A method for rapid tracing of targets at close range in space

Abstract

A method for quickly tracing the source of a close-in approaching target in space belongs to the field of aerospace technology. The implementation method of the present invention is as follows: constructing a space target satellite information database, defining the satellite orbital state in the database as the initial orbital state, and constructing a static index of the space target; when the space target appears within the perception range of the observation spacecraft, using the three-dimensional angle plus distance observation information to determine the target orbit, so as to obtain the approaching orbital state of the space target when it appears within the perception range of the observation spacecraft; solving the optimal orbital fuel consumption required for each target satellite in the database to transfer from the initial orbital state to the approaching orbital state based on a hybrid optimization method, and constructing a dynamic index of the space target satellite; combining static and dynamic indicators to give a comprehensive index score for the satellites in the database. Using this comprehensive index score, a preset number of satellites with the highest probability of origin in the database are screened out to achieve the tracing of unknown target satellites in space.

Description

Technical Field

[0001] The present invention relates to a method for quickly tracing a target approaching at a close distance in space, which is particularly suitable for solving the problem of quickly tracing a target approaching at a close distance in an unknown space, and belongs to the field of aerospace technology. Background Art

[0002] The current space environment is complex, and space situational awareness is a crucial foundation for ensuring the safety of satellites on orbit and the smooth execution of space missions. Essentially, it requires timely and accurate tracing of unknown targets. Tracing unknown targets involves two key requirements: first, leveraging limited observational information to rapidly determine the target's orbit; second, combining the space target satellite information database with orbit determination results, matching the target with the database information, and accurately calculating the target's source probability indicators. This indicator is then used to rank the target's source probability, enabling rapid tracing of the target.

[0003] Among the developed methods, the prior art [1] (Dai Pei, Feng Dongzhu, Guo Hehe, et al. Space target threat assessment method based on optimized combined weighted model [P]. Shaanxi Province: CN202310761671.9, 2023-10-20.) proposed a space target threat assessment method based on the optimized combined weighted model. This method calculates the target dynamic threat assessment index based on the space target type and relative distance, relative speed, relative attitude and other information. The disadvantage of this method is that it does not take into account the historical orbital properties of the space target, so it cannot realize the traceability function of the target, and the evaluation index dimension is relatively single.

[0004] Prior art [2] (He Wucan, Liao Shouyi, Su Delun, et al. Analysis and simulation of threat characteristics of optical imaging reconnaissance satellites [J]. Modern Defense Technology, 2015, 43(06): 21-26) established an optical imaging reconnaissance threat prediction model based on target detection probability, and studied and classified the threat levels of optical reconnaissance satellites. This method mainly analyzes and studies the threat situation of reconnaissance satellites to ground targets. Currently, there are few methods that use space satellites as the main research object to analyze their orbital tracing. Summary of the Invention

[0005] In order to solve the problems of limited application scenarios and single indicator dimension in the existing methods of space target tracing research, the main purpose of the present invention is to provide a method for fast tracing of space close-range targets. The existing two-row root satellite database and satellite basic attribute information database are used to construct a space target satellite information database, which contains information such as satellite name, NORAD number, satellite orbit root number, satellite function, and launch year. The basic attributes of the above satellites are sorted and analyzed, and static indicators of space target satellites are proposed and constructed and included in the database. When the target appears in the space near the spacecraft, the onboard sensor is used to The target is observed relative to the target, and the absolute orbit of the target is determined using the observation information to obtain the orbital state of the target satellite at the time of approach. The database satellite orbit information and the target satellite approach orbit state obtained by orbit determination are used to solve the optimal transfer orbit and the fuel consumption required for transfer for each satellite in the database from the initial state to the approach orbit state based on a hybrid optimization method, and on this basis, a dynamic index of the space target satellite is constructed. The static and dynamic indicators are combined to give a comprehensive evaluation index score for the satellites in the database. Based on this index, a preset number of satellites with the greatest possibility of origin in the database are screened out, thus realizing rapid tracing of close-range space approach targets.

[0006] The purpose of the present invention is achieved through the following technical solutions:

[0007] The present invention discloses a method for rapidly tracing the origin of close-in approaching space targets. The method constructs a database of space target satellite information, considers the orbital states of satellites in the database as initial orbital states, and proposes a static index for the space targets based on this. When a space target appears within the sensing range of an observing spacecraft, the target orbit is determined using three-dimensional angle and distance observation information to obtain the approaching orbital state of the space target at the time of appearance. Combining the initial orbital states of the target satellites in the database with the approaching orbital states obtained through orbit determination, a hybrid optimization method is used to determine the optimal orbital fuel consumption required for each target satellite in the database to transition from the initial orbital state to the approaching orbital state. Based on this, a dynamic index for the space target satellites is constructed. The static and dynamic indexes are combined to produce a comprehensive index score for the satellites in the database. This index is used to quickly select a preset number of satellites in the database with the highest likelihood of origin, thereby achieving the purpose of tracing the origin of unknown space target satellites. The preset number of satellites is ten.

