliptic obliquity, ecliptic longitude nutation, intersection angle nutation, and instantaneous ecliptic obliquity may include: retaining the mean ecliptic obliquity ε A The constant term or the constant term and the linear term in the polynomial involved in the calculation of the ecliptic nutation Δψ, the intersection angle nutation Δε and / or the instantaneous ecliptic obliquity ρ.

[0051] In some embodiments, the calculation of at least one of the simplified mean obliquity, the nutation of the ecliptic longitude, the nutation of the angle of intersection, and the instantaneous obliquity may additionally or alternatively include: for the Greenwich sidereal hour angle S involvedg , the simplified Greenwich sidereal hour angle S in the above embodiment can be used g The operations involved in the calculation.

[0052] The IAU2000 model is a set of precession and nutation models adopted by the International Astronomical Union at its 2000 General Assembly, which aims to provide more accurate Earth rotation parameters. The IAU2000 model includes a large number of constant parameter matrices used to describe Earth rotation parameters, such as a 77×11 two-dimensional matrix used to describe Earth rotation nutation.

[0053] In some embodiments, simplifying the calculation of the ecliptic longitude nutation may include discarding the constant parameter matrix involved in the IAU2000 model, for example, discarding the above-mentioned 77×11 two-dimensional matrix.

[0054] The precession angle is a parameter that describes the long-term slow motion of the Earth's rotation axis in space. It can represent the angular change of the projection of the Earth's rotation axis on the ecliptic plane relative to the vernal equinox.

[0055] In some embodiments, considering that the precession angle changes very little within a year and the coefficients of higher-order terms are very small, simplifying the calculation of the precession angle may include: retaining the polynomial involved in the calculation of the precession angle up to the first-order term and discarding higher-order terms.

[0056] In some embodiments, the first coordinate system is one of the WBS84 coordinate system and the J2000 coordinate system, and the second coordinate system is the other of the WBS84 coordinate system and the J2000 coordinate system.

[0057] In some embodiments, the above steps S110 and S120 may be performed by a satellite. In particular, steps S110 and S120 may be performed by an onboard navigation system. Of course, steps S110 and S120 may also be performed by other devices that perform similar functions to the onboard navigation system, and the embodiments of the present application are not limited thereto.

[0058] The simplified calculations introduced in the above embodiments may be applied individually or in combination, as long as the requirements for orbit information conversion accuracy can be met.

[0059] In the above embodiment, the calculation items with little impact on accuracy are removed by simplifying the calculation, thereby greatly simplifying the calculation method for converting orbital information between different coordinate systems while meeting the accuracy requirements, thereby saving the demand for on-board hardware computing resources.

[0060] The above describes several simplified operations that can be generally used when converting orbit information between different coordinate systems. The present application is further described below in conjunction with a common situation in the coordinate system conversion of orbit information.

[0061] In practical applications, a common situation is the conversion between the position and velocity in the J2000 coordinate system and the position and velocity in the WGS84 coordinate system.

[0062] In the prior art, the conversion of satellite orbit information between the WGS84 coordinate system and the J2000 coordinate system on board has the following deficiencies: the conversion of the coordinate system involves leap seconds, precession, nutation, obliquity of the ecliptic, polar motion, Greenwich mean sidereal time, Julian century number and other parameters, and the calculation formula is very complicated. It is unrealistic for the onboard navigation system to give the position and velocity of these two coordinate systems with different sampling frequencies based on the prior art, which will put forward huge hardware resource requirements for the onboard navigation system. Moreover, although the conversion calculation between the two coordinate systems in the prior art is very complicated, the improvement of the orbit conversion accuracy is very limited, and the impact on the use of the satellite orbit during the life of the satellite is very small.

[0063] To this end, an embodiment of the present application provides a simplified method for converting the position and velocity between the high-precision WGS84 coordinate system on board and the J2000 coordinate system. Through simulation analysis, the method greatly simplifies the calculation method and saves onboard computing resources by removing the calculation items that have little impact on the accuracy while meeting the accuracy requirements.

[0064] The following is a detailed introduction to this embodiment of the present application.

[0065] Assumption: At time t, the satellite is in the WGS84 coordinate system O f The position below is Speed And, the satellite is in the J2000 coordinate system O j The position below is Speed WGS84 coordinate system f With J2000 coordinate system O j The conversion between them can involve the WGS84 coordinate system O f , instantaneous earth coordinate system O e 、Instantaneous true celestial spherical coordinate system O t , instantaneous mean celestial spherical coordinate system O m and J2000 coordinate system O j conversion between .

