CN103472849A - Satellite attitude maneuver tracking method based on cooperative target tracking in closed loop mode - Google Patents

Abstract

A satellite attitude maneuver tracking method based on cooperative target tracking in a closed loop mode includes the steps of firstly, determining emission time, theoretical flight path data and satellite orbit data of a cooperative target; secondly, calculating a relative position relationship between a satellite and the cooperative target, and expressing the position relationship through an azimuth angle and a pitch angle; thirdly, in the determined tracking time period, determining data which are about the azimuth angle and the pitch angle, uses time as a variable and are required for keeping the Z-axis of a satellite body to be coincide with a target visual axis at different moments; fourthly, conducting cubic polynomial fitting on the data about the azimuth angle and the pitch angle, and obtaining a fitting coefficient; fifthly, uploading the fitting coefficient, tracking starting time and tracking ending time through data blocks; sixthly, continuously adjusting a satellite attitude according to the orbit data of a satellite and according to the data blocks uploaded from the ground, and achieving tracking of the cooperative target; seventhly, enabling the satellite to return to an original flight state after completing curve tracking.

Description

The attitude of satellite maneuver tracking method of following the tracks of based on the closed loop mode cooperative target

Technical field

The present invention relates to a kind of attitude of satellite maneuver tracking ground moving target (target of interior emission of designated time), the method for a kind of Satellite Tracking moving-target in the time of emission in moving-target does not have according to the designated time (leading or delay).

Background technology

Attitude of satellite maneuver tracking cooperative target generally has two kinds of modes, i.e. quiet target following and tracking of maneuvering target.When the quiet target of attitude of satellite maneuver tracking, can be by the time of annotating longitude, latitude, the elevation of ground static target and start to follow the tracks of on satellite, tracking concluding time, the relative position Processing Algorithm such as passing of satelline target, track realize from motion tracking.But for tracking of maneuvering target, especially movement velocity moving-target faster, satellite will realize that attitude maneuver stares tracking to moving-target, must know the concrete orientation of concrete movement locus with the relative satellite of the target optical axis of target, could realize the motor-driven tracking of staring.Also have an important prerequisite, the moving-target that cooperation is followed the tracks of must be at the time point setting in motion of agreement, otherwise satellite only can start attitude maneuver according to the time point of original agreement, but now can not follow the tracks of target.

In order to overcome involutory some shortcomings of making tracking of maneuvering target of satellite under open loop situations, need to realize the method for Satellite Tracking cooperation moving-target under the closed loop state, allow moving-target the shifting to an earlier date or lag motion (or emission) in the regular hour section of cooperation, satellite still can be realized high-precision tracking of maneuvering target.

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 closed loop to realize the method for attitude of satellite maneuver tracking moving-target, stare the demand of function for moving-target according to existing satellite, pass through the mode of piecewise fitting target optical axis position angle coefficient for moving-target, in the situation that there is error in the setting in motion of the cooperative target moment (or target x time), by the mode of star ground closed loop, still can realize high-precision tracking of maneuvering target.

Technical solution of the present invention is: the attitude of satellite maneuver tracking method of following the tracks of based on the closed loop mode cooperative target, and step is as follows:

(1) obtain the x time of cooperative target, theoretical flight path data, and satellite is in the orbital data of cooperative target x time;

(2) calculate the relative position relation between satellite and cooperative target on ground; Described relative position relation adopts the target optical axis under the satellite orbit coordinate system to mean, the target optical axis points to cooperative target by satellite, and the direction vector of the target optical axis means with the position angle under the satellite orbit coordinate system and the angle of pitch;

(3), within the time period to the cooperation target following of drafting, determine not that the theory of described target optical axis direction vector is in the same time pointed to and decomposed to obtain take target optical axis bearing data and the pitch angle data that time t is variable; Described target optical axis bearing data and pitch angle data adopt the form of following the tracks of matched curve to mean, described tracking matched curve at least comprises that cooperative target is moved in advance, the cooperative target situation of setting in motion, cooperative target time delay campaign in scope at the appointed time;

(4) the cubic polynomial matching is carried out respectively in tracking matched curve step (3) obtained, and obtains the fitting coefficient of cubic polynomial; Fitting coefficient should make the data fitting error minimum in whole tracking time section;

(5) fitting coefficient step (4) obtained, and satellite start to follow the tracks of cooperative target time, follow the tracks of the form of concluding time by data block and start front upper notes to satellite at tracking time, ground will be annotated to satellite on the orbital data of satellite simultaneously;

