A method for identifying motion parameters of non-cooperative spacecraft based on constellation fingerprint library

Abstract

The present invention provides a method for identifying motion parameters of non-cooperative spacecraft based on a star cluster fingerprint library, including: using a position positioning method based on field strength distance information to obtain the relative motion state and position relationship of star cluster members; the observation satellite uses a satellite-borne radar to detect, search and roughly locate the non-cooperative spacecraft, and selects a suitable sub-star cluster as an adsorption satellite according to the positioning information; the adsorption satellite approaches the non-cooperative spacecraft using a Lambert guidance method; the satellite-borne adsorption device works after the target enters the adsorption range according to the high-precision ranging information calculated by the satellite-borne camera, so that the adsorption satellite is adsorbed on the surface of the non-cooperative spacecraft; the motion parameters of the adsorption satellite assembly are obtained by using a position positioning method based on field strength distance information, thereby realizing the identification of the motion parameters of the non-cooperative spacecraft. The present invention has the advantages of no need for image processing and multi-source information fusion, and is simple to operate and convenient for engineering implementation.

Description

Technical Field

[0001] The invention belongs to the field of aerospace technology, and in particular relates to a non-cooperative spacecraft motion parameter identification method based on a constellation fingerprint library, which can be used for on-orbit service. Background Art

[0002] With the continuous development of aerospace technology, the number of spacecraft in orbit has increased exponentially, and the demand for space operation tasks such as space capture, debris cleaning, and on-orbit refueling has become increasingly urgent. Most of the above mission objects are non-cooperative spacecraft in motion and with unknown mass characteristics, which brings great challenges to the realization of on-orbit services. How to obtain the motion information of non-cooperative spacecraft in a limited time domain has become a key technology for on-orbit services and has attracted widespread attention from scholars.

[0003] For the motion recognition of non-cooperative spacecraft, most of the existing methods are based on the observation of the target by a single spacecraft. Among them, there have been many achievements in the information measurement of non-cooperative spacecraft based on monocular vision. However, considering the influence of the complex space environment, it is impossible to guarantee that a single spacecraft can be in a good observation position for a long time. In this regard, some studies have proposed a multi-viewpoint observation method that uses multiple spacecraft to conduct collaborative measurements of non-cooperative spacecraft from different perspectives. However, in the dim space environment, the observation breadth and accuracy of the onboard camera are limited, and the onboard computing power is limited. It is very difficult to realize image processing and multi-source information fusion, and it is difficult to directly measure and obtain the precise motion parameters of non-cooperative spacecraft.

[0004] Therefore, how to utilize limited onboard observation conditions to obtain precise motion parameters of non-cooperative spacecraft within a limited time domain is a technical problem that needs to be solved urgently. Summary of the invention

[0005] The purpose of the present invention is to realize the identification of precise motion parameters of non-cooperative spacecraft in a limited time domain. In the dynamic environment of a micro-nano satellite cluster, a non-cooperative spacecraft motion parameter identification method based on a satellite cluster fingerprint library is proposed through inter-satellite links, simple receiving devices, satellite cameras, satellite radars and electromagnets.

[0006] The technical solution of the present invention is: a non-cooperative spacecraft motion parameter identification method based on a constellation fingerprint library, comprising the following steps:

[0007] S1. Using the location positioning method based on field strength distance information, the relative motion state and position relationship of the star cluster members are obtained;

[0008] S2, the observation satellite uses the onboard radar to detect, search and roughly locate the non-cooperative spacecraft, and selects the appropriate sub-constellation as the adsorption satellite according to the positioning information;

[0009] S3, the adsorption satellite uses Lambert guidance to approach the non-cooperative spacecraft;

[0010] S4. The onboard adsorption device works according to the high-precision ranging information calculated by the onboard camera after the target enters the adsorption range, so that the adsorption satellite is adsorbed on the surface of the non-cooperative spacecraft;

[0011] S5. Use the position positioning method based on field strength distance information to obtain the motion parameters of the adsorption satellite assembly, and then realize the identification of the motion parameters of the non-cooperative spacecraft.