[0066] WGS84 coordinate system f:Use the 1984.0 epoch reference frame defined by the Bureau International de l'Heure (BIH). The origin of the coordinate system is defined at the center of mass of the earth. The Z axis points to the BIH1984.0 agreed terrestrial pole. The X axis points to the intersection of the zero meridian plane of BIH1984.0 and the corresponding equator of the agreed terrestrial pole (Conventional Terrestrial Pole, CTP). The Y axis, X axis and Z axis form a right-handed coordinate system.

[0067] Instantaneous Earth Coordinate System O e : The origin is at the center of mass of the earth, the Z axis points to the instantaneous axis of rotation of the earth, the X axis points to the intersection of the Greenwich meridian plane and the instantaneous equator, and the Y axis, X axis and Z axis form a right-handed coordinate system.

[0068] Instantaneous true celestial spherical coordinate system O t : The origin is located at the center of mass of the earth, the Z axis points to the instantaneous true north celestial pole, the X axis points to the instantaneous vernal equinox, and the Y axis, X axis and Z axis form a right-hand coordinate system.

[0069] Instantaneous mean celestial coordinate system O m : The origin is located at the center of mass of the earth, the Z axis points to the instantaneous celestial north pole, the X axis points to the instantaneous mean equinox, and the Y axis, X axis and Z axis form a right-hand coordinate system.

[0070] J2000 Coordinate System O j : The origin is at the center of mass of the Earth, the X-axis points to the mean equinox of the J2000.0 epoch, the Z-axis is perpendicular to the mean equatorial plane of the J2000.0 epoch, and the Y-axis forms a right-handed coordinate system with the X-axis and the Z-axis.

[0071] Specifically, Figure 2 As shown, WGS84 coordinate system O f With J2000 coordinate system O j The orbit information conversion between WGS84 coordinate system O f To J2000 coordinate system O j Conversion from and to the J2000 coordinate system O j To WGS84 coordinate system O f The relationship between the two is reversible, and one conversion can be derived from the other.

[0072] See also Figure 3 , showing a simplified scheme for parameter calculation involved in converting between different coordinate systems.

[0073] The present application embodiment is first based on Figure 3 The simplified calculation scheme of the parameters shown is calculated from the WGS84 coordinate system O f To J2000 coordinate system O jThe conversion of the J2000 coordinate system O is then given according to the inverse relationship. j To WGS84 coordinate system O f conversion.

[0074] 1. Calculate from WGS84 coordinate system O f To J2000 coordinate system O j conversion.

[0075] 1) Calculate the Julian century number T, where t is the accumulated seconds corresponding to the satellite orbit relative to 12:0:00 on January 1, 2000, excluding leap seconds.

[0076] T=t / 86400 / 36525

[0077] 2) Calculate the simplified mean longitude Ω and mean obliquity ε of the ascending node of the moon A 、Sun's mean anomaly S o , lunar latitude argument F1, sun-moon mean angular distance F2, ecliptic longitude nutation Δψ, intersection nutation Δε, instantaneous ecliptic obliquity ρ, Greenwich sidereal hour angle S g Among them, S c , Δψ c are the five sinusoidal terms of the ecliptic nutation Δψ and the corresponding coefficient matrix, C c , Δε c They are the five cosine terms of the intersection angle nutation Δε and the corresponding coefficient matrix.

[0078] Ω=-33.75704595363087*T+2.182439196615671,

[0079] ε A =0.409092600600583,

[0080] S o =628.3019551713969T+6.240060126922979,

[0081] F1=628.3319653690288T-1.388122310497314,

[0082] F2=8399.709110962742T+3.810344278153190,

[0083] S c =[sin(Ω)sin(2Ω)sin(2F1)sin(S o )sin(2F2)] T ,

[0084] Cc =[cos(Ω)cos(2Ω)cos(2F1)cos(S o )cos(2F2)] T ,

[0085] Δψ c =[-8.338601389611576,0.099968581044786,-0.639323801279145,0.069134430926220,-0.110246631084308],

[0086] Δε c =[4.461497900410506,-0.043390824459303,0.278089127484430,0.002647082698858,0.047366296644402],

[0087] Δψ=Δψ c ·S c 10 -5 ,

[0088] Δε=Δε c ·C c 10 -5 ,

[0089] ρ=ε A +Δε,

[0090] S g =4.8949612+230121.6753154T+0.000006770708T 2 +Δψcos(ε A ).