[0008] The present invention discloses a method for quickly tracing a target at close range in space, comprising the following steps:

[0009] Step 1: Using the publicly released two-line root number data and satellite basic attribute information as the main information sources, establish a space target satellite information database;

[0010] Merge the CelesTrak database and the space-track database to obtain a two-row root number database; extract two rows of root number data from the two-row root number database and parse the two rows of root number data to obtain the satellite name, orbital root number and NORAD number; compare the NORAD number with the number in the UCS database, and add the functional attributes, orbit type and launch quality information of the satellite with the corresponding number in the UCS database to the two-row root number database. If there is no corresponding information, the corresponding information of the satellite with the number is coded as "unknown" to obtain the space target satellite information database. Determine the satellite orbital state in the database as the initial orbital state of the target satellite;

[0011] Step 2: Construct a static index score of the target satellite based on the space target satellite information database information obtained in step 1;

[0012] The static indicators take into account four properties:

[0013] Step 2.1: The semi-major axis, inclination and eccentricity properties of the target satellite orbit are as shown in formula (1):

[0014]

[0015] Where a, i, e represent the semi-major axis, eccentricity, and orbital inclination of the target satellite orbit, respectively; a′, i′, e′ represent the semi-major axis, eccentricity, and orbital inclination of the high-probability source orbit, respectively; r p ,r a Respectively represent the perigee and apogee radii of the target satellite orbit; ε a ,ε e ,ε i They represent the deviation setting values ​​about the semi-major axis, eccentricity, and orbital inclination respectively;

[0016] According to formula (1), when an unknown target satellite is located near a high-probability source orbit, it is determined to be a high-probability target satellite; when the target satellite passes through the orbit, that is, the orbit perigee radius is less than a′, the orbit apogee radius is greater than a′, and the orbit inclination is close to i′, it is determined to be a medium-probability target satellite; in other cases, it is determined to be a low-probability target satellite.

[0017] Step 2.2: Target satellite maneuver direction attribute: By comparing the orbital element data of the same target satellite at the historical and current times, it can be determined whether the target satellite has a tendency to transfer to a high-probability orbit. If it maneuvers and transfers to a high-probability orbit, it is determined to be a high-probability target satellite. If it maneuvers but does not transfer to a high-probability orbit, it is determined to have the potential to transfer to a high-probability orbit and is considered a medium-probability target satellite. If it does not maneuver, it is considered a low-probability target satellite.

[0018] Step 2.3: Target satellite functional attributes; If the satellite is a "space-based surveillance satellite," it is a surveillance satellite targeting space-based satellites and is the most likely satellite to conduct close-in surveillance. Therefore, it is determined to be the satellite with the highest possible source. If the satellite is a "space science research satellite" or a "communications satellite," it generally has a higher orbital altitude and carries high-precision observation sensors, allowing it to conduct close-in observations of space targets. Therefore, it is determined to be the satellite with the second highest possible source. If the satellite is an "earth science research satellite" or an "earth observation satellite," it carries high-precision observation sensors and is capable of conducting close-in observations of space targets. Therefore, it is determined to be a satellite with a medium possible source. If the satellite is a "navigation satellite" or a "satellite of unknown attributes," it is determined to be a satellite with a low possible source. If the satellite is a "technical research satellite" or other type of satellite, it is determined to be the satellite with the lowest possible source.

[0019] Step 2.4: Launch year of the target satellite. If the satellite was launched within 10 years, it is considered relatively new, has a certain degree of maneuverability, and its equipment has not aged. Therefore, the probability of determining that a satellite launched in this period is the source satellite is the highest. If the satellite was launched between 10 and 25 years ago, its maneuverability is considered to have degraded and its equipment has aged. Therefore, the probability of determining that a satellite launched in this period is the source satellite is medium. If the satellite was launched more than 25 years ago, it is considered to have basically lost its maneuverability and approach capability. Therefore, the probability of determining that a satellite launched in this period is the source satellite is the lowest.

[0020] The static index score of the target satellite is calculated by assigning points to each item and weighting the overall score. For each attribute, the probability of it being the source satellite is specified on a percentage basis. The satellite with the highest probability of being the source satellite has a score of 100 points, while the satellite with the lowest probability of being the source satellite has a score of zero points. In addition, the weights of the above four attributes are also different. The static index score of each satellite is calculated by combining the internal hierarchical assignment of each attribute and the external weighted summation of the four attributes:

[0021]

[0022] Among them, P sat Score the static index of space target satellite, σ i is the weight of each attribute of the space target satellite, P i Score the attributes of space target satellites;

[0023] Step 3: The spatial range with the observation spacecraft as the origin and the radius of dkm is the perception range of the observation spacecraft. When the target satellite appears in the perception range of the observation spacecraft, three relative observations are made to the target satellite, and the information of each observation is the relative angle and relative distance information. The spatial state of the observation spacecraft is known. Combined with the observation information, the absolute orbit state of the target satellite is determined using the initial orbit determination method to obtain the target orbit state when the unknown target satellite approaches the observation spacecraft.

