Celestial body orientation parameter resolving method and system based on inverse VLBI interferometry and medium

Abstract

The invention provides a celestial body orientation parameter resolving method and system based on inverse VLBI interferometry and a medium. The method comprises the following steps: firstly, establishing a rotation orientation physical model and an inverse VLBI differential measurement model of a celestial body, and introducing a lander coordinate and a celestial body orientation parameter into the model by combining conversion between a non-inertial system coordinate and an inertial system coordinate; through inverse VLBI high-precision differential measurement tracking data, a lander position and celestial body orientation model parameters are determined based on the principle of a least square method, so that the residual sum of squares between an inverse VLBI calculation theory observation value and a ground observation value is minimum, and high-precision extraterrestrial celestial body orientation parameters are inverted. According to the method, precise positioning of the lander and calculation of the celestial body orientation parameters can be achieved, the obtained data is high in precision, the calculation precision of the celestial body orientation model parameters can be remarkably improved through high-precision inverse VLBI differential measurement data, then information of the internal structure and surface mass distribution change of the celestial body is provided, and additional constraints are provided for improvement of a celestial body physical model.

Description

Technical Field

[0001] The present invention relates to the field of precise positioning of a landing probe and deep space exploration, and in particular to a method, system and medium for precisely positioning a landing probe and calculating high-precision orientation parameters of an extraterrestrial body based on an inverse VLBI measurement mode. Background Art

[0002] The transformation of celestial body rotation contains important information about its internal structure and surface mass distribution. The determination of high-precision orientation parameters helps to provide additional constraints for the improvement of astrophysical models, thereby revealing the internal structure of celestial bodies. At present, the high-precision measurement of lunar orientation parameters is based on lunar laser ranging using lunar reflectors, and the high-precision measurement of Mars orientation parameters is based on two-way ranging and velocity measurement using radio tracking of the Mars lander. However, due to insufficient detection data, the orientation parameters of other celestial bodies have low accuracy. Generally speaking, new deep space exploration missions and more tracking observation data can effectively improve the physical model of celestial body rotation.

[0003] Traditional Very Long Baseline Interferometry (VLBI) is to use two antennas on the ground to receive electromagnetic waves radiated by radio sources and then measure the delay and delay rate. This measurement method is used to study the rotation of the earth, such as Figure 3 As shown in Figure 2, traditional VLBI has limitations in the study of extraterrestrial objects.

[0004] New measurement modes, such as the realization of inverse VLBI, are effective means for us to further improve the accuracy of directional parameters. Inverse VLBI measurement uses a ground antenna to receive signals simultaneously emitted from different positions on other celestial bodies. By taking advantage of the fact that the geometric path difference of electromagnetic waves reaching the ground antenna is constantly changing due to the rotation of the extraterrestrial body, we can study the rotation of the extraterrestrial body in reverse. The measurement diagram is as follows: Figure 2 .

[0005] In summary, we need a method and system for precise positioning of landing probes and high-precision orientation parameter calculation of extraterrestrial objects based on the inverse VLBI measurement mode that can break the limitations of traditional measurements. Summary of the invention

[0006] In view of the defects in the prior art, the purpose of the present invention is to achieve precise positioning of the lander and solution of celestial body orientation parameters so that the obtained data has high accuracy.

[0007] A method for calculating celestial body orientation parameters based on inverse VLBI interferometry provided by the present invention comprises the following steps:

[0008] Step S1: Establish the rotation orientation physical model of the celestial body and the inverse VLBI differential measurement model according to the research objectives;

[0009] Step S2: Based on the rotation orientation physical model and the inverse VLBI differential measurement model, the theoretical observation values ​​of the inverse VLBI differential measurement and the partial derivatives of the theoretical observation values ​​with respect to the coordinates of the lander to be estimated and the orientation parameters of the celestial body are calculated;

[0010] Step S3: fitting the ground observations of the inverse VLBI differential measurement according to the theoretical observations and partial derivatives, solving the correction values ​​of the position vector of the lander and the orientation parameters of the celestial body, adding the correction values ​​to the parameters to be estimated, and obtaining the optimal estimate;

[0011] Step S2 and step S3 are repeated until the difference between the two optimal estimation values ​​before and after correction is less than the convergence condition.

[0012] Preferably, step S1 includes the following sub-steps:

[0013] S1.1, establish the physical model of the lunar rotation orientation;

[0014] S1.2, establish an inverse VLBI differential measurement model.

