CN102298540B - Method for scheduling task with preferential comprehensive benefit - Google Patents

Abstract

The invention discloses a method for scheduling a task with a preferential comprehensive benefit, which comprises the following steps: dividing a task area into stripes; calculating the best observing time of each task; judging whether the current task conflicts with the task arranged at last if the current task is arranged at the best observing time point according to the attitude maneuver time between the current task and the task arranged at last; if so, determining that the current task dose not need to be foreseen and can not be arranged, and if not, determining that the current task is foreseen, so as to acquire the foresight result; for the task which has a reserved foreseen result and influences the subsequent tasks, judging whether the current task can be arranged in a visible time window of the current task, and if not, processing the next task; and writing the current task which can be arranged at the best observing time point or in the visible window into a satellite action sequence; and finally outputting the processing results of all tasks to be used as the task scheduling results.

Description

The method for scheduling task that a kind of comprehensive benefit is preferential

Technical field

The invention belongs to satellite mission planning and scheduling field, relate to a kind of Satellite Mission Scheduling method.

Background technology

The rapid attitude maneuver imaging satellite can be realized the Various Complex imaging pattern by the rapid attitude maneuver ability.Compare with the traditional earth observation satellite that adopts the substar imaging, the rapid attitude maneuver ability has increased the observation airplane meeting of satellite to target greatly, thereby has stronger observing capacity.Each imaging pattern of rapid attitude maneuver imaging satellite all is accompanied by the operations such as a plurality of attitude maneuvers, camera switch machine, and these operations form the steering order sequence that front and back link up.Because instruction is various, can't guarantee the reliability of instruction layout and upper notes and the real time problems that instruction is carried out, therefore must set up cover mission planning and a dispatching system, finish the automatic analysis ﹠ process of observation mission in enormous quantities.

Task scheduling for the ease of the rapid attitude maneuver imaging satellite, observation mission is carried out pre-service, comprise with Task-decomposing be a plurality of can be by the atomic task finished of observation once, namely be divided into a plurality of single task bands, calculate visible time window, observation duration, the Observable chance etc. of each band.

Method for scheduling task is the core of mission planning and dispatching system, because Satellite Mission Scheduling is a very complicated combinatorial optimization problem, even it is less to work as the task number, the optimum solution that wants the problem of trying to achieve also is very difficult, the scale of problem is usually so that the complete formula of enumerating method is infeasible, therefore Incompletely algorithm (or approximate data) has all been adopted in nearly all existing research, such as people such as Bensana in 1996 and the article " Exact and Approximate Methods for the Daily Management of an Earth Observing Satellite " and " Earth Observing Satellite Management " delivered in 1999, study the scheduler routine problem of SPOT-5 satellite, compared respectively complete searching algorithm (depth-first search, dynamic programming, Russian Doll Search) and not exclusively searching algorithm (greedy search, tabu search) calculated performance under the different scales problem-instance.The result shows, when problem scale is little, obtain an optimum solution in the time of adopting complete searching algorithm to lack, but when problem scale is larger, adopt complete searching algorithm just can not within rational time, obtain the solution of problem, and tabu search can obtain a satisfactory solution of problem within rational time.Pemberton is in " Towards scheduling over-constrained remote sensing satellites " literary composition that the 2nd international space planning and scheduling meeting in 2000 delivered, a kind of method to extensive problem iterative has been proposed, its basic thought is at first according to certain rule all observation requirementses to be sorted, n one group, with all observation requirements groupings, then all adopt Complete Algorithm to try to achieve optimum solution by order of packets to the observation requirements in every group.In scheduling process, the scheduling result of dividing into groups previously will be as the constraint condition of back packet scheduling.

Also have in addition some for the method for scheduling task of the application design of satellite in orbit, in " A Photo Album of Earth:Sched uling LANSDAT 7 Mission Daily A ctivities " literary composition of delivering in calendar year 2001 such as William Potter and John Gasch, the derivation algorithm of Landsat 7 satellite resource scheduling problems has been discussed, its main thought is after the demand of considering long-term Global survey task and other tasks, with the task subdivision of satellite to every day.The substep of finding the solution of scheduler routine problem carries out: at first calculate all scene informations that satellite can collect in 48 hours, then based on the scene selection factor scene is screened, default priority to scene is adjusted, discharge scheduling scheme by time and priority orders according to admittedly depositing capacity again, when admittedly depositing when being finished, do not consider the follow-up work of low priority, just replace low priority task with high-priority task when only occurring the task of high priority.R.Sherwood etc. have delivered respectively " Using ASPEN to automate EO-1activity planning " and " Iterative planning for spacecraft operations using the ASPEN system " at 1998 and 1999, adopt the ASPEN system that task scheduling and arrangement are carried out in the daily routines of EO-1 satellite.ASPEN has adopted a kind of local search algorithm based on revising, and its basic thought is at first to generate an initiating task scheduling scheme, then constantly clears up conflict by adjusting variable-value.

All there is certain limitation in existing dispatching method, can not satisfy well practical application request, is mainly manifested in:

First, the everything of most of method for scheduling task hypothesis satellites is instantaneous finishing, but satellite remote sensor generally all has side-sway degree of freedom and the pitching degree of freedom of one dimension or two dimension, carrying out when specifying the observation mission of terrain object, can obtain larger visible time window or better image quality by side-sway or the certain angle of pitching.The motor-driven time that needs consumption can not ignore of satellite side-sway automotive or pitching, and the size of this time span and side-sway or luffing angle and the attitude maneuver ability of satellite are relevant, traditional dispatching method does not consider that satellite carries out the attitude maneuver time between the different observation missions, causes easily the disconnection of plan and reality;

Second, aspect the conflict judgement and choice of task, existing method take the expression modeling technique of Traditional Man intelligent scheduling problem as the basis, is carried out unified Modeling to satellite fields basically, then problem is converted to single constraint planning problem, utilizes the constraint solving technology to find the solution.The deficiency of this method is to cause problem scale larger owing to the complicacy of constraint, and it is long to find the solution difficulty height, time.For example in the ASPEN system, because the conflict identification and the resolution rule that adopt are cumbersome, its solution efficiency is lower, and in the application of EO-1, can only dispatch every day to 4 tasks, is difficult to satisfy the requirement of multi-task scheduling;

The 3rd, existing dispatching method is associated with concrete applied satellite mostly, and the design of model is closely related with concrete satellite borne equipment, does not have generality and versatility.