[0012] Furthermore, the location positioning method based on field strength distance information in step S1 specifically includes the following steps:

[0013] Define AP as a wireless access point, set N dynamic reference stars in the micro-nano star cluster as the APs required for relative positioning, and establish a dynamic coordinate system; the dynamic coordinate system is a three-dimensional dynamic coordinate system with the center of mass of the virtual central star as the origin, the center of mass moving direction as the X direction, the center of the earth as the Z direction, and the Y direction satisfying the right-hand screw rule. The relationship between it and the earth's inertial coordinate system is as follows:

[0014] O M =C1·O1

[0015] in,

[0016]

[0017] Where u is the latitude argument, is the orbital inclination, and Ω is the right ascension of the ascending node. Therefore, the dynamic reference star obtains its own absolute position information based on the Beidou navigation system as the reference benchmark for cluster positioning, and completes the relative positioning of the reference star among the cluster stars based on the relative coordinate conversion.

[0018] Based on real sampling data and free space propagation model, a dynamic fingerprint library is established. RSSI is defined as signal strength indication. The RSSI of AP in the fingerprint information vector in the fingerprint library is the relative RSSI. The reference point is set to receive the received signal strength indication of the i-th AP. Let ΔRSSI 1，i =RSSI1-RSSI i , that is, the relative power of the strength of the ith AP and the first AP. Assuming a reference point is (x, y, z), the fingerprint information vector can be expressed as (x, y, z, ΔRSSI 1，2 , ΔRSSI 1，3 , ..., ΔRSSI 1，p , MAC, ...).

[0019] This form of expression eliminates the power compensation step due to changes in terminal transmit power, improves positioning accuracy and reduces complexity.

[0020] The reference satellite broadcasts periodically; the member satellite receives the signal, downloads the fingerprint library, and completes the relative position fingerprint identification; the relative position information of the unknown satellite is obtained as follows:

[0021] Assume that the signal vector received by the satellite from p APs at time t is (RSSI′1, ..., RSSI′ p ), taking RSSI′1 as the reference, the error signal obtained by subtraction can be recorded as (ΔRSSI′ 12′ , ..., ΔRSSI′ 1p ).

[0022] Calculate the Euclidean distance between the current data and p APs:

[0023]

[0024] Among them, d i is the Euclidean distance between the current measurement data and the i-th fingerprint in the database; ΔRSSI′ 1t Indicates the relative power of the tth AP and the first AP in the measured data; ΔRSSI i，1t It represents the relative power between the t-th AP and the 1st AP in the ith reference point in the fingerprint library.

[0025] Select the reference points corresponding to the smallest k d values ​​as the k neighboring points of the current satellite, and then the satellite position (x, y, z) can be obtained by the k-nearest algorithm:

[0026]

[0027] Where: d i is the distance between the relative power sequence of the mobile terminal and the i-th fingerprint data; ε is a very small positive constant to avoid the situation where the denominator is 0; (x i ,y i , z i ) is the position coordinate of the i-th fingerprint reference point; (x, y, z) is the position coordinate given by positioning.

[0028] Each member satellite informs the reference satellite of the relative positioning result through inter-satellite directional communication, and the reference satellite obtains the relative position information between cluster satellites through filtering.

[0029] Furthermore, the surface of the non-cooperative spacecraft included in step S2 has magnetic material, which can be adsorbed by the adsorption device onboard the adsorption satellite.

[0030] The adsorption satellite included in step S2 is: a satellite with an adsorption device installed in the star cluster and having an adsorption function is called an adsorption satellite. Adsorption satellites are mostly satellites with good power performance and communication performance, distributed at the periphery of the cluster, which is convenient for chasing non-cooperative spacecraft.

