Space-based observation information assisted space debris collision early warning method

Abstract

The invention discloses a space-based observation information assisted space debris collision early warning method, and belongs to the field of space situation awareness. According to the method, the space-based observed quantity of fragments having collision danger to the satellite is obtained through visible light imaging detection equipment carried on the satellite, and the problems of fragment collision false alarm and missed alarm caused by time delay and inaccurate orbit extrapolation model of fragment cataloguing information are corrected according to the space-based observed quantity of the fragments. Therefore, higher-precision space debris collision early warning is realized.

Description

Technical Field

[0001] The present invention relates to the field of space situational awareness and is a high-precision space debris collision warning method, which mainly involves the association between space-based observations and cataloging information of space debris. Background Art

[0002] At present, space debris collision warning is mostly achieved by using debris catalog information through orbital extrapolation model prediction. Debris catalog is mostly calculated from observation data of ground-based telescopes. Due to the constraints of observation distance, debris visibility and model accuracy, there are errors in the debris catalog information and orbital extrapolation results. Taking the TLE and SGP4 models as examples, the SGP4 model does not consider the influence of the Earth's non-spherical gravitational field on orbit determination accuracy. Studies have shown that the prediction error of the TLE epoch and the prediction time interval of 1 day is 1km, the prediction error of 3 days is 5km, and when the interval reaches 5 days, the prediction error can reach 10km. Summary of the invention

[0003] The technical problem solved by the present invention is: to overcome the shortcomings of the prior art and to provide a space debris collision warning method assisted by space-based observation information, so as to solve the problem of false alarm and missed alarm of debris collision caused by time lag of debris cataloging information and inaccurate orbit extrapolation model, thereby achieving higher-precision space debris collision warning.

[0004] The technical solution of the present invention is: a space-based observation information-assisted space debris collision warning method, the method comprising the following steps:

[0005] S1. Associating the space-based observation information of space debris with the cataloging information to obtain the space-based measurement information of the space debris to be warned; the cataloging information of the space debris includes the six orbital numbers of the space debris and the corresponding epoch time;

[0006] S2. Use the space-based observation information of the space debris to be warned to optimize the catalog information of the space debris to be warned, and update the orbital elements of the space debris to be warned;

[0007] S3. Taking the satellite orbital elements and the updated orbital elements of the space debris to be warned as input, calculate the intersection line of the satellite and the orbital plane of the space debris to be warned, and realize space debris collision warning according to the arrival time of the space debris to be warned and the satellite on the orbital plane and the difference of the semi-major axis of the orbit.

[0008] Preferably, the specific steps of associating the space debris observation information with the cataloging information are as follows:

[0009] S1.1. Obtain the predicted trajectory of the space debris to be warned based on the catalog information of the space debris to be warned;

[0010] S1.2. Solve the trajectory consistency criterion between the actual trajectory and the predicted trajectory of all visible debris obtained by space-based measurements;

[0011] S1.3, take the actual trajectory with the smallest trajectory consistency criterion as the preliminary matching trajectory with the predicted trajectory;

[0012] S1.4, calculate the residual s of the distance between the preliminary matching trajectory and the predicted trajectory. If the residual s satisfies the preset distribution law, it is considered that the preliminary matching trajectory and the predicted trajectory do match, and enter step S1.5; otherwise, it is considered that the preliminary matching trajectory and the predicted trajectory do not match;

[0013] S1.5. Determine the space-based measurement information of the space debris corresponding to the actual trajectory matching the predicted trajectory as the space-based measurement information of the space debris to be warned.

[0014] Preferably, in step S1.1, the trajectory of the space debris to be warned is predicted by orbit extrapolation method.

[0015] Preferably, according to the principle that the distance residual s between the actual trajectory matched with the predicted trajectory and the predicted trajectory obeys a normal distribution with a mean of 0 and a standard deviation of σ, the preset distribution law is:

[0016]

[0017] Among them, the confidence interval is [-εσ,+εσ], and ε is the proportionality coefficient.

