A situation awareness method for close-range tracking of a rocket's final stage

Abstract

The present application belongs to the technical field of space-based situation awareness, and particularly relates to a situation awareness method for close-range orbiting tracking of a rocket final stage, comprising: installing a situation awareness sensor on a satellite, establishing a satellite coordinate system, a rocket coordinate system, an orbit coordinate system and a Hill coordinate system; formulating a rocket final stage and satellite release constraint strategy; formulating a satellite awareness tracking pointing guidance law; according to the satellite awareness tracking pointing guidance law, the satellite performs close-range orbiting tracking of the rocket final stage, and the situation awareness sensor is used to realize space-based situation awareness of the rocket final stage. The present application utilizes the kinetic energy of the satellite released by the rocket, forms a natural orbiting observation orbit by designing a suitable release angle, installs a situation awareness sensor on the released satellite, and realizes detailed orbiting observation of the rocket final stage from near to far based on the natural orbiting strategy and attitude pointing control guidance, thereby providing a very economical and on-site and timely space-based situation awareness means for the rocket final stage.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of space-based situation awareness, and particularly relates to a situation awareness method for close-range orbiting tracking of a rocket final stage, which realizes efficient and very economical situation awareness measurement of the rocket final stage after star-rocket separation. BACKGROUND

[0002] With the vigorous development of global aerospace industry, various types of aerospace launch activities are becoming more and more frequent. In the past decade, the number of global aerospace launches has shown an increasing trend year by year, with an average of more than 100 times per year. Such high-intensity launch activities make the rocket orbital stage, if not properly disposed of, an important source of space debris. In recent years, the disintegration of the rocket's second stage (final stage) has occurred several times, and the disintegration of large final stages has generated a large amount of space debris, which has affected the orbital resources and subsequent launch tasks. These space debris run at high speed in orbit, like a "space bullet", seriously threatening the safety of on-orbit spacecraft.

[0003] Space-based situation awareness is an important field of aerospace development, and the monitoring and early warning of space debris require detection and identification of space debris. After accurate identification and tracking of space debris, ground personnel can calculate their position, velocity and orbit, and catalog these "space targets". This not only can provide early warning of collision risks, but also can lay the foundation for future debris cleanup and space resource recovery. Currently, many countries and space agencies have built specialized space target telescopes and monitoring networks through independent research and development or international cooperation, such as the European Space Agency's Space Debris Telescope SDT, the University of Bern Institute of Astronomy's Laser and Astrometry Telescope, and the U.S. space agency (NASA)'s Michigan Orbital Debris Survey Telescope MODEST. They are typical ground-based optical observation equipment for space debris monitoring, used to improve the detection and tracking capabilities of space debris. More and more aerospace companies and agencies are turning to space-based situation awareness platforms, providing timely, accurate and in-depth space safety information through autonomous and intelligent situation awareness satellites. SUMMARY

[0004] To solve the above technical problems, the present application provides a situation awareness method for close-range orbiting tracking of a rocket final stage, which utilizes the kinetic energy of a satellite released by a rocket, forms a natural orbiting observation orbit by designing a suitable release angle, installs a situation awareness sensor on the released satellite, and realizes detailed orbiting observation of the rocket final stage from close to far based on the natural orbiting strategy combined with attitude pointing control guidance, thereby providing a very economical and on-site timely space-based situation awareness means for the rocket final stage.

[0005] The present application is implemented as follows: a situation awareness method for close-range orbiting tracking of a rocket final stage is provided, comprising the following steps:

[0006] Step 1: install the situational awareness sensor on the satellite, establish the satellite coordinate system, the rocket coordinate system, the orbit coordinate system and the Hill coordinate system;

[0007] Step 2: formulate the rocket final stage and satellite release constraint strategy: the satellite and rocket final stage separation time is defined as the time when the rocket sends the unlocking instruction, when the satellite and rocket separate, the rocket makes the satellite separate in the orbit plane X o OZ o inner separation;