In addition, traditional dispatching method supposes that usually observed object all is point target, can ignore to the observation duration of task.The rapid attitude maneuver imaging satellite is by the rapid attitude maneuver performance of whole star, can realize the imaging pattern of Various Complex, such as multi-ribbon joining image-forming and continuous strip imaging etc., the observed object that the rapid attitude maneuver imaging satellite is faced is not only point target, also comprises regional aim, rectangular band target etc., in general, target is larger, and the observation time that needs is just longer, therefore the observation duration of task can not be ignored again, otherwise will cause planning the fully disconnection with actual conditions.Traditional dispatching method is inapplicable for the rapid attitude maneuver imaging satellite, can't satisfy the demand of rapid attitude maneuver imaging satellite task scheduling.

Summary of the invention

Technology of the present invention is dealt with problems and is: overcome the deficiencies in the prior art, provide a kind of comprehensive benefit preferential Satellite Mission Scheduling method, can satisfy the needs of rapid attitude maneuver imaging satellite task scheduling.

Technical solution of the present invention is: the method for scheduling task that a kind of comprehensive benefit is preferential, and step is as follows:

(1) according to the camera fabric width mission area is divided band;

(2) according to the maximum angle of pitch of satellite and maximum roll angle and the taskbar information Calculation of Satellite visible time interval [t to each band ₀, t _n], reject the visible time interval of nothing and time interval in the task in shadow zone, ground; Visible time interval [the t of each band ₀, t _n] by the visible time interval [t of satellite to these four summits of band ₁, t ₂] _k, k=1,2,3,4 seek common ground and reject behind the time interval in shadow zone, ground obtains; Satellite is determined by the maximum angle of pitch and the maximum roll angle of satellite the visible time interval on the single summit of band; Then according to the priority of zero hour of visible time window, with all task rankings, obtain task sequence TaskList;

(3) the observation duration T of each task band among the employing Secant Method calculation task sequence TaskList _Last, T _LastFor the summit of observing at first from this band begins to finish duration to the summit of the last observation of this band;

(4) according to visible time window and observation duration, obtain the observation moment t of the optimal imaging quality of each task _Best

(5) according to the attitude maneuver time between current task and last the arrangement task, if judge that current task is arranged in best observation time point, arranged task whether to conflict with last, if conflict, current task need not be looked forward to the prospect and can not be arranged, and turns step (10); If do not conflict, turn step (6);

(6) obtain the prediction task groups Group of current task, judging whether current task and task in the prediction task groups exist conflicts, if do not conflict, turns step (8), if there is conflict, turns step (7); Described prediction task groups Group is can execute the task in whole or in part after the current task that come among the task sequence TaskList;

(7) accept or reject current task according to the rule of setting, turn step (9) if current task is rejected; If current task is retained, turn step (8);

(8) be arranged in its best observation moment point if calculate current task, whether the next task of current task also can be arranged in the best observation moment point of this next task, if can, turn step (11), if can not, step (9) turned;

(9) judge whether current task can be arranged in the visible time window of this current task, if can, step (11) turned; If can not, turn step (10)

(10) next task among the Processing tasks sequence TaskList turns step (5); If all tasks among the task sequence TaskList all are disposed, turn step (12)

(11) attitude maneuver of satellite being carried out current task moves and observes action to write the satellite action sequence, turns step (10);

(12) reason that can not finish of output satellite action sequence and the task of not arranging is as the result of task scheduling.

The present invention's advantage compared with prior art is:

(1) the inventive method faces the task One's name is legion for the task scheduling of rapid attitude maneuver imaging satellite, the characteristics that problem scale is larger, adopt the mode of prediction that task is analyzed comparison, determine whether to arrange current task, the prediction step-length is set according to actual conditions by the user, and the conflict that has not only effectively solved between the task is judged and choice, and process is simple, computing velocity is fast, can satisfy Large-scale Optimization Problems for the constraint of algorithm time complexity;

(2) the rapid attitude maneuver imaging satellite possesses the Various Complex imaging pattern, and attitude maneuver is frequent between the task, and the time of expending is different, and observed object is not of uniform size, and the observation duration also has than big difference.The inventive method is according to the specifying information of satellite and task, calculate the attitude maneuver time between accurate task, according to the accurate task observation duration, judge whether task exists conflict again, improve the precision of scheduling, satisfied the needs of rapid attitude maneuver imaging satellite task scheduling;

(3) the inventive method is applicable to the planning of wall scroll band task and the mixing of multi-ribbon task, has stronger versatility;

(4) the inventive method is at first with the mid point of task arrange at visible time window, to obtain the observed image of best in quality, if influential to follow-up work, then with this task arrange in visible time window near the previous moment point that has arranged task, the comprehensive benefit that is embodied as image quality and task quantity is maximum, performance rapid attitude maneuver imaging satellite dynamical advantage, and the design of all models do not rely on concrete satellite, has stronger versatility.

Description of drawings

Fig. 1 is the process flow diagram of the inventive method;

Fig. 2 is the visible time window calculation flow chart of the present invention;

Fig. 3 is that the present invention judges the process flow diagram whether prediction task groups and current task conflict;

Fig. 4 is the present invention accepts or rejects current task according to rule process flow diagram.

