CN117725506A - Method for calculating threat degree of reentry vehicle - Google Patents

Abstract

The invention provides a method for calculating threat degrees of reentry aircrafts, which comprises the following steps: selecting a reentry vehicle to be monitored, and determining initial speeds and initial positions of all flight directions of the reentry vehicle; determining an optimal track of each flight direction by utilizing a historical database, wherein each optimal track corresponds to an optimal position; determining an optimal position and an optimal value through all the optimal positions; updating the update speed and the update position of the reentry vehicle in all directions according to time; establishing a space motion model according to the optimal position, the optimal value and the initial speed; and establishing a threat value evaluation model of the reentry vehicle, and obtaining a threat degree value of the reentry vehicle based on the spatial motion model and the threat value evaluation model. The method can rapidly judge the falling threat degree of the reentry vehicle, simplifies the whole calculation process and greatly improves the efficiency.

Description

A method for calculating the threat level of re-entry aircraft

Technical field

The present invention relates to the technical field of spacecraft orbit prediction, and specifically to a method for calculating the threat degree of a re-entry vehicle.

Background technique

The flight path of an aircraft in the air is called an orbit. While aerospace personnel are controlling their own aircraft, in order to avoid collisions between other re-entering aircraft and their own aircraft, they need to calculate the threat level of other re-entering aircraft. The perturbation force model is usually used to calculate the threat degree of other re-entry vehicles. The prediction accuracy of its low-order analytical solution is low, and the process of its high-order analytical solution is very cumbersome; it is not conducive for aerospace personnel to quickly and accurately grasp other re-entry vehicles. into the flight path of the aircraft.

Contents of the invention

In order to solve existing technical problems, embodiments of the present invention provide a method for calculating the threat level of a re-entry aircraft. The method includes:

Select the re-entry aircraft to be monitored and determine the initial speed and initial position of the re-entry aircraft in all flight directions;

Use a historical database to determine the best trajectory for each flight direction, and each of the best trajectories corresponds to the best position;

Determine the optimal position through all said optimal positions and determine the optimal value;

Update according to time and obtain the updated speed and updated position of the re-entry vehicle in all directions;

Establish a spatial motion model based on the optimal position, the optimal value, the initial speed, the initial position, the updated speed and the updated position;

A threat value assessment model of the re-entry aircraft is established, and a threat value of the re-entry aircraft is obtained based on the space motion model and the threat value assessment model.

In the solution provided by the first aspect of this application, the initial speed and initial position of the re-entry aircraft are obtained by determining the re-entry aircraft that needs to be monitored, and the best trajectory of the re-entry aircraft in each flight direction and the best trajectory of each flight are determined through the historical database. The best position corresponding to the best trajectory, use the best position to determine the optimal value, and obtain the update speed and update position of the re-entry aircraft again at the update time, and build a space motion model based on the optimal value, initial speed and best position; based on the re-entry The aircraft constructs a threat value assessment model, and determines the threat value of the re-entry vehicle based on the threat value assessment model and the space motion model to determine the threat degree of the re-entry vehicle; compared with the semi-analytical method in related technologies, only the space motion of the re-entry vehicle is constructed model and threat value assessment model. Through these two models, the threat degree of the re-entry aircraft to the ground can be judged. It can quickly determine the threat of the re-entry vehicle falling, and the entire calculation process is simplified, and the efficiency is greatly improved.

In order to make the above-mentioned objects, features and advantages of the present invention more obvious and understandable, preferred embodiments are given below and described in detail with reference to the accompanying drawings.

Description of the drawings

In order to more clearly explain the technical solutions in the embodiments of the present invention or the background technology, the accompanying drawings required to be used in the embodiments or the background technology of the present invention will be described below.

Figure 1 shows a flow chart of a re-entry vehicle threat degree calculation method provided by an embodiment of the present invention;

Figure 2 shows a schematic connection diagram of each module of the re-entry aircraft threat calculation system provided by the embodiment of the present invention;

FIG. 3 shows a schematic structural diagram of an electronic device for executing a re-entry vehicle threat degree calculation method provided by an embodiment of the present invention.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention. In order to enable those skilled in the art to better understand the solution of the present invention, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

Orbits are the routes along which various types of aircraft operate and are an indispensable element in aerospace technology research. While aerospace personnel control their own aircraft to follow its own orbit, they must have the ability to predict and sense the orbits of other aircraft in order to ensure the safety of operations on their own track and avoid collision accidents in time. Therefore, a reasonable calculation method for the threat degree of re-entry vehicles is an indispensable element in aerospace application research.