[0008] Step 3: formulate the satellite awareness tracking pointing guidance law:

[0009] Step 301: calculate the satellite and rocket final stage positions in the Hill coordinate system;

[0010] Step 302: convert the satellite relative to the rocket final stage position in the Hill coordinate system to the orbit coordinate system;

[0011] Step 303: calculate the position angle of the satellite coordinate system relative to the orbit coordinate system at the current time of each observation ;

[0012] Step 304: calculate the satellite awareness tracking pointing guidance law in the orbit coordinate system according to the position angle ;

[0013] Step 4: according to the satellite awareness tracking pointing guidance law, the satellite performs close-in fly-around tracking on the rocket final stage, and realizes the space-based situational awareness of the rocket final stage through the situational awareness sensor.

[0014] Preferably, in the step 1, the satellite coordinate system takes the center point of the satellite and rocket final stage separation plane as the coordinate origin, the Xs axis points to the boresight direction along the situational awareness sensor mounting surface, the Z s axis is perpendicular to the satellite and rocket final stage separation plane and points from the satellite release mechanism to the rocket satellite separation plane, and the Ys axis is orthogonal to the Xs axis and the Zs axis according to the right-hand rule;

[0015] The rocket coordinate system takes the overall instantaneous center of mass of the rocket and satellite as the coordinate origin, the X LV axis coincides with the rocket longitudinal axis and points to the rocket head, the Y LV axis is perpendicular to the X LV axis and points to the third quadrant line, and the Z LV axis is orthogonal to the X LV axis and the Y LV axis according to the right-hand rule;

[0016] The orbit coordinate system takes the satellite center of mass in the orbit as the coordinate origin, the Z o axis points to the Earth center O i in the satellite orbit plane, and the Y oX axis is in the opposite direction of the satellite orbit normal, Y axis is in the direction of the satellite orbit plane, and Z axis is in the direction of the satellite orbit plane normal o X axis is in the opposite direction of the satellite orbit normal, Y axis is in the direction of the satellite orbit plane, and Z axis is in the direction of the satellite orbit plane normal

[0017] The Hill coordinate system takes the observed rocket final stage as the coordinate system origin, the Hill-X0 axis is in the direction of the orbit radius, and points to the direction of the rocket final stage movement; the Hill-Y0 axis is in the direction of the orbit tangent, is perpendicular to the direction of the rocket final stage movement, and points to the direction of the orbit movement normal; and the Hill-Z0 axis is in the direction of the orbit angular momentum, is perpendicular to the orbit plane.

[0018] Preferably, the step 301 of calculating the satellite and rocket final stage positions in the Hill coordinate system comprises the following specific contents:

[0019] Step 301-1: The relative motion of the satellite and the rocket final stage in the XY plane in the Hill coordinate system is described according to the following non-perturbed dynamic equation set in the Hill:

[0020] ;

[0021] Wherein, t is the current satellite on-board time, T0 is the separation time of the released satellite, μ is the earth gravity constant, a is the satellite semi-major axis, represents the satellite current time orbit parameter, the initial position components of the released satellite are x0=0, y0=0, and the initial velocity components are 、 , The initial velocity components are from the release velocity:

[0022] ;

[0023] is the separation release angle, is determined by the rocket release capacity, and is defined as is the release velocity vector and the angle between the orbit coordinate system X o axis;

[0024] Step 301-2: The position vector of the released satellite in the Hill coordinate system is represented as:

[0025] .

[0026] Further preferably, the step 302 of converting the satellite relative rocket final stage position in the Hill coordinate system to the orbit coordinate system comprises the following specific contents:

[0027] Step 302-1: Express the motion state in the orbit coordinate system by rotation matrix, the rotation matrix Loh from Hill coordinate system to orbit coordinate system is:

[0028]

[0029] Step 302-2: The position vector of the released satellite in the orbit coordinate system is expressed as:

[0030] .