[0018] Preferably, let the semi-major axis of the orbit of the debris be a1, the semi-major axis of the orbit of the satellite be a2, the time when the debris reaches the intersection of the orbital plane be t1, and the time when the satellite reaches the intersection of the orbital plane be t2, then if:

[0019] |t1-t2|<Δt

[0020] |a1-a2|<Δa

[0021] It is believed that the satellite and the space debris to be warned will issue a collision warning, otherwise, it is believed that the satellite and the space debris to be warned will not collide. Δt and Δa are the time difference threshold and orbital semi-major axis difference threshold, respectively.

[0022] Preferably, the trajectory consistency criterion between the actual trajectory and the predicted trajectory is calculated by the following method:

[0023] Calculate the Euclidean distance Dis between each scattered point between the real trajectory of space debris and the predicted trajectory i,j ,i=1~m,j=1~n, the Euclidean distances between the scattered points form a matrix of size m×n; m is the number of scattered points of the real trajectory, and n is the number of scattered points of the predicted trajectory;

[0024] The trajectory consistency criterion D(m,n) between the actual trajectory and the predicted trajectory is calculated according to the following formula:

[0025] D(m,n)=|Dis m,n |+min{|Dis m-1,n |,|Dis m-1,n-1 |,|Dis m,n-1 |}.

[0026] Preferably, the Euclidean distance between the i-th scattered point in the real trajectory and the j-th scattered point in the predicted trajectory is:

[0027] Dis i,j =(U i -U′ j )+(V i -V′ j ),0 <i≤m,0<j≤n

[0028] Among them, (U i , V i ) is the coordinate of the i-th scattered point in the real trajectory on the image plane;

[0029] (U′ j ,V′ j ) is the image plane coordinate of the jth scattered point in the prediction trajectory.

[0030] Preferably, the method for optimizing the catalog information of space debris to be warned is:

[0031] The position r0 and velocity vector v0 of the space debris to be warned in the geocentric inertial coordinate system are obtained by extrapolating the debris orbit recorded in the debris catalog library, which are recorded as the initial value of the state quantity of the space debris to be warned X0 = [r0, v0];

[0032] The space-based observation value of the space debris to be warned is recorded as the space debris observation vector Y = [α, β], where (α, β) is the right ascension and declination of the space debris;

[0033] The real position and velocity vector of the space debris to be warned in the geocentric inertial coordinate system are recorded as the estimated state quantity X of the space debris to be warned;

[0034] The least squares method is used to calculate the state deviation of the space debris to be warned based on the observation vector Y.

[0035] The estimated state quantity X of the space debris to be warned is calculated according to the following formula:

[0036]

[0037] The optimal estimated state quantities of the position and velocity vector of the space debris to be warned are converted into orbital cataloging information.

[0038] Preferably, the state deviation of the space debris to be warned is for:

[0039]

[0040] Among them, h is the state transfer matrix, ΔY is the observation vector deviation of the space debris to be warned, and W is the weight.

[0041] Preferably, the weight W is taken as the inverse of the observation noise matrix, that is:

[0042] R n =E(nn T )

[0043] W=R n -1

[0044] Among them, E(nn T ) is nn T The mathematical expectation of .

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

[0046] (1) The present invention takes into account the problems of delayed debris cataloging information and inaccurate orbital extrapolation models, and introduces space-based observations of debris to correct prediction errors, thereby achieving more accurate space debris collision warning.

[0047] (2) The present invention uses trajectory consistency as a criterion to achieve the association between space-based observations of space debris and cataloging information. It has the characteristics of not being affected by factors such as target motion characteristics and observation environment, and can effectively reduce the probability of false association. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 This is a flow chart of a method for using space-based observation information to assist in warning of space debris collisions according to an embodiment of the present invention. DETAILED DESCRIPTION

[0049] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0050] Compared with ground-based telescopes, space-based observation equipment is less affected by the observation environment and can obtain more observation information of space debris relative to the satellite body. If cataloging information is used as a reference and combined with space-based observation information, a more accurate assessment of the motion state of debris relative to the satellite can be achieved.

