CN103235870B - Take into account the sun synchronous orbit Inclination biased method of multitask height - Google Patents

Abstract

The present invention discloses the sun synchronous orbit Inclination biased method taking into account multitask height, according to the operating altitude H of subtask_j, calculate corresponding consideration J₄Item design meets the nominal inclination angle of sun synchronous orbit characteristicDragon's tail local time initial value uses general assignment LTDN⁰As input, it may also be useful to iteration method, calculate the first time subtask dragon's tail local time LTDN under a kind of Inclination biased amount �� i₁(t) and inclination angle i₁(t), and by the LTDN at the end of last subtask_j(T_j) and i_j(T_j) as the initial conditions of this subtask, according to the arrangement of j=1��N, complete the dragon's tail local time shift analysis of all subtasks piecemeal; Final taking �� i as the independent variable(s) of general assignment, in lifetime, dragon's tail local time drifts about positive and negative difference in magnitude as objective function, and when objective function value is minimum, the Inclination biased amount �� i obtained is preferred embodiment. The present invention can make general assignment during dragon's tail local time comprehensively drift about change minimum.

Description

Take into account the sun synchronous orbit Inclination biased method of multitask height

Technical field

The present invention relates to a kind of sun synchronous orbit Inclination biased method taking into account multitask height.

Background technology

Along with the development of spationautics and the lifting of industrial level, satellite increases life in-orbit gradually, and task object is changed into diversification by early stage unicity. Task design flexibly, it is desired to the particular feature of a certain track can be obtained, the disadvantageous effect owing to selecting difference to cause can be reduced again as far as possible.

Due to sun synchronous orbit have stable in-orbit with ground illumination condition, favourable for the energy of satellite, thermal control and on-board equipment operating mode, be therefore widely used in the low rail tasks such as remote sensing, detection and test. On the sun synchronous orbit of multitask height, remote sensing satellite can obtain different time resolving power and the geography information of different images quality, the sounding satellites such as Kennelly heaviside layer, magnetosphere, thermosphere and terrestrial gravitation can obtain the detection information of different heights, and the multiplex pattern of this kind star can improve the service efficiency of satellite greatly. Owing to sun synchronous orbit self is subject to the impact taking sun gravitation as main perturbation, dragon's tail local time as one of its important indicator is not invariable, need inclination angle is done certain passive pre-control in actual engineering uses, dragon's tail local time is made to remain within variation range little as far as possible, and the Inclination biased amount of different heights sun synchronous orbit is different, therefore for the sun synchronous orbit of multitask height, need according to constraint conditions such as task period, distribution spaces, Inclination biased is considered as a whole.

Summary of the invention

Technical problem to be solved by this invention is: provide a kind of sun synchronous orbit inclination angle for multitask height to plan as a whole biased optimization method, satellite is made to obtain the mission effectiveness of different heights, and the dragon's tail local-time variation in lifetime remains within minimum extent.

The technical scheme of the present invention is:

Taking into account a sun synchronous orbit Inclination biased method for multitask height, described multitask highly comprises the orbit altitude H of N subtask_j, j=1��N; The time interval of jth time shared by subtask is T_j-1��t��T_j, T₀=0, step is as follows:

(1) according to the orbit altitude H of subtask_jCalculate the sun synchronous orbit nominal inclination angle of this subtaskJ=1��N; Described nominal inclination angleFor at consideration J₄The nominal inclination angle of sun synchronous orbit characteristic is met under item design; J₄For the terrestrial gravitation four rank humorous term coefficient of band;

(2) according to nominal dragon's tail local time LTDN⁰The initial value of setting sun synchronous orbit Inclination biased amount �� i and convergence direction; And set Inclination biased amount adjustment step-length initial value; Described Inclination biased amount �� i is first time nominal inclination angle, subtask relatively, inclination angle of entering the orbitSun synchronous orbit Inclination biased amount;

(3) with Inclination biased amount �� i and nominal dragon's tail local time LTDN⁰As input, inclination angle i during iterative computation first time subtask₁Dragon's tail local time LTDN during (t) and for the first time subtask₁(t), t �� [0, T₁];

(4) from second time subtask, by the dragon's tail local time LTDN at the end of last subtask_j(T_j) and inclination angle i_j(T_j) as the initial conditions of this subtask, the dragon's tail local time LTDN during this subtask of iterative computation_j+1(t) and inclination angle i_j+1(t), T_j��t��T_j+1, until completing the dragon's tail local time during all subtasks and Dip countion;

