CN112257343A - High-precision ground track repetitive track optimization method and system - Google Patents
High-precision ground track repetitive track optimization method and system Download PDFInfo
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Abstract
The invention provides a high-precision ground track repetitive orbit optimization method and system, wherein a corresponding satellite orbit dynamics recursion model is established according to the requirement analysis of an earth gravity field non-spherical perturbation order; the method comprises the steps of providing heavy rail interference track parameters under a J2 low-order gravity field according to an analytical formula, and obtaining correction parameters under J4 perturbation through iterative calculation to serve as initial values of a high-precision ground track repeated track parameter self-adaptive setting algorithm; and according to the requirement of the repeated track precision, carrying out self-adaptive optimization setting on the repeated track parameters of the high-precision ground track. The method solves the problems that the traditional low-order gravity field orbit model is low in ground track repetition precision, the high-order gravity field orbit model is high in nonlinearity, many in iterative correction parameters, incapable of resolving and the like, and has more general engineering practicability.
Description
Technical Field
The invention relates to astronavigation aircraft orbital dynamics, in particular to a high-precision ground track repeated orbit optimization method and system.
Background
The revisiting characteristic of the track of the subsatellite point is an important index for the design of the earth observation satellite track, the requirement of the traditional satellite ground track on the return precision of the track is not high, the track deviation can be from thousands of meters to dozens of kilometers, and the flight task of the satellite is not influenced. In recent years, with the requirement of imaging precision greatly improved, the limitation of the existing regression orbit design method is increasingly obvious, and particularly for a surveying and mapping task, in order to realize accurate surveying and mapping and efficient task planning, high-precision regression of a satellite reference orbit ground track needs to be ensured.
At present, many regression orbit design schemes are applied at home and abroad, but most of the regression orbit design schemes are based on an analysis method of a low-order gravitational field model, and the regression precision deviation is as high as 3km to 10 km. In the Chinese patent 'a method for determining a strict regression orbit of a near earth satellite' (CN106092105A), Yang Shengqing, Du Keke, Wang Gift and the like, iterative correction is carried out by establishing the relationship among a semi-major axis of the orbit, an orbit inclination angle and a longitude and latitude of a point under the satellite by taking regression precision as an index; and aiming at the characteristic of the eccentricity ratio vector limit ring, repeatedly carrying out iterative correction on the eccentricity ratio and the argument of the near place by adopting an averaging method. In the method, the function relationship between the subsatellite point for iterative correction and the semi-major axis and the inclination angle of the orbit only considers the perturbation of the earth 2-order gravity field to influence the regression precision; each iteration correction of eccentricity and argument of near place needs to acquire 4-month period data for averaging, the calculated amount is large, and the iteration convergence speed is influenced; the regression precision of the obtained orbit can only reach the meter level, and engineering application is influenced.
In summary, a high-precision ground track repetitive track design under the influence of high-order gravity field perturbation needs to be developed for centimeter-level regression precision requirements.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to provide a high-precision ground track repetitive track optimization method and system.
The invention provides a high-precision ground track repetitive track optimization method, which comprises the following steps:
step A: according to the requirement analysis of the earth gravity field non-spherical perturbation order, establishing a corresponding satellite orbit dynamics recursion model;
and B: the method comprises the steps of providing heavy rail interference track parameters under a J2 low-order gravity field according to an analytical formula, and obtaining correction parameters under J4 perturbation through iterative calculation to serve as initial values of a high-precision ground track repeated track parameter self-adaptive setting algorithm;
and C: and according to the requirement of the repeated track precision, carrying out self-adaptive optimization setting on the repeated track parameters of the high-precision ground track.
Preferably, the precision of the heavy rail track is less than 0.01 m.
Preferably, the step a includes:
taking the numerical simulation test result as a basis, comprehensively considering the ground track repetition precision and the orbit recursion computation amount, establishing a satellite orbit dynamics model corresponding to the following steps, and adopting an expression method of an earth gravity field potential function:
wherein the content of the first and second substances,is the earth-centered position vector of the satellite;is the function of the field potential of the earth gravity;
the gravity field potential function comprises two parts of earth central gravity and earth non-spherical gravity, and if the earth is considered as a rigid body and an equatorial plane is superposed with a basic plane of an epoch inertial system, the gravity field potential function is expanded into a series form in the earth central inertial system as follows:
wherein mu is the gravitational constant of the earth, r is the earth center distance of the satellite, Cn0And CnmAnd SnmAll are spherical harmonic coefficients, ReIs the equatorial radius,The geocentric latitude and the lambda are geocentric longitude which are obtained by calculating a position vector in a satellite geostationary system;andthe terms are Legendre and associated Legendre polynomials respectively, are correction parts of a real earth gravitational potential pair uniform sphere and comprise a band harmonic term and a field harmonic term;
and obtaining coefficient values of each order of a gravitational field potential function through an earth gravitational field table, calculating to obtain a perturbation force expression under a satellite geostationary system, and further integrating to obtain the position and the speed of the satellite.