[0051] like Figure 1 As shown, the present invention provides a space-based observation information-assisted space debris collision warning method comprising the following steps:

[0052] S1. Associating the space-based observation information of space debris with the cataloging information to obtain the space-based measurement information of the space debris to be warned; the cataloging information of the space debris includes the six orbital numbers of the space debris and the corresponding epoch time;

[0053] S2. Use the space-based observation information of the space debris to be warned to optimize the catalog information of the space debris to be warned, and update the orbital elements of the space debris to be warned;

[0054] S3. Taking the satellite orbital elements and the updated orbital elements of the space debris to be warned as input, calculate the intersection line of the satellite and the orbital plane of the space debris to be warned, and realize space debris collision warning according to the arrival time of the space debris to be warned and the satellite on the orbital plane and the difference of the semi-major axis of the orbit.

[0055] The following is a detailed description of the important contents

[0056] (1) Correlation between space-based observations of debris and catalog information

[0057] The potential risk debris catalog library may contain multiple debris, and the visible light imaging detection equipment may also detect multiple debris at the same time. It is necessary to achieve a one-to-one correspondence between the debris observation quantity and the catalog information in the catalog library according to the characteristics of the debris.

[0058] Visible light imaging detection equipment cannot obtain information about the distance of debris from the satellite. The direct observation quantity is the image point of the debris on the detector image plane, which has photometric, geometric and motion characteristics. Due to the small size of the debris and the lack of an attitude stabilization mechanism, the photometric and geometric characteristics of the image point formed by the debris are unstable. The motion characteristics are an important basis for associating the space-based observation quantity of the debris with the cataloging information.

[0059] The present invention adopts a dynamic time planning space debris matching method. The method uses the real trajectory of debris actually detected by the visible light imaging detection equipment carried by the satellite as the amount to be matched, and the predicted trajectory of debris in the same time period predicted based on the debris catalog information and the orbit extrapolation model as the template. The specific steps of associating the space debris observation information with the catalog information are as follows:

[0060] S1.1. Obtain the predicted trajectory of the space debris to be warned based on the catalog information of the space debris to be warned. In this step, the trajectory of the space debris to be warned can be predicted by orbital extrapolation.

[0061] S1.2. Solve the trajectory consistency criterion between the actual trajectory and the predicted trajectory of all visible debris obtained by space-based measurements;

[0062] S1.3, take the actual trajectory with the smallest trajectory consistency criterion as the preliminary matching trajectory with the predicted trajectory;

[0063] S1.4, calculate the residual s of the distance between the preliminary matching trajectory and the predicted trajectory. If the residual s satisfies the preset distribution law, it is considered that the preliminary matching trajectory and the predicted trajectory do match, and enter step S1.5; otherwise, it is considered that the preliminary matching trajectory and the predicted trajectory do not match;

[0064] S1.5. Determine the space-based measurement information of the space debris corresponding to the actual trajectory matching the predicted trajectory as the space-based measurement information of the space debris to be warned.

[0065] Let the real trajectory of the debris be (U, V) and the predicted trajectory be (U ′ ,V ′ ), the number of scattered points in the two trajectories is m and n respectively, and the Euclidean distance between the i-th scattered point in the true trajectory and the j-th scattered point in the predicted trajectory is:

[0066] Dis i,j =(U i -U′ j )+(V i -V′ j ),0 <i≤m,0<i≤n

[0067] Among them, (U i , V i ) is the coordinate of the i-th scattered point in the real trajectory on the image plane;

[0068] (U′ j ,V′ j ) is the image plane coordinate of the jth scattered point in the prediction trajectory.

[0069] The distances between the scattered points form a matrix of size m×n. The trajectory consistency criterion between the real trajectory and the predicted trajectory is calculated by the following method:

[0070] Calculate the Euclidean distance Dis between each scattered point between the real trajectory of space debris and the predicted trajectory i,j ,i=1~m,j=1~n, the Euclidean distances between the scattered points form a matrix of size m×n; m is the number of scattered points of the real trajectory, and n is the number of scattered points of the predicted trajectory;

[0071] The trajectory consistency criterion D(m,n) between the actual trajectory and the predicted trajectory is calculated according to the following formula:

[0072] D(m,n)=|dis m,n |+min{|Dis m-1,n |,|Dis m-1,n-1 |,|Dis m,n-1 |}.

