A method and system for TLE target library matching of radar observation data

Abstract

The application discloses a TLE target library matching method and system for radar observation data, and belongs to the field of space target monitoring; the method comprises the following specific steps: S1, using an SGP4 model to derive and store position information of all targets in a TLE library; S2, converting radar measurement data into position coordinates of targets in an inertial system; S3, using an extended Laplace algorithm to perform initial orbit determination on a measurement arc segment; S4, screening targets in the TLE library according to the orbit determination result; S5, performing coarse matching of an observation arc segment and a space target by taking position mean square error as a criterion, and obtaining candidate targets; and S6, considering observation error and TLE orbit error, and determining a matching result according to covariance analysis; the application reduces the calculation amount of orbit prediction by using Lagrange interpolation technology, and screens TLE by using initial orbit determination results, so that unnecessary matching calculation can be avoided, coarse matching and fine matching are combined, the target matching speed can be ensured, and the matching precision can also be ensured.

Description

TECHNICAL FIELD

[0001] The application discloses a TLE target library matching method and system for radar observation data, and relates to the technical field of space target monitoring. BACKGROUND

[0002] Space targets refer to spacecraft and space debris running in space, which run regularly along respective orbits. A space target monitoring system can detect, track, catalog and manage important space targets. Ground-based radars are important detection equipment of the space target monitoring system and are mainly used for monitoring low-orbit space targets. Through emission of electromagnetic waves to irradiate targets and reception of echoes, the radars can obtain information such as azimuth angles, elevation angles and distances of the space targets. With the progress of technology, modern radars can simultaneously track multiple space targets and can obtain a large number of observation arcs (thousands or even tens of thousands) in one day.

[0003] A TLE orbit library refers to a database containing orbit information of cataloged space targets. Orbit information of each space target is given in the form of two-line elements (TLE). In combination with an SGP4 dynamics model matched with the TLE, the orbit state (position and velocity) of the space target at any time can be obtained. As of November 2020, the TLE library disclosed by the United States contains 21293 space targets, of which 6079 are spacecraft and 15214 are space debris.

[0004] Target matching refers to matching observation data with targets in the TLE library to confirm which space target each observation arc belongs to. Due to the large number of observation arcs and cataloged targets, the calculation amount of one-to-one matching is large.

[0005] Therefore, the application provides a TLE target library matching method and system for radar observation data to solve the above problems. SUMMARY

[0006] The application provides a TLE target library matching method and system for radar observation data to solve the above problems.

[0007] S1, using an SGP4 model to derive and store position information of all targets in the TLE library;

[0008] S2, converting radar measurement data into position coordinates of the target in an inertial system;

[0009] S3, using an extended Laplace algorithm to determine an initial orbit of the measurement arc;

[0010] S4 screens the targets in the TLE library according to the orbit determination result;

[0011] S5 performs coarse matching between the observation arc and the space target according to the position mean square error to obtain a candidate target;

[0012] S6 considers the observation error and the TLE orbit error, and determines the matching result according to the covariance analysis.

[0013] The TLE library in S1 is an orbit library composed of TLE information of cataloged space targets;

[0014] The time span of the stored TLE orbit covers all observation data.

[0015] The specific steps of S2 for converting the radar measurement data into the position coordinates of the target in the inertial system are as follows:

[0016] S21 takes the azimuth angle, the elevation angle and the distance in the station horizontal coordinate system as the radar measurement data;

[0017] S22 converts the radar measurement data from the station horizontal coordinate system to the earth-fixed coordinate system;

[0018] S23 converts the radar measurement data from the earth-fixed coordinate system to the earth-inertial coordinate system.

[0019] S4 screens the targets in the TLE library according to the orbit determination result, and uses four orbit parameters in the orbit determination result: semi-major axis, eccentricity, orbit inclination and ascending node right ascension;

[0020] The average orbit root number information contained in the TLE is used to screen the targets in the TLE library.

[0021] The specific steps of S5 for performing coarse matching between the observation arc and the space target according to the position mean square error to obtain a candidate target are as follows:

[0022] S51 uses Lagrange interpolation to obtain the position of the TLE orbit at the observation time;

[0023] S52 calculates the mean square error of the TLE orbit position and the observation orbit position;

[0024] S53 uses the mean square error as a criterion to determine whether the TLE orbit corresponds to a candidate target.