Preferably, the step B includes:
step S4.1: according to the overall design constraint, giving a semi-major axis analytic solution a of the heavy rail interference track under the J2 low-order gravity fieldJ2Orbit dip angle analytic solution iJ2A heavy rail period T and a rail turn number Q;
according to the load working power, the satellite weight, the carrying and launching capacity and other overall constraints, the semi-major axis a of the heavy-rail interference orbit can be determinedJ2;
Orbit dip analytic solution iJ2:
Track number of turns Q, heavy rail period T:
T=Tn×Q
wherein, TnIs a period of intersection, weThe rotational angular velocity of the earth;
step S4.2: according to the J2 perturbation analysis orbit, a J4 perturbation correction orbit based on a Newton iteration method is provided, and the method comprises the following steps:
step S4.2.1: selecting t according to the requirement of satellite task on ground track arrangement0Latitude and longitude lambda of time point under star0、Establishing a functional relation of longitude and latitude about a semi-major axis and an inclination angle after the following tracks are repeated;
wherein the content of the first and second substances,
M=n(t-t0)
G0is t0At time Greenwich mean sidereal time omega0Is t0The right ascension at the ascending crossing point of the moment,is J4Perturbation of the rising point right ascension drift rate;
step S4.2.2: obtaining the following heavy rail interference track eccentricity e by utilizing the constraint relation of the frozen trackJ3And estimating the initial value of the argument w of the near place:
step S4.2.3: firstly, with the satellite t0Time ground track initial longitude and latitude lambda0、Taking the starting point as the point of integration of the heavy track period T to obtain T0Satellite ground track longitude and latitude lambda at + T momentn、Then calculating to obtain the longitude and latitude deviation delta lambda of the initial end of the heavy railn-λ0,Judging whether the deviation meets the heavy rail interference precision index or not; if the index is satisfied, outputting a semimajor axis and a tilt angle correction value aJ4、iJ4If the iteration parameter is out of tolerance, the following parameter correction is carried out, and the integral judgment process is converted back again until the iteration parameter meets the precision index;
ak=ak-1+Δak-1
ik=ik-1+Δik-1
wherein the content of the first and second substances,
akfor the semi-major axis of the orbit at time k, ak-1Is the semimajor axis of the track at time k-1, ikFor the track inclination at time k, ik-1Is the inclination angle of the orbit at the moment of k-1;
step S4.2.4: calculating to obtain t by using the functional relationship between the semi-major axis and the inclination angle of the track and the longitude and latitude of the subsatellite point in the step S4.2.10Time aJ4、iJ4Corresponding rising point right ascension omegaJ4Angle M close to the meanJ4。
Preferably, the step C includes:
step S5.1: the method comprises the steps of converting a track repeated nonlinear parameter solving problem under a high-order gravity field into a multivariable and multi-target optimization problem, guiding parameter self-adaptive setting by combining target track characteristic information, and describing an optimization model as follows:
optimizing variables: [ Δ a, Δ e, Δ i, Δ Ω, Δ w, Δ M ]
Initial conditions: [ a ] AJ4,eJ3,iJ4,ΩJ4,w=90°,MJ4]
Constraint conditions are as follows:
delta a is correction of track semimajor axis, delta e is correction of track eccentricity, delta i is correction of track inclination angle, delta omega is correction of right ascension at track ascending intersection point, delta w is correction of amplitude at track perigee, delta M is correction of angle at track mean perigee,as a vector of the acceleration of the satellite,in order to be a satellite position deviation,for the satellite position vector at time T,is t0A time satellite position vector;
step S5.2: selecting individuals through a binary system tournament method, and performing crossing and variation to generate a new population;
step S5.3: calculating and updating a new population objective function value, namely the position and speed deviation of the satellite earth-fixed system;
step S5.4: generating a new combined population by a merging method, and carrying out non-dominant sorting;
step S5.5: selecting individuals to form a new generation of population through a displacement and elite retention strategy;
step S5.6: and skipping to the step S5.2, and circularly updating until the termination condition is met.
The invention provides a high-precision ground track repetitive track optimization system, which comprises:
a module A: according to the requirement analysis of the earth gravity field non-spherical perturbation order, establishing a corresponding satellite orbit dynamics recursion model;
and a module B: the method comprises the steps of providing heavy rail interference track parameters under a J2 low-order gravity field according to an analytical formula, and obtaining correction parameters under J4 perturbation through iterative calculation to serve as initial values of a high-precision ground track repeated track parameter self-adaptive setting algorithm;
and a module C: and according to the requirement of the repeated track precision, carrying out self-adaptive optimization setting on the repeated track parameters of the high-precision ground track.