(5) temporally sequential series dragon's tail local time LTDN during subtask each time_j(t), T_j-1��t��T_j, draw dragon's tail local time LTDN (t) during performing all subtasks under current Inclination biased amount �� i, 0��t��T_N; Dragon's tail local time LTDN (t) during all subtasks is subtracted nominal dragon's tail local time LTDN⁰Dragon's tail local time drift during obtaining all subtasks;

(6) during judging all subtasks, whether the absolute value of the difference of the absolute value of maximum value and the absolute value of minimum value of the drift of dragon's tail local time is less than 1s, if being less than 1s, then �� i now is the best Inclination biased amount �� i_f, proceed to step (7); If being not less than 1s, then recalculating �� i along described convergence direction, then returning step (3);

(7) with best Inclination biased amount �� i_fAs the Inclination biased amount that task starts, inclination angle when entering the orbit is

In described step (3), the termination condition of iterative computation is: t �� [0, T₁] all moment of interior (n+1)th cycle calculations are all satisfied in the same time relative to the phase of n-th cycle calculations

In described step (4), the termination condition of iterative computation is: T_j��t��T_j+1All moment of interior (n+1)th cycle calculations are all satisfied in the same time relative to the phase of n-th cycle calculations

$|{\mathrm{LTDN}}_{j+1}^{n+1}\left(t\right)-{\mathrm{LTDN}}_{j+1}^n\left(t\right)|<1s.$

The method that step (6) recalculates �� i along described convergence direction is as follows:

For track in the morning, judge whether the absolute value of the minimum value that dragon's tail local time is drifted about is greater than maximum value; If being not more than maximum value, then keeping current step-length constant, �� i before being subtracted this step-length and obtains new �� i; If the absolute value of minimum value is greater than maximum value, then changing step-length, new step-length is the step-length of an order of magnitude less of step-length before, by �� i before is added with step-length before and subtract new step-length and obtain new �� i;

For track in afternoon, judge whether the maximum value that dragon's tail local time is drifted about is greater than the absolute value of minimum value; If the absolute value being not more than minimum value, then keep current step-length constant, �� i before is added that this step-length obtains new �� i; If maximum value is greater than the absolute value of minimum value, then changing step-length, new step-length is the step-length of an order of magnitude less of step-length before, adds that new step-length obtains new �� i by the step-length before being subtracted by �� i before.

The present invention's advantage compared with prior art is: the inventive method be for multitask height sun synchronous orbit Inclination biased, it is possible to the dragon's tail local time during making general assignment comprehensively drift about change minimum. Comparing the Inclination biased method of existing single task role height, reducing the maintenance on other subsequent child task dragon's tail local time to greatest extent affects.

Accompanying drawing explanation

Fig. 1 is the schema of the inventive method;

Fig. 2 is the dragon's tail local time drift figure of single task role height after Inclination biased;

Fig. 3 is that the sun synchronous orbit inclination angle of multitask height is at biased and when only considering single height amount of bias dragon's tail local time drift figure;

Fig. 4 is the sun synchronous orbit Inclination biased amount optimum result of multitask height.

Embodiment

As shown in Figure 1, a kind of sun synchronous orbit Inclination biased method taking into account multitask height of the present invention, according to the operating altitude H of subtask_j, calculate corresponding consideration J₄Item design meets the nominal inclination angle of sun synchronous orbit characteristicDragon's tail local time initial value uses the nominal dragon's tail local time LTDN of general assignment selection⁰As input, it may also be useful to iteration method, calculate the first time subtask dragon's tail local time LTDN under a kind of Inclination biased amount �� i₁(t) and inclination angle i₁(t), and by the LTDN at the end of last subtask_j(T_j) and i_j(T_j) as the initial conditions of this subtask, according to the arrangement of j=1��N, complete the dragon's tail local time shift analysis of all subtasks piecemeal; Final taking �� i as the independent variable(s) of general assignment, in lifetime, dragon's tail local time drifts about positive and negative difference in magnitude as objective function, and when objective function value is minimum, the Inclination biased amount �� i obtained is preferred embodiment. Described multitask highly comprises the orbit altitude H of N subtask_j, j=1��N; The time interval of jth time shared by subtask is T_j-1��t��T_j, T₀=0.

Specifically comprise the steps:

(1) according to the orbit altitude H of subtask_jCalculate the nominal inclination angle of this subtaskJ=1��N; Described nominal inclination angleFor at consideration J₄The nominal inclination angle of sun synchronous orbit characteristic is met under item design.

Subtask operating altitude H_jCorresponding nominal inclination angleRelation between the two meets following condition.