[0015] Preferably, in step S1.1, the conversion relationship of the lunar rotation orientation physical model from the lunar center celestial sphere coordinate system to the lunar center lunar fixed coordinate system is as follows:

[0016]

[0017] Among them, r bf and r icrs are the lunar solid coordinates and lunar celestial coordinates, R (x，y，z) Represents the rotation matrix around the x, y, and z axes, three Euler angles Calculated by the following formula:

[0018]

[0019] θ=90°-δ0

[0020] ψ=W

[0021] Among them, α0, δ0 and W define the direction of the celestial body's rotation axis and the position of the prime meridian.

[0022] Preferably, in step S1.2, the inverse VLBI differential measurement system includes: multiple celestial body landers, a relay satellite and a ground receiving antenna, the ground receiving antenna is used to receive information sent by multiple landers at the same time, measure the receiving delay, and obtain ground observation values, the ground observation values ​​include delay and delay rate data; the relay satellite is used to perform two-way time synchronization between the multiple landers;

[0023] The delay measurement model is as follows:

[0024] Tivlbi =τ g +Δτ t +Δτ p

[0025] Among them, τ g is the geometric delay, Δτ t is the time difference correction between landers, Δτ p is the propagation path delay correction.

[0026] Preferably, in step S2,

[0027] The calculation formula of the theoretical observation value of inverse VLBI differential measurement is as follows:

[0028]

[0029] Where R1 and R2 are the distances from the two landers to the ground antenna, c is the speed of light, RLT is the gravitational delay in the signal propagation process, t1 and t2 represent the time when the ground receives the signals from the two landers, and since the observations recorded by the ground antenna are given in UTC, the second half is the correction to convert the time scale from UTC to TDB.

[0030] The calculation formula of partial derivative is as follows:

[0031]

[0032]

[0033] Where (x, y, z) represents the position vector of the lander in the lunar fixed system, are the three Euler angle parameters that describe the rotation orientation of the moon.

[0034] Preferably, step S3 includes the following sub-steps:

[0035] S3.1, fitting the ground observations of the inverse VLBI differential measurement to the theoretical observations;

[0036] S3.2, based on the partial derivatives, solve the correction values ​​of the position vector of the lander and the orientation parameters of the celestial body;

[0037] S3.3, add the correction value to the parameter to be estimated to obtain the optimal estimate.

[0038] Preferably, in step S3.2, the normal equation is constructed according to the partial derivatives, that is, the principle of the least squares method is used to determine the lander position and the orientation model parameters of the celestial body so that the sum of squares of the residuals between the theoretical observations and the ground observations is minimized, and based on the lander position and the orientation model parameters of the celestial body, the correction values ​​of the lander position vector and the orientation parameters of the celestial body are solved.

[0039] Preferably, in step S3, the convergence condition is determined, and multiple iterations are performed to obtain the best estimated values ​​of the lander position vector and the orientation parameter model of the celestial body.

[0040] The present invention also provides a celestial body orientation parameter solution system based on inverse VLBI interferometry, comprising:

[0041] Model building module: according to the research objectives, establish the rotation orientation physical model of celestial bodies and the inverse VLBI differential measurement model;

[0042] Theoretical observation value and partial derivative calculation module: Based on the rotation orientation physical model and the inverse VLBI differential measurement model, the theoretical observation value of the inverse VLBI differential measurement and the partial derivatives of the theoretical observation value for the coordinates of the estimated lander and the orientation parameters of the celestial body are calculated;

[0043] Optimal estimate generation module: According to the theoretical observation values ​​and partial derivatives, the ground observation values ​​of the inverse VLBI differential measurement are fitted, the correction values ​​of the position vector of the lander and the orientation parameters of the celestial body are solved, and the correction values ​​are added to the parameters to be estimated to obtain the optimal estimate; the theoretical observation value and partial derivative calculation module and the optimal estimate generation module are repeatedly triggered until the difference between the optimal estimates before and after the correction is less than the convergence condition.

[0044] The present invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the above-mentioned method for solving celestial body orientation parameters based on inverse VLBI interferometry.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] The present invention carries out deep space exploration missions based on the inverse VLBI measurement mode, and utilizes the inverse VLBI differential measurement data to achieve precise positioning of the lander and calculation of celestial body orientation parameters.