Preferably, the precision of the heavy rail track is less than 0.01 m.
Preferably, the module a comprises:
taking the numerical simulation test result as a basis, comprehensively considering the ground track repetition precision and the orbit recursion computation amount, establishing a satellite orbit dynamics model corresponding to the following steps, and adopting an expression method of an earth gravity field potential function:
wherein the content of the first and second substances,is the earth-centered position vector of the satellite;is the function of the field potential of the earth gravity;
the gravity field potential function comprises two parts of earth central gravity and earth non-spherical gravity, and if the earth is considered as a rigid body and an equatorial plane is superposed with a basic plane of an epoch inertial system, the gravity field potential function is expanded into a series form in the earth central inertial system as follows:
wherein mu is the gravitational constant of the earth, r is the earth center distance of the satellite, Cn0And CnmAnd SnmAll are spherical harmonic coefficients, ReIs the equatorial radius,The geocentric latitude and the lambda are geocentric longitude which are obtained by calculating a position vector in a satellite geostationary system;andthe terms are Legendre and associated Legendre polynomials respectively, are correction parts of a real earth gravitational potential pair uniform sphere and comprise a band harmonic term and a field harmonic term;
and obtaining coefficient values of each order of a gravitational field potential function through an earth gravitational field table, calculating to obtain a perturbation force expression under a satellite geostationary system, and further integrating to obtain the position and the speed of the satellite.
Preferably, the module B comprises:
module S4.1: according to the overall design constraint, giving a semi-major axis analytic solution a of the heavy rail interference track under the J2 low-order gravity fieldJ2Orbit dip angle analytic solution iJ2A heavy rail period T and a rail turn number Q;
according to the load working power, the satellite weight, the carrying and launching capacity and other overall constraints, the semi-major axis a of the heavy-rail interference orbit can be determinedJ2;
Orbit dip analytic solution iJ2:
Track number of turns Q, heavy rail period T:
T=Tn×Q
wherein, TnIs a period of intersection, weThe rotational angular velocity of the earth;
module S4.2: according to the J2 perturbation analysis orbit, a J4 perturbation correction orbit based on a Newton iteration method is provided, and the method comprises the following steps:
module S4.2.1: selecting t according to the requirement of satellite task on ground track arrangement0Latitude and longitude lambda of time point under star0、Establishing a functional relation of longitude and latitude about a semi-major axis and an inclination angle after the following tracks are repeated;
wherein the content of the first and second substances,
M=n(t-t0)
G0is t0Greenwich mean timeStar time omega0Is t0The right ascension at the ascending crossing point of the moment,is J4Perturbation of the rising point right ascension drift rate;
module S4.2.2: obtaining the following heavy rail interference track eccentricity e by utilizing the constraint relation of the frozen trackJ3And estimating the initial value of the argument w of the near place:
module S4.2.3: firstly, with the satellite t0Time ground track initial longitude and latitude lambda0、Taking the starting point as the point of integration of the heavy track period T to obtain T0Satellite ground track longitude and latitude lambda at + T momentn、Then calculating to obtain the longitude and latitude deviation delta lambda of the initial end of the heavy railn-λ0,Judging whether the deviation meets the heavy rail interference precision index or not; if the index is satisfied, outputting a semimajor axis and a tilt angle correction value aJ4、iJ4If the iteration parameter is out of tolerance, the following parameter correction is carried out, and the integral judgment process is converted back again until the iteration parameter meets the precision index;
ak=ak-1+Δak-1
ik=ik-1+Δik-1
wherein the content of the first and second substances,
akis time kSemi-major axis of the track, ak-1Is the semimajor axis of the track at time k-1, ikFor the track inclination at time k, ik-1Is the inclination angle of the orbit at the moment of k-1;
module S4.2.4: t is calculated by utilizing the functional relation between the semi-major axis and the inclination angle of the orbit and the longitude and latitude of the satellite point in the module S4.2.10Time aJ4、iJ4Corresponding rising point right ascension omegaJ4Angle M close to the meanJ4。
Preferably, the module C comprises:
module S5.1: the method comprises the steps of converting a track repeated nonlinear parameter solving problem under a high-order gravity field into a multivariable and multi-target optimization problem, guiding parameter self-adaptive setting by combining target track characteristic information, and describing an optimization model as follows:
optimizing variables: [ Δ a, Δ e, Δ i, Δ Ω, Δ w, Δ M ]
Initial conditions: [ a ] AJ4,eJ3,iJ4,ΩJ4,w=90°,MJ4]
Constraint conditions are as follows:
delta a is correction of track semimajor axis, delta e is correction of track eccentricity, delta i is correction of track inclination angle, delta omega is correction of right ascension at track ascending intersection point, delta w is correction of amplitude at track perigee, delta M is correction of angle at track mean perigee,as a vector of the acceleration of the satellite,in order to be a satellite position deviation,for the satellite position vector at time T,is t0A time satellite position vector;
module S5.2: selecting individuals through a binary system tournament method, and performing crossing and variation to generate a new population;
module S5.3: calculating and updating a new population objective function value, namely the position and speed deviation of the satellite earth-fixed system;
module S5.4: generating a new combined population by a merging method, and carrying out non-dominant sorting;
module S5.5: selecting individuals to form a new generation of population through a displacement and elite retention strategy;
module S5.6: and jumping to a module S5.2, and circularly updating until a termination condition is met.