[0025] The specific steps of S6 for determining the matching result according to the covariance analysis considering the observation error and the TLE orbit error are as follows:

[0026] S61 uses the unscented transformation algorithm to solve the mean value and the covariance of the observation true value according to the TLE orbit error characteristics;

[0027] S62 According to the observation error characteristics, a normal distribution to which the actual observation value is subjected is obtained;

[0028] S63 A statistic quantity subjected to a 3-degree-of-freedom chi-square distribution, Mahalanobis distance, is constructed;

[0029] S64 The candidate orbit obtained in S5 is accepted or rejected by taking the Mahalanobis distance as a criterion.

[0030] A TLE target library matching system for radar observation data, the system specifically comprises a position processing module, a data processing module, an arc segment orbit determination module, a target screening module, a target matching module and a result analysis module:

[0031] The position processing module: using the SGP4 model to derive and store the position information of all targets in the TLE library;

[0032] The data processing module: converts the radar measurement data into the position coordinates of the target in the inertial system;

[0033] The arc segment orbit determination module: uses an extended Laplace algorithm to determine the initial orbit of the measurement arc segment;

[0034] The target screening module: screens the targets in the TLE library according to the orbit determination result;

[0035] The target matching module: performs coarse matching of the observation arc segment and the space target by taking the position mean square error as a criterion, and obtains the candidate target;

[0036] The result analysis module: considers the observation error and the TLE orbit error, and determines the matching result according to the covariance analysis.

[0037] The TLE library in the position processing module is composed of the TLE information of the cataloged space targets;

[0038] The time span of the stored TLE orbit covers all observation data.

[0039] The data processing module specifically comprises a data acquisition module, a first coordinate conversion module and a second coordinate conversion module:

[0040] The data acquisition module: takes the azimuth angle, the elevation angle and the distance in the station horizontal coordinate system as the radar measurement data;

[0041] The first coordinate conversion module: converts the radar measurement data from the station horizontal coordinate system to the earth-fixed coordinate system;

[0042] The second coordinate conversion module: converts the radar measurement data from the earth-fixed coordinate system to the earth-inertial coordinate system.

[0043] The target screening module screens the targets in the TLE library according to the orbit determination result, and four orbit parameters in the orbit determination result are used: semi-major axis, eccentricity, orbit inclination and ascending node right ascension.

[0044] The targets in the TLE library are screened using the average orbit root number information contained in the TLE.

[0045] The beneficial effects of the present application are: the present application aims at the problem of large amount of calculation in radar observation data target matching, uses Lagrange interpolation technology to reduce the calculation amount of orbit prediction, uses the initial orbit determination result to screen the TLE, can avoid unnecessary matching calculation, and combines coarse matching and fine matching, that is, can ensure the target matching speed and also ensure the matching accuracy; the present application can solve the problem of fast matching of a large amount of radar observation data and TLE orbit library. BRIEF DESCRIPTION OF DRAWINGS

[0046] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced as follows. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0047] Figure 1 is the position mean square error and average Mahalanobis distance of the successfully matched arc segment in the matching result of September 8, 2020 in the method embodiment three of the present application; Figure 2 is the position mean square error and average Mahalanobis distance of the successfully matched arc segment in the matching result of September 9, 2020 in the method embodiment three of the present application; Figure 3 is the position mean square error and average Mahalanobis distance of the successfully matched arc segment in the matching result of September 10, 2020 in the method embodiment three of the present application; Figure 4 is the flowchart of the method embodiment of the present application. DETAILED DESCRIPTION

[0048] The present application will be further described below in combination with the drawings and specific embodiments, so that those skilled in the art can better understand the present application and implement it, but the embodiments are not limiting to the present application.