[0047] Inverse VLBI measurements eliminate most of the errors in satellite-to-earth signal propagation through differential means, and the data obtained is highly accurate. High-precision inverse VLBI differential measurement data can significantly improve the accuracy of solving the parameters of celestial body orientation models, and then provide information on changes in the internal structure of celestial bodies and surface mass distribution, providing additional constraints for the improvement of astrophysical models.

[0048] The present invention applies the inverse VLBI measurement mode to the calculation of the rotation orientation parameters of extraterrestrial objects. The high-precision inverse VLBI differential measurement data is sensitive to the celestial body orientation parameters. The high-quality data contains the transformation information of the celestial body rotation, which can significantly constrain the celestial body rotation physical model, improve the calculation accuracy of the orientation parameters, and further reveal the internal structure and material composition of the celestial body. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0050] Figure 1 A schematic diagram of a reference system for defining the orientation of a celestial body in an embodiment of the present invention;

[0051] Figure 2 Schematic diagram of an inverse VLBI differential measurement model in an embodiment of the present invention;

[0052] Figure 3 Schematic diagram of the traditional VLBI measurement model;

[0053] Figure 4 Schematic diagram of the physical model of extraterrestrial body rotation and inverse VLBI differential measurement. DETAILED DESCRIPTION

[0054] The present invention is applicable to the field of deep space exploration. Considering that multiple detectors land on the surface of a celestial body to carry out a joint inverse VLBI measurement experiment, two-way time synchronization is carried out with the assistance of a relay satellite and radio signals are transmitted back to the same ground station. The present invention is based on the inverse VLBI interferometric measurement mode. The differential delay data solves the method of high-precision positioning information and celestial body orientation parameters of the lander. The method eliminates most of the errors in the interplanetary propagation of the signal by means of differential data processing, and then provides high-precision inverse VLBI measurement delay and delay rate data, so as to achieve high-precision positioning of the lander and high-precision solution of celestial body orientation parameters. First, an inverse VLBI interferometric measurement mode and a mathematical and physical model of celestial body rotation are established, and the lander coordinates and celestial body orientation parameters are introduced into the model in combination with the conversion between non-inertial system and inertial system coordinates. Through the inverse VLBI high-precision differential measurement tracking data, based on the principle of the least squares method, a lander position and celestial body orientation model parameters are determined, so that the residual square sum between the theoretical observation value of the inverse VLBI calculation and the ground observation value is minimized, and high-precision extraterrestrial celestial body orientation parameters are inverted.

[0055] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0056] Embodiment 1:

[0057] The present invention uses the inverse VLBI interferometric measurement mode to eliminate the influence of interplanetary propagation errors of signals by differential means, and obtains high-precision differential tracking measurement data between landers. Due to the rotation of celestial bodies, the geometric path of signals reaching the ground receiving antenna is constantly changing. The physical change information of the rotation of celestial bodies is contained in the inverse VLBI measurement data. Using the principle of the least squares method, the orientation parameters of celestial bodies can be inverted with high precision.

[0058] The embodiment of the present invention provides a method for calculating celestial body orientation parameters based on inverse VLBI interferometry, comprising the following steps:

[0059] Step S1: According to the research objectives, establish the rotation orientation physical model of the celestial body and the inverse VLBI differential measurement model.

[0060] Establish a mathematical and physical model of the rotation and orientation of extraterrestrial bodies, obtain the position coordinate transformation matrix between the lander's inertial system and the non-inertial system, unify the time and space framework, and establish the connection between the measured values ​​and the model parameters.

[0061] By tracking and measuring the signals emitted simultaneously by multiple landers for a long time, the geometric path difference to the ground antenna is calculated to obtain differential inverse VLBI measurement values ​​containing information on the physical changes in the rotation orientation of extraterrestrial bodies.

[0062] In this embodiment, the high-precision orientation parameter solution of the moon is taken as an example.

[0063] Step S1 includes the following sub-steps:

[0064] S1.1, establish a physical model of the moon's rotation orientation.

[0065] In the classical Newtonian space-time framework, we divide the coordinate system into inertial coordinate system and non-inertial coordinate system, and the rotation orientation physical model of extraterrestrial bodies is used to convert between these two coordinate systems. Generally speaking, different celestial bodies have their own non-inertial systems. For example, the moon, from the moon-centered celestial coordinate system to the moon-centered moon-fixed coordinate system, needs to consider the rotation orientation physical model of the moon under the influence of the moon's libration. This conversion model is generally expressed by three Euler angles, and the conversion relationship is as follows:

[0066]

[0067] Among them, r bf and r icrs are the lunar solid coordinates and lunar celestial coordinates, R (x，y，z) Represents the rotation matrix around the x, y, and z axes, three Euler angles Calculated by the following formula:

[0068]

[0069] θ=90°-δ0

[0070] ψ=W

[0071] Among them, α0, δ0 and W define the direction of the celestial body's rotation axis and the position of the prime meridian.