(6) before the cooperative target emission, satellite is according to the orbital data of self, the Z axis that utilizes satellite to point to control method control satellite body overlaps with the target optical axis of cooperative target x time, then according to the fitting coefficient of annotating on ground, the Z axis of adjusting satellite body overlaps with the cooperative target flight target optical axis constantly, realizes the attitude maneuver of cooperative target is followed the tracks of;

(7) the emission situation of ground Real-Time Monitoring cooperative target, if zero-time at the appointed time in error range, is not intervened, satellite is followed the tracks of the matched curve target following of cooperating according to former acquiescence; If ground-level finding target first motion time delays or leading, switch to the immediate tracking matched curve of cooperative target x time satellite by instruction and followed the tracks of;

(8), after having followed the tracks of, satellite returns to the state of flight of following the tracks of between cooperative target.

The present invention's advantage compared with prior art is: the inventive method has proposed definite method and the Attitude Tracking method of the target optical axis for moving-target (especially high dynamic moving-target), utilizes position angle, the angle of pitch of the relative satellite of moving-target to carry out the sensing of the objective definition optical axis; Due to during tracking of maneuvering target, directly upload position angle, the angle of pitch equal angles data of target, data volume excessive (about 1Mbytes), by three sections cubic term matching optical axis angles, only will annotate satellite (the not upper angle of annotating) on the cubic term coefficient of matching, data volume reduces greatly, mode by segmentation (three sections) matching, realized the description of the high-precision target optical axis, effectively reduced error of fitting, the target error of fitting is less than 0.1 °, has improved the pointing accuracy of target following.In the situation that the setting in motion of the cooperative target moment (target x time) shifts to an earlier date or postpones, by selecting different tracking matched curves, the close-loop feedback that forms star ground is controlled, and still can realize high-precision cooperative target sensing.

The accompanying drawing explanation

The FB(flow block) that Fig. 1 is the inventive method;

Fig. 2 is that the target optical axis is described schematic diagram;

Fig. 3 is position angle curve schematic diagram and graph of errors;

Fig. 4 is angle of pitch curve schematic diagram and graph of errors;

Fig. 5 satellite closed cycle is followed the tracks of the sequential chart of dynamic cooperative target;

Fig. 6 is time optimal attitude maneuver figure;

Target tracking accuracy curve when Fig. 7 satellite does not carry out the curve switching;

Fig. 8 satellite carries out the target tracking accuracy curve after the curve switching.

Embodiment

During the present invention is directed under closed loop mode the attitude of satellite follow the tracks of cooperative target (as target or the hot spot region, ground of launching) within the designated time, the passing of satelline is calculated the target optical axis position data of above annotating in advance and is adjusted in real time attitude of satellite maneuver tracking target, carries out a kind of Attitude Tracking method that moving-target or quiet target are stared.Even cooperative target shifted to an earlier date or delay voltage than the setting in motion of the agreement moment (or target x time), still can realize high-precision target following.

As shown in Figure 1, be the FB(flow block) of the inventive method, key step is as follows:

At first, by mission planning and the flow arrangement of ground application system layout cooperative target tracing task.After mission planning and flow process form, ground application system, target emission coefficient and satellite system are according to orbital phase and the extrapolation result of satellite, determine the target emission period that satellite can be followed the tracks of, also determine (absolute time T0 launch time of target, be also that satellite starts to carry out the start time that attitude maneuver is followed the tracks of cooperative target), definite principle is to guarantee that satellite can pass through target launching site overhead during cooperative target is followed the tracks of, and the motor-driven angle of the attitude of satellite in tracing process (satellite body+Z axis is with respect to the angle of orbital coordinate system+Z axis) is greater than 30 ° and is less than 70 °.It is to avoid satellite to cross top to target to follow the tracks of that setting is greater than the purpose of 30 ° as far as possible, and when crossing top and follow the tracks of, the motor-driven angular velocity of satellite is excessive, can influence curve fitting precision and attitude pointing accuracy; According to general moonlet orbit altitude, when satellite body+Z axis reaches 70 ° with respect to the angle of orbital coordinate system+Z axis, satellite has pointed to the zone in cold space, earth edge, and the motor-driven angle of satellite is excessive, the part sensor is unavailable can affect control accuracy, therefore can be by angle limits in the scope that is less than 70 °.Wherein, the initial point of satellite body system is centroid of satellite, and X-axis is pointed to the satellite flight direction, and Z-direction is consistent with the camera boresight direction, and Y-axis becomes right-handed system with X-axis, Z axis.In satellite state of flight over the ground, the satellite body coordinate system is consistent with orbital coordinate system.