[0031] Further preferably, in the step 303, the position angle of the satellite coordinate system relative to the orbit coordinate system at the current time of each observation is calculated :

[0032] ;

[0033] with positive and negative, the value range in the four quadrants of the orbit coordinate system is: the first quadrant third quadrant , the second quadrant fourth quadrant .

[0034] Further preferably, in the step 304, the satellite perception tracking pointing guidance law in the orbit coordinate system is calculated according to the position angle , which specifically includes:

[0035] Step 304-1: When the satellite is separated, there are four separation directions:

[0036] , , denoted as separation direction 1;

[0037] , , denoted as separation direction 2;

[0038] , , denoted as separation direction 3;

[0039] , , denoted as separation direction 4;

[0040] Step 304-2: For the released satellite tracking pointing guidance law output, it needs to be noted that the quadrant of the current released satellite in the final orbit system is different. In different quadrants, the expression form of the required rocket final stage satellite body X axis pointing relative to the orbit coordinate system pitch angle is different, which is as follows:

[0041] (1): The guidance law output of the first quadrant:

[0042] Criterion of being in the first quadrant: ;

[0043] The three-axis vector of the satellite coordinate system coincides with the three-axis vector of the orbit coordinate system at the beginning, and the Ys axis of the satellite coordinate system rotates clockwise around the Y axis of the orbit coordinate system o Since , the orbit system pitch angle is ;

[0044] The output guidance law is: the expected roll angle , the expected pitch angle , and the expected yaw angle ; the expected roll angular velocity , the expected roll angular velocity , and the expected roll angular velocity ;

[0045] (2): The guidance law output of the second quadrant:

[0046] Criterion of being in the second quadrant: ;

[0047] The three-axis vector of the satellite coordinate system coincides with the three-axis vector of the orbit coordinate system at the beginning, and the Ys axis of the satellite coordinate system rotates clockwise around the Y axis of the orbit coordinate system o Since , the orbit system pitch angle is ;

[0048] The output guidance law is: the expected roll angle , the expected pitch angle , and the expected yaw angle ; the expected roll angular velocity , the expected roll angular velocity , and the expected roll angular velocity ;

[0049] (3): The guidance law output of the third quadrant:

[0050] Criterion of being in the third quadrant: ;

[0051] The three-axis vector of the satellite coordinate system coincides with the three-axis vector of the orbit coordinate system at the beginning, and the Ys axis of the satellite coordinate system rotates clockwise around the Y axis of the orbit coordinate system o Since , the orbit system pitch angle is ;

[0052] The output guidance law is: the expected roll angle , the expected pitch angle​​​ , desired yaw angle ; desired roll angular velocity , desired roll angular velocity , desired roll angular velocity ;

[0053] (4) The guidance law output when in the fourth quadrant:

[0054] The criterion for whether in the fourth quadrant: ;

[0055] The three-axis vectors of the satellite body coordinate system coincide with the three-axis vectors of the orbit coordinate system at the beginning, and the satellite body Ys axis rotates counterclockwise around the orbit Y o axis Since , the orbit pitch angle is: ;

[0056] The output guidance law is: desired roll angle , desired pitch angle , desired yaw angle ; desired roll angular velocity , desired roll angular velocity , desired roll angular velocity ;

[0057] (5) The guidance law output when exactly on the -Z o axis of the orbit coordinate system:

[0058] The criterion for whether on the -Z o axis: ;

[0059] The output guidance law is: desired roll angle , desired pitch angle , desired yaw angle ; desired roll angular velocity , desired roll angular velocity , desired roll angular velocity ;

[0060] (6) The guidance law output when exactly on the -X o axis of the orbit coordinate system:

[0061] The criterion for whether on the -X o axis: ;

[0062] The output guidance law is: desired roll angle , desired pitch angle , desired yaw angle ; desired roll angular velocity Desired roll angle velocity Desired roll angle velocity ;

[0063] (7) Just in orbit coordinate system +Z o axis output:

[0064] whether in +Z o axis criterion: ;

[0065] directly guide law is: desired roll angle , desired pitch angle , desired yaw angle ; desired roll angle velocity , desired roll angle velocity , desired roll angle velocity ;

[0066] (8) Just in orbit coordinate system +X o axis output:

[0067] whether in +X o axis criterion: ;

[0068] directly guide law is: desired roll angle , desired pitch angle , desired yaw angle ; desired roll angle velocity , desired roll angle velocity , desired roll angle velocity .