[0031] In step S2, the adsorption satellite adopts electromagnetic adsorption. Existing adsorption methods include electric adsorption, chemical adsorption, physical adsorption, electromagnetic adsorption, etc. The principle of electric adsorption is to form an electrostatic field between electrodes by applying an external voltage. The charged particles are forced to move to the electrode plate with the opposite charge by the electrostatic force in the electrostatic field, forming a double electric layer on the surface of the electrode plate, and the charged particles are adsorbed and temporarily stored in the double electric layer; the principle of chemical adsorption is that the adsorbate molecules and the atoms (or molecules) on the solid surface transfer, exchange or share electrons to form adsorption chemical bonds; the principle of physical adsorption is that the adsorbent and the adsorbed substance produce adsorption through intermolecular van der Waals forces; electromagnetic adsorption uses the principle of electromagnetism to generate magnetic force through the magnetic field effect of current to adsorb on the wall. Since electromagnetic adsorption has the advantages of continuous control and strong load capacity, it is superior to other adsorption methods, so electromagnetic adsorption is selected.

[0032] The satellite-borne radar detection search and rough positioning included in step S2 is: using the satellite-borne radar to scan and search the non-cooperative spacecraft operation area, and calculating the position of the target relative to the observation satellite in real time based on the detection information.

[0033] The appropriate position included in step S2 is: the task of the adsorption satellite is to chase the target, approach and adsorb on the target, and the selected adsorption satellite should have the characteristics of short pursuit time and low energy consumption. At the same time, in order to avoid collision with the target, the adsorption satellite and the non-cooperative spacecraft should move in the same direction. The adsorption satellite moving in the opposite direction to the non-cooperative spacecraft measures and calculates the relative distance to the target through the onboard camera, and can reselect a satellite with a shorter distance and fewer obstacles to perform the pursuit mission.

[0034] Furthermore, in step S3, the adsorption satellite gradually approaches the non-cooperative spacecraft by first selecting a point on the non-cooperative spacecraft as a predetermined adsorption point, and predetermining the time for the adsorption satellite to reach the adsorption point according to the initial position of the adsorption satellite and the position of the non-cooperative spacecraft. Lambert guidance and velocity gain guidance are applied to make the adsorption satellite reach the adsorption point at the predetermined time.

[0035] The Lambert guidance method is specifically as follows: the adsorption satellite first reaches the same orbital altitude as the predetermined adsorption point and enters the mid-range guidance process. The minimum energy strategy in the Lambert guidance is used to guide it into an elliptical orbit containing the predetermined adsorption point until the onboard camera on the adsorption satellite captures and continuously tracks the non-cooperative spacecraft, then it enters the terminal guidance. The terminal guidance process uses the sliding mode variable structure guidance law for control.

[0036] Furthermore, in step S4, in order to meet the requirements of approaching and adsorbing the target, the adsorption satellite needs to be equipped with a small engine and a satellite camera. In order to realize the guidance process, the adsorption satellite needs to be equipped with a satellite navigation receiver.

[0037] In the process of motion prediction, the satellite used to observe the target and provide guidance and other signals to the adsorption satellite is called an observation satellite. In order to meet the observation and guidance requirements, the observation satellite needs to be equipped with an onboard camera and an omnidirectional antenna. The observation satellite needs to roughly calculate the relative position of the non-cooperative spacecraft and perform guidance, and has stronger data processing capabilities than the adsorption satellite. The adsorption satellite receives the observation satellite signal, starts the onboard camera to observe in real time and calculate the position and attitude of the target relative to the adsorption satellite with high precision.