However, the perturbation force model is usually used to calculate the threat level of re-entry vehicles. The prediction accuracy of its low-order analytical solutions is low, and the process of its high-order analytical solutions is very cumbersome; it is not conducive for aerospace personnel to quickly and accurately grasp other re-entry vehicles. flight track.

Based on this, the embodiments of the present invention provide the following Examples 1 to 3 to solve the above problems.

Example 1

The execution subject of the re-entry vehicle threat degree calculation method proposed in this embodiment is the server.

Referring to the flow chart of the re-entry aircraft threat level calculation method shown in Figure 1, this embodiment provides a re-entry aircraft threat level calculation method, which includes the following specific steps:

Step 100: Select the re-entry aircraft to be monitored, and determine the initial speed and initial position of the re-entry aircraft in all flight directions.

In the above step 100, the re-entry vehicle refers to an object located in space. The aircraft enters the atmosphere due to special factors. The above-mentioned specific factors can be subjective destruction and generated rocket debris, a failed satellite caused by force majeure factors, or missiles under test, etc. Therefore, the re-entry vehicle cannot be simply understood as a satellite. The initial speed refers to the operating speed of the reentry vehicle at the beginning of monitoring, which can be monitored and measured by satellites operating normally in orbit. The initial position refers to the coordinates corresponding to the reentry vehicle. The above coordinates can be provided by the longitude and latitude lines of the earth. The initial velocity and initial position of the reentry vehicle in all possible directions can be determined through the orbital altitude, load registration and operation period of the reentry vehicle.

Among them, determining the speed and position of an object using orbit height, load registration, and operating cycle is common knowledge in the art, and therefore will not be described again.

Step 101: Use the historical database to determine the best trajectory for each flight direction. Each best trajectory corresponds to an optimal position. Determine the optimal position and determine the optimal value through all the optimal positions.

In the above step 101, the re-entry aircraft will have multiple flight directions during the process of entering the atmosphere. However, depending on the parameters of the re-entry aircraft and the atmospheric environment, the re-entry aircraft will have multiple flight directions during the process of entering the atmosphere. The optimal trajectory in each direction appears in multiple directions. The optimal trajectory can be understood as the flight route that the reentry aircraft may pass. In each optimal trajectory, there is a best position that the reentry aircraft is about to reach. However, the reentry vehicle can only fly in one direction in the end, so there will only be one optimal position in the end. Among them, the optimal value refers to the coordinate point of the best position of the re-entry aircraft. The coordinate point is a three-dimensional coordinate, including the x-axis, y-axis and z-axis. The x-axis and y-axis of the re-entry vehicle are provided by the normal satellite in orbit, and the z-axis (height from the earth's surface) of the re-entry vehicle is provided by the ground station and the normal satellite in orbit.

Among them, the above-mentioned optimal position belongs to the predicted value. At this time, the re-entry aircraft has not yet reached the optimal position, and the optimal position is provided by the historical database in step 101. The historical database refers to the trajectories and positions that the aircraft of the same model or series as the re-entry aircraft entered the atmosphere in historical time. The aircraft manufacturer or professional telemetry agency monitors the aircraft's entry into the atmosphere in real time and records it as a historical database.

The historical database stores the correspondence between various re-entry vehicle models and optimal positions.

The best position is the corresponding best position of the reentry vehicle from the historical database using the model of the reentry vehicle.

Step 102: Update and obtain the updated speed and updated position of the re-entry aircraft in all directions according to time.

In the above step 102, the update speed after the update time can be understood as the flight speed at the second time, and the initial speed in the above step 100 can be understood as the flight speed at the first time.

In particular, the update time refers to any time after the initial time, which can be one second longer than the initial time, or one minute longer than the initial time, etc. You need to determine the time of the update speed according to specific needs. Therefore, it is not appropriate for the second time. The time is specifically limited. In the same way, the updated position after the update time can be understood as the position coordinate point passed by the re-entry aircraft at the second time.