[0049] Embodiment one:

[0050] A TLE target library matching method for radar observation data, the specific steps of the method are as follows:

[0051] S1 uses SGP4 model to derive and store the position information of all targets in the TLE library;

[0052] S2 converts the radar measurement data into position coordinates of the target in the inertial system;

[0053] S3 performs initial orbit determination on the measurement arc segment using an extended Laplace algorithm;

[0054] S4 screens the target in the TLE library according to the orbit determination result;

[0055] S5 performs coarse matching of the observation arc segment and the space target according to the position mean square error criterion to obtain a candidate target;

[0056] S6 determines the matching result according to covariance analysis by considering the observation error and the TLE orbit error;

[0057] Further, the TLE library in S1 is an orbit library composed of TLE information of cataloged space targets;

[0058] The time span for storing the TLE orbit covers all observation data;

[0059] The SGP4 dynamic model and TLE information are used for space target orbit prediction; the time span for storing the TLE orbit should cover all observation data, generally from 0 o'clock to 24 o'clock of the observation data; the time step for storing the TLE orbit is 10 minutes;

[0060] S2-S6 are the matching process of a single observation arc segment, and all observation arc segments need to perform these steps to determine their respective matching results;

[0061] Further, the specific steps of S2 for converting the radar measurement data into position coordinates of the target in the inertial system are as follows:

[0062] S21 takes the azimuth angle, elevation angle and distance in the station ground coordinate system as the radar measurement data;

[0063] S22 converts the radar measurement data from the station ground coordinate system to the earth-fixed coordinate system;

[0064] S23 converts the radar measurement data from the earth-fixed coordinate system to the earth inertial coordinate system;

[0065] Further, S3 uses an extended Laplace algorithm to perform initial orbit determination on the measurement arc segment, and the data used is the position coordinates in the inertial system in S2;

[0066] The extended Laplace algorithm, whose basic algorithm is the Laplace algorithm for optical observation data, can be used for radar observation data after extension;

[0067] Further, the S4 screens the target in the TLE library according to the orbit determination result, and uses four orbit parameters in the orbit determination result: semi-major axis, eccentricity, orbit inclination, and ascending node right ascension;

[0068] The target in the TLE library is screened using the average orbit root number information contained in the TLE;

[0069] Further, the S5 performs coarse matching between the observation arc segment and the space target using the position mean square error as a criterion, and the specific steps of obtaining the candidate target are as follows:

[0070] S51 uses Lagrange interpolation to obtain the position of the TLE orbit at the observation time;

[0071] S52 calculates the mean square error of the TLE orbit position and the observation orbit position;

[0072] S53 uses the mean square error as a criterion to determine whether the TLE orbit corresponding target is a candidate target;

[0073] The Lagrange interpolation algorithm is 9th order;

[0074] The threshold of the mean square error is 50 kilometers;

[0075] Further, the S6 considers the observation error and the TLE orbit error, and the specific steps of determining the matching result according to the covariance analysis are as follows:

[0076] S61 uses the unscented transformation algorithm to solve the mean value and covariance of the observation true value according to the TLE orbit error characteristics;

[0077] S62 obtains the normal distribution to which the actual observation value is subjected according to the observation error characteristics;

[0078] S63 constructs a statistical quantity--Mahalanobis distance, which is subjected to 3-degree-of-freedom chi-square distribution;

[0079] S64 uses the Mahalanobis distance as a criterion to accept or reject the candidate orbit obtained in S5;

[0080] The threshold of the Mahalanobis distance is ;

[0081] Suppose that the radar obtains M groups of observation data (observation arc segments) on a day ; suppose that Ti contains mi groups of measurement points,

[0082] (1)

[0083] Wherein, A represents the azimuth angle, E represents the elevation angle, represents the distance between the radar and the target, and t is the observation time;

[0084] Let the total number of cataloged space objects in the TLE orbit library be N, denoted as ;

[0085] The method of the present application can determine which target in the TLE the arbitrary observation arc segment belongs to.

[0086] Example two:

[0087] On the basis of example one, first, according to S1, the position information of all targets in the TLE library is derived and stored using the SGP4 model:

[0088] Using the SGP4 dynamic model, the spatial position of the space target at any time can be obtained; since there are many radar observation data, the measurement time corresponding to each group of data is different, and if the SPG4 model is frequently called for orbit calculation, a large amount of computing resources is required; to solve this problem, the method of the present application learns from the publication and use mode of the navigation satellite precise ephemeris, and pre-derives the position points of each space target at several times and stores them; in subsequent calculation, the orbit position at any time can be realized through Lagrange interpolation;

[0089] For any target TLEk in the TLE library, using the SGP4 model to obtain the position information of the target from 0 o'clock to 24 o'clock on the current day at a step of 10 minutes, denoted as

[0090] (2)

[0091] Wherein, S=145 is the total number of stored positions;