[0038] Furthermore, in step S5, the adsorption satellite is adsorbed on the surface of the non-cooperative spacecraft and moves in space with the non-cooperative spacecraft. The reference satellite broadcasts periodically, and the adsorption satellite continues to receive the field strength signal and downloads the fingerprint library to complete fingerprint identification; through inter-satellite communication, the motion parameters of the adsorption satellite assembly are obtained, thereby realizing the identification of the motion parameters of the non-cooperative spacecraft.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] The present invention uses a position positioning method based on field intensity distance information to obtain the continuous relative position relationship of clusters; uses a position positioning method based on field intensity distance information to obtain the relative motion state and position relationship of cluster members; an observation satellite uses an onboard radar to detect, search and roughly position a non-cooperative spacecraft, and selects a suitable sub-cluster as an adsorption satellite according to the positioning information; the adsorption satellite approaches the non-cooperative spacecraft using a Lambert guidance method; a satellite-borne adsorption device works after the target enters the adsorption range according to the high-precision ranging information calculated by an onboard camera, so that the adsorption satellite is adsorbed on the surface of the non-cooperative spacecraft; uses a position positioning method based on field intensity distance information to obtain the motion parameters of the adsorption satellite assembly, and then realizes the recognition of the motion parameters of the non-cooperative spacecraft, without the need for image processing and multi-source information fusion, reducing the amount of onboard calculation, shortening the onboard calculation time, and being simple to operate and convenient for engineering implementation. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 The figure is a flow chart of a non-cooperative spacecraft motion parameter identification method based on a constellation fingerprint library provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0042] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0043] like Figure 1 The figure is a flow chart of a non-cooperative spacecraft motion parameter identification method based on a constellation fingerprint library proposed in an embodiment of the present application, which specifically includes the following steps:

[0044] Step S1, using a location positioning method based on field strength distance information to obtain the relative motion state and position relationship of the star cluster members.

[0045] In the embodiment of the present application, the location positioning method based on field strength distance information in step S1 specifically includes the following steps:

[0046] Define AP as a wireless access point, set N dynamic reference stars in the micro-nano star cluster as the APs required for relative positioning, and establish a dynamic coordinate system; the dynamic coordinate system is a three-dimensional dynamic coordinate system with the center of mass of the virtual central star as the origin, the center of mass moving direction as the X direction, the center of the earth as the Z direction, and the Y direction satisfying the right-hand screw rule. The relationship between it and the earth's inertial coordinate system is as follows:

[0047] O M =C1·O1

[0048] in,

[0049]

[0050] Where u is the latitude argument, is the orbital inclination, and Ω is the right ascension of the ascending node. Therefore, the dynamic reference star obtains its own absolute position information based on the Beidou navigation system as the reference benchmark for cluster positioning, and completes the relative positioning of the reference star among the cluster stars based on the relative coordinate conversion.

[0051] Based on real sampling data and free space propagation model, a dynamic fingerprint library is established. RSSI is defined as signal strength indication. The RSSI of AP in the fingerprint information vector in the fingerprint library is the relative RSSI. The reference point is set to receive the received signal strength indication of the i-th AP. Let ΔRSSI 1，i =RSSI1-RSSI i , that is, the relative power of the strength of the ith AP and the first AP. Assuming a reference point is (x, y, z), the fingerprint information vector can be expressed as (x, y, z, ΔRSSI 1，2 , ΔRSSI 1，3 , ..., ΔRSSI 1，p , MAC, ...).

[0052] This form of expression eliminates the power compensation step due to changes in terminal transmit power, improves positioning accuracy and reduces complexity.

[0053] The reference satellite broadcasts periodically; the member satellite receives the signal, downloads the fingerprint library, and completes the relative position fingerprint identification; the relative position information of the unknown satellite is obtained as follows:

[0054] Assume that at time t, the satellite receives the following signal vectors from p APs (RSSI′1, ..., RSSI′ p ), taking RSSI′1 as the reference, the error signal obtained by subtraction can be recorded as (ΔRSSI′ 12′ , ..., ΔRSSI′ 1p ).

[0055] Calculate the Euclidean distance between the current data and p APs:

[0056]

[0057] Among them, d i is the Euclidean distance between the current measurement data and the i-th fingerprint in the database; ΔRSSI′ 1t Indicates the relative power of the tth AP and the first AP in the measured data; ΔRSSI i，1t It represents the relative power between the t-th AP and the 1st AP in the ith reference point in the fingerprint library.