Compared with the prior art, the invention has the following beneficial effects:
the method solves the problems that the traditional low-order gravity field orbit model is low in ground track repetition precision, the high-order gravity field orbit model is high in nonlinearity, many in iterative correction parameters, incapable of resolving and the like, and has more general engineering practicability.
Drawings
Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments with reference to the following drawings:
FIG. 1 is a schematic block diagram of a high-precision ground track repetitive orbit optimization method;
FIG. 2 is a schematic block diagram of iterative correction of an initial value of a high-precision ground track repetitive orbit J4;
FIG. 3 is a schematic diagram of high-precision ground track repetitive orbit parameter adaptive setting optimization;
FIG. 4 is a high-precision ground track repetitive orbit high-order gravity field model order determination simulation diagram.
Detailed Description
The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that it would be obvious to those skilled in the art that various changes and modifications can be made without departing from the spirit of the invention. All falling within the scope of the present invention.
As shown in the attached figure 1, the invention provides a high-precision ground track repetitive track optimization method with self-adaptive parameter setting under the influence of high-order gravity field perturbation. The method specifically comprises the following steps:
step A: according to the requirement analysis of the earth gravity field non-spherical perturbation order, establishing a corresponding satellite orbit dynamics recursion model;
and B: the method comprises the steps of providing heavy rail interference track parameters under a J2 low-order gravity field according to an analytical formula, and obtaining correction parameters under J4 perturbation through iterative calculation on the basis, wherein the correction parameters are used as initial values of a high-precision ground track repeated track parameter self-adaptive setting algorithm;
and C: and according to the requirement of the repeated track precision, carrying out self-adaptive optimization setting on the repeated track parameters of the high-precision ground track.
In this embodiment, the regression accuracy is better than 0.01 m.
In the step A: as shown in fig. 4, the orbit repetition position precision of the regression orbit under each other low-order perturbation model is calculated by a numerical simulation test method with 120 × 120-order earth gravity field as a standard, and then the orbit recursion computation amount is considered comprehensively, so that a suggestion that the order of the gravity field model is selected to be 90 × 90 is given, and the following corresponding satellite orbit dynamics model is established.
In order to facilitate the description of the numerical integration of the satellite orbit in the gravity field, a representation method of the potential function of the earth gravity field is adopted, namely:
wherein the content of the first and second substances,as the earth's center location vector of the satelliteAn amount;is a function of the field potential of the earth's gravity.
The gravity field potential function includes two parts of earth central gravity and earth non-spherical gravity, and if the earth is considered as a rigid body and an equatorial plane is superposed with a basic plane of an epoch inertial system, the gravity field potential function can be expanded into a series form in the earth central inertial system as follows:
wherein mu is the gravitational constant of the earth, r is the earth center distance of the satellite, Cn0And CnmAnd SnmAll are spherical harmonic coefficients, ReIs the equatorial radius,The geocentric latitude and the lambda are geocentric longitude which can be obtained by calculating a position vector in a satellite earth-fixed system;andthe terms are Legendre and associated Legendre polynomials respectively, are correction parts of a real earth gravitational potential pair uniform sphere, comprise a band harmonic term and a field harmonic term, and reflect the unevenness of the earth.
The coefficient values of each order of the gravitational field potential function are obtained through the earth gravitational field table, a perturbation force expression under the satellite earth-solid system can be obtained through calculation, and then the satellite position and the satellite speed are obtained through integration.
Preferably, the step B comprises the following steps:
step S4.1: according to the overall design constraint, giving a semi-major axis analytic solution a of the heavy rail interference track under the J2 low-order gravity fieldJ2Orbit dip angle analytic solution iJ2And a heavy track period T, a track turn number Q.
According toThe semi-major axis a of the heavy-rail interference orbit can be determined by the total constraints of load working power, satellite weight, carrying and launching capacity and the likeJ2;
Orbit dip analytic solution iJ2:
Track number of turns Q, heavy rail period T:
T=Tn×Q
wherein, TnIs a period of intersection, weIs the rotational angular velocity of the earth.