[0024] The relative angle observation data of the target satellite relative to the observation spacecraft are expressed by right ascension α and declination δ, and the relative distance observation value is expressed by slant distance ρ; the position velocity vectors of the target satellite and the observation spacecraft at a certain moment in the Earth's J2000 coordinate system are [r tar ,v tar ] and [r ob ,v ob ], where the superscript "tar" represents the unknown target satellite and the superscript "ob" represents the observation spacecraft; the relative position vector between the two is ρ, which is expressed as the product of the slant range and the angle vector L; at a certain moment, the geometric relationship between the target satellite and the observation spacecraft is:

[0025] r tar =r ob +ρL (3)

[0026] The angle vector L is expressed by formula (4):

[0027]

[0028] Based on the relative angle and distance information of the target satellite relative to the observing spacecraft at any three consecutive observation moments, the position vector of the target satellite in the Earth's J2000 coordinate system at the three observation moments is obtained using formula (3):

[0029] based on The Gibbs initial orbit determination method is used to obtain the velocity information of the target satellite at the time of observation:

[0030]

[0031] Among them, r represents the position vector, v represents the velocity vector, e represents the eccentricity vector, h represents the angular momentum scalar, μ represents the earth's gravitational constant; h represents the angular momentum vector.

[0032] Based on the assumption that the three vectors are coplanar, we get formula (6):

[0033]

[0034] in,

[0035]

[0036] The expression for angular momentum is:

[0037]

[0038] And the expression of h×e is:

[0039]

[0040] in,

[0041] Substituting formula (7) and formula (8) into formula (5), the velocity vector at the intermediate moment is obtained as:

[0042]

[0043] In formula (9), all the terms on the right side are only related to the known target satellite position vector; at this point, the position and velocity vectors of the target satellite in space at the intermediate observation time are all known, that is, the target orbit state when the unknown target satellite approaches the observation spacecraft at the intermediate observation time is obtained, which is called the approaching orbit state;

[0044] Step 4: Combining the initial orbital state of the target satellite in the space target satellite information database constructed in step 1 and the approaching orbital state of the target satellite obtained through orbit determination in step 4, the hybrid optimization method is used to solve the optimal orbital fuel consumption δv required for each target satellite in the space target satellite information database to transfer from the initial orbital state to the approaching orbital state;

[0045] According to the target satellite determined in step 3, at the intermediate observation time t f The approaching orbit state x f =[r f ,v f ], where r f and v f are epoch t f At the moment, the position vector and velocity vector of the target satellite in the geocentric J2000 coordinate system; on the other hand, based on the space target satellite information database constructed in step 1, the initial orbital state x0 = [r0, v0] of the target satellite at epoch t0 is obtained, where r0 and v0 are the position vector and velocity vector of the target satellite in the geocentric J2000 coordinate system at epoch t0, respectively;

[0046] The target satellite realizes the orbit state from x0 to x through the optimal two-pulse transfer method. f The transfer of the two pulse maneuvers is defined as t1 and t f, where t1 ≥ t0, and the corresponding two pulse maneuver vectors are δv1 and δv2 respectively. The optimal transfer pulse maneuvers δv1 and δv2 are solved by constructing and solving the following optimization problem:

[0047]

[0048] Where X = t1 represents the optimization variable, J represents the performance index, and f represents the dynamic integral function. The target state is integrated from epoch t0 to the time t1 when the first pulse maneuver is applied, and the target orbit state x1 at time t1 is obtained; g lambert Represents the Lambert solver, which is used to solve the transfer from the target orbit state x1 at epoch t1 to the target orbit state x1 at epoch t f The orbital state at time x f v1′ represents the speed of the target satellite after the maneuver at time t1, and v2′ represents the speed of the target satellite at time t f The speed before the maneuver is applied at all times. A hybrid optimization method combining the differential evolution algorithm and the sequential quadratic programming algorithm is used to solve the optimal transfer orbit for this optimization problem. Using the solution of the differential evolution algorithm as the initial value for the sequential quadratic programming iterative solution can ensure the robustness of the solution and the optimality of the result, thereby obtaining the fuel consumption required for each satellite to transfer from the initial orbit state to the optimal orbit state:

[0049] δv=||δv1||+||δv2|| (11)

[0050] Step 5: Using the optimal orbit fuel consumption δv obtained in step 4, the linear interpolation method is used to calculate the satellite dynamic index score in the space target satellite information database;

