An interactive ground-based space target monitoring sensor simulation system

Abstract

This invention discloses an interactive ground-based space target monitoring sensor simulation system, comprising a ground-based sensor simulation subsystem, a space target simulation subsystem, a space situation display subsystem, and a simulation data management subsystem. The sensor simulation subsystem is used to set sensor parameter information, generate simulated sensor operating states, and produce simulated detection data. The space target simulation subsystem is used to calculate ephemeris information and predict ephemeris based on input ephemeris files, and also to predict re-entry and collision events based on input ephemeris. The space situation display subsystem is used to set space environment parameters and dynamically display the space situation scene in real time. The simulation data management subsystem is used to manage the simulation scene, simulated detection data, and simulation parameters. The advantage of this invention is that it simulates space target trajectories and space events, thereby enabling debugging of the sensor backend software system based on space target motion trajectory data.

Description

Technical Field

[0001] This invention relates to the field of sensor simulation, and more specifically to an interactive ground-based space target monitoring sensor simulation system. Background Technology

[0002] The mission of a space target surveillance system is to detect and precisely track space targets, complete space target orbit determination and cataloging, predict space events, and determine the mission, size, shape, and orbital parameters of spacecraft that may pose a threat to the space system. Space targets mainly refer to satellites, including operational and defunct satellites, as well as various space debris, such as abandoned spacecraft in orbit, launch vehicle debris, and collision debris.

[0003] Ground-based space target surveillance equipment (hereinafter referred to as sensors) has the advantages of all-weather operation and strong wide-area acquisition capability. It can track and predict the trajectory of objects in space and provide early warning of possible space events such as collisions and re-entry.

[0004] During sensor debugging, it is often necessary to verify the ability of the sensor's backend software system to detect and track targets and process detection data by detecting satellites. However, the detection power of sensors is limited; targets or space events are not always within the sensor's detection range, and due to hardware limitations and cost issues, sensors cannot always be in a state of continuous operation. To facilitate the debugging of the sensor's backend software system, the support of space target motion trajectory data is required. The paper "Research on Space Target Surveillance System and Its Information Processing Technology," published on October 18, 2013, by Ding Shuai, Fu Tuo, and Gao Meiguo of Beijing Institute of Technology in the proceedings of the 11th National Doctoral Academic Conference—Information Technology and Security, discusses the main information processing technologies of a space target surveillance system from the aspects of system detection model, key processing algorithms, and performance evaluation, and explores the main factors affecting the system's information processing capability and related improvement strategies. However, this paper does not study how to simulate space target trajectories and space events, thus preventing the debugging of the sensor's backend software system based on space target motion trajectory data. Summary of the Invention

[0005] The technical problem to be solved by this invention is that the existing technology lacks relevant research on simulating the trajectory of space targets and space events, thus making it impossible to debug the sensor back-end software system based on the motion trajectory data of space targets, and unable to verify the ability of the sensor back-end software system to detect and track targets and process detection data.

[0006] This invention solves the above-mentioned technical problems through the following technical means: an interactive ground-based space target monitoring sensor simulation system, comprising a ground-based sensor simulation subsystem, a space target simulation subsystem, a space situation display subsystem, and a simulation data management subsystem. The ground-based sensor simulation subsystem is used to set sensor parameter information, generate simulated sensor working states, and produce simulated detection data. The space target simulation subsystem is used to calculate ephemeris information and predict orbits based on input ephemeris files, and also to predict re-entry and collision events based on input ephemeris. The space situation display subsystem is used to set space environment parameters and dynamically display the space situation scene in real time. The simulation data management subsystem is used to manage the simulation scene, simulated detection data, and simulation parameters.

[0007] This invention sets the parameter information of the ground-based sensor, generates a simulated sensor working state and produces simulated detection data, calculates ephemeris information and predicts orbits based on the input ephemeris file, completes the simulation of the trajectory of space targets, and predicts re-entry and collision events based on the input ephemeris, completes the simulation of space events. Thus, even when the satellite or space event is outside the detection range of the sensor or the sensor is not in the firing state, the sensor backend software system can still be debugged based on the simulated space target motion trajectory data, verifying the sensor backend software system's ability to detect and track targets and process detection data.