[0091] 3) Calculate WGS84 coordinate system O f To the instantaneous earth coordinate system O e The transformation matrix M ef The transformation matrix M ef It needs to be calculated based on the polar shift parameters at the corresponding time in the Earth Orientation Parameters (EOP) file. However, since the polar shift is very small, with an amplitude of about 0.4″, it has little impact on the use of the satellite, so the on-board calculation can be ignored. ef becomes the identity matrix (it is retained here to illustrate the transformation process).

[0092]

[0093] 4) Calculate the instantaneous earth coordinate system O eTo the instantaneous true celestial coordinate system O t Transformation matrix M te .

[0094]

[0095] 5) Calculate the instantaneous true celestial coordinate system O t To the instantaneous mean celestial coordinate system O m The transformation matrix M mt .

[0096]

[0097] 6) Calculate the instantaneous mean celestial coordinate system O m To J2000 coordinate system O j The transformation matrix M jm .

[0098] ζ=0.0111808608650244T

[0099] z=0.0111808608650244T

[0100] θ=0.00971717345516967T

[0101]

[0102] 7) According to the angular velocity of the earth's rotation And the coordinate transformation relationship, we can get the position of the satellite in the J2000 coordinate system and speed They are:

[0103]

[0104] The satellite position in the WGS84 coordinate system is given by the satellite simulation tool, namely the Satellite Tool Kit (STK). and speed And the satellite positions in the J2000 coordinate system and speed According to the simplified calculation method above, the position in the J2000 coordinate system is obtained through simplified calculation. and speed Therefore, the position error and speed error They are:

[0105]

[0106] See also Figure 4, shows the orbit conversion error from the WGS84 coordinate system to the J2000 coordinate system. Specifically, it shows the satellite position conversion error and velocity conversion error when a set of satellite orbits between 0:0:0:0 on January 1, 2024 and 0:0:0:0 on January 1, 2029 are used as the basis for simulation analysis. Figure 4 It can be seen that the satellite position conversion error within 5 years Speed ​​conversion error The accuracy is high enough and the conversion accuracy amplification changes very slowly over time, which can meet most satellite orbit usage needs during the satellite's life span.

[0107] 2. Calculate from J2000 coordinate system O j To WGS84 coordinate system O f conversion.

[0108] Based on the reversible transformation relationship, according to the corresponding relationship in Part 1, the J2000 coordinate system O is calculated using the transpose of the transformation matrix j To WGS84 coordinate system O f The conversion can get the WGS84 coordinate system O f Satellite positions below and speed They are:

[0109]

[0110] The satellite position in the WGS84 coordinate system is given by the satellite simulation tool STK and speed And the position in the J2000 coordinate system and speed According to the simplified calculation method above, the position in the J2000 coordinate system and speed As input, the satellite position in the WGS84 coordinate system is obtained through simplified calculation and speed The position error and speed error They are:

[0111]

[0112] See also Figure 5 , shows the orbit conversion error from the J2000 coordinate system to the WGS84 coordinate system. Specifically, it shows the satellite position conversion error and velocity conversion error when a set of satellite orbits between 00:00:00 on January 1, 2024 and 00:00:00 on January 1, 2029 is used as the basis for simulation analysis. Figure 5 It can be seen that the satellite position conversion error within 5 years Speed ​​conversion error The accuracy is high enough, and the orbit conversion accuracy amplification changes very slowly over time, which can meet most satellite orbit usage needs during the satellite's life cycle.

[0113] The above-mentioned embodiment of the present application can provide a high-precision simplified conversion method for satellite orbits between the on-board WGS84 coordinate system and the J2000 coordinate system. Through this simplified conversion method, in the calculation of precession, nutation, polar motion, Greenwich sidereal hour angle, leap second, etc., the calculation items with little effect on accuracy are removed, thereby greatly simplifying the calculation method and saving on-board computing resources. At the same time, through this simplified conversion method, a high conversion accuracy is also maintained, which can meet the orbit conversion requirements of 5m to 50m accuracy.