[0069] Compared with the prior art, the application has the advantages that:

[0070] 1. Compared with the ground-based and space-based rocket final stage situation awareness method, the application utilizes the opportunity of satellite release by rocket, designs relative position relationship and relative velocity, forms a natural fly-around observation orbit, guarantees a good close observation window, and is economical and efficient.

[0071] 2. A method for installing a situation awareness sensor on a satellite is provided, which is based on Hill relative motion equation, calculates an output satellite observation tracking pointing guide law along the fly-around orbit in real time, guarantees that the observation sensor pointing axis is aligned with the target at all times, and grasps the rocket final stage in-orbit state and data in the first time. BRIEF DESCRIPTION OF DRAWINGS

[0072] Figure 1 is a schematic diagram of a satellite coordinate system;

[0073] Figure 2 is a schematic diagram of a rocket coordinate system;

[0074] Figure 3 is a schematic diagram of an orbit coordinate system;

[0075] Figure 4 is a schematic diagram of a Hill coordinate system;

[0076] Figure 5 is a schematic diagram of the angle and velocity vector of a satellite released by a rocket final stage in a Hill coordinate system;

[0077] Figure 6 is a relative motion trajectory of a released satellite and a rocket final stage after separation in a Hill coordinate system. DETAILED DESCRIPTION

[0078] The application will be described in greater detail below with specific embodiments. The following examples will help those skilled in the art to further understand the application, but do not limit the application in any form. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the application. These are within the scope of protection of the application.

[0079] REFERENCE Figures 1-6 The application provides a situation awareness method for close-range flying tracking of a rocket final stage, comprising the following steps:

[0080] Step 1: installing a situation awareness sensor on a satellite, establishing a satellite coordinate system, a rocket coordinate system, an orbit coordinate system and a Hill coordinate system;

[0081] The satellite coordinate system takes the center point of the satellite and the rocket final stage separation surface as the coordinate origin, the Xs axis points to the boresight direction along the situation awareness sensor mounting surface, the Zs axis is perpendicular to the satellite and the rocket final stage separation surface, the Ys axis is orthogonal to the Xs axis and the Zs axis according to the right-hand rule; s

[0082] The rocket coordinate system takes the instantaneous center of mass of the rocket and the satellite as the coordinate origin, the Xr axis coincides with the rocket longitudinal axis and points to the rocket head, the Yr axis is perpendicular to the Xr axis and points to the third quadrant line, the Zr axis is orthogonal to the Xr axis and the Yr axis according to the right-hand rule; LV LV LV LV LV LV

[0083] The satellite orbit coordinate system is a non-inertial coordinate system, which is the reference for the satellite attitude in orbit flight and is used to determine the attitude angle of the satellite. The orbit coordinate system takes the satellite center of mass in orbit as the coordinate origin, the Zo axis points to the Earth center Oe in the satellite orbit plane, the Yo axis is perpendicular to the Zo axis and points to the third quadrant line, and the Xo axis is orthogonal to the Zo axis and the Yo axis according to the right-hand rule. o i o ​​​​​​​​​X o The axis is determined according to the right-hand rule, and the circular orbit is directed to the satellite speed direction.

[0084] The Hill coordinate system is a coordinate system for describing relative motion of two or more spacecrafts in formation flight. The Hill coordinate system takes the observed rocket final stage as the coordinate system origin. The Hill-X0 axis is along the orbital radius direction and is directed to the rocket final stage motion direction. The Hill-Y0 axis is along the orbital tangent direction and is perpendicular to the rocket final stage motion direction and is directed to the normal direction of the orbital motion. The Hill-Z0 axis is along the orbital angular momentum direction and is perpendicular to the orbital plane.