[0008] Furthermore, the ground-based sensor simulation subsystem includes a sensor setting module, a sensor operating state simulation module, and a detection data generation module. The sensor setting module is used to set the sensor's parameter information, including: number, name, country, sensor type, location coordinates, observation range, data rate, observation time range, and beam color. The sensor operating state simulation module is used to generate simulated sensor operating states, such as beam search, acquisition, and tracking states. The detection data generation module generates simulated detection data based on the sensor's detection range, accuracy, and data rate. The detection data includes radar detection data and optical equipment detection data. Radar detection data includes range, azimuth, and elevation angles, while optical equipment detection data includes right ascension and declination.

[0009] Furthermore, the method for generating the distance, azimuth, and elevation angles includes:

[0010] 1) Set the sensor's position coordinates, power range, and detection accuracy. The power range includes distance range, azimuth range, and angle range. The detection accuracy includes distance accuracy, azimuth accuracy, and angle accuracy. 2) Predict the orbit of a space target at a sampling interval of 1 minute, and calculate the longitude, latitude and altitude of each point on the orbit; 3) Based on the target's longitude, latitude, and altitude, when the target enters the Chinese side of the Northern Hemisphere, it is determined that the target may be captured by the sensor and may enter the sensor's observation range. 4) For points that may enter the observation range, the Lagrange ninth-order interpolation method is used to calculate the coordinates at the corresponding time according to the sensor's data rate. Then, the distance, azimuth, and elevation angle from the sensor are calculated. Points that fall within the sensor's range are the observable points. 5) Add white noise to the distance, azimuth, and elevation angles of the above points according to the sensor's detection accuracy.

[0011] Furthermore, the method for calculating right ascension and declination is mainly applied to ground-based optical equipment tracking geostationary satellites. It eliminates the need to calculate visibility; it only requires calculating right ascension and declination according to the user-defined observation time and adding white noise to the right ascension and declination based on the sensor's accuracy. The calculation method for right ascension and declination is as follows: Let the observation vector be , and Representing the observations of right ascension and declination, then the observation vector and... , The relationship between them is:

[0012] Therefore, the measurement equation for right ascension-declination observations is expressed as: , in, , , express Each component, .

[0013] Furthermore, the space target simulation subsystem includes an ephemeris setting module, a space target orbit prediction module, and a space event calculation module. The ephemeris setting module is used for inputting various ephemeris files, including: TLE ephemeris, J2000.0 coordinate ephemeris, and ECEF coordinate ephemeris. Ephemeris information includes: number, name, country, epoch, time stamp, and predicted orbit number, and supports multiple selections. The space target orbit prediction module is used to calculate ephemeris information. For TLE ephemeris, the SGP4 prediction method is used for prediction, while for J2000.0 coordinate ephemeris and ECEF coordinate ephemeris, the space target dynamics model is used for prediction. The space event calculation module is used to predict re-entry and collision events based on the input ephemeris.

[0014] Furthermore, the SGP4 forecasting method includes: 1) The SGP4 forecast software reads in the TLE ephemeris and performs calculations; 2) The SGP4 model is used to predict TLE ephemeris; The SGP4 model is a simplified model derived using Lane and Cranford's generalized analysis theory. It considers the effects of Earth's oblateness, long-term and periodic perturbations of lunar and solar gravity, as well as gravitational resonance and orbital decay of the main atmospheric model parameters. The gravitational model employs the Brouwer solution, while the atmospheric model uses a power density function.

[0015] The SGP4 model is represented by the following function:

[0016] In the formula: Orbital eccentricity, Track inclination, Ascending node right ascension, Perimeter argument, True close angle, It is the average velocity of the average orbital element. These are the ballistic coefficients used in the SGP4 model.

[0017] Furthermore, the process of predicting a meteorite impact event includes: 1) Predict the spatial trajectory of space targets for more than one month; 2) Calculate the change in target altitude. When the target altitude continues to decrease and eventually falls below 120km, it is determined that the target will fall.