[0114] The above-mentioned embodiment of the present application can provide a high-precision satellite orbit simplified conversion method between the on-board WGS84 coordinate system and the J2000 coordinate system. The simplified conversion method can simplify thousands of parameters into dozens of parameters, the calculation method is simple, but the conversion accuracy is high, the on-board calculation amount is small, the calculation complexity is reduced, and the on-board calculation is convenient.

[0115] Combination of the above Figures 1 to 5 The method embodiment of the present application is described in detail. Figure 6 to Figure 7 The device embodiment of the present application is described in detail. It should be understood that the description of the method embodiment corresponds to the description of the device embodiment, so the parts not described in detail can refer to the previous method embodiment.

[0116] Figure 6 FIG. 6 is a schematic diagram showing the structure of a satellite orbit information conversion device 600 provided in an embodiment of the present application. Figure 6 The satellite orbit information conversion device 600 may include an acquisition unit 610 and a calculation unit 620 .

[0117] The acquisition unit 610 may be configured to acquire orbit information of the satellite in the first coordinate system.

[0118] The calculation unit 620 may be configured to convert the orbit information from the first coordinate system to the second coordinate system by simplifying the calculation.

[0119] The orbital information includes the position and velocity of the satellite, and the simplified calculation includes at least one of the following: simplifying the calculation of the time involved in the first coordinate system and the second coordinate system respectively; simplifying the calculation of the polar shift transformation matrix; simplifying the calculation of the Greenwich sidereal hour angle; simplifying the calculation of at least one of the mean obliquity, nutation of the ecliptic longitude, nutation of the intersection angle and instantaneous obliquity; and simplifying the calculation of the precession angle.

[0120] Optionally, simplifying the calculations of the first coordinate system and the second coordinate system respectively related to time may include at least one of the following: unifying the starting points of the first coordinate system and the second coordinate system respectively related to time; and ignoring leap seconds.

[0121] Optionally, simplifying the calculation of the pole shift conversion matrix may include: the pole shift conversion matrix adopts a unit matrix.

[0122] Optionally, simplifying the calculation of the Greenwich sidereal hour angle may include at least one of the following: retaining the polynomial involved in the calculation of the Greenwich sidereal hour angle up to quadratic terms and discarding higher-order terms; and retaining the mean obliquity and nutation of the ecliptic.

[0123] Optionally, simplifying the calculation of at least one of the mean obliquity, nutation of the ecliptic longitude, nutation of the intersection angle and instantaneous obliquity may include: retaining the constant term or the constant term and the linear term in the polynomial involved in the respective calculations of the mean obliquity, nutation of the ecliptic longitude, nutation of the intersection angle and / or instantaneous obliquity.

[0124] Optionally, simplifying the calculation of the ecliptic longitude nutation may include discarding a constant parameter matrix involved in the IAU2000 model.

[0125] Optionally, simplifying the calculation of the precession angle may include: retaining the polynomial involved in the calculation of the precession angle up to first-order terms and discarding higher-order terms.

[0126] Optionally, the first coordinate system is one of the WBS84 coordinate system and the J2000 coordinate system, and the second coordinate system is the other of the WBS84 coordinate system and the J2000 coordinate system.

[0127] Figure 7 FIG. 7 is a schematic diagram of the structure of a satellite orbit information conversion device 700 provided in another embodiment of the present application. The satellite orbit information conversion device 700 can be used to implement the method described in the above method embodiment.

[0128] The satellite orbit information conversion device 700 may include one or more processors 710. The processor 710 may support the satellite orbit information conversion device 700 to implement the method described in the above method embodiment.

[0129] The processor 710 may be a general-purpose processor or a special-purpose processor. For example, the processor may be a central processing unit (CPU). Alternatively, the processor may be other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or the processor may be any conventional processor, etc.

[0130] The satellite orbit information conversion device 700 may further include one or more memories 720. The memory 720 stores a program, which can be executed by the processor 710 to control the satellite orbit information conversion device 700 to execute the method described in the above method embodiment. The memory 720 may be independent of the processor 710 or integrated in the processor 710.

[0131] The satellite orbit information conversion device 700 may further include a transceiver 730. The processor 710 may communicate with other devices through the transceiver 730. For example, the processor 710 may transmit and receive data with other devices through the transceiver 730.

[0132] The present application also provides a chip in an embodiment, including a processor, which can be used to call and run a computer program from a memory, so that a device equipped with the chip performs the method described in the above method embodiment. It is understood that the processor can be any type of processor mentioned above. It is understood that the memory can be independent of the chip or integrated in the chip.