Step S4.2: and (3) resolving the orbit according to J2 perturbation, and proposing a J4 perturbation correction orbit based on a Newton iteration method. The research idea of the method is as follows:
step S4.2.1: selecting t according to the requirement of satellite task on ground track arrangement0Latitude and longitude lambda of time point under star0、And establishing the following functional relationship of longitude and latitude about the semi-major axis and the inclination angle after the track is repeated.
Wherein the content of the first and second substances,
M=n(t-t0)
G0is t0At time Greenwich mean sidereal time omega0Is t0The right ascension at the ascending crossing point of the moment,is J4The rate of ascension drift at the point of ascension under perturbation.
Step S4.2.2: and obtaining the following heavy rail interference orbit eccentricity and the initial value estimation of the argument of the near place by utilizing the constraint relation of the frozen orbit.
Step S4.2.3: as shown in the calculation flow of FIG. 2, firstly, the satellite t is used0Time ground track initial longitude and latitude lambda0、Taking the starting point as the point of integration of the heavy track period T to obtain T0Satellite ground track longitude and latitude lambda at + T momentn、Then calculating to obtain the longitude and latitude deviation delta lambda of the initial end of the heavy railn-λ0,Judging whether the deviation meets the heavy rail interference precision index or not; if the index is satisfied, outputting a semimajor axis and a tilt angle correction value aJ4、iJ4And if the iteration parameter is out of tolerance, the following parameter correction is carried out, and the integral judgment process is converted back until the iteration parameter meets the precision index.
ak=ak-1+Δak-1
ik=ik-1+Δik-1
Wherein the content of the first and second substances,
akfor the semi-major axis of the orbit at time k, ak-1Is the semimajor axis of the track at time k-1, ikFor the track inclination at time k, ik-1Is the inclination angle of the orbit at the moment of k-1;
step S4.2.4: t can be calculated by using the relationship between the semi-major axis and the inclination of the orbit and the longitude and latitude function of the satellite point in the step S4.2.10Time aJ4、iJ4Corresponding rising point right ascension omegaJ4Angle M close to the meanJ4。
As shown in fig. 3, the step C includes the following steps:
step S5.1: the problem of solving the track repeated nonlinear parameters in the high-order gravity field is converted into a multivariable and multi-target optimization problem, and the parameters are guided to be self-adaptively adjusted by combining target track characteristic information (freezing property and regression period). The optimization model is described below.
optimizing variables: [ Δ a, Δ e, Δ i, Δ Ω, Δ w, Δ M ]
Initial conditions: [ a ] AJ4,eJ3,iJ4,ΩJ4,w=90°,MJ4]
Constraint conditions are as follows:
delta a is correction of track semimajor axis, delta e is correction of track eccentricity, delta i is correction of track inclination angle, delta omega is correction of right ascension at track ascending intersection point, delta w is correction of amplitude at track perigee, delta M is correction of angle at track mean perigee,as a vector of the acceleration of the satellite,in order to be a satellite position deviation,for the satellite position vector at time T,is t0A time satellite position vector;
step S5.2: selecting individuals through a binary system tournament method, and performing crossing and variation to generate a new population;
step S5.3: calculating and updating a new population objective function value, namely the position and speed deviation of the satellite earth-fixed system;
step S5.4: generating a new combined population by a merging method, and carrying out non-dominant sorting;
step S5.5: selecting individuals to form a new generation of population through a displacement and elite retention strategy;
step S5.6: and skipping to the step S5.2, and circularly updating until the termination condition is met.
In the embodiment, the design input is the orbit height 6989.90km, and the longitude and latitude of the initial starting point of the satellite are 0.135 degrees S and 90.019 degrees W. The 90 × 90-order earth gravity field model of the EGM2008 model is selected for orbit recursion, and the initial epoch is 0 minute 0 second (UTCG) at 6 months, 1 day, 12 hours, 2023 years.
As shown in table 1, firstly, according to the design constraint, an analytic solution under perturbation of the regression trajectory J2 and regression characteristics are obtained according to step a; then obtaining a correction value under J4 perturbation according to the step B on the basis, and taking the correction value as an initial value of high-precision ground track repeated orbit parameter self-adaptive optimization design; and finally, according to the step C, combining the track freezing characteristic and the regression characteristic determined in the initial value solving process to perform parameter self-adaptive optimization of the high-precision ground track repeated track until the regression precision meets centimeter-level design requirements (shown in a table 2), and outputting a group of high-precision ground track repeated track parameters.