[0058] Select the reference points corresponding to the smallest k d values ​​as the k neighboring points of the current satellite, and then the satellite position (x, y, z) can be obtained by the k-nearest algorithm:

[0059]

[0060] Where: d i is the distance between the relative power sequence of the mobile terminal and the i-th fingerprint data; ε is a very small positive constant to avoid the situation where the denominator is 0; (x i ,y i , z i ) is the position coordinate of the i-th fingerprint reference point; (x, y, z) is the position coordinate given by positioning.

[0061] Each member satellite informs the reference satellite of the relative positioning result through inter-satellite directional communication, and the reference satellite obtains the relative position information between cluster satellites through filtering.

[0062] Step S2: The observation satellite uses the onboard radar to detect, search and roughly locate the non-cooperative spacecraft, and selects a suitable sub-constellation as the adsorption satellite according to the positioning information.

[0063] In the embodiment of the present application, the surface of the non-cooperative spacecraft included in step S2 carries magnetic material, which can be adsorbed by the adsorption device onboard the adsorption satellite.

[0064] The adsorption satellite is a satellite with an adsorption device installed in the star cluster. Most of the adsorption satellites have good power and communication performance and are distributed outside the cluster to facilitate the pursuit of non-cooperative spacecraft.

[0065] In step S2, the adsorption satellite adopts electromagnetic adsorption. Existing adsorption methods include electric adsorption, chemical adsorption, physical adsorption, electromagnetic adsorption, etc. The principle of electric adsorption is to form an electrostatic field between electrodes by applying an external voltage. The charged particles are forced to move to the electrode plate with the opposite charge by the electrostatic force in the electrostatic field, forming a double electric layer on the surface of the electrode plate, and the charged particles are adsorbed and temporarily stored in the double electric layer; the principle of chemical adsorption is that the adsorbate molecules and the atoms (or molecules) on the solid surface transfer, exchange or share electrons to form adsorption chemical bonds; the principle of physical adsorption is that the adsorbent and the adsorbed substance produce adsorption through intermolecular van der Waals forces; electromagnetic adsorption uses the principle of electromagnetism to generate magnetic force through the magnetic field effect of current to adsorb on the wall. Since electromagnetic adsorption has the advantages of continuous control and strong load capacity, it is superior to other adsorption methods, so electromagnetic adsorption is selected.

[0066] The satellite-borne radar detection search and rough positioning are: using the satellite-borne radar to scan and search the non-cooperative spacecraft operation area, and calculating the position of the target relative to the observation satellite in real time based on the detection information.

[0067] The suitable position is: the task of the adsorption satellite is to chase the target, approach and adsorb on the target. The selected adsorption satellite should have the characteristics of short pursuit time and low energy consumption. At the same time, in order to avoid collision with the target, the adsorption satellite and the non-cooperative spacecraft should move in the same direction. The adsorption satellite moving in the opposite direction of the non-cooperative spacecraft measures and solves the relative distance to the target through the onboard camera, and can re-select a satellite with a shorter distance and fewer obstacles to perform the pursuit mission.

[0068] Step S3: The adsorption satellite approaches the non-cooperative spacecraft using Lambert guidance.

[0069] In the embodiment of the present application, the adsorption satellite gradually approaches the non-cooperative spacecraft in step S3 as follows: first, a point on the non-cooperative spacecraft is appropriately selected as a predetermined adsorption point, and the time for the adsorption satellite to reach the adsorption point is predetermined according to the initial position of the adsorption satellite and the position of the non-cooperative spacecraft. Lambert guidance and velocity gain guidance methods are applied to enable the adsorption satellite to reach the adsorption point at the predetermined time.

[0070] The Lambert guidance method is specifically as follows: the adsorption satellite first reaches the same orbital altitude as the predetermined adsorption point and enters the mid-range guidance process. The minimum energy strategy in the Lambert guidance is used to guide it into an elliptical orbit containing the predetermined adsorption point until the onboard camera on the adsorption satellite captures and continuously tracks the non-cooperative spacecraft, then it enters the terminal guidance. The terminal guidance process uses the sliding mode variable structure guidance law for control.