It should be noted that in step 101, the best position of the re-entry aircraft is predicted, so the historical database is called, but the updated position coordinate point in step 102 is the real coordinate of the re-entry aircraft itself.

Step 103: Establish a spatial motion model based on the optimal position, the optimal value, the initial speed, the initial position, the updated speed and the updated position.

In the above step 103, the spatial motion model can be constructed through the optimal position, optimal value, initial speed, initial position, update speed and update position. The spatial motion model can obtain the motion speed of the re-entry aircraft at time t+1 and time t The space motion model satisfies the following formula:

V _id (t+1)＝w _s *V _id (t)+c ₁ *r ₁ *[(p _id (t)-x _id (t))]+c ₂ *r ₂ *[(g _gd ( t)-x _id (t))];

x _id (t+1)＝x _id (t)+V _id (t+1), 1≤d≤14;

Among them, d represents the spatial dimension of the re-entry aircraft, w _s represents the inertia factor, i represents the movement direction of the re-entry aircraft, c ₁ represents the first acceleration constant, c ₂ represents the second acceleration constant, t represents the initial moment, x _id (t) represents the initial position, V _id (t+1) represents the movement speed of the reentry aircraft in the movement direction i at time t+1, r ₁ and r ₂ represent uniform random numbers between 0 and 1, p _id (t) represents the optimal value of the best position of the re-entry aircraft in the direction of motion i at time t, V _id (t) represents the initial speed of the re-entry aircraft at time t, x _id (t) represents the velocity of the re-entry aircraft at time t Position, x _id (t+1) represents the position of the re-entry aircraft at time t+1, g _gd (t) represents the best position of the re-entry aircraft in all movement directions at time t.

In this embodiment, after V _id (t+1) and x _id (t+1) are calculated through the space motion model, the falling speed and position of the re-entry aircraft can be obtained, and then the threat value can be obtained Re-entry vehicle threat level.

In one implementation, the inertia factor of the spatial motion model satisfies:

Among them, w _max represents the maximum value of the inertia factor of the re-entry aircraft along the direction of movement, w _g represents the basic inertia of the re-entry aircraft along the direction of movement, Ni represents the current number of iterations, and Ni _max represents the maximum number of iterations.

The first acceleration constant and the second acceleration constant in the spatial motion model satisfy:

Among them, c _1min represents the minimum value of the acceleration weight factor of the extreme value of the equilibrium movement direction, c _1max represents the maximum value of the acceleration weight factor of the extreme value of the equilibrium movement direction, and c _2min represents the acceleration weight of the global extreme value of the equilibrium movement direction. The minimum value of the value factor, c _2max represents the maximum value of the acceleration weight factor of the global extreme in the direction of equilibrium motion, Ni _max represents the maximum number of iterations, and Ni represents the current number of iterations.

Step 104: Establish a threat assessment model of the re-entry aircraft, and obtain a threat value of the re-entry aircraft based on the spatial motion model and the threat assessment model.

In the above step 104, a threat value assessment model is constructed, and the prior probability of parameter θ in the threat value assessment model obeys the Dirichlet distribution, and the posterior probability is:

Among them, P(D|G) is the posterior probability of the threat value assessment model, I represents the I-th variable, n represents the total number of variables, qI represents the total number of nodes in the Bayesian network, and J represents the nodes in the Bayesian network. . In particular, the above α _IJ =∑ _k α _IJk , where k represents the parent node of node J, and rk represents the number of parent nodes of node J. above Among them, α _IJk represents the individual elements in the data set that meet the conditions, and N _IJk represents the number of instances in the data set that meet the conditions.