[0051] Step 4: The minimum fuel consumption required for the kth target satellite in the database to approach is δv k , then the fuel consumption of all target satellites in the database forms the following array:

[0052]

[0053] The satellite with the lowest transfer cost in the array has a fuel consumption of δv min ; The satellite with the largest transfer cost has a corresponding fuel consumption of δv max ; The dynamic index score of the kth satellite is:

[0054]

[0055] Among them, the satellite with the smallest transfer cost has the highest dynamic index score, and the satellite with the largest transfer cost has the lowest dynamic index score;

[0056] Step 6: Combine the static index score obtained in step 2 and the dynamic index score obtained in step 5 to calculate the comprehensive index score of the target satellite. Based on the comprehensive index score, a preset number of satellites with the greatest likelihood of origin in the database are selected to complete the orbit tracing of the unknown target satellite.

[0057] The comprehensive index score is shown in formula (13):

[0058] P sum =σ δv P δv +σ sat P sat (13)

[0059] Among them, σ δv ,σ sat are the weights of dynamic indicators and static indicators respectively, P sum Score the composite indicator;

[0060] The higher the comprehensive index score, the more likely the corresponding satellite is to be the source satellite. Based on this score, the unknown target satellites in the database with the highest probability of being the source satellite can be quickly screened and ranked, completing the orbital tracing function for the unknown target satellite.

[0061] Beneficial effects:

[0062] This invention discloses a method for rapidly tracing close-in space targets. Based on publicly available satellite two-line element data, usage, and launch information, a space target satellite information database is constructed. This database contains orbital parameters, functional information, launch year, and quality information for the space target satellites. Based on this database, a static indicator score is established. Based on scoring criteria, static indicator scores are assigned to all satellites in the database and incorporated into the database. This database, which contains both the target satellite's own attribute information and the assigned static indicator scores, can also provide a data source for subsequent rapid tracing of space target satellites.

[0063] 2. The present invention discloses a method for rapidly tracing the origin of a close-range space target. When a space target approaches an observation spacecraft, the space target is observed and its initial orbit is determined using the observation information and its own state information. Based on the initial orbit determination result and combined with the satellite orbit state information in the database, the optimal transfer orbit is solved to obtain the transfer cost of each satellite in the database for the approach. Based on this, a dynamic index is proposed. Combining static and dynamic indicators, a comprehensive evaluation index is proposed. Based on the score of this index, the satellite with the highest probability of origin in the database can be quickly screened, thus realizing the rapid tracing function of close-range space targets. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Figure 1 A schematic flow chart of a method for rapid tracing of a target at close range in space according to the present invention;

[0065] Figure 2 Statistical histogram of the semi-major axis of space target satellites in the space target satellite information database;

[0066] Figure 3 Statistical histogram of static index scores of space target satellites in the space target satellite information database;

[0067] Figure 4 Schematic diagram of the relative orbit of the spacecraft in the RTN coordinate system in the flyby scenario. DETAILED DESCRIPTION

[0068] In order to better illustrate the purpose and advantages of the present invention, the invention is further described below with reference to the accompanying drawings and examples.

[0069] like Figure 1 As shown, this embodiment discloses a method for quickly tracing the source of a close-range target in space. In this example, a GEO orbit spacecraft is selected as the observation spacecraft, and a space target satellite is simulated to approach and fly around the observation spacecraft, ultimately tracing the source of the space target satellite. The specific steps are as follows:

[0070] Step 1: Using the publicly released two-line root number data as the main information source, establish a space target satellite information database.

[0071] Merge the CelesTrak database and the space-track database to obtain a two-row root number database; extract two rows of root number data from the two-row root number database, and parse the two rows of root number data to obtain the satellite name, orbital root number and NORAD number; compare the NORAD number with the number in the UCS database, and add the functional attributes, orbit type and launch quality information of the satellite with the corresponding number in the UCS database to the two-row root number database. If there is no correspondence, the corresponding information of the satellite with the number is coded as "unknown" to obtain the space target satellite information database. The satellite orbit state in the database is considered to be the initial orbit state of the target satellite. The database contains 2498 satellites. Statistics are performed on the semi-major axis of the space target satellite orbit in the "space target satellite information database", such as Figure 2 The database contains approximately 504 satellites at GEO orbit altitude, 112 satellites at medium orbit altitude, and 1,825 satellites at low orbit altitude.

[0072] Step 2: Construct a static index score for the target satellite based on the space target satellite information database information obtained in step 1:

[0073] For the database established in step 1, a space target static index score is established. This index comprehensively considers the satellite orbit semi-major axis, inclination and eccentricity attributes, satellite function attributes, target satellite maneuvering direction attributes and target satellite launch year as the standard for determining its static index.