Embodiment

As shown in Figure 1, the flow process of the inventive method comprises: 1. the mission area band is divided; 2. the position of Calculation of Satellite and speed; 3. Calculation of Satellite is to the visible time interval of each task band; 4. calculate the observation duration to mission area; 5. calculate best observation moment point; 6. judge whether current task (processing of task) is looked forward to the prospect; 7. judge whether the prediction task groups exists with current task and conflict; 8. accept or reject current task according to rule; 9. judge whether current task can be arranged in the best time point; 10. calculate the impact on follow-up work; 11. whether judge current task can be arranged in the visible time window; 12. judge whether to arrange current task; 13. arrangement current task; 14. output task scheduling result.The detailed step of the inventive method is as follows:

One, the mission area band is divided

Usually, the observation mission zone is described by the longitude and latitude on a plurality of summits, these summits is connected successively namely obtain mission area.Among the present invention, adopt following method that mission area is divided into the band that is parallel to satellite orbit, be convenient to satellite and implement observation:

1. from Satellite roll off the production line, as width, do the parallel lines that star rolls off the production line take substar camera fabric width (satellite side-sway angle as camera fabric width) at 0 o'clock, until cover mission area; It is the set of substar (the vertical projection point that satellite position point is gone up at the earth's surface;on the face of the globe) that star rolls off the production line;

2. do the vertical line that Satellite rolls off the production line from each summit of mission area, and calculate the distance between the intersection point, two the longest intersection points of distance are respectively L1 and L2 between the note intersection point, and the mission area summit corresponding with L1 is D1, and the mission area summit corresponding with L2 is D2;

3. connect respectively L1 and D1, L2 and D2 obtain and the roll off the production line intersection point of parallel lines of step 1 culminant star, consist of tetragonal 4 intersection points and namely form a task band, thus mission area are divided;

4. select to cover fully one or more task bands of mission area, as the elementary cell of mission planning and scheduling.

Two, the position of Calculation of Satellite and speed

Employing is to orbital position and the speed of satellite under the J2000 inertial coordinates system in the method forecast limiting time section of dynamics of orbits equation numerical value Integration Solving.

According to the orbital tracking of satellite, can extrapolate the orbital position R under the task scheduling initial time J2000 inertial coordinates system _SatWith speed V _Sat, adopt again the Cowell method to find the solution dynamics of orbits equation (selecting Gauss perturbed motion equation), obtain the orbital position R of satellite under the J2000 inertial coordinates system in the limiting time section _SatWith speed V _SatGauss perturbed motion equation and Cowell method have detailed explanation in " spacecraft orbit is theoretical " (Liu Linzhu, 2000) book that National Defense Industry Press publishes.The J2000 inertial coordinates system defines the document that sees reference " Additional perturbation due to the change of coordinate system and reference frame are selected problem in the earth satellite motion " (" space science journal " the 2nd phase of the 28th volume in 2008, author Liu Lin, Tang Jingshi).

Three, Calculation of Satellite is to the visible time interval of each task band

To each band, the orbital position R that obtains according to second portion _SatWith speed V _SatCalculate the attitude angle that each discrete moment point satellite points to each band summit, according to attitude of satellite maneuvering range each discrete moment point is traveled through again, obtain the visible time window of each band, according to the result of calculation of target sun altitude, reject the observation window in the shadow zone, ground at last.The below describes with the example that is calculated as of a band.

1. according to the orbital position R under the J2000 coordinate system _SatWith speed V _Sat, calculate the attitude angle on each each summit of moment point satellite sensing band in the limiting time section.The below only describes with the example that is calculated as of a point.The orbital position R of known satellite _Sat, speed V _Sat, the earth longitude and latitude of terrain object point

And Coordinated Universal Time(UTC) UTC time t.At first according to the earth longitude and latitude of impact point, calculate the constantly position vector R of impact point under the J2000 inertial coordinates system of t _{T, f}(t), then according to R _{T, f}(t) with satellite t position vector R constantly _Sat, obtain the attitude angle that t moment satellite points to this impact point.Concrete steps are as follows:

Terrain object is put the earth longitude and latitude be converted into the earth's core longitude and latitude

Computing formula is:

λ _c＝λ _d，

Wherein

The expression compression of the earth, then calculate impact point the earth's core distance:

R _e=6378.140km is the terrestrial equator radius.

Be tied to the transition matrix R of J2000 inertial coordinates system according to UTC Time Calculation body-fixed coordinate system _If(t), computing method have a detailed description in " spacecraft orbit is theoretical " (Liu Linzhu, 2000) that National Defense Industry Press publishes.By coordinate transform, obtain the position vector of impact point under the J2000 inertial coordinates system:

R _x(α), R _y(α), R _z(α) represent respectively primitive transformation matrix around the rotation of x, y, z axle:

$R_x\left(\mathrm{\α}\right)=\left[\begin{array}{ccc}1& 0& 0\\ 0& \cos \mathrm{\α}& \sin \mathrm{\α}\\ 0& -\sin \mathrm{\α}& \cos \mathrm{\α}\end{array}\right],$ $R_y\left(\mathrm{\α}\right)=\left[\begin{array}{ccc}\cos \mathrm{\α}& 0& -\sin \mathrm{\α}\\ 0& 1& 0\\ \sin \mathrm{\α}& 0& \cos \mathrm{\α}\end{array}\right],$ $R_z\left(\mathrm{\α}\right)=\left[\begin{array}{ccc}\cos \mathrm{\α}& \sin \mathrm{\α}& 0\\ -\sin \mathrm{\α}& \cos \mathrm{\α}& 0\\ 0& 0& 1\end{array}\right]$