[0085] Step 2: Formulate the rocket final stage and satellite release constraint strategy: the satellite and rocket separation time is defined as the time when the rocket issues the unlocking instruction. When the satellite and rocket are separated, the rocket makes the satellite have a speed component in the X o OZ o inner separation; the principle is to use the rocket final stage to generate a speed component in the X axis direction of the same orbital plane, thereby forming a fly-around energy, and naturally forming an elliptical fly-around observation orbit of the orbital plane, without the need for additional forced control by the satellite carrying a propulsion system, so as to realize the fly-around of the rocket final stage, which is a very simple and economical fly-around method.

[0086] Step 3: Formulate the satellite sensing tracking pointing guidance law:

[0087] In step 2, after the fly-around orbit is formed, the satellite observation axis needs to be directed to the observed rocket final stage at all times, so it is necessary to know the relative motion relationship between the released satellite and the rocket final stage at each observation time. Since the satellite attitude control is commonly described in the orbital system, but the relative motion relationship between two spacecrafts in space uses the Hill coordinate system, the following method is adopted:

[0088] Step 301: Calculate the positions of the satellite and the rocket final stage in the Hill coordinate system, including the following specific contents:

[0089] Step 301-1: According to the following non-perturbed dynamic equation group in Hill, the relative motion of the satellite and the rocket final stage in the XY plane in Hill is described:

[0090] ;

[0091] wherein, t is the current satellite time, T0 is the separation time of the released satellite, μ is the earth gravity constant, a is the satellite semi-major axis, and a represents the satellite orbital parameter at the current time. The initial position components of the released satellite are x0=0 and y0=0, and the initial velocity components are 、 , The initial velocity component comes from the release velocity:

[0092] ;

[0093] The release angle, is determined by the rocket release capability, and is defined as the release velocity vector with respect to the orbit coordinate system X o axis;

[0094] Step 301-2: The position vector of the released satellite in the Hill coordinate system is represented as:

[0095] .

[0096] Step 302: Convert the satellite position relative to the rocket final stage in the Hill coordinate system to the orbit coordinate system, including the following specific contents:

[0097] Step 302-1: Express the motion state in the orbit coordinate system by rotating the matrix, and the rotation matrix Loh from the Hill coordinate system to the orbit coordinate system is:

[0098]

[0099] Step 302-2: The position vector of the released satellite in the orbit coordinate system is represented as:

[0100] .

[0101] Step 303: Calculate the position angle of the satellite coordinate system relative to the orbit coordinate system at the current time of each observation ;

[0102] ;

[0103] with positive and negative, the value range in the four quadrants of the orbit coordinate system is: the first quadrant third quadrant , the second quadrant fourth quadrant .

[0104] Step 304: Calculate the satellite perception tracking pointing guidance law in the orbit coordinate system according to the position angle , including:

[0105] Step 304-1: When the satellite is separated, there are four kinds of separation directions:

[0106] , , denoted as separation heading 1;

[0107] , , denoted as separation heading 2;

[0108] , , denoted as separation heading 3;

[0109] , , denoted as separation heading 4;

[0110] Step 304-2: For the release satellite tracking pointing guidance law output, it needs to be noted that the quadrant of the current released satellite in the final stage orbit system, in different quadrants, the expression form of the satellite body X axis pointing to the rocket final stage required relative to the orbit coordinate system pitch angle is different, as follows:

[0111] (1): The guidance law output of the first quadrant:

[0112] Whether in the first quadrant criterion: ;

[0113] The three-axis vector of the satellite coordinate system is coincident with the three-axis vector of the orbit coordinate system at the initial time, and the Ys axis of the satellite coordinate system rotates clockwise around the Y o axis of the orbit coordinate system , since , the orbit system pitch angle ;

[0114] The output guidance law is: the expected roll angle , the expected pitch angle , and the expected yaw angle , the units of the above three angles are rad; the expected roll angular velocity , the expected roll angular velocity , and the expected roll angular velocity , the units of the above three angular velocities are rad / s;