[0018] Furthermore, the process of predicting collision events includes: 1) Read in the TLE ephemeris; 2) Calculate the semi-major axis, semi-minor axis, and inclination of each target in the TLE ephemeris; 3) Collision events are only considered based on the probability of collision with important targets. Important targets are designated as primary targets, and other targets as secondary targets. An exhaustive method is used to predict the distances between the secondary targets and the primary target in the TLE ephemeris over the next 24 hours, and collision events are then selected. a) Assume the semi-major axis of the primary target is a1, the semi-minor axis is b1, and the semi-major axis of the secondary target is a2, the semi-minor axis is b2. or If so, the two targets cannot collide; b) Predict the positions of two targets and calculate the distance between them every 5 minutes, with a prediction period of 24 hours. If the distance between the two targets is less than 2000 km, predict the target positions and calculate the distance at 30-second intervals; calculate the minimum distance. ,like If so, it is determined that there is a risk of collision between the two.

[0019] c) Further screen targets with collision risk. Predict target positions in 1-second increments. Issue a collision warning when a secondary target enters a 25km radius around the primary target.

[0020] Furthermore, the space situation display subsystem includes a space environment parameter setting module and a visualization module. The space environment parameter setting module is used for setting Earth's gravity field parameters, selecting atmospheric environment models, selecting three-body forces, and setting tidal force parameters. The visualization module uses two-dimensional and three-dimensional model real dynamic display technology to display the space situation scene in real time according to the observation point and observation direction.

[0021] Furthermore, the simulation data management subsystem includes a database management module and a data output module. The database management module is used to manage simulation scene data, simulation result data, and simulation parameters through a database. The data output module is used to output simulation results and intermediate process files according to templates, which can also be created by users.

[0022] The advantages of this invention are as follows: This invention sets the parameter information of the ground-based sensor, generates a simulated sensor working state and produces simulated detection data, calculates ephemeris information and predicts ephemeris based on the input ephemeris file, completes the simulation of the trajectory of space targets, and predicts re-entry and collision events based on the input ephemeris, thus completing the simulation of space events. Therefore, even when the satellite or space event is outside the detection range of the sensor or the sensor is not in the firing state, the sensor back-end software system can still be debugged based on the simulated space target motion trajectory data, verifying the ability of the ground-based sensor back-end software system to detect and track targets and process detection data. Attached Figure Description

[0023] Figure 1 This is a structural block diagram of an interactive ground-based space target monitoring sensor simulation system provided in an embodiment of the present invention; Figure 2 A flowchart illustrating the workflow of an interactive ground-based space target monitoring sensor simulation system provided in this embodiment of the invention; Figure 3 This is a display interface diagram of the ephemeris selection module in an interactive ground-based space target monitoring sensor simulation system provided in an embodiment of the present invention; Figure 4 This is a flowchart illustrating the TLE ephemeris prediction of a space target in an interactive ground-based space target monitoring sensor simulation system provided in an embodiment of the present invention; Figure 5 This is a display interface diagram of the sensor setting module in an interactive ground-based space target monitoring sensor simulation system provided in an embodiment of the present invention; Figure 6 This is a display interface diagram of the space event calculation module in an interactive ground-based space target monitoring sensor simulation system provided in an embodiment of the present invention; Figure 7 This is a diagram of the interface for storing simulation detection data of a sensor in a database in an interactive ground-based space target monitoring sensor simulation system provided in an embodiment of the present invention. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] like Figure 1 As shown, an interactive ground-based space target monitoring sensor simulation system includes a ground-based sensor simulation subsystem, a space target simulation subsystem, a space situation display subsystem, and a simulation data management subsystem. The ground-based sensor simulation subsystem is used to set sensor parameter information, generate simulated sensor operating states, and produce simulated detection data. The space target simulation subsystem is used to calculate ephemeris information and predict ephemeris based on input ephemeris files, and also to predict re-entry and collision events based on input ephemeris. The space situation display subsystem is used to set space environment parameters and dynamically display the space situation scene in real time. The simulation data management subsystem is used to manage the simulation scene, simulated detection data, and simulation parameters.