Then calculate the vector of satellite directed towards ground impact point under the J2000 inertial coordinates system:

R _f(t)＝R _T，f(t))-R _sat

With vector R _f(t) transform to the satellite orbit coordinate system by the J2000 inertial coordinates system:

$R_o\left(t\right)=R_{\mathrm{oi}}{R}_f\left(t\right)=\left(\begin{array}{c}{v}_x\left(t\right)\\ v_y\left(t\right)\\ v_z\left(t\right)\end{array}\right)$

Wherein, R _OiExpression J2000 inertial coordinate is tied to the transition matrix of satellite orbit coordinate system.Above-mentioned body-fixed coordinate system definition, satellite orbit Coordinate system definition and J2000 inertial coordinate are tied to the conversion derivation of satellite orbit coordinate system and see " satellite orbit and attitude dynamics and control " (Zhang Renwei writes, 1998) that publishing house of BJ University of Aeronautics ﹠ Astronautics publishes.

Crab angle is 0 o'clock, according to geometric relationship between the attitude Eulerian angle, obtains satellite to the observation attitude angle of target (turning order is 312):

$\left[\begin{array}{c}\mathrm{yaw}\left(t\right)\\ \mathrm{roll}\left(t\right)\\ \mathrm{pitch}\left(t\right)\end{array}\right]=\left[\begin{array}{c}\\ 0\\ \arcsin \left(\frac{v_x\left(t\right)}{\left|R_o\left(t\right)\right|}\right)\\ -\arctan \left(\frac{v_y\left(t\right)}{v_z\left(t\right)}\right)\end{array}\right]$

Yaw in the following formula (t), roll (t) and pitch (t) represent that respectively satellite points to the corresponding relation of time t and crab angle, roll angle and the angle of pitch in the attitude angle of impact point.

2. each the moment point satellite that obtains according to attitude of satellite maneuvering range and step 1 points to the attitude angle on each summit of band, and Calculation of Satellite is to the visible time interval [t on each summit of band ₁, t ₂] _k, k=1,2,3,4.

Satellite is subject to the attitude maneuver ability of satellite to the observation of target, so only has in the attitude maneuver scope of the targeted attitude of satellite at satellite, could carry out observation mission.For k summit,

T represents the time range that limits, if corresponding attitude angle [yaw roll pitch] satisfies | and roll|≤roll _Max, | pitch|≤pitch _Max, roll wherein _Max, pitch _MaxThe maximum roll angle of expression satellite and the maximum angle of pitch, then t ∈ [t ₁, t ₂] _k, i.e. [t ₁, t ₂] _kSet for the t that satisfies above-mentioned condition.Calculation process as shown in Figure 2.

3. according to the visible time interval [t of satellite to each summit of band ₁, t ₂] _k, k=1,2,3,4, Calculation of Satellite is to the visible time interval [t of band ₀, t _n].

To the visible time interval [t of satellite to each summit ₁, t ₂] _k, k=1,2,3,4 seek common ground, and namely obtain satellite to the visible time interval [t of band ₀, t _n].

4. according to ground sun altitude result of calculation, reject the time interval in the shadow zone, ground.

[t between the visible range that calculates of step 3 generally ₀, t _n] have a plurality of solutions, wherein between the part visible range in the shadow zone, ground, can't satisfy the image-forming condition of optical camera, should give rejecting.

[t between the visible range that step 3 is obtained ₀, t _n], a bit calculate the sun altitude ε of this moment point observed object from wherein optional, if ε＜0, then this is rejected in the shadow zone, ground, otherwise keeps.

Sun altitude is relevant with the time, and computation process is seen " spacecraft flight principle of dynamics " (Xiao Yelun writes, nineteen ninety-five) that the Yuhang Publishing House publishes.

5. obtain the visible time window [t of all mission areas ₀, t _n] after, according to the t zero hour of this window ₀Priority, with all task rankings, the task sequence TaskList that is arranged in chronological order.

Four, calculate the observation duration of each task band

The observation duration of band, namely from beginning to observe the duration that finishes observation, depend on the length of band.To a multi-ribbon task, because therefore the equal in length of all bands only needs an optional band to calculate, can obtain the observation duration of all bands.To each band, the satellite that at first obtains according to the step 1 of third part points to the attitude angle on each summit, adopt again Secant Method to calculate beginning observation time and the end observation time of band, obtain the observation duration of band, judge at last whether the visible time window of band can comprise the observation duration of band, if can not, then this task can not be carried out.The below describes as an example of a band example:

1. each the moment point satellite that obtains according to the step 1 of third part points to the attitude angle on each summit of band, [the t that obtains in the step 2 of third part ₁, t ₂] _k, k=1, in 2,3,4, adopting Secant Method to calculate the angle of pitch is 0 o'clock, satellite points to the time on each summit of band.

Satellite determines visible time of target attitude maneuver ability by satellite, and satellite is changed to 0 to the observation angle of pitch of fixed target by positive maximal value in the rail motion process, become negative maximal value by 0 again, also namely at the visible time interval [t of summit k ₁, t ₂] _kOn, satellite is at first t ₁The angle of pitch be roll _Max, 1 t in the end ₂The angle of pitch be-roll _Max, therefore interval [t ₁, t ₂] _kIn the satellite angle of pitch must be arranged is 0 moment point, namely as Pitch (t ₁) Pitch (t ₂)＜0 o'clock,

And satisfy Pitch (t _p)=0 adopts Secant Method can obtain t _p

Secant Method (also claiming secant method) is to find the solution complex nonlinear equation a kind of numerical solution commonly used, and its advantage is that speed of convergence is very fast, and the rank of speed of convergence are at least 1.618, and has avoided Newton method to need the deficiency of computing function derivative.Secant Method has detailed explanation in " numerical analysis " (Yan Qingjin writes, 2000) book that publishing house of BJ University of Aeronautics ﹠ Astronautics publishes.