[0074] The launch year of the target satellite; if the satellite was launched between 2015 and the present, it is judged to be relatively new, has certain maneuverability, and its equipment has not aged, so the probability of determining that the satellite launched in this period is the source satellite is the highest; if the satellite was launched between 2000 and 2015, it is judged that the satellite's maneuverability has degraded and its equipment has aged, so the probability of determining that the satellite launched in this period is the source satellite is medium; if the satellite was launched before 2000, it is judged that the satellite has basically lost its maneuverability and approach capability, so the probability of determining that the satellite launched in this period is the source satellite is the lowest;

[0075] The static index score of the target satellite is calculated by assigning points to each item and weighting the overall score. For each attribute, its source probability is specified in percentages. Among them, the satellite with the highest source probability has a score of 100 for this attribute, and the satellite with the lowest source probability has a score of zero for this attribute. In addition, the influence of the above four attributes is different, so their respective weights are also different. In this embodiment, the weights of attributes one and three are set as follows: Larger; weights of attributes two and four The static index score of each satellite is calculated by combining the internal hierarchical assignment of each attribute and the external weighted summation of the four attributes.

[0076] The static index scores of space target satellites in the “space target satellite information database” are statistically analyzed, such as Figure 3 As shown, the largest number of satellites have static indicator scores between 30 and 40, with the majority concentrated between 10 and 90. There are no cases of excessively high or low static indicator scores, and overall, the scores conform to a normal distribution. Therefore, the established static indicator scoring system and the assigned weights are considered reasonable and can reflect the static properties of space target satellites.

[0077] Step 3: With the selected GEO orbiting observation spacecraft as the origin and a 200km radius as the spacecraft's sensing range, parameters such as observation duration and observation error are set. Assuming a target satellite approaches and orbits the observation spacecraft within approximately 200km, the simulation generates orbital data for the target satellite and the observation spacecraft. Three relative observations of the target satellite by the observation spacecraft are simulated, generating observation information, each containing relative angle and distance information.

[0078] The total observation time is set to two hours, and the relative observation of the target satellite is carried out with an observation interval of one hour. The distance observation error is 0.1 km, and the angle observation error is 5 arc seconds.

[0079] In this example, it is assumed that the target satellite approaches and then flies around the observing GEO orbit satellite. By setting the satellite orbit parameters of the space target satellite and the GEO orbit satellite at the initial observation time, a flyby scenario is simulated. The position and velocity of the space target satellite and the GEO orbit satellite at the initial observation time are shown in Table 1.

[0080] Table 1 Position and velocity parameters of the space target satellite and the observation spacecraft at the initial observation time

[0081]

[0082]

[0083] The relative orbit diagram of the two satellites in the RTN coordinate system of the observation spacecraft is as follows Figure 4 As shown, the relative configuration is a flyby orbit.

[0084] Step 4: Use the initial orbit determination method to determine the absolute orbit state of the target satellite, and obtain the orbit state parameters of the target satellite at the intermediate observation moment when the space target satellite approaches and flies around the observation spacecraft.

[0085] The target satellite is observed three times at the following times: And the spacecraft's spatial state in the Earth's J2000 coordinate system is observed at the time of observation Combined with the observation information, based on the relative angle and distance information of the target satellite relative to the observation spacecraft at three moments, the position vector of the target satellite in the Earth's J2000 coordinate system at the three observation moments can be obtained by formula (3): The Gibbs initial orbit determination method is used to determine the orbital state of the target satellite, ultimately obtaining the position and velocity parameters of the space target satellite at the intermediate observation time. The actual position and velocity of the space target satellite at the intermediate time and the position and velocity determined by the orbit are shown in Table 2.

[0086] Table 2 Position and velocity parameters of the space target satellite at the intermediate observation time and the position and velocity parameters determined by orbit determination

[0087] The actual position and velocity of the target satellite at the intermediate observation moment: The position and velocity of the target satellite orbit determination result at the intermediate observation time: x:-42233.6782km x:-42233.6786km y:113.7564km y:113.7529km z: 1272.9193km z: 1272.9189km vx: -0.0169km / s vx: -0.0164km / s vy:-3.0606km / s vy:-3.0602km / s vz:-0.2511km / s vz:-0.2512km / s

[0088] The orbit determination results show that compared with the true value, the position error is about 1e-3km, and the velocity error is about 1e-4km / s, indicating that the orbit determination accuracy is relatively high.

[0089] Step 5: Combine the initial orbital state of the space target satellite in the space target satellite information database constructed in step 1 and the initial orbital state of the space target satellite at the observation time obtained in step 4. The approaching orbit state of the space target satellite is solved based on the hybrid optimization method on the space target satellite information database to obtain the optimal orbital fuel consumption required for each target satellite to transfer from the initial orbital state to the approaching orbital state.