[0026] The ground-based sensor simulation subsystem includes a sensor setting module, a sensor operating state simulation module, and a detection data generation module. The sensor setting module is used to set the sensor's parameter information, including: number, name, country, sensor type, location coordinates, observation range, data rate, observation time range, and beam color. The sensor operating state simulation module is used to generate simulated sensor operating states, such as beam search, acquisition, and tracking. The detection data generation module generates simulated detection data based on the sensor's detection range, accuracy, and data rate. The detection data includes radar detection data and optical equipment detection data. Radar detection data includes range, azimuth, and elevation angles, while optical equipment detection data includes right ascension and declination.

[0027] The methods for generating the distance, azimuth, and elevation angles include: 1) Set the position coordinates, power range (including distance range, azimuth range, and angle range) and detection accuracy (including distance accuracy, azimuth accuracy, and angle accuracy) of the detection equipment (i.e., the sensor mentioned above). 2) Predict the orbit of a space target at a sampling interval of 1 minute, and calculate the longitude, latitude and altitude of each point on the orbit; 3) Based on the target's longitude, latitude, and altitude, when the target enters the Chinese side of the Northern Hemisphere, it is determined that the target may be captured by the detection equipment. 4) For points that may enter the observation range, the Lagrange ninth-order interpolation method is used to calculate the coordinates at the corresponding time according to the data rate of the detection equipment. Then, the distance, azimuth, and elevation angle from the detection equipment are calculated. Points that fall within the range of the sensor's power are the observable points. 5) Add white noise to the distance, azimuth, and elevation angles of the above points according to the detection accuracy of the equipment.

[0028] The method for calculating right ascension and declination is mainly applied to ground-based optical equipment tracking geostationary satellites. It eliminates the need to calculate visibility; instead, it simply calculates right ascension and declination according to the user-defined observation time and adds white noise to them based on the sensor's accuracy. The calculation method for right ascension and declination is as follows: Let the observation vector be , and Representing the observations of right ascension and declination, then the observation vector and... , The relationship between them is:

[0029] Therefore, the measurement equation for right ascension-declination observations is expressed as: , in, , , express Each component, .

[0030] The space target simulation subsystem includes an ephemeris setting module, a space target orbit prediction module, and a space event calculation module. The ephemeris setting module is used for inputting various ephemeris files, including TLE ephemeris, J2000.0 coordinate ephemeris, and ECEF coordinate ephemeris. Ephemeris information includes: number, name, country, epoch, time stamp, and predicted orbit number, and supports multiple selections. The space target orbit prediction module is used to calculate ephemeris information. For TLE ephemeris, the SGP4 prediction method is used for prediction, while for J2000.0 coordinate ephemeris and ECEF coordinate ephemeris, the space target dynamics model is used for prediction. The space event calculation module is used to predict re-entry and collision events based on the input ephemeris.

[0031] The SGP4 forecasting method includes: 1) The SGP4 forecast software reads in the TLE ephemeris and performs calculations; 2) The SGP4 model is used to predict TLE ephemeris; The SGP4 model is a simplified model derived using Lane and Cranford's generalized analysis theory. It considers the effects of Earth's oblateness, long-term and periodic perturbations of lunar and solar gravity, as well as gravitational resonance and orbital decay of the main atmospheric model parameters. The gravitational model employs the Brouwer solution, while the atmospheric model uses a power density function.

[0032] The SGP4 model is represented by the following function:

[0033] In the formula: Orbital eccentricity, Track inclination, Ascending node right ascension, Perimeter argument, True close angle, It is the average velocity of the average orbital element. These are the ballistic coefficients used in the SGP4 model.

[0034] The specific details of the space target dynamics model are as follows: Space targets orbiting the Earth are affected by various perturbations, which can be categorized into two types: conservative forces and non-conservative forces. Conservative forces include: the Earth's central gravity, the Earth's non-spherical gravity, the gravitational pull of the Sun, Moon, and other three bodies, Earth's solid tides and ocean tides, and general relativistic perturbations. Their magnitudes depend only on the target's position and are independent of its velocity and surface characteristics; therefore, they can be described using potential functions. Non-conservative forces include atmospheric drag, solar radiation pressure, and Earth's radiation pressure. Non-conservative forces are not only related to the target's position but also closely related to its velocity, geometry, and surface properties. They cannot be expressed using potential functions and must be represented using differential forms of force models.