The above Bayesian statistical scoring satisfies:

Among them, logP(D|G) represents the Bayesian statistical score of threat value assessment. With the same network structure and different parameters, the accuracy of threat value assessment will be different. In order to more accurately evaluate the threat value at an uncertain time, this embodiment optimizes the threat value evaluation network parameters. The idea of the optimization algorithm is to use Bayesian inference to calculate the probability of missing data when the threat assessment network structure and underwater environment observation data are determined, use expected sufficient statistical factors to complete the missing data set, and re-estimate the maximum value of the current model. Optimal parameters.

set up is the current estimate of parameter θ,/> is based on/> The complete data obtained by patching; let θ be based on/> The log-likelihood function of is:

in, Indicates weight;/> X _I in represents the updated position in all directions (the same as the updated position in step 2); x _i represents the position in the target direction. In particular, the above target direction refers to a specific direction among all directions, but it can only for one direction;

when When, suppose/> Represents the empty set and performed t1 iterations. Calculate the expected log-likelihood function Q(θ∣θ ^t1 ) and the value of θ at which Q(θ∣θ ^t1 ) reaches the maximum, where θ ^t+1 =argsup Q(θ ∣θ ^t+1 ).

Assuming that based on the ground target observation data sample X _I = _xi , the characteristic function of D _i is:

Among them, X _I =k and π(X _I )=J, π(X _I ) is the value of the parent node, which can be simplified from the above:

The above formula can be simplified to:

Therefore, when θ takes the following value, that is:

Q(θ∣θ ^t ) reaches the maximum, and the Bayesian statistical score of threat assessment has an optimal parameter solution. It should be noted that the above optimal parameter solution is actually the threat degree finally output by the threat value model. In particular, the threat value refers to the probability of the re-entry aircraft falling, but knowing only the probability of falling without knowing the location of the fall has no practical significance. On the contrary, knowing only the drop location but not the drop probability has no practical significance. Therefore, only by knowing both the probability of falling and the location of falling can we take precautions in advance. Therefore, after obtaining the above threat level and combining it with the position of the reentry aircraft at time t+1, the final threat level of the reentry aircraft can be determined. In particular, using the threat value and the landing position of the re-entry aircraft to determine the threat level of the re-entry aircraft is common knowledge in the art, and therefore the principle will not be repeated.

In particular, the above threat value assessment model does not refer to a single calculation formula, but refers to the collective name of posterior probability, Bayesian statistical score and likelihood function, which is called the threat value assessment model.

To sum up, the embodiment of the present invention proposes a method for calculating the threat degree of a re-entry aircraft. By determining the re-entry aircraft that needs to be monitored, the initial speed and initial position of the re-entry aircraft are obtained, and the historical database is used to determine the location of the re-entry aircraft at each location. The best trajectory in the flight direction and the best position corresponding to each best trajectory, use the best position to determine the optimal value, and obtain the update speed and update position of the re-entry aircraft again at the update time. Based on the optimal value, initial speed and best Build a space motion model at the best position; build a threat value assessment model based on the re-entry vehicle, determine the threat value of the re-entry vehicle based on the threat value assessment model and the space motion model, and determine the threat degree of the re-entry vehicle; compared with the semi-analytical method in related technologies , it is only necessary to construct a space motion model and a threat value assessment model through the re-entry aircraft. Through these two models, the threat degree of the re-entry aircraft to the ground can be judged. It can quickly determine the threat of reentry aircraft falling, and the entire calculation process is simplified, and the efficiency is greatly improved.

Example 2

Referring to the schematic connection diagram of each module of the re-entry aircraft threat degree calculation system shown in Figure 2, this embodiment also proposes a re-entry aircraft threat degree calculation system, which is applied to the re-entry aircraft threat degree calculation method in the above embodiment. , the system includes:

Selection module: select the re-entry aircraft to be monitored and determine the initial speed and initial position of the re-entry aircraft in all flight directions.

Determination module: Use the historical database to determine the best trajectory for each flight direction, and each best trajectory corresponds to the best position; determine the optimal position and determine the optimal value through all the best positions.

Processing module: Update according to time and obtain the updated speed and updated position of the re-entry vehicle in all directions.

Spatial motion module: establishes a spatial motion model based on the optimal position, the optimal value, the initial speed, the initial position, the updated speed and the updated position.

Threat value module: establishes a threat value assessment model of the re-entry aircraft, and obtains a threat value of the re-entry aircraft based on the spatial motion model and the threat value assessment model.