[0115] (2): The guidance law output of the second quadrant:

[0116] Whether in the second quadrant criterion: ;

[0117] The three-axis vector of the satellite coordinate system is coincident with the three-axis vector of the orbit system at the initial time, and the Ys axis of the satellite coordinate system rotates clockwise around the Y o axis of the orbit coordinate system , since , the orbit system pitch angle: ;

[0118] The output guidance law is: desired roll angle , desired pitch angle , desired yaw angle ; desired roll angular velocity , desired roll angular velocity , desired roll angular velocity ;

[0119] (3) The guidance law output in the third quadrant:

[0120] The criterion for whether it is in the third quadrant: ;

[0121] The three-axis vectors of the satellite body coordinate system coincide with the three-axis vectors of the orbit coordinate system at the beginning, and the satellite body Ys axis rotates counterclockwise around the orbit coordinate Y o axis , and since , the orbit pitch angle is: ;

[0122] The output guidance law is: desired roll angle , desired pitch angle , desired yaw angle ; desired roll angular velocity , desired roll angular velocity , desired roll angular velocity ;

[0123] (4) The guidance law output in the fourth quadrant:

[0124] The criterion for whether it is in the fourth quadrant: ;

[0125] The three-axis vectors of the satellite body coordinate system coincide with the three-axis vectors of the orbit coordinate system at the beginning, and the satellite body Ys axis rotates counterclockwise around the orbit coordinate Y o axis , and since , the orbit pitch angle is: ;

[0126] The output guidance law is: desired roll angle , desired pitch angle , desired yaw angle ; desired roll angular velocity , desired roll angular velocity , desired roll angular velocity ;

[0127] (5) The guidance law output when exactly on the orbit coordinate system-Z o axis:

[0128] The criterion for whether it is on the-Z oCriterion on the X-axis: ;

[0129] Direct guidance law: desired roll angle , desired pitch angle , desired yaw angle ; desired roll angular velocity , desired roll angular velocity , desired roll angular velocity ;

[0130] (6) Just on the -X o axis of the orbital coordinate system:

[0131] Criterion on the -X o axis: ;

[0132] Direct guidance law: desired roll angle , desired pitch angle , desired yaw angle ; desired roll angular velocity , desired roll angular velocity , desired roll angular velocity ;

[0133] (7) Just on the +Z o axis of the orbital coordinate system:

[0134] Criterion on the +Z o axis: ;

[0135] Direct guidance law: desired roll angle , desired pitch angle , desired yaw angle ; desired roll angular velocity , desired roll angular velocity , desired roll angular velocity ;

[0136] (8) Just on the +X o axis of the orbital coordinate system:

[0137] Criterion on the +X o axis: ;

[0138] Direct guidance law: desired roll angle , desired pitch angle , desired yaw angle ; desired roll angular velocity , desired roll angular velocity , desired roll angular velocity .

[0139] Step 4: According to the satellite awareness tracking and pointing guidance law, the satellite performs close-range fly-around tracking on the rocket final stage, and the space-based situational awareness of the rocket final stage is realized through the situational awareness sensor.