[0073] According to the principle that the distance residual s between the actual trajectory matched with the predicted trajectory and the predicted trajectory obeys a normal distribution with a mean of 0 and a standard deviation of σ, the preset distribution law is:

[0074]

[0075] Among them, the confidence interval is [-εσ, +εσ], ε is the proportionality coefficient, and its value range is [1, 3].

[0076] The distance residual s between the true trajectory and the predicted trajectory is calculated as follows:

[0077]

[0078] Where, k = min(m,n), E t =(U t -U′ t )+(V t -V′ t ),(0 <t≤k)

[0079] (2) Update of space debris catalog information

[0080] The optimization method for cataloging information of space debris to be warned is as follows:

[0081] 2.1. Extrapolate the debris orbit recorded in the debris catalog library to obtain the position r0 and velocity vector v0 of the space debris to be warned in the geocentric inertial coordinate system, which are recorded as the initial value of the state quantity of the space debris to be warned X0 = [r0, v0];

[0082] 2.2. The space-based observation value of the space debris to be warned is recorded as the space debris observation vector Y = [α, β], where (α, β) is the right ascension and declination of the space debris, which is obtained by converting the direct observation value (U, V) coordinates.

[0083] 2.3. The state quantity to be estimated X and the observation vector Y satisfy the following relationship:

[0084] Y=h(X)+n

[0085] Among them, h is the state transfer matrix; n is the observation noise.

[0086] 2.4. The real position and velocity vector of the space debris to be warned in the geocentric inertial coordinate system are recorded as the estimated state quantity X of the space debris to be warned;

[0087] 2.5. Using the least squares method, calculate the state deviation of the space debris to be warned based on the observation vector Y

[0088] Assume that the optimal estimate of the state quantity X is when The state equation satisfies the following conditions:

[0089]

[0090] Where J is the quasi-measurement function; W is the weight, which is usually taken as the inverse of the observation noise matrix, that is:

[0091]

[0092] The necessary condition for the criterion function to obtain the minimum value is:

[0093]

[0094] The linearized state equation can be obtained:

[0095]

[0096] ΔY is the observed residual.

[0097] After finishing, we can get:

[0098]

[0099] The solution of the above formula is:

[0100]

[0101] Then the optimization result of the initial state quantity is:

[0102]

[0103] Finally, the optimal estimate of the position and velocity vector of the debris at that moment is converted into orbital catalog information.

[0104] (3) Estimation of the relative motion state between debris and satellite

[0105] The intersection line of the two orbital planes is calculated using the updated orbital elements of the debris and the satellite as inputs. Let the orbital semi-major axis of the debris be a1, the orbital semi-major axis of the satellite be a2, the time when the debris reaches the intersection line of the orbital plane be t1, and the time when the satellite reaches the intersection line of the orbital plane be t2. If it satisfies;

[0106] |t1-t2|<Δt

[0107] |a1-a2|<Δa

[0108] A collision warning is issued, where Δt and Δa are the time difference and orbit semi-major axis difference thresholds, respectively, which can be changed as needed.

[0109] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A space debris collision warning method assisted by space-based observation information, characterized in that The steps include: S1. Associating the space-based observation information of space debris with the cataloging information to obtain the space-based measurement information of the space debris to be warned; the cataloging information of the space debris includes the six orbital numbers of the space debris and the corresponding epoch time; S2. Use the space-based observation information of the space debris to be warned to optimize the catalog information of the space debris to be warned, and update the orbital elements of the space debris to be warned; S3. Taking the satellite orbital elements and the updated orbital elements of the space debris to be warned as input, calculate the intersection line of the satellite and the orbital plane of the space debris to be warned, and realize space debris collision warning according to the arrival time of the space debris to be warned and the satellite on the orbital plane and the difference of the semi-major axis of the orbit.

2. The method of claim 1, wherein the method comprises: The specific steps for associating space debris observation information with catalog information are as follows: S1.

1. Obtain the predicted trajectory of the space debris to be warned based on the catalog information of the space debris to be warned; S1.