2. because satellite must start from certain summit to the observation of band, also end at certain summit, therefore according to the visible time of satellite to each summit, can determine satellite to the beginning observation time of band and finish observation time.

With t _pAccording to the sequencing ordering, the note time the earliest is T _Start, the time the latest is T _End, represent respectively the beginning observation time of band and finish observation time.

3. calculate the lasting observation time of band according to following formula

T _last＝T _end-T _start

Five, calculate best observation moment point t _Best

Divide the result according to band, task is divided into wall scroll band and multi-ribbon task, for wall scroll band task, calculates best observation moment point according to following step (), for the multi-ribbon task, adopt process of iteration to calculate best observation moment point according to step (two).

(1) the best of calculating wall scroll band task is observed moment point

Satellite depends on side-sway and the pitching maneuverability of satellite to the Observable time interval of intended target, in whole Observable time interval, image quality present rise first after downward trend, reach the highest at the mid point of Observable time interval.Therefore for wall scroll band task, image quality the best when the observation of band mid point is overlapped with the mid point of Observable time interval constantly, namely

$t_{\mathrm{best}}+\frac{T_{\mathrm{last}}}{2}=t_0+\frac{t_n-t_0}{2}$

So have

$t_{\mathrm{best}}=\frac{t_n+t_0-T_{\mathrm{last}}}{2}$

(2) process of iteration is calculated the best observation moment point of multi-ribbon task

For the multi-ribbon task, get the union of the Observable time interval of all bands, the Observable time as whole task, be designated as equally [t ₀, t _n].Starting point t with the Observable time interval ₀Be initial solution, calculate the attitude maneuver time of bar interband and the execution time of whole task, then adopt the best observation moment point of process of iteration calculation task, concrete steps are as follows:

1. what make task begins constantly t of observation _B0=t ₀

2. according to t _B0Calculate the attitude maneuver time t of bar interband _m ⁱ, i=1 ..., N-1, N are the number of band, t _m ⁱBe the attitude maneuver time between band i and the band i+1.The below is only with the attitude maneuver time between band 1 and the band 2

The example that is calculated as describe.

What the beginning observation time of band 1 was task begins constantly t of observation _B0, at first according to the observation duration T of band 1 _Last1, obtain the moment t of the complete band 1 of moonscope _End1, calculate again t _End1The attitude of the complete band 1 of constantly moonscope

As the reference attitude of attitude maneuver, obtain attitude maneuver time between band 1 and the band 2 by iteration, concrete steps are as follows:

(1) is the attitude maneuver time

An empirical value is set;

(2) note

t _End1Be the observation concluding time of band 1

t _end1＝t _b0+T _last1

Result according to second portion obtains the constantly orbital position R of satellite of t _SatWith speed V _Sat

The orbital position, the speed that are engraved in during (3) according to satellite t under the J2000 coordinate system are calculated the attitude angle on constantly satellite sensing of t band 2 first Observable summits

Circular is with third part step 1;

(4) calculate

The motor-driven Euler's angle of rotation Δ Ω of the attitude of satellite in time.

Known satellite has been observed the attitude angle of band 1

Begin to observe the attitude angle of band 2 with satellite

Can obtain the Eulerian angle between these two vectors, namely satellite exists

Euler's angle of rotation Δ Ω in time, method is as follows:

Order

Vector V ₁With V ₂Dot product be the cosine value of Euler's angle of rotation Δ Ω, therefore can obtain Δ Ω according to following formula:

$\mathrm{\Δ\Ω}=\arccos \left(V_1^T{V}_2\right);$

(5) based on Satellite Attitude control power curve (Time _i, A _l), i=1,2,3 ..., adopt linear interpolation method Calculation of Satellite attitude maneuver The changing value Δ Ω of the Euler's angle of rotation after the time ^*

(6) allowable error of note ε for setting, order

If

Turn (7); If

Be the required attitude maneuver time, iteration finishes;

(7) adopt the Newton Algorithm equation

Turn step (2).Newton method has detailed explanation in " numerical analysis " (Yan Qingjin writes, 2000) book that publishing house of BJ University of Aeronautics ﹠ Astronautics publishes.

3. calculate the observation execution time T of whole task according to following formula, comprise the observation duration of all bands and the attitude maneuver time of bar interband,

$T=\underset{i=0}{\overset{N}{\mathrm{\Σ}}}{T_{\mathrm{last}}}^i+\underset{i=1}{\overset{N-1}{\mathrm{\Σ}}}{t_m}^i$

Wherein N is the band number that task comprises,

Be the attitude maneuver time between band i and the band i+1;

4. calculate t according to following formula _B1, t _B1When being T for observation execution time of task, the corresponding observation zero hour,

${\mathrm{<figure-callout\; id="1"\; label="t\; b"\; filenames="HSA00000523145100021.png"\; state="\{\{state\}\}">t</figure-callout>}}_b=t_0+\frac{t_n-t_0}{2}-\frac{T}{2}$

$=\frac{t_0+t_n-T}{2}$

5. calculate Δ t=t _B1-t _B0If, Δ t≤σ _t, σ _tBe the error of calculation of license, termination of iterations, best observation time t _Best=t _B1, otherwise, make t _B0=t _B1, turn step 2.

Six, judge whether current task is looked forward to the prospect

Task among the task sequence TaskList is processed successively.If current task Task (i) is first task among the task sequence TaskList, make t _End=0, attitude Equal the initial attitude of satellite

(input value); If current task Task (i) is not first task among the task sequence TaskList, can from the result of previous task, obtain the concluding time t that last has arranged task _End, and execute the attitude of satellite after the task

According to the attitude maneuver time between current task and last the arrangement task, whether judge to have arranged task to conflict with last, if conflict, current task need not be looked forward to the prospect and can not be arranged, current task is labeled as " with arranging task conflict ", turns the 12 part; If do not conflict, turn the 7th part.