[0092] In this way, for the entire TLE orbit library, only 145×N times of SPG4 model are called for orbit calculation;

[0093] For any observation arc segment, executing subsequent S2~S6 can determine the matching result of the arc segment;

[0094] Then, according to S2, the radar measurement data is converted into the position coordinates of the target in the inertial system:

[0095] In the station horizontal coordinate system (south-east-sky), the observation arc segment The position at tj can be expressed as Wherein,

[0096] (3)

[0097] Convert to the coordinates of the space target in the inertial system, and the expression is

[0098] (4)

[0099] Wherein, The conversion matrix from the station horizontal coordinate system to the earth fixed coordinate system, The conversion matrix from the earth fixed coordinate system to the earth inertial coordinate system, The coordinates of the station in the earth fixed coordinate system;

[0100] Continue to use the extended Laplace algorithm to determine the initial orbit of the measurement arc segment according to S3:

[0101] The original Laplace algorithm uses three sets of angle measurement data to determine the orbit, Liu Lin improves and extends the algorithm to make it suitable for radar and navigation data orbit determination, and can use all observation data as follows:

[0102] Assume that the orbit determination epoch is , and the goal of the initial orbit determination is to determine the position and velocity of the spacecraft at time ; under the two-body dynamics model, there are the following mechanical conditions:

[0103] (5)

[0104] In the formula, , are the Lagrange coefficients at time , which are only related to the initial state and the time difference ;

[0105] The perturbation combines the target observation positions obtained in S2 to obtain the conditional equation

[0106] (6)

[0107] Expanding the conditional equation, we have

[0108] (7)

[0109] This equation group is linear in form and can be abstracted as

[0110] (8)

[0111] There are 6 unknowns in the above equation group, a total of equations, which can be solved at ; the orbit determination problem is converted into the following optimization problem:

[0112] (9)

[0113] It can be solved through simple iteration;

[0114] Next, based on the orbit determination results from S4, targets in the TLE database will be filtered:

[0115] Through S3, the arc segment can be obtained. The orbit determination result, i.e., the orbit determination epoch. orbital state This state is represented by classical orbital elements as: The six parameters are, in order: semi-major axis, eccentricity, orbital inclination, right ascension of the ascending node, argument of perigee, and true anomaly.

[0116] TLE includes the target in the TLE epoch. The average orbital elements, including eccentricity. Track inclination Right ascension of ascending node And the average motion rate (which can be used to calculate the semi-major axis) The TLE filtering criteria are as follows:

[0117] (10)

[0118] If the TLE information of a certain space target does not meet the above conditions, then the arc segment is considered to be... It definitely does not belong to the target in this space and will not be included in subsequent calculations;

[0119] Furthermore, following S5, using the mean square error of position as the criterion, a coarse matching is performed between the observed arc segment and the spatial target to obtain candidate targets:

[0120] Targets and filters through TLE The actual targets have similar orbital parameters, and typically only a few dozen to a few hundred remain. To further reduce the computational load, irrelevant targets can be further eliminated based on the mean square error of position, as shown in the table below:

[0121] Table 1. Pseudocode of the coarse matching algorithm

[0122]

[0123] All spatial targets with a root mean square error of position less than 50 km are listed as candidate targets; the number of candidate targets is usually 1, but may also be 0 or greater than 1.

[0124] Finally, considering observation errors and TLE orbital errors according to S6, the matching results are determined based on covariance analysis:

[0125] Since both radar measurements and TLE trajectories contain errors, a more reasonable criterion is needed to determine whether to accept candidate targets as matching results.

[0126] Let the mean of the TLE orbital error be denoted as , the covariance is denoted as ; let the position of the target at a certain time be obtained by TLE , then the real orbit position of the target obeys the following normal distribution:

[0127] (11)

[0128] Given the satellite orbit position and station position at a certain time (known), the observation value (right ascension, declination) that the station can obtain is calculated; in other words, the observation value is a function of the satellite position:

[0129] (12)

[0130] After nonlinear transformation of the observation function, we hope to obtain the mean and covariance of the observation true value ; this is a typical mapping problem of mean and covariance under nonlinear transformation, and there are various common methods, and we use the unscented transformation method to solve the statistical characteristics of the measurement data, as shown in the following table.