[0035] 1) Earth's gravity According to theoretical mechanics, if the Earth is considered a perfectly spherical object with uniform density, its attraction to a space target can be equated to a point mass, thus forming a two-body system. According to Newton's second law, the target's equation of motion is:

[0036] in, ρ is the Earth's gravitational constant, as recommended by the 16th International Geodesy Union and the International Astronomical Union. .

[0037] 2) Non-spherical gravity In the Earth-fixed coordinate system, the potential function of Earth's shape perturbation can be expanded into the form of a spherical harmonic function:

[0038] in, , The normalized Earth's gravitational field coefficient; For the normalized Legendre function; These represent the radial distance, latitude, and longitude from the satellite to the Earth's center, respectively. , These are the Earth's gravitational constant and mean equatorial radius, respectively.

[0039] 3) Gravitational pull of planets such as the Sun and Moon Besides Earth's gravity, space targets are also affected by the gravity of the Sun, Moon, and other celestial bodies. The gravitational perturbations of the Sun, Moon, and planets can be approximated by a point mass. According to Newton's law of universal gravitation, the acceleration of the space target caused by the point mass M is:

[0040] In the formula, Represents the gravitational constant of a celestial body; and These are the geocentric position vectors of the space target and M, respectively.

[0041] 4) Earth's tides The gravitational pull of the Sun and Moon exerts an effect on the Earth, causing it to deform over time. This small-scale, periodic deformation of the solid Earth is called Earth tides. The oceans respond differently to tidal perturbations caused by the Sun and Moon, and this is called ocean tides. All these deformations, in addition to causing geometric changes in the coordinates of ground-based measuring stations, also affect the spherical harmonic coefficient of the Earth's gravitational potential. and The change in [something] leads to a change in the corresponding gravitational potential.

[0042] 5) Relativistic effects The motion of near-Earth space objects should strictly adhere to the framework of general relativity. By introducing a new theory of gravity to modify the framework of Newtonian gravity—the so-called post-Newtonian correction—the motion of space objects can be described with greater precision. The perturbation equation for the post-Newtonian correction is:

[0043] In the formula, These represent the unit position vector and unit velocity vector of the spatial target, respectively. The speed of light; is the gravitational constant.

[0044] 6) Atmospheric drag Atmospheric drag is the maximum non-gravitational perturbation acting on low-Earth orbit (LEO) targets. As the region with the highest concentration of space debris, LEO requires a precise description of atmospheric drag when calculating the orbital perturbations of LEO targets.

[0045] The acceleration of a space target caused by atmospheric drag perturbation is:

[0046] In the formula, Atmospheric density; is the atmospheric drag coefficient, used to describe the interaction between the atmosphere and the surface material of a space target, typically with a value of 1.5 to 3.0; A is the distance between the space target and the atmospheric drag coefficient. Cross-sectional area in the direction; For the quality of space targets; The velocity of a space target relative to the atmosphere; for A unit vector in direction.

[0047] 7) Solar radiation pressure Space targets exposed to solar radiation experience a small force generated by the absorption or reflection of solar photons, known as solar radiation pressure. The acceleration caused by solar radiation pressure depends on factors such as solar intensity, the area of ​​the space target exposed to sunlight, the geometric relationship between the exposed surface and the sunlight rays, and the emission and absorption characteristics of the exposed surface. The acceleration of a space target caused by solar radiation pressure perturbation is:

[0048] In the formula, For the ground shadow model factor, a cone-shaped ground shadow model is often used; The solar radiation pressure coefficient is generally equal to the reflectivity. The sum of the constant 1, i.e. , The typical value ranges from 0.2 to 0.9; The luminosity of the sun is approximately [value missing]. ; The surface-to-mass ratio of a space target; These are the geocentric vectors of the space target and the Sun, respectively.