Claims

1. A situation awareness method for close-in tracking of a rocket's final stage, characterized by, The method comprises the following steps: Step 1: installing a situation awareness sensor on the satellite, establishing a satellite coordinate system, a rocket coordinate system, an orbit coordinate system and a Hill coordinate system; The satellite coordinate system takes the center point of the satellite and the rocket final stage separation surface as the coordinate origin, the Xs axis points to the direction of the optical axis along the situational awareness sensor mounting surface, the Zs axis is perpendicular to the satellite and the rocket final stage separation surface, the Ys axis is orthogonal to the Xs axis and the Zs axis according to the right-hand rule. s The satellite coordinate system takes the center point of the satellite and the rocket final stage separation surface as the coordinate origin, the Xs axis points to the direction of the optical axis along the situational awareness sensor mounting surface, the Zs axis is perpendicular to the satellite and the rocket final stage separation surface, the Ys axis is orthogonal to the Xs axis and the Zs axis according to the right-hand rule. The rocket coordinate system takes the overall instantaneous center of mass of the rocket and satellite as the coordinate origin, X LV The X axis coincides with the rocket longitudinal axis and points to the arrow head, Y LV The Y axis is perpendicular to the X LV The Z axis points to the third quadrant line, Z LV The Z axis is perpendicular to the X LV The Y axis and the X LV The Z axis is orthogonal; The orbit coordinate system takes the satellite mass center on the orbit as the coordinate origin, Z o axis points to the earth center O in the satellite orbit plane i , Y o axis points to the earth center O in the satellite orbit plane o axis is determined according to the right-hand rule, and the circular orbit points to the satellite speed direction The Hill coordinate system takes the observed rocket final stage as the coordinate system origin, the Hill-X0 axis is along the orbit radius direction, and points to the rocket final stage movement direction; the Hill-Y0 axis is along the orbit tangent direction, and is perpendicular to the rocket final stage movement direction, and points to the normal direction of the orbit movement; the Hill-Z0 axis is along the orbit angular momentum direction, and is perpendicular to the orbit plane; Step 2: Establishing the rocket final stage and satellite release constraint strategy: the satellite and rocket final stage separation time is defined as the time when the rocket sends the unlocking command. When the satellite and rocket are separated, the rocket makes the satellite in the orbit coordinate system o OZ o inner separation; Step 3: formulating a satellite awareness tracking pointing guidance law: Step 301: calculating the satellite and rocket final stage positions in the Hill coordinate system; Step 302: converting the satellite relative rocket final stage position in the Hill coordinate system to the orbit coordinate system; Step 303: Calculate the position angle of the satellite coordinate system relative to the orbital coordinate system at the current time of each observation ; Step 304: According to the position angle The satellite perception tracking pointing guidance law in the orbit coordinate system is calculated. Step 4: according to the satellite awareness tracking pointing guidance law, the satellite performs close-range fly-around tracking on the rocket final stage, and realizes the space-based situation awareness of the rocket final stage through the situation awareness sensor.

2. The situational awareness method for close-proximity tracking of a rocket's final stage according to claim 1, wherein, In the step 301, the calculation of the satellite and rocket final stage positions in the Hill coordinate system comprises the following specific contents: Step 301-1: describing the relative motion of the satellite and the rocket final stage in the XY plane in the Hill coordinate system according to the following non-perturbed dynamic equation set in the Hill: ； wherein, , t is the current on-board time of the released satellite, T0is the separation time of the released satellite, , μ is the Earth gravitational constant, a is the semi-major axis of the satellite, represents the orbit parameters of the satellite at the current time, the initial position components of the released satellite are x0=0, y0=0, and the initial velocity components are 、 , is the separation velocity of the released satellite, and the initial velocity components are derived from the release velocity: ； to separate release angles, defined by the rocket release capability to release velocity vector with the orbital coordinate system X o the angle of the axis; Step 301-2: the position vector of the released satellite in the Hill coordinate system is represented as: 。 3. The situational awareness method of claim 2, wherein, In the step 302, the conversion of the satellite relative rocket final stage position in the Hill coordinate system to the orbit coordinate system comprises the following specific contents: Step 302-1: the motion state in the orbit coordinate system is expressed through a rotation matrix, and the rotation matrix Loh from the Hill coordinate system to the orbit coordinate system is: ； Step 302-2: the position vector of the released satellite in the orbit coordinate system is represented as: 。 4. The situational awareness method of close proximity tracking of a final stage of a rocket according to claim 3, characterized in that, In step 303, the position angle of the satellite coordinate system relative to the orbital coordinate system at the current time of each observation is calculated : ； with positive and negative, The numerical interval in the four quadrants of the orbital coordinate system is: the first quadrant third quadrant , the second quadrant fourth quadrant .