$n_s=-{\mathrm{cosi}}_j^0\left(\frac{3J_2{R}_e^2}{2p^2}n\right)\{1+\left(\frac{3J_2}{2p^2}\right)\&lsqb;(\frac{3}{2}+\frac{1}{6}{e}^2+\sqrt{1-e^2})-{\sin }^2{i}_j^0(\frac{5}{3}-\frac{5}{24}{e}^2+\frac{3}{2}\sqrt{1-e^2})-O\&lsqb;\frac{J_4}{J_2^2}\&rsqb;\&rsqb;\}---\left(1\right)$

Wherein, p=a (1-e²),A=R_e+H_j, R_eFor earth semi-major axis, e is track excentricity, and �� is Gravitational coefficient of the Earth, J₂For the terrestrial gravitation two rank humorous term coefficient of band, J₄For the terrestrial gravitation four rank humorous term coefficient of band, n_sFor revolution of earth circular frequency,For earth aspherical gravitation four rank perturbation item.

As given H_jAfter e, it may be determined that corresponding nominal inclination angle, each subtask

(2) according to nominal dragon's tail local time LTDN⁰The initial value of setting sun synchronous orbit Inclination biased amount �� i and convergence direction; Described Inclination biased amount �� i is first time nominal inclination angle, subtask relatively, satellier injection inclination angleInclination biased amount. And set Inclination biased amount adjustment step-length initial value; Described adjustment step-length initial value is such as 0.1 degree.

Such as, as selection LTDN⁰During for track in the morning, the Initial value choice of �� i is+1⁰And select convergence direction to be negative, work as LTDN⁰During for track in afternoon, the Initial value choice of �� i is-1⁰And select convergence direction for just.

(3) with Inclination biased amount �� i and nominal dragon's tail local time LTDN⁰As input, it may also be useful to inclination angle i during iteration method calculating first time subtask₁Dragon's tail local time LTDN during (t) and for the first time subtask₁(t), t �� [0, T₁]��

Consider that the 3rd body sun Gravitational perturbation is on the impact at inclination angle, has following variable quantity.

$\frac{di}{dt}=-\frac{3}{16}\frac{n_s^2}{n}sin(i_1^0+\mathrm{\&Delta;}i){(1+{\mathrm{cosi}}^{*})}^{2}sin\left(2u^{*}\right)---\left(2\right)$

$i_1\left(t\right)=i_1^0+{\&Integral;}_0^{T_1}\frac{di}{dt}dt---\left(3\right)$

Wherein, i^*For ecliptic inclination angle, u^*=15 LTDN₁T () (first time calculates and gets LTDN₁(t)=LTDN⁰)��

Dragon's head right ascension velocity of variation is as follows with the variation relation at inclination angle and dragon's tail local time:

$\frac{d\mathrm{\&Omega;}}{dt}=\frac{3}{2}\frac{n_s^2}{n}{\mathrm{cosi}}_1\left(t\right)\{\left(\frac{3}{2}{\sin }^2{i}_1\right(t)-1)+\frac{1}{8}{(1+{\mathrm{cosi}}^{*})}^{2}cos\left(2u^{*}\right)\}---\left(4\right)$

The interact relation of dragon's tail local time is by the change of dragon's head right ascension:

${\mathrm{LTDN}}_1\left(t\right)={\mathrm{LTDN}}^0+\frac{1}{15}{\&Integral;}_0^{T_1}\frac{d\mathrm{\&Omega;}}{dt}dt---\left(5\right)$

To i₁(t) and LTDN₁T () carries out iterative computation, until t �� [0, T₁] phase of relative n-th cycle calculations of all moment of interior (n+1)th cycle calculations is all less than 1s in the same time.

$|{\mathrm{LTDN}}_1^{n+1}\left(t\right)-{\mathrm{LTDN}}_1^n\left(t\right)|<1s---\left(6\right)$

(4) from second time subtask, by the dragon's tail local time LTDN at the end of last subtask_j(T_j) and inclination angle i_j(T_j) as the initial conditions of this subtask, it may also be useful to iteration method calculates the dragon's tail local time LTDN during this subtask_j+1(t) and inclination angle i_j+1(t), T_j��t��T_j+1, until completing the dragon's tail local time during all subtasks and Dip countion.