Before the cooperative target of plan starts to follow the tracks of, ground application system is annotated accurate orbital data on satellite.Simultaneously, ground application system starts to follow the tracks of constantly the relative position relation with cooperative target according to accurately orbital data, the flight path data of target, satellite, determines the position angle, the angle of pitch of target location and the corresponding data (for example corresponding position angle of per second, angle of pitch value) of tracking time.Again according to position angle, the angle of pitch and time data, carry out respectively three sections cubic term matchings of position angle, the angle of pitch, generation comprises multinomial coefficient, waypoint position, starts the upper notes data block of tracking time T0, tracking time length, data check, and ground application system will be annotated satellite at the beginning tracking time on data block.After satellite is received data block, data block is resolved, in satellite transit to T0 constantly, is started to calculate in real time position angle, the angle of pitch angle of the target optical axis, and by momenttum wheel controls the satellite body coordinate system+Z axis sensing target boresight direction.The now cooperative target on ground emission, along the trajectory parameters flight of planning, satellite starts it is carried out to Attitude Tracking.

The data block of above-mentioned upper notes is cooperative target data blocks in designated time (as the T0 moment) emission situation, for the closed loop that realizes system is followed the tracks of, realization is in target emission in advance or in the delay situation, satellite still can carry out high precision tracking to cooperative target, also needs many curves of upper notes simultaneously.Every curve respectively with postpone after x time or the x time that shifts to an earlier date corresponding.

Position angle and the angle of pitch of cooperative target are defined as follows:

Position angle: by optical axis vector, in orbital coordinate system, (initial point is at centroid of satellite, X-axis is pointed to the satellite working direction, and Y-axis is track normal negative direction, and Z axis becomes right-handed system with X, Y-axis) projection of XOY face, axis of projection and+angle between X-axis is position angle, sign is followed the right-hand rule.

The angle of pitch: cry again angular altitude, the optical axis and the optical axis angle between the axis of projection of XOY face, symbol is consistent with the symbol of Z axis.

The definition of the target optical axis as shown in Figure 2, is calculated target vector

(three axle components under orbital coordinate system) are:

$\stackrel{\→}{O}=\left[\begin{array}{c}{O}_x\\ O_y\\ O_z\end{array}\right]=\left[\begin{array}{c}\cos (\mathrm{\β}\×\mathrm{\π}/180)\×\cos (\mathrm{\α}\×\mathrm{\π}/180)\\ \cos (\mathrm{\β}\×\mathrm{\π}/180)\×\sin (\mathrm{\α}\×\mathrm{\π}/180)\\ \sin (\mathrm{\β}\×\mathrm{\π}/180)\end{array}\right],$ Wherein α is position angle, and β is the angle of pitch

The eye tracking curve adopts the mode (three sections matchings) of piecewise fitting, according to the time length of theory locus (powered phase tracking time general<180s), adopt the method for global optimizing (be the mode of pointwise traversal, guarantee total error of fitting minimum) to find out two waypoints.Concrete method is: starting ergodic state, suppose that first waypoint is the 2nd point (the 2nd second), second waypoint traverses n point (n means total tracking time length) from the 3rd always, records the maximum error of fitting value of curve of each traversal.Then first waypoint continues to traverse the 3rd point, and second waypoint traverses the n point from the 4th always; The like, until first waypoint traverses the n-1 point.In the maximum error of fitting minimum of all state lower curves, corresponding first waypoint and second waypoint is exactly the waypoint that will look for.Whole section angle-data is divided into to three sections and carries out respectively matching, be divided into three groups of fitting coefficients, the form of cubic term Coefficient Fitting optical axis location positioning is as follows:

First paragraph

α ₁=A ₁₁t ³+B ₁₁t ²+C ₁₁t+D ₁₁

β ₁=A ₁₂t ³+B ₁₂t ²+C ₁₂t+D ₁₂

Second segment

α ₂=A ₂₁t ³+B ₂₁t ²+C ₂₁t+D ₂₁

β ₂=A ₂₂t ³+B ₂₂t ²+C ₂₂t+D ₂₂

The 3rd section

α ₃=A ₃₁t ³+B ₃₁t ²+C ₃₁t+D ₃₁

β ₃=A ₃₂t ³+B ₃₂t ²+C ₃₂t+D ₃₂

In formula, each meaning of parameters is as follows:

α ₁β ₁, α ₂β ₂, α ₃β ₃: position angle, the angle of pitch of every section in three segmentations;

A: the cubic term coefficient of every section angle matching;

B: the quadratic term coefficient of every section angle matching;

C: the Monomial coefficient of every section angle matching;

D: the constant term of every section angle matching.Wherein footmark the first bit digital means the sequence number of segmentation, and second-order digit is for distinguishing position angle or the angle of pitch.