TABLE 1 high-precision ground track repeat orbit initial value and high-order optimization solution
TABLE 2 ground track position repeat accuracy
The invention provides a high-precision ground track repetitive track optimization system, which comprises:
a module A: and establishing a corresponding satellite orbit dynamics recursion model according to the requirement analysis of the earth gravity field non-spherical perturbation order.
And a module B: and (3) giving out heavy rail interference track parameters under a J2 low-order gravity field according to an analytical formula, and performing iterative calculation to obtain correction parameters under J4 perturbation, wherein the correction parameters are used as initial values of a high-precision ground track repeated track parameter self-adaptive setting algorithm.
And a module C: and according to the requirement of the repeated track precision, carrying out self-adaptive optimization setting on the target track parameter of the high-precision ground track repeated track parameter self-adaptive setting algorithm.
Those skilled in the art will appreciate that, in addition to implementing the system and its various devices, modules, units provided by the present invention as pure computer readable program code, the system and its various devices, modules, units provided by the present invention can be fully implemented by logically programming method steps in the form of logic gates, switches, application specific integrated circuits, programmable logic controllers, embedded microcontrollers and the like. Therefore, the system and various devices, modules and units thereof provided by the invention can be regarded as a hardware component, and the devices, modules and units included in the system for realizing various functions can also be regarded as structures in the hardware component; means, modules, units for performing the various functions may also be regarded as structures within both software modules and hardware components for performing the method.
The foregoing description of specific embodiments of the present invention has been presented. It is to be understood that the present invention is not limited to the specific embodiments described above, and that various changes or modifications may be made by one skilled in the art within the scope of the appended claims without departing from the spirit of the invention. The embodiments and features of the embodiments of the present application may be combined with each other arbitrarily without conflict.
Claims (10)
1. A high-precision ground track repetitive track optimization method is characterized by comprising the following steps:
step A: according to the requirement analysis of the earth gravity field non-spherical perturbation order, establishing a corresponding satellite orbit dynamics recursion model;
and B: the method comprises the steps of providing heavy rail interference track parameters under a J2 low-order gravity field according to an analytical formula, and obtaining correction parameters under J4 perturbation through iterative calculation to serve as initial values of a high-precision ground track repeated track parameter self-adaptive setting algorithm;
and C: and according to the requirement of the repeated track precision, carrying out self-adaptive optimization setting on the repeated track parameters of the high-precision ground track.
2. A high accuracy ground track repeat trajectory optimization method as claimed in claim 1, wherein said heavy trajectory accuracy is less than 0.01 m.
3. The high-precision ground track repetitive track optimization method according to claim 1, wherein the step A comprises:
taking the numerical simulation test result as a basis, comprehensively considering the ground track repetition precision and the orbit recursion computation amount, establishing a satellite orbit dynamics model corresponding to the following steps, and adopting an expression method of an earth gravity field potential function:
wherein the content of the first and second substances,is the earth-centered position vector of the satellite;is the function of the field potential of the earth gravity;
the gravity field potential function comprises two parts of earth central gravity and earth non-spherical gravity, and if the earth is considered as a rigid body and an equatorial plane is superposed with a basic plane of an epoch inertial system, the gravity field potential function is expanded into a series form in the earth central inertial system as follows:
wherein mu is the gravitational constant of the earth, r is the earth center distance of the satellite, Cn0And CnmAnd SnmAll are spherical harmonic coefficients, ReIs the equatorial radius,The geocentric latitude and the lambda are geocentric longitude which are obtained by calculating a position vector in a satellite geostationary system;andthe terms are Legendre and associated Legendre polynomials respectively, are correction parts of a real earth gravitational potential pair uniform sphere and comprise a band harmonic term and a field harmonic term;
and obtaining coefficient values of each order of a gravitational field potential function through an earth gravitational field table, calculating to obtain a perturbation force expression under a satellite geostationary system, and further integrating to obtain the position and the speed of the satellite.