[0072] Figure 1 Schematic diagram of a reference system for defining the orientation of a celestial body in an embodiment of the present invention.

[0073] like Figure 1 As shown in the figure, the celestial north pole is represented by the right ascension α0 and declination δ0 of the rotation axis projected on the celestial sphere, and W is the angle from the ascending node of the celestial body's mean equator and the earth's mean equator from west to east to the prime meridian, which describes the rotation of the celestial body. However, due to the precession and nutation of the celestial body's rotation axis, the parameters α0, δ0 and W will change with the occurrence time, so we need to further use observational data for correction to obtain high-precision rotation orientation parameter values ​​of extraterrestrial bodies.

[0074] S1.2, establish an inverse VLBI differential measurement model.

[0075] Figure 2 is a schematic diagram of an inverse VLBI differential measurement model in an embodiment of the present invention, Figure 4 Schematic diagram of the physical model of extraterrestrial body rotation and inverse VLBI differential measurement.

[0076] In this embodiment, Figure 2 , 4 As shown, the inverse VLBI differential measurement system consists of three parts: two or more celestial body landers, a relay satellite and a ground receiving antenna.

[0077] The specific measurement mode is: use the ground receiving antenna to receive the information sent simultaneously by the lander, measure the receiving delay, and obtain ground observation values, which include time delay and delay rate data; the role of the relay satellite is to perform two-way time synchronization between the landers to eliminate factors that cause time drift.

[0078] The specific delay measurement model is as follows:

[0079] τ ivlbi =τ g +Δτ t +Δτ p

[0080] Among them, τ g is the geometric delay, Δτ t is the time difference correction between landers, Δτ p is the propagation path delay correction. Specifically, τ gIt is the main body of the inverse VLBI differential measurement, which is the geometric distance difference from the lander to the ground receiving antenna. Because the clocks on the lander may not be completely stable and synchronized, the clocks between the landers are synchronized bidirectionally through the relay satellite, and the resulting time difference correction Δτ t At the same time, the propagation process of electromagnetic waves is affected by many factors, and it is necessary to correct the propagation time change Δτ caused by the relativistic effect in the solar system. p .

[0081] Step S2: Based on the rotation orientation physical model and the inverse VLBI differential measurement model, the theoretical observation values ​​of the inverse VLBI differential measurement and the partial derivatives of the observation values ​​with respect to the coordinates of the lander to be estimated and the orientation parameters of the celestial body are calculated.

[0082] The calculation formula of the theoretical observation value of inverse VLBI differential measurement is as follows:

[0083]

[0084] Among them, R1 and R2 are the distances from the two landers to the ground antenna, c is the speed of light, RLT is the gravitational delay in the signal propagation process, t1 and t2 respectively represent the time when the ground receives the signals from the two landers. Since the ground antenna generally records the observation values ​​in UTC time scale, the corresponding time scale needs to be corrected. The second half is the correction to convert the time scale from UTC to TDB time scale.

[0085] It is worth noting that the inverse VLBI differential observation data contains the relative position changes between the landers, so the positions of the two landers cannot be solved at the same time. Therefore, the inverse VLBI differential measurement only determines the partial derivatives of the position vector and lunar orientation parameters of a certain lander.

[0086] The calculation formula of partial derivative is as follows:

[0087]

[0088]

[0089] Where (x, y, z) represents the position vector of the lander in the lunar fixed system. These are the three Euler angle parameters that describe the rotation orientation of the moon. According to the accuracy of the observation values, these three Euler angles can be further subdivided into J2000 value, change rate and correction term.

[0090] Step S3: According to the theoretical observation values ​​and partial derivatives, the ground observation values ​​of the inverse VLBI differential measurement are fitted, and the correction values ​​of the position vector of the lander and the orientation parameters of the celestial body are solved. The correction values ​​are added to the parameters to be estimated to obtain the optimal estimate.

[0091] Step S3 includes the following sub-steps:

[0092] S3.1, fit the ground observations of the inverse VLBI differential measurement to the theoretical observations.