[0131] Table 2. Mean and covariance of the observation true value solved by unscented transformation algorithm

[0132]

[0133] Under the normal distribution assumption, the observation true value at tjobeys the following distribution

[0134]

[0135] The actual observation value is , according to the observation error characteristics, we have

[0136]

[0137] In the formula, represents the observation error:

[0138]

[0139] Adding the two formulas, we can get

[0140]

[0141] The statistical quantity called "Mahalanobis distance" is constructed

[0142]

[0143] Then obeys the distribution with 3 degrees of freedom, that is, ; let Quantile is Then

[0144]

[0145] Let The meaning of this formula is that if the target and the observation sequence are the same target, the Mahalanobis distance at any time is less than with a probability of up to 99.5%; under the short-arc observation arc segment, the error at each time is not much different, in order to save computing resources, only the Mahalanobis distance of the initial observation time t1, the middle time and the last observation time is used to determine whether to accept the candidate orbit as the matching result, and the acceptance condition is:

[0146]

[0147] For a certain observation file, if all candidate orbits are rejected, it is considered that the file has no matching result; if only one candidate orbit is accepted, the matching is successful; if more than one candidate orbit is accepted, the target with the smallest sum of three Mahalanobis distances is taken as the matching result.

[0148] Example three:

[0149] On the basis of example two, the matching result of an observation arc segment is divided into three kinds, which are:

[0150] Correct matching: the observation arc segment is matched to the correct target;

[0151] Mis-matching: the observation arc segment is matched to the target, but the matching is wrong;

[0152] Miss-matching: the observation arc segment itself has a corresponding entity, but the algorithm does not match any target;

[0153] The space target orbit and radar observation data are obtained through simulation; the simulated observation site is selected as the Xinglong Observation Station of the National Astronomical Observatory, with the geodetic coordinates being (117.575°, 40.396°, 960m); the measurement errors of azimuth, elevation and distance are 0.1 degree (1), 0.1 degree (1) and 50 meters (1) respectively; when generating the simulated observation data, the observation elevation is greater than 15°;

[0154] The simulation date is from September 8, 2020 to September 10, 2020; 2303 space targets are randomly selected from the TLE library, and 7042, 7128 and 7090 simulation observation arcs are generated in three days respectively; the TLE orbit error characteristics of different types of space targets are shown in the following table; in the table, LEO represents a low earth orbit satellite, MEO represents a medium earth orbit satellite, and GEO represents a geosynchronous orbit satellite; R represents the radial error, T represents the tangential error, and N represents the normal error;

[0155]

[0156] A matching program is written using Matlab software, and a CPU model Inter Core(TM) i7-8565U with a frequency of 1.8GHz is used; the matching results are shown in the following table;

[0157] Table 3 Matching results of simulation data

[0158]

[0159] Using simulation data, the target matching accuracy can reach more than 99%; for more than 7000 observation arcs and more than 17000 catalog targets, the matching can be completed in about 5 minutes;

[0160] For the matched arcs, the mean square deviation of the position of the observation value in S5 and the TLE orbit and the mean value of the three Mahalanobis distances in S6 are plotted, as shown in Figures 1-3 It can be seen that for the matched arcs, the position mean square deviation and the Mahalanobis distance are very small, and the matching result is reliable.

[0161] Example four

[0162] A TLE target library matching system for radar observation data, the system specifically comprises a position processing module, a data processing module, an arc orbit determination module, a target screening module, a target matching module and a result analysis module:

[0163] Position processing module: using SGP4 model to derive and store the position information of all targets in TLE library;

[0164] Data processing module: convert radar measurement data into position coordinates of the target in the inertial system;

[0165] Arc orbit determination module: using an extended Laplace algorithm to determine the initial orbit of the measurement arc;

[0166] Target screening module: screening the targets in the TLE library according to the orbit determination result;

[0167] Target matching module: coarse matching of observation arc and space target is carried out with position mean square error as criterion, and candidate target is obtained;

[0168] Result analysis module: considering observation error and TLE orbit error, matching result is determined according to covariance analysis;

[0169] Further, the TLE library in the position processing module is an orbit library composed of TLE information of cataloged space targets;

[0170] The time span of the stored TLE orbit covers all observation data;

[0171] Further, the data processing module specifically includes a data acquisition module, a first coordinate conversion module and a second coordinate conversion module:

[0172] Data acquisition module: azimuth, elevation and distance in station horizontal coordinate system are taken as radar measurement data;

[0173] First coordinate conversion module: conversion of radar measurement data from station horizontal coordinate system to earth fixed coordinate system;

[0174] Second coordinate conversion module: conversion of radar measurement data from earth fixed coordinate system to earth inertial coordinate system;

[0175] Further, the target screening module screens targets in the TLE library according to the orbit determination result, and four orbit parameters in the orbit determination result are used: semi-major axis, eccentricity, orbit inclination and ascending node right ascension;

[0176] The average orbit root information contained in TLE is used to screen targets in the TLE library.