[0049] 8) Earth's radiation pressure When Earth is exposed to sunlight, in addition to absorbing some energy itself, the ground and oceans also reflect some solar energy back into space. Simultaneously, Earth's own thermal radiation exerts a small pressure on near-Earth space targets; this pressure is collectively known as Earth radiation pressure. The acceleration caused by Earth radiation pressure perturbation on space targets decreases with increasing altitude. For low-Earth orbit targets, the acceleration caused by Earth radiation pressure typically accounts for 10% to 35% of the solar radiation pressure.

[0050] 9) Experience-based power model Although the force models involved in determining and predicting the orbits of space targets are already quite accurate, it is becoming increasingly difficult to further improve their accuracy, mainly due to the complexity of the models and the amount of computation required, especially since non-conservative force models are not perfect.

[0051] Based on the high-precision perturbation model, some empirical force models are introduced into the orbital motion equations of the space target to describe the unmodeled small perturbation forces. Most model errors occur at frequencies occurring once per revolution; correspondingly, constant terms and empirical accelerations occurring once per revolution are used to construct empirical force models, specifically expressed as follows:

[0052] In the formula, , , and The parameter to be estimated; This is the true anomaly angle. The directions of empirical acceleration are generally defined in the star-based coordinate system, pointing in three directions: along the track, normal, and radial. In actual orbit calculations, it is necessary to transform the star-based coordinate system to the inertial coordinate system using a transformation matrix.

[0053] The process of predicting a meteorite impact event includes: 1) Predict the spatial trajectory of space targets for more than one month; 2) Calculate the change in target altitude. When the target altitude continues to decrease and eventually falls below 120km, it is determined that the target will fall.

[0054] The process of predicting collision events includes: 1) Read in the TLE ephemeris; 2) Calculate the semi-major axis, semi-minor axis, and inclination of each target in the TLE ephemeris; 3) Collision events are only considered based on the probability of collision with important targets. Important targets are designated as primary targets, and other targets as secondary targets. An exhaustive method is used to predict the distances between the secondary targets and the primary target in the TLE ephemeris over the next 24 hours, and collision events are then selected. a) Assume the semi-major axis of the primary target is a1, the semi-minor axis is b1, and the semi-major axis of the secondary target is a2, the semi-minor axis is b2. or If so, the two targets cannot collide; b) Predict the positions of two targets and calculate the distance between them every 5 minutes, with a prediction period of 24 hours. If the distance between the two targets is less than 2000 km, predict the target positions and calculate the distance at 30-second intervals; calculate the minimum distance. ,like If so, it is determined that there is a risk of collision between the two. c) Further screen targets with collision risk. Predict target positions in 1-second increments. Issue a collision warning when a secondary target enters a 25km radius around the primary target.

[0055] The space situation display subsystem includes a space environment parameter setting module and a visualization module. The space environment parameter setting module is used for setting Earth's gravity field parameters, selecting atmospheric environment models, selecting three-body forces, and setting tidal force parameters. The visualization module uses two-dimensional and three-dimensional model real dynamic display technology to display the space situation scene in real time according to the observation point and observation direction.

[0056] The simulation data management subsystem includes a database management module and a data output module. The database management module is used to manage simulation scene data, simulation result data, and simulation parameters through the database. The data output module is used to output simulation results and intermediate process files according to templates, which can also be created by users.

[0057] like Figure 2 As shown, the working process of this invention is as follows: 1) Users first configure the spatial environment parameters through the initial parameter file to build the spatial environment; 2) The user interface provided by the ephemeris setting module, such as... Figure 3 As shown, select the space target to be simulated and input the simulation control parameters, including: simulation start time, simulation end time, simulation step size, and ephemeris type. The ephemeris selection module transmits the user-selected ephemeris information and the input simulation control information to the space target simulation subsystem.

[0058] 3) The human-machine interface provided by the user based on the sensor setting module, such as... Figure 5As shown, select the sensor to be simulated and input simulation parameters, including latitude and longitude, detection range, clutter, interference, etc., and transmit them to the space target simulation subsystem.