4. The high-precision ground track repetitive track optimization method of claim 3, wherein the step B comprises:
step S4.1: according to the overall design constraint, giving a semi-major axis analytic solution a of the heavy rail interference track under the J2 low-order gravity fieldJ2Orbit dip angle analytic solution iJ2A heavy rail period T and a rail turn number Q;
according to the load working power, the satellite weight, the carrying and launching capacity and other overall constraints, the semi-major axis a of the heavy-rail interference orbit can be determinedJ2;
Orbit dip analytic solution iJ2:
Track number of turns Q, heavy rail period T:
T=Tn×Q
wherein, TnIs a period of intersection, weThe rotational angular velocity of the earth;
step S4.2: according to the J2 perturbation analysis orbit, a J4 perturbation correction orbit based on a Newton iteration method is provided, and the method comprises the following steps:
step S4.2.1: selecting t according to the requirement of satellite task on ground track arrangement0Latitude and longitude lambda of time point under star0、Establishing a functional relation of longitude and latitude about a semi-major axis and an inclination angle after the following tracks are repeated;
wherein the content of the first and second substances,
M=n(t-t0)
G0is t0At time Greenwich mean sidereal time omega0Is t0The right ascension at the ascending crossing point of the moment,is J4Perturbation of the rising point right ascension drift rate;
step S4.2.2: obtaining the following heavy rail interference track eccentricity e by utilizing the constraint relation of the frozen trackJ3And estimating the initial value of the argument w of the near place:
step S4.2.3: firstly, with the satellite t0Time ground track initial longitude and latitude lambda0、Taking the starting point as the point of integration of the heavy track period T to obtain T0Satellite ground track longitude and latitude lambda at + T momentn、Then calculating to obtain the longitude and latitude deviation delta lambda of the initial end of the heavy railn-λ0,Judging whether the deviation meets the heavy rail interference precision index or not; if the index is satisfied, outputting a semimajor axis and a tilt angle correction value aJ4、iJ4If the iteration parameter is out of tolerance, the following parameter correction is carried out, and the integral judgment process is converted back again until the iteration parameter meets the precision index;
ak=ak-1+Δak-1
ik=ik-1+Δik-1
wherein the content of the first and second substances,
akfor the semi-major axis of the orbit at time k, ak-1Is the semimajor axis of the track at time k-1, ikFor the track inclination at time k, ik-1Is the inclination angle of the orbit at the moment of k-1;
step S4.2.4: calculating to obtain t by using the functional relationship between the semi-major axis and the inclination angle of the track and the longitude and latitude of the subsatellite point in the step S4.2.10Time aJ4、iJ4Corresponding rising point right ascension omegaJ4Angle M close to the meanJ4。
5. The high accuracy ground track repetitive track optimization method of claim 4, wherein said step C comprises:
step S5.1: the method comprises the steps of converting a track repeated nonlinear parameter solving problem under a high-order gravity field into a multivariable and multi-target optimization problem, guiding parameter self-adaptive setting by combining target track characteristic information, and describing an optimization model as follows:
optimizing variables: [ Δ a, Δ e, Δ i, Δ Ω, Δ w, Δ M ]
Initial conditions: [ a ] AJ4,eJ3,iJ4,ΩJ4,w=90°,MJ4]
Constraint conditions are as follows:
Δ a is correction amount of track semimajor axis, Δ e is correction amount of track eccentricity, and Δ i is correction amount of track eccentricityThe track inclination angle correction quantity, delta omega is the track ascending intersection point right ascension correction quantity, delta w is the track perigee amplitude correction quantity, delta M is the track mean perigee angle correction quantity,as a vector of the acceleration of the satellite,in order to be a satellite position deviation,for the satellite position vector at time T,is t0A time satellite position vector;
step S5.2: selecting individuals through a binary system tournament method, and performing crossing and variation to generate a new population;
step S5.3: calculating and updating a new population objective function value, namely the position and speed deviation of the satellite earth-fixed system;
step S5.4: generating a new combined population by a merging method, and carrying out non-dominant sorting;
step S5.5: selecting individuals to form a new generation of population through a displacement and elite retention strategy;
step S5.6: and skipping to the step S5.2, and circularly updating until the termination condition is met.
6. A high-precision ground track repeat trajectory optimization system, comprising:
a module A: according to the requirement analysis of the earth gravity field non-spherical perturbation order, establishing a corresponding satellite orbit dynamics recursion model;
and a module B: the method comprises the steps of providing heavy rail interference track parameters under a J2 low-order gravity field according to an analytical formula, and obtaining correction parameters under J4 perturbation through iterative calculation to serve as initial values of a high-precision ground track repeated track parameter self-adaptive setting algorithm;
and a module C: and according to the requirement of the repeated track precision, carrying out self-adaptive optimization setting on the repeated track parameters of the high-precision ground track.
7. The high accuracy ground track repeat trajectory optimization system of claim 6, wherein the heavy track trajectory accuracy is less than 0.01 m.
8. The high accuracy ground track repetitive track optimization system of claim 6, wherein the module A comprises:
taking the numerical simulation test result as a basis, comprehensively considering the ground track repetition precision and the orbit recursion computation amount, establishing a satellite orbit dynamics model corresponding to the following steps, and adopting an expression method of an earth gravity field potential function:
wherein the content of the first and second substances,is the earth-centered position vector of the satellite;is the function of the field potential of the earth gravity;
the gravity field potential function comprises two parts of earth central gravity and earth non-spherical gravity, and if the earth is considered as a rigid body and an equatorial plane is superposed with a basic plane of an epoch inertial system, the gravity field potential function is expanded into a series form in the earth central inertial system as follows:
wherein mu is the gravitational constant of the earth, r is the earth center distance of the satellite, Cn0And CnmAnd SnmAll are spherical harmonic coefficients, ReIs the equatorial radius,The geocentric latitude and the lambda are geocentric longitude which are obtained by calculating a position vector in a satellite geostationary system;andthe terms are Legendre and associated Legendre polynomials respectively, are correction parts of a real earth gravitational potential pair uniform sphere and comprise a band harmonic term and a field harmonic term;
and obtaining coefficient values of each order of a gravitational field potential function through an earth gravitational field table, calculating to obtain a perturbation force expression under a satellite geostationary system, and further integrating to obtain the position and the speed of the satellite.