[0071] Specifically, the classic Lambert problem is described as follows: Given the initial time t0, the vectors of two points P1 and P2 in space relative to the gravitational center F1, that is, the radius r1 and r2 of P1 and P2 and their angle θ0, let the transfer time Δt = t f -t0 is fixed, find the elliptical transfer orbit, which satisfies the trajectory starting from point P1 and at time t f Just arrive at point P2.

[0072] S4. The satellite-borne adsorption device works according to the high-precision ranging information calculated by the satellite-borne camera after the target enters the adsorption range, so that the adsorption satellite is adsorbed on the surface of the non-cooperative spacecraft.

[0073] In the embodiment of the present application, in step S4, in order to meet the requirements of approaching and adsorbing to the target, the adsorbing satellite needs to be equipped with thrusters and onboard cameras.

[0074] During the guidance process, the observation satellite is used to roughly calculate the relative position of the non-cooperative spacecraft and send a guidance signal. The adsorption satellite receives the observation satellite signal and activates the onboard camera to observe in real time and calculate the position and attitude of the target relative to the adsorption satellite with high precision.

[0075] Specifically, the observation and solution process of the onboard camera is as follows: the adsorption satellite receives the adsorption signal of the observation satellite, turns on the binocular ranging camera, and shoots the target; the image is stereo corrected and stereo matched, and the position and attitude of the target relative to the adsorption satellite are calculated by reprojection after correction; the adsorption satellite is started according to the correction result after the target enters the working range of the adsorption device.

[0076] The stereo correction is as follows: stereo correct the image through the Bought algorithm so that the optical axes of the image are parallel and the rows are aligned. Given the intrinsic camera parameters and the translation and rotation matrix between cameras, the rotation matrix R is obtained, and the rotation matrix R of the right image plane relative to the left image plane is decomposed into two rotation matrices R1 and R2. Each image is rotated by half to maximize the common area of ​​the left and right views and ensure that the optical axes of the two cameras are parallel. The rotation of the image can make the two image planes coplanar, but the pixel rows of the image are not calibrated. In order to align the pixel rows, the Bought algorithm is used to correct the image so that the poles of the camera are transformed to infinity to ensure the alignment of the pixel rows. In order to transform the poles to infinity, even if the pole lines and the baselines are parallel, the direction of the poles is the direction of the translation vector between the projection centers of the left and right cameras, that is:

[0077]

[0078] Among them, e1 is the translation vector, T is the translation matrix T = [T x T y T z ].

[0079] e2 is a vector orthogonal to e1 and the optical axis, which can be obtained by the cross product of e1 and the optical axis and then normalized to a unit vector:

[0080]

[0081] e3 is orthogonal to e1 and e2, so e3 is the cross product of e1 and e2: e3 = e1 × e2. So far, the matrix R that transforms the right pole to infinity is r for:

[0082]

[0083] This matrix rotates the right image about the right center of projection so that the epipolar lines are parallel to the baseline and the poles intersect at infinity.

[0084] The stereo matching is as follows: using the absolute error sum algorithm, a window template is created with the point to be matched in the left image as the center pixel, and the characteristic value of the center pixel is quantified using the grayscale distribution of all pixels in the image of the area. Then, an image matching window of the same size and shape is taken out from the right image, and the pixel grayscale distribution of the left and right image windows is compared. The center points of the two windows with the most similar window grayscale distribution are the feature points that are successfully matched.

[0085] The grayscale distribution of the left and right images is represented by f L (x, y) and f R (x, y). The size of the matching window is (2m+1)*(2n+1), so the matching cost function is:

[0086] G sad (x, y, d) = ∑ (a，b) |f L (x+d+a,y+b)-f R (x+a,y+b)|

[0087] Among them, C sad is the absolute value of the grayscale difference of all corresponding coordinate pixels, a∈[-m, m], b∈[-n, n], and all points within the threshold step range are obtained by changing a and b. d represents the disparity, and (x, y) is the centroid.