To sum up, the embodiment of the present invention proposes a re-entry aircraft threat degree calculation system that obtains the initial speed and initial position of the re-entry aircraft by determining the re-entry aircraft that needs to be monitored, and determines the re-entry aircraft at each location through a historical database. The best trajectory in the flight direction and the best position corresponding to each best trajectory are used to determine the optimal value. The update time is used to obtain the updated speed and updated position of the re-entry aircraft again. Based on the optimal value, initial speed and optimal Build a space motion model at the best position; build a threat value assessment model based on the re-entry vehicle, determine the threat value of the re-entry vehicle based on the threat value assessment model and the space motion model, and determine the threat degree of the re-entry vehicle; compared with the semi-analytical method in related technologies , it is only necessary to construct a space motion model and a threat value assessment model through the re-entry aircraft. Through these two models, the threat degree of the re-entry aircraft to the ground can be judged. It can quickly determine the threat of reentry aircraft falling, and the entire calculation process is simplified, and the efficiency is greatly improved.

Example 3

This embodiment provides a computer-readable storage medium. A computer program is stored on the computer-readable storage medium. When the computer program is run by a processor, it executes the steps of the acceleration parameter identification method described in Embodiment 1. For specific implementation, please refer to Method Embodiment 1, which will not be described again here.

In addition, referring to the schematic structural diagram of an electronic device shown in Figure 3, this embodiment also provides an electronic device. The electronic device includes a bus 300, a processor 301, a transceiver 302, a bus interface 303, a memory 304 and a user interface. 305. The above-mentioned electronic device includes a memory 304.

In this embodiment, the above-mentioned electronic device also includes: one or more programs stored in the memory 304 and executable on the processor 301, configured to be executed by the above-mentioned processor to perform the following: Step (1) to step (5):

(1) Select the re-entry aircraft to be monitored and determine the initial speed and initial position of the re-entry aircraft in all flight directions.

(2) Use the historical database to determine the best trajectory for each flight direction, and each of the best trajectories corresponds to the best position; determine the optimal position and determine the optimal value through all the best positions.

(3) Update and obtain the updated speed and updated position of the reentry vehicle in all directions according to time.

(4) Establish a spatial motion model based on the optimal position, optimal value, initial speed, initial position, update speed and update position.

(5) Establish a threat assessment model of the re-entry vehicle, and obtain the threat value of the re-entry vehicle based on the space motion model and the threat assessment model.

Transceiver 302 is used to receive and send data under the control of processor 301.

Among them, the bus architecture (represented by bus 300), the bus 300 can include any number of interconnected buses and bridges, the bus 300 will include one or more processors represented by the processor 301 and various types of memory represented by the memory 304. Circuits are linked together. The bus 300 may also link together various other circuits such as peripheral devices, voltage regulators, and power management circuits, which are well known in the art and therefore will not be further described in this embodiment. Bus interface 303 provides an interface between bus 300 and transceiver 302. Transceiver 302 may be one component or may be multiple components, such as multiple receivers and transmitters, providing a unit for communicating with various other devices over a transmission medium. For example: transceiver 302 receives external data from other devices. The transceiver 302 is used to send data processed by the processor 301 to other devices. Depending on the nature of the computing system, a user interface 305 may also be provided, such as a keypad, display, speakers, microphone, joystick.

The processor 301 is responsible for managing the bus 300 and general processing, running a general-purpose operating system 3041 as described above. The memory 304 may be used to store data used by the processor 301 when performing operations.

Optionally, the processor 301 may be, but is not limited to: a central processing unit, a single chip microcomputer, a microprocessor or a programmable logic device.

It can be understood that the memory 304 in the embodiment of the present application may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory can be read-only memory (Read-Only Memory, ROM), programmable read-only memory (Programmable ROM, PROM), erasable programmable read-only memory (Erasable PROM, EPROM), electrically removable memory. Erase programmable read-only memory (Electrically EPROM, EEPROM) or flash memory. The volatile memory may be random access memory (RAM), which is used as an external cache. By way of illustration, but not limitation, many forms of RAM are available, such as static random access memory (SRAM), dynamic random access memory (Dynamic RAM, DRAM), synchronous dynamic random access memory (Synchronous DRAM, SDRAM), double data rate synchronous dynamic random access memory (Double Data RateSDRAM, DDRSDRAM), enhanced synchronous dynamic random access memory (Enhanced SDRAM, ESDRAM), synchronous link dynamic random access memory (Synchlink DRAM, SLDRAM) and Direct memory bus random access memory (DirectRambus RAM, DRRAM). The memory 304 of the systems and methods described in this embodiment is intended to include, but is not limited to, these and any other suitable types of memory.