The purpose of prediction is for when considering current task, considers that in advance it is on impact and the contingent conflict of follow-up observation mission, to raise the efficiency.

Concrete steps are as follows:

1. the attitude maneuver time t between calculation task _m

Computing method are identical with the middle attitude maneuver time of calculating between band of the 5th part (two).

2. judge current task whether with arrange task conflict

Note t=t _End+ t _m, according to t and best observation moment t _BestRelation, judge that current task and last have arranged task whether to conflict.

(1) if t≤t _Best, current task is not conflicted with arranging task, turns the 7th part;

(2) if t＞t _Best, current task with arrange task conflict, current task is labeled as " with arranging task conflict ", turn the 12 part.

Seven, judging whether the prediction task groups exists with current task conflicts

The prediction task groups is that the dense degree according to task, the execution efficient of algorithm etc. consider, from task sequence TaskList, choose the afterwards task groups of the task composition of some (being called prediction step-length M) of current task, be used for comparing with current task, reduce possible conflict.

Flow process as shown in Figure 3, concrete steps are as follows:

1. prediction step-length M is set, from task sequence TaskList, obtains M task behind the current task Task (i), put into the formation Group that looks forward to the prospect;

2. to the task Group (k) of prediction in the formation, k=1 ..., M, carry out:

(1) judges whether Group (k) conflicts with Task (i), judge current task consistent with the method that last has arranged task whether to conflict (having arranged task for last depending on Task (i)) in concrete grammar and the 6th part.If conflict turns (2); If do not conflict and k ≠ M, make k=k+1 turn 2, k=M and turn Session 9;

(2) judge whether Group (k) conflicts with last task that has arranged, judge that current task is consistent with the method that last has arranged task whether to conflict in concrete grammar and the 6th part.If do not conflict, turn the 8th part, if conflict then Group (k) can not arrange, make k=k+1, turn 2.

Eight, accept or reject current task according to rule

Choice rule during according to task conflict, Task (i) and Group (k) are compared, determine whether to arrange current task, specific rules is formulated as required, for example, arrange first the high task of priority, then arrange the less task of residue observation airplane meeting, arrange again short task of observation duration, etc.Priority is the input parameter of task scheduling, and Observable chance and observation duration etc. derives from pre-service.The below as shown in Figure 4, illustrates how to accept or reject task take above-mentioned rule as example:

1. the priority P RI (Group (k)) and the PRI (Task (i)) that compare Group (k) and Task (i):

(1) if PRI (Group (k))＞PRI (Task (i)), then Task (i) can not arrange, and is marked as " time conflict can't be finished ", turns the 12 part;

(2) if PRI (Group (k))＜PRI (Task (i)) needs the relatively size of k and M, if k＜M makes k=k+1, turn 2 of step 7, if k=M turns Session 9;

(3) if PRI (Group (k))=PRI (Task (i)) turns 2;

2. the observation duration of comparing Group (k) and Task (i):

(1) if T _Last(Group (k))＜T _Last(Task (i)), Task (i) can not arrange, and is marked as " time conflict can't be finished ", turns the 12 part;

(2) if T _Last(Group (k))＞T _Last(Task (i)), and k＜M make k=k+1, turn 2 of the 7th part, if k=M turns Session 9;

(3) if T _Last(Group (k))=T _Last(Task (i)), optional conduct person of being rejected in two tasks, if Task (i) is selected, then it is labeled as " time conflict can't be finished ", turn the 12 part, if Group (k) is selected, if k＜M makes k=k+1, turn 2 of the 7th part, if k=M turns Session 9;

Nine, judge whether current task can be arranged in the best time point

If current task can not be arranged in best observation moment point, turn the tenth part; If current task can be arranged in the best time point, make t _Begin=t _Best, turn the tenth part;

Ten, calculating is on the impact of follow-up work

Be arranged in best observation moment point t if calculate current task Task (i) _Best, whether next task Task (i+1) also can be arranged in its best observation moment point.

1. calculate the attitude maneuver time t between current task Task (i) and Task (i+1) _m', concrete grammar makes t with 1 of the 6th part _End'=t _Best+ T _Ob,

Substitute wherein tend and

2. judge whether Task (i+1) conflicts with Task (i)

Note t '=t _Best+ t _Ob+ t _m', according to the best observation moment t of t ' with Task (i+1) _Best' relation, judge whether Task (i+1) conflicts with Task (i).

(1) if t '≤t _Best', Task (i+1) does not conflict with Task (i), turns the 12 part;

(2) if t '＞t _Best', Task (i+1) conflicts with Task (i), turns the tenth part.

11, judge whether current task can be arranged in the visible time window

Note t=t _End+ t _m(t _mBe 1 result of calculation of the 6th part), according to t and t ₀, judge that current task and last have arranged task whether to conflict, then turn the 12 part:

1. if t≤t ₀, current task is not conflicted with arranging task, makes t _Begin=t ₀

2. if t ₀≤ t≤t+t _Last≤ t _n, current task is not conflicted with arranging task, makes t _Begin=t;

3. if t ₀≤ t≤t _n＜t+t _LastCurrent task with arrange task conflict, current task is labeled as " with arranging task conflict ";

4. if t _n≤ t, current task with arrange task conflict, current task is labeled as " with arranging task conflict ".

12, judge whether to arrange current task

If current task is labeled, turn the next task among the Processing tasks sequence TaskList, turn the 6th part; If current task is not labeled, turn the 13 part.