9. The high accuracy ground track repetitive track optimization system of claim 8, wherein the module B comprises:
module S4.1: according to the overall design constraint, giving a semi-major axis analytic solution a of the heavy rail interference track under the J2 low-order gravity fieldJ2Orbit dip angle analytic solution iJ2A heavy rail period T and a rail turn number Q;
according to the load working power, the satellite weight, the carrying and launching capacity and other overall constraints, the semi-major axis a of the heavy-rail interference orbit can be determinedJ2;
Orbit dip analytic solution iJ2:
Track number of turns Q, heavy rail period T:
T=Tn×Q
wherein, TnIs a period of intersection, weThe rotational angular velocity of the earth;
module S4.2: according to the J2 perturbation analysis orbit, a J4 perturbation correction orbit based on a Newton iteration method is provided, and the method comprises the following steps:
module S4.2.1: selecting t according to the requirement of satellite task on ground track arrangement0Latitude and longitude lambda of time point under star0、Establishing a functional relation of longitude and latitude about a semi-major axis and an inclination angle after the following tracks are repeated;
wherein the content of the first and second substances,
M=n(t-t0)
G0is t0At time Greenwich mean sidereal time omega0Is t0The right ascension at the ascending crossing point of the moment,is J4Perturbation of the rising point right ascension drift rate;
module S4.2.2: obtaining the following heavy rail interference track eccentricity e by utilizing the constraint relation of the frozen trackJ3And estimating the initial value of the argument w of the near place:
module S4.2.3: firstly, with the satellite t0Time ground track initial longitude and latitude lambda0、Taking the starting point as the point of integration of the heavy track period T to obtain T0Satellite ground track longitude and latitude lambda at + T momentn、Then calculating to obtain the longitude and latitude deviation delta lambda of the initial end of the heavy railn-λ0,Judging whether the deviation meets the heavy rail interference precision index or not; if the index is satisfied, outputting a semimajor axis and a tilt angle correction value aJ4、iJ4If the error is out of tolerance, the following parameter correction is performedAnd then the integral judgment process is switched back again until the iteration parameter meets the precision index;
ak=ak-1+Δak-1
ik=ik-1+Δik-1
wherein the content of the first and second substances,
akfor the semi-major axis of the orbit at time k, ak-1Is the semimajor axis of the track at time k-1, ikFor the track inclination at time k, ik-1Is the inclination angle of the orbit at the moment of k-1;
module S4.2.4: t is calculated by utilizing the functional relation between the semi-major axis and the inclination angle of the orbit and the longitude and latitude of the satellite point in the module S4.2.10Time aJ4、iJ4Corresponding rising point right ascension omegaJ4Angle M close to the meanJ4。
10. The high accuracy ground track repetitive track optimization system of claim 9, wherein the module C comprises:
module S5.1: the method comprises the steps of converting a track repeated nonlinear parameter solving problem under a high-order gravity field into a multivariable and multi-target optimization problem, guiding parameter self-adaptive setting by combining target track characteristic information, and describing an optimization model as follows:
optimizing variables: [ Δ a, Δ e, Δ i, Δ Ω, Δ w, Δ M ]
Initial conditions: [ a ] AJ4,eJ3,iJ4,ΩJ4,w=90°,MJ4]
Constraint conditions are as follows:
delta a is correction of track semimajor axis, delta e is correction of track eccentricity, delta i is correction of track inclination angle, delta omega is correction of right ascension at track ascending intersection point, delta w is correction of amplitude at track perigee, delta M is correction of angle at track mean perigee,as a vector of the acceleration of the satellite,in order to be a satellite position deviation,for the satellite position vector at time T,is t0A time satellite position vector;
module S5.2: selecting individuals through a binary system tournament method, and performing crossing and variation to generate a new population;
module S5.3: calculating and updating a new population objective function value, namely the position and speed deviation of the satellite earth-fixed system;
module S5.4: generating a new combined population by a merging method, and carrying out non-dominant sorting;
module S5.5: selecting individuals to form a new generation of population through a displacement and elite retention strategy;
module S5.6: and jumping to a module S5.2, and circularly updating until a termination condition is met.
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