5. The situational awareness method of close proximity tracking of a rocket's final stage according to claim 4, characterized in that, In step 304, the position angle is calculated according to the position and the velocity of the satellite The satellite perception tracking pointing guidance law in the orbit coordinate system specifically comprises: Step 304-1: when the satellite is separated, there are four separation directions: , , as the separation goes to 1; , , as the separation proceeds 2; , , as the separation proceeds 3; , , as the separation goes on 4; Step 304-2: for the release satellite tracking pointing guidance law output, it is necessary to pay attention to the quadrant of the released satellite in the final stage orbit system, and in different quadrants, the expression form of the satellite body X axis pointing to the rocket final stage relative to the orbit coordinate system pitch angle is different, and the specific contents are as follows: (1): the guidance law output of the first quadrant: Criterion for being in the first quadrant: ; The three-axis vectors of the satellite coordinate system initially coincide with the three-axis vectors of the orbit coordinate system, and the Ys axis of the satellite coordinate system rotates clockwise around the Y o axis of the orbit coordinate system Since , the orbit system pitch angle ; The output guidance law is: desired roll angle , desired pitch angle , desired yaw angle ; desired roll angle velocity , desired roll angle velocity , desired roll angle velocity ; (2): the guidance law output of the second quadrant: Criterion for whether in second quadrant: ; The three-axis vectors of the satellite coordinate system are initially coincident with the three-axis vectors of the orbit coordinate system, and the Ys axis of the satellite coordinate system rotates clockwise around the Y o axis of the orbit coordinate system Since , the orbit coordinate system pitch angle is: ; The output guidance law is: desired roll angle , desired pitch angle , desired yaw angle ; desired roll angle rate , desired roll angle rate , desired roll angle rate ; (3): the guidance law output of the third quadrant: Criterion for being in the third quadrant: ; The three-axis vectors of the satellite body coordinate system initially coincide with the three-axis vectors of the orbit coordinate system, and the satellite body Ys axis rotates counterclockwise around the orbit coordinate system Y o The three-axis vectors of the satellite body coordinate system initially coincide with the three-axis vectors of the orbit coordinate system, and the satellite body Ys axis rotates counterclockwise around the orbit coordinate system Y Since , the orbit system pitch angle is: ; The output guidance law is: desired roll angle , desired pitch angle , desired yaw angle ; desired roll angle velocity , desired roll angle velocity , desired roll angle velocity ; (4): the guidance law output of the fourth quadrant: Criterion for whether in the fourth quadrant: ; The three-axis vectors of the satellite body coordinate system initially coincide with the three-axis vectors of the orbit coordinate system, and the satellite body Ys axis rotates counterclockwise around the orbit Y o axis Since , the orbit pitch angle is: ; The output guidance law is: desired roll angle , desired pitch angle , desired yaw angle ; desired roll angular velocity , desired roll angular velocity , desired roll angular velocity ; (5) exactly on the -Z axis of the orbital coordinate system o Guidance law output on the axis: whether in -z o criterion on the axis: ; The direct feedforward law is: desired roll angle , desired pitch angle , desired yaw angle ; desired roll angular velocity , desired roll angular velocity , desired roll angular velocity ; (6) exactly in the orbit coordinate system -X o Guidance law output on the axis: whether in -X o on the axis: ; The direct feedforward law is: desired roll angle , desired pitch angle , desired yaw angle ; desired roll angular velocity , desired roll angular velocity , desired roll angular velocity ; (7) exactly on the orbit coordinate system +Z o Guidance law output on the axis: Is in +Z o axis: ; The direct feedforward law is: desired roll angle , desired pitch angle , desired yaw angle ; desired roll angular velocity , desired roll angular velocity , desired roll angular velocity ; (8) exactly on the orbit coordinate system +X o guidance law output on the axis: Is in +X o axis: ; The direct feedforward law is: desired roll angle , desired pitch angle , desired yaw angle ; desired roll angle velocity , desired roll angle velocity , desired roll angle velocity .

Images