[0088] After obtaining the matching cost function of all points within the threshold step range, the point with the minimum matching cost in the area is obtained, and this point is the desired feature point, that is, D sad (x, y) = arg d minC sad (x, y, d).

[0089] S5. Use the position positioning method based on field strength distance information to obtain the motion parameters of the adsorption satellite assembly, and then realize the identification of the motion parameters of the non-cooperative spacecraft.

[0090] In the embodiment of the present application, in step S5, the adsorption satellite is adsorbed on the surface of the non-cooperative spacecraft and moves in space with the non-cooperative spacecraft. The reference satellite broadcasts periodically, and the adsorption satellite continues to receive the field strength signal and downloads the fingerprint library to complete the fingerprint identification; through inter-satellite communication, the motion parameters of the adsorption satellite assembly are obtained, thereby realizing the identification of the motion parameters of the non-cooperative spacecraft.

[0091] Those skilled in the art will appreciate that the embodiments described herein are intended to help readers understand the principles of the present invention, and should be understood that the protection scope of the present invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific variations and combinations that do not deviate from the essence of the present invention based on the technical revelations disclosed by the present invention, and these variations and combinations are still within the protection scope of the present invention.

Claims

1. A non-cooperative spacecraft motion parameter identification method based on a constellation fingerprint library, characterized in that: The method comprises: S1. Design a positioning method based on field strength distance information, complete the relative positioning of the reference star among the cluster stars based on relative coordinate transformation, and establish a dynamic fingerprint library based on real sampling data and free space propagation model. The member stars receive the periodic broadcast signal of the reference star and download the fingerprint library, calculate and process the received signal, complete the relative position fingerprint recognition, and feed it back to the reference star through inter-satellite directional communication, so as to obtain the relative motion state and position relationship of the star cluster members; S2, the observation satellite uses the onboard radar to detect, search and roughly locate the non-cooperative spacecraft, and selects the appropriate sub-constellation as the adsorption satellite according to the positioning information; S3. Select a point on the non-cooperative spacecraft as the predetermined adsorption point. According to the initial position of the adsorption satellite and the position of the non-cooperative spacecraft, predetermine the time for it to reach the adsorption point. The adsorption satellite adopts Lambert guidance. First, it reaches the same orbital altitude as the predetermined adsorption point and enters the mid-guidance process. Then, the adsorption satellite is guided into an elliptical orbit containing the predetermined adsorption point by the minimum energy strategy until the onboard camera on the adsorption satellite captures and continuously tracks the non-cooperative spacecraft. Then, the terminal guidance is entered. The terminal guidance process uses the sliding mode variable structure guidance law for control to achieve the approach to the non-cooperative spacecraft. S4. The onboard adsorption device works according to the high-precision ranging information calculated by the onboard camera after the target enters the adsorption range, so that the adsorption satellite is adsorbed on the surface of the non-cooperative spacecraft; S5. Use the position positioning method based on field strength distance information to obtain the motion parameters of the adsorption satellite assembly, and then realize the identification of the motion parameters of the non-cooperative spacecraft.

2. The non-cooperative spacecraft motion parameter identification method based on a constellation fingerprint library according to claim 1, characterized in that: The position positioning method based on field strength distance information in step S1 specifically comprises the following steps: Define AP as a wireless access point, set N dynamic reference stars in the micro-nano star cluster as the APs required for relative positioning, and establish a dynamic coordinate system; the dynamic coordinate system is a three-dimensional dynamic coordinate system with the center of mass of the virtual central star as the origin, the center of mass moving direction as the X direction, the center of the earth as the Z direction, and the Y direction satisfying the right-hand screw rule. The relationship between it and the earth's inertial coordinate system is as follows: O M =C1·O1 in, Where u is the latitude argument, is the orbit inclination, Ω is the right ascension of the ascending node, therefore, the dynamic reference star obtains its own absolute position information based on the BeiDou navigation system as the reference benchmark for cluster positioning, and completes the relative positioning of the reference star among cluster stars based on relative coordinate conversion; Based on real sampling data and free space propagation model, a dynamic fingerprint library is established; the reference satellite broadcasts periodically; the member satellites receive the signal, download the data link, and complete the relative position information identification; each member satellite informs the reference satellite of the relative positioning result through inter-satellite directional communication, and the reference satellite obtains continuous cluster relative positioning information through filtering.