[0059] 4) The space target trajectory prediction module generates the space target's motion trajectory based on the input ephemeris information and simulation control information. The process is as follows: Figure 4 As shown. The generated trajectory of the spatial target consists of a series of points, and the information of each point includes: a) Time; b) Position coordinates (X, Y, Z) in the geocentric geofixed coordinate system (ECEF); c) Velocity separation in the ECEF coordinate system V x V y V z value; The generated spatial target motion trajectory is transmitted to the visualization module.

[0060] 5) Based on the target's trajectory in step 4), calculate the altitude at each point. When the altitude continues to decrease and eventually becomes ≤120km, determine that the target has fallen. Figure 6 As shown, the judgment result is displayed on the interface; 6) Predict the target trajectories of the primary and secondary targets within 24 hours using the method in step 4), and calculate the target distance at each time point. When the distance is ≤300km, a collision risk is determined. Further predict the target position and calculate the target distance in 1-second increments. A collision warning is issued when the secondary target enters a radius of 25km centered on the primary target. Figure 6 As shown, the judgment result is displayed on the interface; 7) Calculate the observable arc segments of each space target sequentially based on the sensor's detection range. During dynamic simulation, Gaussian white noise is added sequentially to the distance, azimuth, and elevation of each observation point. (This is done according to the method used by the sensor simulation subsystem to generate observable arc segments, i.e., connecting the observable points to generate observable arc segments after obtaining the observable points during the process of generating simulated detection data by the detection data generation module). Due to various reasons, the sensor's measurement values ​​will have certain errors when tracking targets. Normally distributed noise is generated according to the sensor's accuracy (including distance accuracy, azimuth accuracy, and elevation accuracy), and added accordingly to the distance, azimuth, and elevation.

[0061] 8) The visualization module displays the simulated scene in two display modes: three-dimensional scene display and two-dimensional star point display, based on the input spatial target motion trajectory. It also provides a simulation function and supports dynamic display of the real-time position of the spatial target according to the time rhythm.

[0062] 9) Users upload simulation data to the database as needed. Database tables are as follows: Figure 7 As shown.

[0063] Through the above technical solutions, this invention provides an interactive ground-based space target monitoring sensor simulation system. It supports selecting the space target to be simulated based on ephemeris data, generates the space target's motion trajectory, and allows users to configure multiple sensors. All system parameters can be input through a human-machine interface, making it easy for users to learn. The system offers two display modes for the entire simulation scenario: a three-dimensional scene display and a two-dimensional nadir point display. It also supports dynamic simulation, providing a user-friendly and intuitive interface for users to comprehensively observe the generated space target's motion trajectory and space event processes.

[0064] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An interactive ground-based space target monitoring sensor simulation system, characterized in that, It includes a ground-based sensor simulation subsystem, a space target simulation subsystem, a space situation display subsystem, and a simulation data management subsystem; The ground-based sensor simulation subsystem is used to set the sensor's parameter information, generate a simulated sensor operating state, and produce simulated detection data. The space target simulation subsystem is used to calculate ephemeris information and predict orbits based on input ephemeris files, and also to predict reentry and collision events based on input ephemeris. The space target simulation subsystem includes an ephemeris setting module, a space target orbit prediction module, and a space event calculation module. The ephemeris setting module is used for inputting various ephemeris files. The space target orbit prediction module is used to calculate ephemeris information; for TLE ephemeris, the SGP4 prediction method is used for prediction, while for J2000.0 coordinate ephemeris and ECEF coordinate ephemeris, a space target dynamics model is used for prediction. The space event calculation module is used to predict fall and collision events based on the input ephemeris. The process of predicting a meteorite impact event includes: 1) Predict the spatial trajectory of space targets for more than one month; 2) Calculate the change in target altitude. When the target altitude continues to decrease and eventually falls below 120km, it is determined that the target will fall. The process of predicting collision events includes: 1) Read in the TLE ephemeris; 2) Calculate the semi-major axis, semi-minor axis, and inclination of each target in the TLE ephemeris; 3) Designate important targets as primary targets and other targets as secondary targets. Use an exhaustive method to predict the distance between the secondary targets and the primary target in the TLE ephemeris within the next 24 hours, and filter for collision events: a) Assume the semi-major axis of the primary target is a1, the semi-minor axis is b1, and the semi-major axis of the secondary target is a2, the semi-minor axis is b2. or If so, the two targets cannot collide; b) Predict the positions of two targets and calculate the distance between them every 5 minutes, with a prediction period of 24 hours. If the distance between the two targets is less than 2000 km, predict the target positions and calculate the distance at 30-second intervals; calculate the minimum distance. ,like If so, it is determined that there is a risk of collision between the two. c) Further screen targets with collision risk, predict the target position in 1-second steps, and issue a collision warning when the auxiliary target enters the range of 25km centered on the main target. The spatial situation display subsystem is used to set spatial environmental parameters and display the spatial situation scene in real time. The simulation data management subsystem is used to manage simulation scenarios, simulation detection data, and simulation parameters.