[0090] By determining the orbit of the space target satellite in step 4, it can be considered that the target satellite is The orbital state at the moment, that is, the terminal state of the transfer orbit, is x f =[r f ,v f Based on the space target satellite information database established in step 1, the orbital state of the space target satellite at the initial epoch t0 can be obtained. This orbital state can be considered as the initial state of the target satellite transfer orbit, and this state is set to x0 = [r0, v0].

[0091] Considering that the space target satellite realizes the transition from orbit state x0 to x through the optimal two-pulse transfer method f The transfer of the two pulse maneuvers is defined as t1 and t f , where t1≥t0, and the corresponding two pulse maneuver vectors are δv1 and δv2 respectively. By constructing and solving the optimization problem shown in formula (10), the hybrid optimization method of differential evolution algorithm combined with sequential quadratic programming algorithm is used to solve the optimal transfer orbit of the optimization problem. Using the solution of differential evolution algorithm as the initial value of sequential quadratic programming iterative solution can ensure the robustness of the solution and the optimality of the result. Finally, the space target satellite is calculated from the orbital state x0 to x f Minimum fuel consumption required for transfer.

[0092] Step 6: Using the δv obtained in step 5, the linear interpolation method is used to calculate the satellite dynamic index score in the space target satellite information database.

[0093] In step 5, the minimum fuel consumption required for the kth target satellite in the database to approach is calculated as δv k , then the fuel consumption of all target satellites in the database forms the following array:

[0094]

[0095] Assume that the target satellite with the minimum transfer cost has a fuel consumption of δv min ; The target satellite with the largest transfer cost has a corresponding fuel consumption of δv max The dynamic index scores of the remaining target satellites are obtained by linear interpolation, and the dynamic index of the kth satellite is shown in formula (12).

[0096] Among them, the target satellite with the smallest transfer cost has the highest dynamic index score, and the target satellite with the largest transfer cost has the lowest dynamic index score.

[0097] Step 7: Combine the static index score constructed in step 2 and the dynamic index score constructed in step 6 to calculate the comprehensive index score of the space target satellite, and based on the score, select the ten satellites with the highest possibility of origin to complete the orbit tracing of the unknown space target.

[0098] The comprehensive index score is shown in formula (13). δv ,σ sat are the weights of dynamic indicators and static indicators respectively. In this implementation scheme, σ is set δv =σ sat =0.5, which means that the weights of static and dynamic indicators are the same.

[0099] This scoring system is composed of two parts. The calculated score takes into account both static attributes of the target satellite, such as its orbital state and functionality, and dynamic indicators based on actual observational orbit determination results. As a comprehensive indicator parameter for the final determination of the space target satellite, the higher the comprehensive indicator score, the more likely the target satellite is the source satellite. Based on this comprehensive evaluation index, the ten space target satellites with the highest likelihood of being the source satellites in the space target satellite information database can be quickly screened, enabling rapid tracing of space targets.

[0100] In this example, the ten most likely source satellites are shown in Table 3. As can be seen from the table, the top ten most likely source satellites are all GEO satellites. The maneuver sizes in the table indicate that the average maneuver required to approach and then fly around the observation spacecraft is approximately 0.2 km / s, with an overall score above 90.5. The top two satellites in the table, "USA 324" and "USA 325," are both space-based surveillance satellites, namely, "GSSAP 5" and "GSSAP 6," respectively, of the GSSAP satellite constellation.

[0101] Table 3 The top ten space target satellites with the most possible origins

[0102]

[0103] The above specific description further illustrates the purpose, technical solutions and beneficial effects of the invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for rapid tracing of a target at close range in space, characterized by: The following steps are included: Step 1: Using the publicly released two-line root number data and satellite basic attribute information as the main information sources, establish a space target satellite information database; Step 2: Construct a static index score of the target satellite based on the space target satellite information database information obtained in step 1; Step 3: The spatial range with the observation spacecraft as the origin and the radius of dkm is the perception range of the observation spacecraft. When the target satellite appears in the perception range of the observation spacecraft, three relative observations are made to the target satellite, and the information of each observation is the relative angle and relative distance information. The spatial state of the observation spacecraft is known. Combined with the observation information, the absolute orbit state of the target satellite is determined using the initial orbit determination method to obtain the target orbit state when the unknown target satellite approaches the observation spacecraft. Step 4: Combining the initial orbital state of the target satellite in the space target satellite information database constructed in step 1 and the approaching orbital state of the target satellite obtained through orbit determination in step 4, the fuel consumption required for each target satellite in the space target satellite information database to transition from the initial orbital state to the approaching orbital state is calculated based on a hybrid optimization method; Step 5: Using the optimal orbit fuel consumption obtained in step 4, use the linear interpolation method to calculate the satellite dynamic index score in the space target satellite information database; Step 6: Combine the static index score obtained in step 2 and the dynamic index score obtained in step 5 to calculate the comprehensive index score of the target satellite. Based on the comprehensive index score, a preset number of satellites with the greatest possibility of origin in the database are selected to complete the orbit tracing of the unknown target satellite.