Iterative computation process is all using given initial value as input, and the inclination angle that each calculating obtains after terminating and the dragon's tail local time next iteration of variation relation imparting in time, as new calculating input, constantly circulate until meeting stop condition. The coupled relation expression formula at dragon's tail local time and inclination angle is as follows:

$i_{j+1}\left(t\right)=f(i_{j+1}^0,i_j(T_j),{\mathrm{LTDN}}_j(T_j),{\mathrm{LTDN}}_{j+1}(t\left)\right)---\left(7\right)$

LTDN_j+1(t)=f (i_j+1(t))(8)

In described step (4), the termination condition of iterative computation is: for T_j��t��T_j+1Interior any instant t, all moment of (n+1)th cycle calculations are all satisfied in the same time relative to the phase of n-th cycle calculations $|{\mathrm{LTDN}}_{j+1}^{n+1}\left(t\right)-{\mathrm{LTDN}}_{j+1}^n\left(t\right)|<1s.$

(5) temporally sequential series dragon's tail local time LTDN during subtask each time_j(t), T_j-1��t��T_j, draw dragon's tail local time LTDN (t) during performing all subtasks under current Inclination biased amount �� i, 0��t��T_N. Dragon's tail local time LTDN (t) during all subtasks is subtracted nominal dragon's tail local time LTDN⁰Dragon's tail local time drift during can obtaining all subtasks.

(6) during judging all subtasks, whether the absolute value of the absolute value of maximum value of dragon's tail local time drift and the difference of the absolute value of minimum value is less than 1s; If being less than 1s, then �� i now is best Inclination biased amount �� i_f, proceed to step (7); If being not less than 1s, then recalculating �� i along described convergence direction, then returning step (3).

(7) best Inclination biased amount �� i to calculate_fAs the Inclination biased amount that task starts, inclination angle during satellier injection is

The method that described step (6) calculates �� i is as follows: for taking given initial value as+1⁰In track, judge whether the absolute value of the minimum value that dragon's tail local time is drifted about is greater than maximum value in the morning started; If being not more than maximum value, then keeping current step-length constant, �� i before being subtracted this step-length and obtains new �� i; If the absolute value of minimum value is greater than maximum value, step-length turns into the step-length (being namely original 1/10) of more decimal magnitude, by the calculation formula of this �� i is: the step-length of the step-length-Xin before �� i+.

For taking given initial value as-1⁰In orbit computation, first judge whether the maximum value that dragon's tail local time is drifted about is greater than the absolute value of minimum value in the afternoon started; If the absolute value being not more than minimum value, then keeping current step-length constant, the calculation formula of new �� i is: �� i before adds this step-length; If maximum value is greater than the absolute value of minimum value, then changing step-length, new step-length is the step-length (being namely original 1/10) of an order of magnitude less of step-length before, and the calculation formula of new �� i is: the step-length of the step-length before �� i-before+new.

For orbit computation in the morning, during beginning, the maximum of dragon's tail local time drift is just being worth the absolute value being greater than negative minimum (or not having negative value), then the adjustment step-length (such as 0.1 degree) of Inclination biased amount �� i remains unchanged; Along with the carrying out calculated, there will be the absolute value of minimum value and be greater than and maximum be just worth, now the adjustment step-length of �� i turns into the less step-length than a little order of magnitude before (being namely original 1/10), such as 0.01 degree.

The present invention, when surpassing in reverse occurs in the absolute value of dragon's tail local time drift maxima and minima, enters the less step size computation of a difference order of magnitude; Otherwise step-length is constant. This variable step size method can only use 4 kinds of step-lengths, and often kind of step size computation is no more than 10 times, Inclination biased amount can be accurate to ten thousand/and, counting yield significantly improves.

Embodiment

The satellite of 5 subtasks is had for certain, groundwork in 3 years lifetime is highly 645.333km, have and transfer to one day recurrence track for 2 times and be highly the ability on 568.127km, can realize regularly crossing that the calibration to equipment such as load corrects to complete in target range, or during earthquake emergency every day to the assessment of disaster scenarios it. The sequence of task arrangement is H₁=645.333km, H₂=568.127km, H₃=645.333km, H₄=568.127km, H₅=645.333km, when taking, length is respectively T₁=0.5 year, T₂=0.25 year, T₃=1.5 years, T₄=0.25 year, T₅=0.5 year, the nominal dragon's tail local time LTDN that general assignment is selected⁰=10:30AM.

Highly for the subtask of 645.333km accounts for the 5/6 of satellite life altogether, if all considering on this height according to the life-cycle, orbital inclination only needs positive bias 0.0396 �� that the dragon's tail local time drift value in 3 years can be made to be no more than �� 4.34 minutes, as shown in Figure 2. If this Inclination biased amount applies to above-mentioned 5 subtasks, then dragon's tail local time drift value will reach-4.45 hours at end of life, and effect that is basic and that do not carry out Inclination biased is suitable, as shown in Figure 3. Therefore for the sun synchronous orbit Inclination biased of multitask height, even if it is higher to account for the ratio in life-span with height subtask, the impact that still dragon's tail local time is drifted about and brought by other height subtasks very important.