2. The interactive ground-based space target monitoring sensor simulation system according to claim 1, characterized in that, The ground-based sensor simulation subsystem includes a sensor setting module, a sensor operating state simulation module, and a detection data generation module. The sensor setting module is used to set the sensor's parameter information; the sensor operating state simulation module is used to generate simulated sensor operating states; the detection data generation module generates simulated detection data based on the sensor's detection range, accuracy, and data rate. The detection data includes radar detection data and optical equipment detection data. Radar detection data includes range, azimuth, and elevation angles, while optical equipment detection data includes right ascension and declination.

3. The interactive ground-based space target monitoring sensor simulation system according to claim 2, characterized in that, The methods for generating the distance, azimuth, and elevation angles include: 1) Set the sensor's position coordinates, power range, and detection accuracy. The power range includes distance range, azimuth range, and angle range. The detection accuracy includes distance accuracy, azimuth accuracy, and angle accuracy. 2) Predict the orbit of a space target at a sampling interval of 1 minute, and calculate the longitude, latitude and altitude of each point on the orbit; 3) Based on the target's longitude, latitude, and altitude, when the target enters the Chinese side of the Northern Hemisphere, it is determined that the target may be captured by the sensor and may enter the sensor's observation range. 4) For points that may enter the observation range, the Lagrange ninth-order interpolation method is used to calculate the coordinates at the corresponding time according to the data rate of the detection equipment, and then the distance, azimuth and elevation angles from the detection equipment are calculated.

4. The interactive ground-based space target monitoring sensor simulation system according to claim 3, characterized in that, The methods for calculating right ascension and declination include: Let the observation vector be , and Representing the observations of right ascension and declination, then the observation vector and... , The relationship between them is: Therefore, the measurement equation for right ascension-declination observations is expressed as: ， in, , , express Each component, .

5. The interactive ground-based space target monitoring sensor simulation system according to claim 1, characterized in that, The SGP4 forecasting method includes: 1) The SGP4 forecast software reads in the TLE ephemeris and performs calculations; 2) The SGP4 model is used to predict TLE ephemeris; The SGP4 model is represented by the following function: In the formula: Orbital eccentricity, Track inclination, Ascending node right ascension, Perimeter argument, True close angle, It is the average velocity of the average orbital element. These are the ballistic coefficients used in the SGP4 model.

6. The interactive ground-based space target monitoring sensor simulation system according to claim 1, characterized in that, The space situation display subsystem includes a space environment parameter setting module and a visualization module. The space environment parameter setting module is used for setting Earth's gravity field parameters, selecting atmospheric environment models, selecting three-body forces, and setting tidal force parameters. The visualization module uses two-dimensional and three-dimensional model real dynamic display technology to display the space situation scene in real time according to the observation point and observation direction.

7. The interactive ground-based space target monitoring sensor simulation system according to claim 1, characterized in that, The simulation data management subsystem includes a database management module and a data output module. The database management module is used to manage simulation scene data, simulation result data, and simulation parameters through the database. The data output module is used to output simulation results and intermediate process files according to templates.

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