2. The method for rapid tracing of a target at close range in space according to claim 1, characterized in that: The implementation method of step one is: The CelesTrak database and the space-track database are merged to obtain a two-row root number database. Two rows of root number data are extracted from the two-row root number database and parsed to obtain the satellite name, orbital root number, and NORAD number. The NORAD number is compared with the number in the UCS database, and the functional attributes, orbit type, and launch quality information of the satellite with the corresponding number in the UCS database are added to the two-row root number database. If there is no corresponding information, the corresponding information of the satellite with the number is coded as "unknown", thereby obtaining the space target satellite information database. The orbital state of the satellite in the database is determined to be the initial orbital state of the target satellite.

3. The method for rapid tracing of a target at close range in space according to claim 2, characterized in that: The implementation method of step 2 is: The static indicators take into account four properties: Step 2.1: The semi-major axis, inclination and eccentricity properties of the target satellite orbit are as shown in formula (1): Where a, i, e represent the semi-major axis, eccentricity, and orbital inclination of the target satellite orbit, respectively; a′, i′, e′ represent the semi-major axis, eccentricity, and orbital inclination of the high-probability source orbit, respectively; r p ,r a Respectively represent the perigee and apogee radii of the target satellite orbit; ε a ,ε e ,ε i They represent the deviation setting values ​​about the semi-major axis, eccentricity, and orbital inclination respectively; According to formula (1), when an unknown target satellite is located near a high-probability source orbit, it is determined to be a high-probability target satellite; when the target satellite passes through the orbit, that is, the orbit perigee radius is less than a′, the orbit apogee radius is greater than a′, and the orbit inclination is close to i′, it is determined to be a medium-probability target satellite; in other cases, it is determined to be a low-probability target satellite. Step 2.2: Target satellite maneuver direction attribute: By comparing the orbital element data of the same target satellite at the historical and current times, it can be determined whether the target satellite has a tendency to transfer to a high-probability orbit. If it maneuvers and transfers to a high-probability orbit, it is determined to be a high-probability target satellite. If it maneuvers but does not transfer to a high-probability orbit, it is determined to have the potential to transfer to a high-probability orbit and is considered a medium-probability target satellite. If it does not maneuver, it is considered a low-probability target satellite. Step 2.3: Target satellite functional attributes; If the satellite is a "space-based surveillance satellite," it is a surveillance satellite targeting space-based satellites and is the most likely satellite to conduct close-in surveillance. Therefore, it is determined to be the satellite with the highest possible source. If the satellite is a "space science research satellite" or a "communications satellite," it generally has a higher orbital altitude and carries high-precision observation sensors, allowing it to conduct close-in observations of space targets. Therefore, it is determined to be the satellite with the second highest possible source. If the satellite is an "earth science research satellite" or an "earth observation satellite," it carries high-precision observation sensors and is capable of conducting close-in observations of space targets. Therefore, it is determined to be a satellite with a medium possible source. If the satellite is a "navigation satellite" or a "satellite of unknown attributes," it is determined to be a satellite with a low possible source. If the satellite is a "technical research satellite" or other type of satellite, it is determined to be the satellite with the lowest possible source. Step 2.4: Launch year of the target satellite. If the satellite was launched within 10 years, it is considered relatively new, has a certain degree of maneuverability, and its equipment has not aged. Therefore, the probability of determining that a satellite launched in this period is the source satellite is the highest. If the satellite was launched between 10 and 25 years ago, its maneuverability is considered to have degraded and its equipment has aged. Therefore, the probability of determining that a satellite launched in this period is the source satellite is medium. If the satellite was launched more than 25 years ago, it is considered to have basically lost its maneuverability and approach capability. Therefore, the probability of determining that a satellite launched in this period is the source satellite is the lowest. The static index score of the target satellite is calculated by assigning points to each item and weighting the overall score. For each attribute, the probability of it being the source satellite is specified on a percentage basis. The satellite with the highest probability of being the source satellite has a score of 100 points, while the satellite with the lowest probability of being the source satellite has a score of zero points. In addition, the weights of the above four attributes are also different. The static index score of each satellite is calculated by combining the internal hierarchical assignment of each attribute and the external weighted summation of the four attributes: Among them, P sat Score the static index of space target satellite, σ i is the weight of each attribute of the space target satellite, P i Score each attribute of the space target satellite.