In some embodiments, memory 304 stores the following elements, executable modules or data structures, or a subset thereof, or an extension thereof: operating system 3041 and application programs 3042.

Among them, the operating system 3041 includes various system programs, such as framework layer, core library layer, driver layer, etc., which are used to implement various basic services and process hardware-based tasks. Application program 3042 includes various application programs, such as media player (Media Player), browser (Browser), etc., and is used to implement various application services. The program that implements the method of the embodiment of the present application may be included in the application program 3042.

The above are only specific implementation modes of the embodiments of the present invention, but the protection scope of the embodiments of the present invention is not limited thereto. Any person familiar with the technical field can easily implement the method within the technical scope disclosed in the embodiments of the present invention. Any changes or substitutions that are thought of should be included within the protection scope of the embodiments of the present invention. Therefore, the protection scope of the embodiments of the present invention should be subject to the protection scope of the claims.

Claims (4)

1. A method for calculating the threat level of re-entry aircraft, which is characterized by including: Select the re-entry aircraft to be monitored and determine the initial speed and initial position of the re-entry aircraft in all flight directions; Use a historical database to determine the best trajectory for each flight direction, and each of the best trajectories corresponds to the best position; Determine the optimal position through all said optimal positions and determine the optimal value; Update according to time and obtain the updated speed and updated position of the re-entry vehicle in all directions; Establish a spatial motion model based on the optimal position, the optimal value, the initial speed, the initial position, the updated speed and the updated position; A threat value assessment model of the re-entry aircraft is established, and a threat value of the re-entry aircraft is obtained based on the space motion model and the threat value assessment model. 2. The method for calculating the threat degree of re-entry aircraft according to claim 1, characterized in that the spatial motion model satisfies the following formula: V _id (t+1)＝w _s *V _id (t)+c ₁ *r ₁ *[(p _id (t)-x _id (t))]+c ₂ *r ₂ *[(g _gd ( t)-x _id (t))]; x _id (t+1)＝x _id (t)+V _id (t+1), 1≤d≤14; Among them, d represents the spatial dimension of the re-entry aircraft, w _s represents the inertia factor, i represents the movement direction of the re-entry aircraft, c ₁ represents the first acceleration constant, c ₂ represents the second acceleration constant, t represents the initial moment, x _id (t) represents the initial position, V _id (t+1) represents the movement speed of the reentry aircraft in the movement direction i at time t+1, r ₁ and r ₂ represent uniform random numbers between 0 and 1, p _id (t) represents the optimal value of the best position of the re-entry aircraft in the direction of motion i at time t, V _id (t) represents the initial speed of the re-entry aircraft at time t, x _id (t) represents the velocity of the re-entry aircraft at time t Position, x _id (t+1) represents the position of the re-entry aircraft at time t+1, g _gd (t) represents the best position of the re-entry aircraft in all movement directions at time t. 3. The re-entry aircraft threat degree calculation method according to claim 2, characterized in that the inertia factor satisfies: Among them, w _max represents the maximum value of the inertia factor of the re-entry aircraft along the direction of movement, w _g represents the basic inertia of the re-entry aircraft along the direction of movement, Ni represents the current number of iterations, and Ni _max represents the maximum number of iterations. 4. The method for calculating the threat degree of re-entry aircraft according to claim 2, characterized in that the first acceleration constant and the second acceleration constant satisfy: Among them, c _1min represents the minimum value of the acceleration weight factor of the extreme value of the equilibrium movement direction, c _1max represents the maximum value of the acceleration weight factor of the extreme value of the equilibrium movement direction, and c _2min represents the acceleration weight of the global extreme value of the equilibrium movement direction. The minimum value of the value factor, c _2max represents the maximum value of the acceleration weight factor of the global extreme in the direction of equilibrium motion, Ni _max represents the maximum number of iterations, and Ni represents the current number of iterations.