13, arrange current task

For wall scroll band task, the observation t finish time _e=t _Begin+ T _Last, for the multi-ribbon task, the observation t finish time _e=t _Begin+ t _m'+T _Last, t _m' be the attitude maneuver time sum of the bar interband of current task, circular is with 1 of the 6th part.

Arranged the concluding time t of task with last _EndIt is the attitude maneuver zero hour of satellite execution current task, with the observation moment t of current task _BeginFor observing the zero hour, attitude maneuver action and the observation action of satellite being carried out current task write satellite action sequence: t _EndTo t _End+ t _mBetween satellite carry out attitude maneuver, reach targeted attitude

Then at t _BeginConstantly begin observation, at t _eConstantly finish observation.

14, output task scheduling result

After handling all tasks among the task sequence TaskList, the reason that output satellite action sequence and being labeled of task can not be finished is as the result of task scheduling.

Embodiment

Consider a rapid attitude maneuver imaging satellite that runs on the sun synchronization circular orbit, epoch, July in 2009,00:00:00.000UTC on the 26th wink radical was semi-major axis 7051.2km constantly, 97.3087 ° of orbit inclinations, 249.758 ° of right ascension of ascending node, 0 ° of latitude argument.Attitude of satellite maneuvering range is pitch orientation and rotating direction ± 45 °, and appearance control ability is 0 °/15s, 15 °/25s, and 30 °/35s, 45 °/45s.

The geographical latitude and longitude information of target is as shown in table 1, and the longitude on four summits of each target and latitude are corresponding one by one in order.

The geographical longitude and latitude of table 1 target

The preferential method for scheduling task step of comprehensive benefit is as follows:

(1) the mission area band is divided

According to longitude and latitude and the sub-satellite point of camera fabric width, mission area, mission area is carried out band divide, it is as shown in table 2 to divide the result.

Table 2 mission area band is divided the result

(2) calculate visible time window

According to orbit elements of satellite, calculate 00:00:00.000UTC on July 27,00:00:00.000UTC to 2009 year on the 26th July in 2009 satellite orbital position, speed under the J2000 coordinate system in the time period, then calculate each whole second constantly satellite to the observation angle of each task.According to attitude of satellite maneuvering range, obtain its visibility window of satellite and task, result of calculation is as shown in table 3.

The visible time window of table 3 task

Task number	As seen the zero hour t 0	As seen the finish time t n
			1	03:51:26.397	03:54:51.815
2	03:55:14.229	03:58:37.684
			3	03:56:09.833	03:59:35.814
4	03:56:18.049	03:59:43.984
			5	03:56:28.176	03:59:51.465
6	03:56:57.775	04:00:22.775
			7	03:51:41.532	03:55:08.828
8	03:52:11.926	03:55:36.956
			9	03:54:10.381	03:57:36.511
10	03:57:16.509	04:00:39.41

The task sequence TaskList that arranges according to the zero hour of visible time window is: 1,7,8,9,2,3,4,5,6,10.

(3) the observation duration of calculation task

According to the attitude angle of satellite sensing task, adopt Secant Method to obtain the observation duration of task, the result is as shown in table 4.

The table 4 observation duration

Task number	Observation duration t last(s)
		1	1.944
2	(29.807 4 band)
		3	(28.194 4 band)
4	(32.359 4 band)
		5	(6.825 2 band)
6	1.775
		7	0.848
8	(9.875 2 band)
		9	(4.734 2 band)
10	(14.338 3 band)

(4) calculate best observation moment point

According to visible time window and the observation duration of task, the best observation moment point of calculation task, the result is as shown in table 5.

The best observation of table 5 constantly

Task number	Best observation is t constantly best
		1	03:53:08.134
2	03:56:56.062
		3	03:57:01.473
4	03:57:07.111
		5	03:59:21.252
6	03:58:39.388
		7	03:53:24.756

8	03:53:17.620
		9	03:55:39.008
10	03:58:58.466

(5) successively the task among the task sequence TaskList is processed

The below as current task, illustrates the idiographic flow of the inventive method with No. 3 tasks.

(6) judge whether current task is looked forward to the prospect

According to the order of TaskList sequence, No. 1, No. 7, No. 8, No. 9 and No. 2 tasks are processed, obtaining last arrangement task from the result of front is No. 2 tasks, it observes concluding time t _End=03:56:58.646, attitude of satellite when observation finishes

According to observation concluding time and the attitude of No. 2 tasks, Calculation of Satellite from Attitude maneuver is to the attitude maneuver time t of No. 3 tasks of observation _m=29.677s.

Because t=t _End+ t _m=03:57:28.323, t≤t _BestTherefore No. 3 tasks are not conflicted with No. 2 tasks, turn step (7).

(7) judge whether the prediction task groups exists with current task and conflict, and according to rule choice current task

Prediction step-length M=3 is set, and the prediction task groups is comprised of No. 4, No. 5 and No. 6 tasks.

The first step compares No. 4 tasks and No. 3 tasks.The observation concluding time t of No. 3 tasks _End=03:58:51.252, observation finishes attitude

Attitude maneuver time t between No. 3 tasks and No. 4 tasks _m=15.61s is for No. 4 tasks, t=t _End+ t _m=03:59:06.862, t ₀≤ t≤t _n＜t+t _Last, so No. 3 tasks and No. 4 task conflict.Judge that according to identical method No. 4 task is not conflicted with No. 2 tasks, therefore must between No. 3 tasks and No. 4 tasks, accept or reject according to rule.According to the order of rule, No. 3 task is identical with the priority of No. 4 tasks, and the Observable chance is also identical, and therefore the observation duration of No. 3 tasks gives up No. 4 task less than No. 4 tasks.