4. A method for rapid tracing of a target at close range in space as claimed in claim 3, characterized in that: The implementation method of step three is: The relative angle observation data of the target satellite relative to the observation spacecraft are expressed by right ascension α and declination δ, and the relative distance observation value is expressed by slant distance ρ; the position velocity vectors of the target satellite and the observation spacecraft at a certain moment in the Earth's J2000 coordinate system are [r tar ,v tar ] and [r ob ,v ob ], where the superscript "tar" represents the unknown target satellite and the superscript "ob" represents the observation spacecraft; the relative position vector between the two is ρ, which is expressed as the product of the slant range and the angle vector L; at a certain moment, the geometric relationship between the target satellite and the observation spacecraft is: r tar =r ob +ρL (3) The angle vector L is expressed by formula (4): Based on the relative angle and distance information of the target satellite relative to the observing spacecraft at any three consecutive observation moments, the position vector of the target satellite in the Earth's J2000 coordinate system at the three observation moments is obtained using formula (3): based on The Gibbs initial orbit determination method is used to obtain the velocity information of the target satellite at the time of observation: Where r represents the position vector, v represents the velocity vector, e represents the eccentricity vector, h represents the angular momentum scalar, μ represents the earth's gravitational constant; h represents the angular momentum vector; Based on the assumption that the three vectors are coplanar, we get formula (6): in, The expression for angular momentum is: And the expression of h×e is: in, Substituting formula (7) and formula (8) into formula (5), the velocity vector at the intermediate moment is obtained as: In formula (9), all the terms on the right side are only related to the known target satellite position vector; at this point, the position and velocity vectors of the target satellite in space at the intermediate observation time are all known, that is, the target orbit state when the unknown target satellite approaches the observation spacecraft at the intermediate observation time is obtained, which is called the approaching orbit state.

5. The method for rapid tracing of a target at close range in space according to claim 4, characterized in that: The implementation method of step 4 is: According to the target satellite determined in step 3, at the intermediate observation time t f The approaching orbit state x f =[r f ,v f ], where r f and v f are epoch t f At the moment, the position vector and velocity vector of the target satellite in the geocentric J2000 coordinate system; on the other hand, based on the space target satellite information database constructed in step 1, the initial orbital state x0 = [r0, v0] of the target satellite at epoch t0 is obtained, where r0 and v0 are the position vector and velocity vector of the target satellite in the geocentric J2000 coordinate system at epoch t0, respectively; The target satellite realizes the orbit state from x0 to x through the optimal two-pulse transfer method. f The transfer of the two pulse maneuvers is defined as t1 and t f , where t1 ≥ t0, and the corresponding two pulse maneuver vectors are δv1 and δv2 respectively. The optimal transfer pulse maneuvers δv1 and δv2 are solved by constructing and solving the following optimization problem: Where X = t1 represents the optimization variable, J represents the performance index, and f represents the dynamic integral function. The target state is integrated from epoch t0 to the time t1 when the first pulse maneuver is applied, and the target orbit state x1 at time t1 is obtained; g lambert Represents the Lambert solver, which is used to solve the transfer from the target orbit state x1 at epoch t1 to the target orbit state x1 at epoch t f The orbital state at time x f v1′ represents the speed of the target satellite after the maneuver at time t1, and v2′ represents the speed of the target satellite at time t f The speed before the maneuver is applied at all times; a hybrid optimization method combining the differential evolution algorithm and the sequential quadratic programming algorithm is used to solve the optimal transfer orbit of the optimization problem; the solution of the differential evolution algorithm is used as the initial value of the sequential quadratic programming iterative solution to ensure the robustness of the solution and the optimality of the result, thereby obtaining the required fuel consumption for each satellite to transfer from the initial orbit state to the optimal orbit state: δv=||δv1||+||δv2|| (11).

6. A method for rapid tracing of a target at close range in space according to claim 5, characterized in that: The implementation method of step five is: Step 4: The minimum fuel consumption required for the kth target satellite in the database to approach is δv k , then the fuel consumption of all target satellites in the database forms the following array: The satellite with the lowest transfer cost in the array has a fuel consumption of δv min ; The satellite with the largest transfer cost has a corresponding fuel consumption of δv max ; The dynamic index score of the kth satellite is: Among them, the satellite with the smallest transfer cost has the highest dynamic index score, and the satellite with the largest transfer cost has the lowest dynamic index score.

7. A method for rapid tracing of a target at close range in space according to claim 6, characterized in that: The implementation method of step six is: The comprehensive index score is shown in formula (13): P sum =σ δv P δv +σ sat P sat (13) Among them, σ δv ,σ sat are the weights of dynamic indicators and static indicators respectively, P sum Score the composite indicator; The higher the comprehensive index score, the more likely the corresponding satellite is the source satellite. Based on this score, the unknown target satellites in the database with the highest probability of being the source satellite can be quickly screened and ranked, completing the orbital tracing of the unknown target satellite.

8. The method for rapid tracing of a target at close range in space according to claim 7, characterized in that: The preset number of satellites is ten.

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