3. The non-cooperative spacecraft motion parameter identification method based on a constellation fingerprint library according to claim 1, characterized in that: The non-cooperative spacecraft included in step S2 has magnetic material on its surface, which can be adsorbed by the adsorption device on the adsorption satellite. The specific process is as follows: The adsorption satellites included in step S2 are: satellites with adsorption function installed in the star cluster by adsorption devices are called adsorption satellites. Adsorption satellites are mostly satellites with good power performance and communication performance, distributed at the periphery of the cluster, which are convenient for chasing non-cooperative spacecraft; The onboard radar detection search and rough positioning included in step S2 is: using the onboard radar to scan and search the non-cooperative spacecraft operation area, and calculating the position of the target relative to the observation satellite in real time based on the detection information; The suitable position included in the step S2 is: the task of the adsorption satellite is to pursue the target, approach and adsorb on the target, and the selected adsorption satellite should have the characteristics of short pursuit time and low energy consumption. At the same time, in order to avoid collision with the target, the adsorption satellite and the non-cooperative spacecraft should have the same movement direction. The adsorption satellite in the opposite direction of the non-cooperative spacecraft measures and calculates the relative distance to the target through the onboard camera, and can reselect a satellite with a shorter distance and fewer obstacles to perform the pursuit mission.

4. The non-cooperative spacecraft motion parameter identification method based on a constellation fingerprint library according to claim 1, characterized in that: In step S3, the adsorption satellite gradually approaches the non-cooperative spacecraft as follows: first, a point on the non-cooperative spacecraft is appropriately selected as a predetermined adsorption point, and the time for the adsorption satellite to reach the adsorption point is predetermined according to the initial position of the adsorption satellite and the position of the non-cooperative spacecraft, and Lambert guidance and velocity gain guidance are applied to make the adsorption satellite reach the adsorption point at the predetermined time. The specific method is as follows: The Lambert guidance method is specifically as follows: the adsorption satellite first reaches the same orbital altitude as the predetermined adsorption point and enters the mid-range guidance process. The minimum energy strategy in the Lambert guidance is used to guide it into an elliptical orbit containing the predetermined adsorption point until the onboard camera on the adsorption satellite captures and continuously tracks the non-cooperative spacecraft, then it enters the terminal guidance. The terminal guidance process uses the sliding mode variable structure guidance law for control.

5. A non-cooperative spacecraft motion parameter identification method based on a constellation fingerprint library as claimed in claim 1, characterized in that: In step S4, in order to meet the requirements of approaching and adsorbing to the target, the adsorbing satellite needs to be equipped with thrusters and onboard cameras. The specific process is as follows: During the guidance process, the observation satellite roughly calculates the relative position of the non-cooperative spacecraft and sends a guidance signal. The adsorption satellite receives the observation satellite signal and activates the onboard camera to observe in real time and calculate the position and attitude of the target relative to the adsorption satellite with high precision.

6. The non-cooperative spacecraft motion parameter identification method based on a constellation fingerprint library according to claim 1, characterized in that: In step S5, the adsorption satellite is adsorbed on the surface of the non-cooperative spacecraft and moves in space with the non-cooperative spacecraft. The reference satellite broadcasts periodically, and the adsorption satellite continues to receive the field strength signal and downloads the fingerprint library to complete the fingerprint identification. Through intersatellite communication, the motion parameter information of the adsorbed satellite assembly and non-cooperative spacecraft is obtained.

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