[0093] S3.2, based on the partial derivatives, solve the correction values ​​of the position vector of the lander and the orientation parameters of the celestial body.

[0094] Specifically, based on the partial derivatives, the normal equation is constructed, that is, the principle of least squares method is used to determine a lander position and the orientation model parameters of the moon, so that the sum of squares of residuals between theoretical observations and ground observations is minimized, and based on the lander position and the orientation model parameters of the celestial body, the correction values ​​of the lander position vector and the orientation parameters of the celestial body are solved.

[0095] S3.3, add the correction value to the parameter to be estimated to obtain the optimal estimate.

[0096] Step S2 and step S3 are repeated until the difference between the two optimal estimation values ​​before and after correction is less than the convergence condition.

[0097] Specifically, the convergence conditions are determined and multiple iterations are performed to obtain the best estimates of the position vector of the lander and the orientation parameter model of the celestial body.

[0098] Embodiment 2:

[0099] The present invention also provides a celestial body orientation parameter solution system based on inverse VLBI interferometry. The celestial body orientation parameter solution system based on inverse VLBI interferometry can be realized by executing the process steps of the celestial body orientation parameter solution method based on inverse VLBI interferometry, that is, those skilled in the art can understand the celestial body orientation parameter solution method based on inverse VLBI interferometry as a preferred implementation of the celestial body orientation parameter solution system based on inverse VLBI interferometry.

[0100] An embodiment of the present invention provides a celestial body orientation parameter solution system based on inverse VLBI interferometry, comprising:

[0101] Model building module: according to the research objectives, establish the rotation orientation physical model of celestial bodies and the inverse VLBI differential measurement model;

[0102] Theoretical observation value and partial derivative calculation module: Based on the rotation orientation physical model and the inverse VLBI differential measurement model, the theoretical observation value of the inverse VLBI differential measurement and the partial derivatives of the theoretical observation value for the coordinates of the estimated lander and the orientation parameters of the celestial body are calculated;

[0103] Optimal estimate generation module: According to theoretical observations and partial derivatives, the ground observations of inverse VLBI differential measurement are fitted, the correction values ​​of the position vector of the lander and the orientation parameters of the celestial body are solved, and the correction values ​​are added to the parameters to be estimated to obtain the optimal estimate;

[0104] The theoretical value and partial derivative calculation module and the optimal estimation value generation module are repeatedly triggered to work until the difference between the optimal estimation values ​​before and after correction is less than the convergence condition.

[0105] Embodiment 3:

[0106] An embodiment of the present invention provides a computer-readable storage medium storing a computer program, and when the computer program is executed by a processor, the steps of the above-mentioned method for solving celestial body orientation parameters based on inverse VLBI interferometry are implemented.

[0107] Those skilled in the art know that, in addition to realizing the system and its various devices, modules, and units provided by the present invention in a purely computer-readable program code, it is entirely possible to realize the same functions in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers by logically programming the method steps. Therefore, the system and its various devices, modules, and units provided by the present invention can be considered as a hardware component, and the devices, modules, and units included therein for realizing various functions can also be regarded as structures within the hardware component; the devices, modules, and units for realizing various functions can also be regarded as both software modules for realizing the method and structures within the hardware component.

[0108] In the description of the present application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0109] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A method for calculating celestial body orientation parameters based on inverse VLBI interferometry, characterized in that: The steps include: Step S1, establishing a rotation orientation physical model of the celestial body and an inverse VLBI differential measurement model according to the research target; Step S2, calculating theoretical observation values ​​of inverse VLBI differential measurement and partial derivatives of the theoretical observation values ​​with respect to the coordinates of the lander to be estimated and the orientation parameters of the celestial body based on the rotation orientation physical model and the inverse VLBI differential measurement model; Step S3, fitting the ground observation values ​​of the inverse VLBI differential measurement according to the theoretical observation values ​​and the partial derivatives, solving the correction values ​​of the position vector of the lander and the orientation parameters of the celestial body, adding the correction values ​​to the parameters to be estimated, and obtaining the optimal estimation values; Herein, step S2 and step S3 are repeated until the difference between the two optimal estimation values ​​before and after correction is smaller than the convergence condition.

2. The method for calculating celestial body orientation parameters based on inverse VLBI interferometry according to claim 1, characterized in that: The step S1 includes the following sub-steps: S1.1, establish the physical model of the lunar rotation orientation; S1.2, establish an inverse VLBI differential measurement model.