The inventive method considers that taking into account the orbital inclination that multitask highly carries out is biased, it is possible to by minimum to drift value for the dragon's tail local time global optimization during performing all subtasks. By the Inclination biased optimization to above-mentioned 5 subtasks, when amount of bias is+0.5285 ��, the dragon's tail local time drift value in 3 years lifetime can be controlled in �� within 8.12 minutes, as shown in Figure 4.

The content not being described in detail in specification sheets of the present invention belongs to the known technology of those skilled in the art.

Claims (2)

1. taking into account a sun synchronous orbit Inclination biased method for multitask height, described multitask highly comprises the orbit altitude H of N subtask_j, j=1��N; The time interval of jth time shared by subtask is T_j-1��t��T_j, T₀=0, it is characterised in that, step is as follows:

(1) according to the orbit altitude H of subtask_jCalculate the sun synchronous orbit nominal inclination angle of this subtaskJ=1��N; Described nominal inclination angleFor at consideration J₄The nominal inclination angle of sun synchronous orbit characteristic is met under item design; J₄For the terrestrial gravitation four rank humorous term coefficient of band;

(2) according to nominal dragon's tail local time LTDN⁰The initial value of setting sun synchronous orbit Inclination biased amount �� i and convergence direction; And set Inclination biased amount adjustment step-length initial value; Described Inclination biased amount �� i is first time nominal inclination angle, subtask relatively, inclination angle of entering the orbitSun synchronous orbit Inclination biased amount;

(3) with Inclination biased amount �� i and nominal dragon's tail local time LTDN⁰As input, inclination angle i during iterative computation first time subtask₁Dragon's tail local time LTDN during (t) and for the first time subtask₁(t), t �� [0, T₁]; In described step (3), the termination condition of iterative computation is: t �� [0, T₁] all moment of interior (n+1)th cycle calculations are all satisfied in the same time relative to the phase of n-th cycle calculations

(4) from second time subtask, by the dragon's tail local time LTDN at the end of last subtask_j(T_j) and inclination angle i_j(T_j) as the initial conditions of this subtask, the dragon's tail local time LTDN during this subtask of iterative computation_j+1(t) and inclination angle i_j+1(t), T_j��t��T_j+1, until completing the dragon's tail local time during all subtasks and Dip countion; In described step (4), the termination condition of iterative computation is: T_j��t��T_j+1All moment of interior (n+1)th cycle calculations are all satisfied in the same time relative to the phase of n-th cycle calculations

$|{\mathrm{LTDN}}_{j+1}^{n+1}\left(t\right)-{\mathrm{LTDN}}_{j+1}^n\left(t\right)|<1s;$

(5) temporally sequential series dragon's tail local time LTDN during subtask each time_j(t), T_j-1��t��T_j, draw dragon's tail local time LTDN (t) during performing all subtasks under current Inclination biased amount �� i, 0��t��T_N; Dragon's tail local time LTDN (t) during all subtasks is subtracted nominal dragon's tail local time LTDN⁰Dragon's tail local time drift during obtaining all subtasks;

(6) during judging all subtasks, whether the absolute value of the difference of the absolute value of maximum value and the absolute value of minimum value of the drift of dragon's tail local time is less than 1s, if being less than 1s, then �� i now is the best Inclination biased amount �� i_f, proceed to step (7); If being not less than 1s, then recalculating �� i along described convergence direction, then returning step (3);

(7) with best Inclination biased amount �� i_fAs the Inclination biased amount that task starts, inclination angle when entering the orbit is $i_1^0+{\mathrm{\&Delta;i}}_f.$

2. a kind of sun synchronous orbit Inclination biased method taking into account multitask height according to claim 1, it is characterised in that, the method that step (6) recalculates �� i along described convergence direction is as follows:

For track in the morning, judge whether the absolute value of the minimum value that dragon's tail local time is drifted about is greater than maximum value; If being not more than maximum value, then keeping current step-length constant, �� i before being subtracted this step-length and obtains new �� i; If the absolute value of minimum value is greater than maximum value, then changing step-length, new step-length is the step-length of an order of magnitude less of step-length before, by �� i before is added with step-length before and subtract new step-length and obtain new �� i;

For track in afternoon, judge whether the maximum value that dragon's tail local time is drifted about is greater than the absolute value of minimum value; If the absolute value being not more than minimum value, then keep current step-length constant, �� i before is added that this step-length obtains new �� i; If maximum value is greater than the absolute value of minimum value, then changing step-length, new step-length is the step-length of an order of magnitude less of step-length before, adds that new step-length obtains new �� i by the step-length before being subtracted by �� i before.