Second step compares No. 5 tasks and No. 3 tasks.The observation concluding time t of No. 3 tasks _End=03:58:51.252, observation finishes attitude

Attitude maneuver time t between No. 3 tasks and No. 5 tasks _m=15.63s is for No. 5 tasks, t=t _End+ t _m=03:59:06.882, t ₀≤ t＜t+t _Last≤ t _n, therefore No. 3 tasks are not conflicted with No. 5 tasks.

In the 3rd step, No. 6 tasks and No. 3 tasks are compared.The observation concluding time t of No. 3 tasks _End=03:58:51.252, observation finishes attitude

Attitude maneuver time t between No. 3 tasks and No. 6 tasks _m=16.08s, t=03:59:07.332, t ₀≤ t＜t+t _Last≤ t _n, No. 3 task is not conflicted with No. 6 tasks.

(8) judge whether current task can be arranged in the best time point

No. 3 task is not labeled, and can arrange, and makes t _Begln=t _Best=03:57:01.473 turns next step.

(9) calculating is on the impact of follow-up work

Next task among the task sequence TaskList is No. 4 tasks.If calculate No. 3 task arranges at the best observation moment point t _Best, the attitude maneuver time t between No. 3 tasks and No. 4 tasks _m'=15.61s, the best observation of No. 4 tasks is t constantly _Best'=03:57:07.111, t _Best+ t _Last+ t _m'＞t _Best', No. 3 tasks and No. 4 task conflict turn next step.

(10) judge whether current task can be arranged in the visible time window

According to step (3), the attitude maneuver time t between No. 2 tasks and No. 3 tasks _m=29.677s.

Because t=t _End+ t _m=03:57:28.323, t ₀≤ t≤t+t _Last≤ t _n, therefore No. 3 tasks are not conflicted with No. 2 tasks, can be arranged in the visible time window t _Begin=t turns next step.

(11) judge whether to arrange current task

No. 3 task is not labeled, and can arrange, and turns next step.

(12) arrange current task

No. 3 task is 4 band tasks, and the attitude maneuver time that calculates the bar interband is respectively: 28.56s, 27.249s and 23.582s, so t _m'=79.391s, the observation t finish time _e=t _s+ t _m'+t _Last=03:59:15.908.

With t _End=03:56:58.646 is the attitude maneuver zero hour that satellite is carried out No. 3 tasks, t _s=03:57:28.323 is for observing the zero hour, and attitude maneuver action and the observation action of satellite being carried out current task write the satellite action sequence: satellite carries out attitude maneuver between the 03:56:58.646 to 03:57:28.323, reaches targeted attitude

Then constantly begin observation at 03:57:28.323, constantly finish observation at 03:59:15.908.

(13) output task scheduling result

After handling all tasks among the task sequence TaskList, output satellite action sequence (as shown in table 6), and the reason (as shown in table 7) that can not finish of being labeled of task are as the result of task scheduling.

Table 6 satellite action sequence

The task that table 7 can't be finished

Task number	The reason that can't finish
		4	" time conflict can't be finished "
5	" time conflict can't be finished "
		6	" time conflict can't be finished "

The content that is not described in detail in the instructions of the present invention belongs to those skilled in the art's known technology.

Claims (1)

1. method for scheduling task that comprehensive benefit is preferential is characterized in that step is as follows:

(1) according to the camera fabric width mission area is divided band;

(2) according to the maximum angle of pitch of satellite and maximum roll angle and the taskbar information Calculation of Satellite visible time interval [t to each band ₀, t _n], reject the visible time interval of nothing and time interval in the task in shadow zone, ground; Visible time interval [the t of each band ₀, t _n] by the visible time interval [t of satellite to these four summits of band ₁, t ₂] _k, k=1,2,3,4 seek common ground and reject behind the time interval in shadow zone, ground obtains; Satellite is determined by the maximum angle of pitch and the maximum roll angle of satellite the visible time interval on the single summit of band; Then according to the priority of zero hour of visible time window, with all task rankings, obtain task sequence TaskList;

(3) the observation duration T of each task band among the employing Secant Method calculation task sequence TaskList _Last, T _LastFor the summit of observing at first from this band begins to finish duration to the summit of the last observation of this band;

(4) according to visible time window and observation duration, obtain the observation moment t of the optimal imaging quality of each task _Best

(5) task among the task sequence TaskList is processed successively, if current task Task (i) is first task among the task sequence TaskList, made t _End=0, attitude

Equal the initial attitude of satellite

If current task Task (i) is not first task among the task sequence TaskList, can from the result of previous task, obtain the concluding time t that last has arranged task _End, and execute the attitude of satellite after the task

According to the attitude maneuver time between current task and last the arrangement task, if judge that current task is arranged in best observation time point, arranged task whether to conflict with last, if conflict, current task need not be looked forward to the prospect and can not be arranged, and turns step (10); If do not conflict, turn step (6);

(6) obtain the prediction task groups Group of current task, judging whether current task and task in the prediction task groups exist conflicts, if do not conflict, turns step (8), if there is conflict, turns step (7); Described prediction task groups Group is can execute the task in whole or in part after the current task that come among the task sequence TaskList;

(7) accept or reject current task according to the rule of setting, turn step (9) if current task is rejected; If current task is retained, turn step (8);

(8) be arranged in its best observation moment point if calculate current task, whether the next task of current task also can be arranged in the best observation moment point of this next task, if can, turn step (11), if can not, step (9) turned;

(9) judge whether current task can be arranged in the visible time window of this current task, if can, step (11) turned; If can not, turn step (10)

(10) next task among the Processing tasks sequence TaskList turns step (5); If all tasks among the task sequence TaskList all are disposed, turn step (12)

(11) attitude maneuver of satellite being carried out current task moves and observes action to write the satellite action sequence, turns step (10);

(12) reason that can not finish of output satellite action sequence and the task of not arranging is as the result of task scheduling.

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