3. The method for calculating celestial body orientation parameters based on inverse VLBI interferometry according to claim 2, characterized in that: In step S1.1, the conversion relationship of the lunar rotation orientation physical model from the lunar center celestial sphere coordinate system to the lunar center lunar solid coordinate system is as follows: Among them, r bf and r icrs are the lunar solid coordinates and lunar celestial coordinates, R (x，y，z) Represents the rotation matrix around the x, y, and z axes, three Euler angles Calculated by the following formula: θ=90°-δ0 ψ=W Among them, α0, δ0 and W define the direction of the celestial body's rotation axis and the position of the prime meridian.

4. The method for calculating celestial body orientation parameters based on inverse VLBI interferometry according to claim 2, characterized in that: In step S1.2, the inverse VLBI differential measurement system includes: multiple celestial landers, a relay satellite and a ground receiving antenna, wherein the ground receiving antenna is used to receive information sent simultaneously by the multiple landers, measure the receiving delay, and obtain the ground observation value, wherein the ground observation value includes delay and delay rate data; the relay satellite is used to perform two-way time synchronization between the multiple landers; The delay measurement model is as follows: t ivlbi =t g +Δt t +Δt p Among them, τ g is the geometric delay, Δτ t is the time difference correction between landers, Δτ p is the propagation path delay correction.

5. The method for calculating celestial body orientation parameters based on inverse VLBI interferometry according to claim 4, characterized in that: In the step S2, The calculation formula of the theoretical observation value of the inverse VLBI differential measurement is as follows: Where R1 and R2 are the distances from the two landers to the ground antenna, c is the speed of light, RLT is the gravitational delay in the signal propagation process, t1 and t2 represent the time when the ground receives the signals from the two landers, respectively. Since the observations recorded by the ground antenna are given in UTC time, the second half is the correction to convert the time scale from UTC to TDB time scale. The calculation formula of the partial derivative is as follows: Where (x, y, z) represents the position vector of the lander in the lunar fixed system. are the three Euler angle parameters that describe the rotation orientation of the moon.

6. The method for calculating celestial body orientation parameters based on inverse VLBI interferometry according to claim 5, characterized in that: The step S3 includes the following sub-steps: S3.1, fitting the ground observation values ​​of the inverse VLBI differential measurement according to the theoretical observation values; S3.2, calculating the position vector of the lander and the correction value of the orientation parameter of the celestial body according to the partial derivative; S3.3, adding the correction value to the parameter to be estimated to obtain the optimal estimated value.

7. The method for calculating celestial body orientation parameters based on inverse VLBI interferometry according to claim 6, characterized in that: In step S3.2, a normal equation is constructed based on the partial derivatives, that is, the position of the lander and the orientation model parameters of the celestial body are determined using the principle of the least squares method, so that the sum of squared residuals between the theoretical observation values ​​and the ground observation values ​​is minimized, and based on the position of the lander and the orientation model parameters of the celestial body, the position vector of the lander and the correction values ​​of the orientation parameters of the celestial body are solved.

8. The method for calculating celestial body orientation parameters based on inverse VLBI interferometry according to claim 1, characterized in that: In step S3, the convergence condition is determined, and multiple iterations are performed to obtain the best estimated values ​​of the lander position vector and the orientation parameter model of the celestial body.

9. A celestial body orientation parameter calculation system based on inverse VLBI interferometry, characterized in that: include: Model building module: according to the research objectives, establish the rotation orientation physical model of celestial bodies and the inverse VLBI differential measurement model; Theoretical observation value and partial derivative calculation module: based on the rotation orientation physical model and the inverse VLBI differential measurement model, calculate the theoretical observation value of the inverse VLBI differential measurement, and the partial derivatives of the theoretical observation value with respect to the coordinates of the lander to be estimated and the orientation parameters of the celestial body; Optimal estimate value generation module: According to the theoretical observation value and the partial derivative, the ground observation value of the inverse VLBI differential measurement is fitted, the position vector of the lander and the correction value of the orientation parameter of the celestial body are solved, and the correction values ​​are added to the parameters to be estimated respectively to obtain the optimal estimate value, and the theoretical observation value and partial derivative calculation module and the optimal estimate value generation module are repeatedly triggered until the difference between the optimal estimate values ​​before and after the correction is less than the convergence condition.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the method for solving the celestial body orientation parameters based on inverse VLBI interferometry described in any one of claims 1 to 8 are implemented.

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