[0133] The embodiment of the present application also provides a machine-readable storage medium for storing a program, and the program enables a computer to execute the method in each embodiment of the present application.

[0134] The embodiment of the present application also provides a computer program product. The computer program product includes a program. The program enables a computer to execute the method in each embodiment of the present application.

[0135] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any other combination. When implemented by software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present disclosure is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a machine-readable storage medium, or transmitted from one machine-readable storage medium to another machine-readable storage medium. For example, the computer instructions can be transmitted from a website site, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (Digital Subscriber Line, DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) mode to another website site, computer, server or data center. The machine-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integrations. The available medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a digital video disc (DVD)), or a semiconductor medium (eg, a solid state disk (SSD)).

[0136] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments of the present disclosure can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present disclosure.

[0137] In the several embodiments provided in the present disclosure, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0138] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0139] In addition, each functional unit in each embodiment of the present disclosure may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0140] The above is only a specific embodiment of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any person skilled in the art who is familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present disclosure, which should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.

Claims

1. A satellite orbit information conversion method, characterized in that: include: Obtain the orbit information of the satellite in the first coordinate system; as well as The orbit information is converted from the first coordinate system to the second coordinate system by simplified calculation, Wherein, the orbital information includes the position and velocity of the satellite, and the simplified calculation includes at least one of the following: simplifying the calculation of the first coordinate system and the second coordinate system respectively involving time; simplifying the calculation of the polar shift conversion matrix; simplifying the calculation of the Greenwich sidereal hour angle; simplifying the calculation of at least one of the mean obliquity, nutation of the ecliptic longitude, nutation of the intersection angle and instantaneous obliquity; and simplifying the calculation of the precession angle.

2. The method according to claim 1, characterized in that The simplifying of the calculation of the first coordinate system and the second coordinate system respectively related to time comprises at least one of the following: unifying the starting point of the first coordinate system and the second coordinate system respectively related to time; and ignoring leap seconds.

3. The method according to claim 1 or 2, characterized in that: The calculation of the simplified pole shift conversion matrix includes: the pole shift conversion matrix adopts a unit matrix.

4. The method according to claim 1 or 2, characterized in that: The simplified calculation of the Greenwich sidereal hour angle comprises at least one of the following: retaining the polynomial involved in the calculation of the Greenwich sidereal hour angle up to the quadratic term and discarding the higher order terms; And retain the obliquity of the mean and the nutation of the ecliptic.

5. The method according to claim 4, characterized in that The simplified calculation of at least one of the mean obliquity, nutation of the ecliptic longitude, nutation of the intersection angle and instantaneous obliquity includes: retaining the constant term or the constant term and the linear term in the polynomial involved in the calculation of the mean obliquity, nutation of the ecliptic longitude, nutation of the intersection angle and / or instantaneous obliquity.

6. The method according to claim 5, characterized in that The calculation of simplified ecliptic nutation includes discarding the constant parameter matrix involved in the IAU2000 model.

7. The method according to claim 1 or 2, characterized in that: The simplified calculation of the precession angle includes: retaining the polynomial involved in the calculation of the precession angle up to the first-order terms and discarding higher-order terms.

8. The method according to claim 1 or 2, characterized in that: The first coordinate system is one of a WBS84 coordinate system and a J2000 coordinate system, and the second coordinate system is the other of the WBS84 coordinate system and the J2000 coordinate system.

9. A satellite orbit information conversion device, characterized in that: include: An acquisition unit, used for acquiring orbit information of the satellite in the first coordinate system; as well as a calculation unit, configured to convert the orbit information from the first coordinate system to a second coordinate system by simplified calculation, Wherein, the orbital information includes the position and velocity of the satellite, and the simplified calculation includes at least one of the following: simplifying the calculation of the first coordinate system and the second coordinate system respectively involving time; simplifying the calculation of the polar shift conversion matrix; simplifying the calculation of the Greenwich sidereal hour angle; simplifying the calculation of at least one of the mean obliquity, nutation of the ecliptic longitude, nutation of the intersection angle and instantaneous obliquity; and simplifying the calculation of the precession angle.

10. A satellite orbit information conversion device, characterized in that: include: A memory for storing codes; as well as A processor, configured to execute the code stored in the memory to perform the method according to any one of claims 1 to 8.

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