[0177] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for TLE target library matching of radar observation data, characterized in that The method comprises the following specific steps: S1: using SGP4 model to derive and store position information of all targets in TLE library; S2: converting radar measurement data into position coordinates of the target in inertial system; S3: using extended Laplace algorithm to perform initial orbit determination on the measurement arc segment; S4: screening the targets in TLE library according to the orbit determination result; S5: performing coarse matching between the observation arc segment and the space target by taking position mean square error as the criterion, and obtaining candidate targets; S6: considering observation error and TLE orbit error, and determining the matching result according to covariance analysis; The specific steps of S2 are as follows: S21: taking the azimuth angle, elevation angle and distance in the station horizontal coordinate system as the radar measurement data; S22: converting the radar measurement data from the station horizontal coordinate system to the earth-fixed coordinate system; S23: converting the radar measurement data from the earth-fixed coordinate system to the earth-inertial coordinate system; The specific steps of S4 are as follows: S4: screening the targets in TLE library according to the orbit determination result, using four orbit parameters in the orbit determination result, i.e., semi-major axis, eccentricity, orbit inclination and ascending node right ascension; 2. The method of claim 1, wherein S4: screening the targets in TLE library by using the average orbit root number information contained in TLE. The TLE library in S1 is an orbit library composed of TLE information of cataloged space targets; 3. The method of claim 2, wherein The time span for storing the TLE orbit covers all observation data. The specific steps of S5 are as follows: S51: using Lagrange interpolation to obtain the position of the TLE orbit at the observation time; S52: calculating the mean square error of the TLE orbit position and the observation orbit position; 4. The method of claim 3, wherein S53: taking the mean square error as the criterion to determine whether the target corresponding to the TLE orbit is a candidate target. The specific steps of S6 are as follows: S61: according to the TLE orbit error characteristics, using unscented transformation algorithm to solve the mean value and covariance of the observation true value; S62: according to the observation error characteristics, obtaining the normal distribution to which the actual observation value is subjected; S63: constructing a statistic quantity subjected to 3-degree-of-freedom chi-square distribution, i.e., Mahalanobis distance; 5. A TLE target library matching system for radar observation data, characterized by S64: taking the Mahalanobis distance as the criterion to accept or reject the candidate orbit obtained in S5. The system comprises the following modules: Position processing module: using SGP4 model to derive and store position information of all targets in TLE library; Data processing module: converting radar measurement data into position coordinates of the target in inertial system; Arc segment orbit determination module: using extended Laplace algorithm to perform initial orbit determination on the measurement arc segment; Target screening module: screening the targets in TLE library according to the orbit determination result; Target matching module: performing coarse matching between the observation arc segment and the space target by taking position mean square error as the criterion, and obtaining candidate targets; Result analysis module: considering observation error and TLE orbit error, and determining the matching result according to covariance analysis; The data processing module specifically comprises a data acquisition module, a first coordinate conversion module and a second coordinate conversion module: The data acquisition module: taking the azimuth angle, the elevation angle and the distance in the station horizontal coordinate system as the radar measurement data; The first coordinate conversion module: converting the radar measurement data from the station horizontal coordinate system to the earth-fixed coordinate system; The second coordinate conversion module: converting the radar measurement data from the earth-fixed coordinate system to the earth-inertial coordinate system; The target screening module screens the targets in the TLE library according to the orbit determination result, and uses four orbit parameters in the orbit determination result: semi-major axis, eccentricity, orbit inclination and ascending node right ascension; The average orbit root number information contained in the TLE is used to screen the targets in the TLE library.

6. The system of claim 5, wherein The TLE library in the position processing module is an orbit library composed of the TLE information of cataloged space targets; The time span for storing the TLE orbit covers all observation data.

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