2. Solve the trajectory consistency criterion between the actual trajectory and the predicted trajectory of all visible debris obtained by space-based measurements; S1.3, take the actual trajectory with the smallest trajectory consistency criterion as the preliminary matching trajectory with the predicted trajectory; S1.4, calculate the residual s of the distance between the preliminary matching trajectory and the predicted trajectory. If the residual s satisfies the preset distribution law, it is considered that the preliminary matching trajectory and the predicted trajectory do match, and enter step S1.5; otherwise, it is considered that the preliminary matching trajectory and the predicted trajectory do not match; S1.

5. Determine the space-based measurement information of the space debris corresponding to the actual trajectory matching the predicted trajectory as the space-based measurement information of the space debris to be warned.

3. The method of claim 2, wherein the method comprises: In step S1.1, the trajectory of the space debris to be warned is predicted by using the orbit extrapolation method.

4. The method of claim 3, wherein: According to the principle that the distance residual s between the actual trajectory matched with the predicted trajectory and the predicted trajectory obeys a normal distribution with a mean of 0 and a standard deviation of σ, the preset distribution law is: Among them, the confidence interval is [-εσ,+εσ], and ε is the proportionality coefficient.

5. The method of claim 1, wherein: Let the semi-major axis of the debris' orbit be a1, the semi-major axis of the satellite's orbit be a2, the time when the debris reaches the intersection of the orbital plane be t1, and the time when the satellite reaches the intersection of the orbital plane be t2. If: |t1-t2|<Δt |a1-a2|<Δa It is believed that the satellite and the space debris to be warned will issue a collision warning, otherwise, it is believed that the satellite and the space debris to be warned will not collide. Δt and Δa are the time difference threshold and orbital semi-major axis difference threshold, respectively.

6. The method of claim 3, wherein: The trajectory consistency criterion between the actual trajectory and the predicted trajectory is calculated as follows: Calculate the Euclidean distance Dis between each scattered point between the real trajectory of space debris and the predicted trajectory i,j ,i=1~m,j=1~n, the Euclidean distances between the scattered points form a matrix of size m×n; m is the number of scattered points of the real trajectory, and n is the number of scattered points of the predicted trajectory; The trajectory consistency criterion D(m,n) between the actual trajectory and the predicted trajectory is calculated according to the following formula: D(m,n)=|Dis m,n |+min{|Dis m-1,n |,|Dis m-1,n-1 |,|Dis m,n-1 |}。 7. The method of claim 5, wherein the method comprises: The Euclidean distance between the i-th scattered point in the true trajectory and the j-th scattered point in the predicted trajectory is: Dis i,j =(U i -U j ′ )+(V i -V j ′ ),0 <i≤m,0<j≤n Among them, (U i , V i ) is the coordinate of the i-th scattered point in the real trajectory on the image plane; (U j ′ ,V j ′ ) is the image plane coordinate of the jth scattered point in the prediction trajectory.

8. The method of claim 1, wherein: The optimization method for cataloging information of space debris to be warned is as follows: The position r0 and velocity vector v0 of the space debris to be warned in the geocentric inertial coordinate system are obtained by extrapolating the debris orbit recorded in the debris catalog library, which are recorded as the initial value of the state quantity of the space debris to be warned X0 = [r0, v0]; The space-based observation value of the space debris to be warned is recorded as the space debris observation vector Y = [α, β], where (α, β) is the right ascension and declination of the space debris; The real position and velocity vector of the space debris to be warned in the geocentric inertial coordinate system are recorded as the estimated state quantity X of the space debris to be warned; The least squares method is used to calculate the state deviation of the space debris to be warned based on the observation vector Y. The estimated state quantity X of the space debris to be warned is calculated according to the following formula: The optimal estimated state quantities of the position and velocity vector of the space debris to be warned are converted into orbital cataloging information.

9. The method of claim 8, wherein: The state quantity deviation of the space debris to be warned for: Among them, h is the state transfer matrix, ΔY is the observation vector deviation of the space debris to be warned, and W is the weight.

10. The method of claim 1, wherein: The weight W is taken as the inverse of the observation noise matrix, that is: R n =E(n.n T ) W=R n -1 Among them, E(nn T ) is nn T The mathematical expectation of .

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