Before cooperative target is followed the tracks of, the matching of many curves need to be carried out in ground.In target setting in motion (or the target emission) time range allowed, curve (0 curve) by default, target delay certain hour (as postponed 15s) setting in motion, ground is according to the relative angle relation after target delay and between satellite, re-start position angle, angle of pitch matching, form new matched curve; Target travel (target emission) the in advance situation of (as 10s in advance) is similar, also needs to re-start position angle, angle of pitch matching forms new matched curve.Ground is by the nominal curve, in advance many curves such as curve, delay curve once all are uploaded to satellite, and according to the memory capacity of satellite, ground can generate the curve of more kinds of operating modes.After the target emission, the situation that the launch time of the real-time measurement target in ground and the launch time of nominal postpone or shift to an earlier date, if surpass 5s time delay, but be less than 15s, satellite should corresponding aircraft pursuit course 2, Curve selection instruction (trade-off curve 2 is followed the tracks of) is annotated on ground on T2 is before the time, and satellite is transitioned into curve 2 from current nominal aircraft pursuit course (0 curve), restarts aim curve and follows the tracks of.If ground monitoring is leading launch time to target, the mode that sends instruction is similar.If ground monitoring, did not send instructions to target launch time within the time range of nominal, satellite is given tacit consent to according to 0 curve and is carried out.

The sequential chart of track following (the delay emission situation of take is example) as shown in Figure 5.The implication of the several moment sign representatives in sequential chart is as follows:

Former T0: under the state of open-loop tracking, the x time of ground system and target emission coefficient agreement;

New T0: the actual transmission of target constantly, may shift to an earlier date or postpone with respect to former T0;

T1: receive on satellite that ground-launched Curve selection instruction constantly;

T2: satellite starts the time that curve is followed the tracks of, and is also the UTC time in the curve corresponding data piece of Curve selection instruction.

Fig. 3, Fig. 4 have provided respectively position angle, the actual angle curve of the angle of pitch and the curve after matching, and provided the calculated value of waypoint position and error of fitting, if adopt single hop matching rather than piecewise fitting, in angle, there is the position error of fitting of flex point obviously to strengthen.In upper notes data, as long as will annotate on the data of coefficient A, the B of matching, C, D, common upper notes data block format is shown in Table 1.The factor mainly comprised in table 1 is: the content of packet comprise length, the curve of the indications of packet, valid data selection marker, start the time point of start time that attitude maneuver follows the tracks of, tracking time end point, every section position angle, the angle of pitch, every section position angle, angle of pitch fitting coefficient value, verification and data.

Table 1 target tracking data piece note on formats

Annotate 1): Curve selection herein is masked as at 0～2 o'clock, and corresponding 0～2 amounts to 3 curves respectively, wherein:

0 curve: mean that target is allowing emission in the time interval (± 5s) launch time;

1～2 curve: mean the target emission in advance or postpone the new matched curve over the 5s emission, delay relatively former T0 launch time of target generally is no more than 15s.

Annotate 2):

On ground, in advance to before starting to follow the tracks of after sending data block on star, ground is by sending the parameter instruction of " Curve selection X " (X gets 0～2) band, realize one of them the selection of 3 curves of upper notes, if do not send instruction, on star acquiescence according to 0 curve execution;

After obtaining target vector, according to the attitude of pointing to control method and obtain satellite body relative orbit coordinate system, control celestial body+Z axis overlaps with the target vector axle.When starting from initial attitude (absolute orientation attitude or Direct to the sun) at satellite to follow the tracks of to the target optical axis, satellite will take the mode of optimal path, shortest time to carry out the attitude maneuver tracking.Motor-driven in order to realize time optimal, adopt the leg-of-mutton path in Fig. 6 motor-driven, even celestial body carries out attitude motion with maximum angular acceleration, treat that the half that the attitude maneuver angle approaches targeted attitude reduces speed now, when approaching targeted attitude, satellite is accurately controlled, after satellite is followed the tracks of cooperative target, according to the optical axis orientation of calculating, in each control cycle according to shortest path, the mode that mean angular velocity is followed the tracks of is carried out the position angle of optical axis target, the lasting tracking of the angle of pitch, until tracking time finishes, satellite returns over the ground or to the day initial attitude.

When not needing to carry out the curve switching, only by the targeted target tracking accuracy of satellite in 0 curve tracking situation as shown in Figure 7; Receiving ground surface curve switching command, after satellite carries out the curve switching, the targeted tracking accuracy simulation result of satellite as shown in Figure 8.This shows, adopt the inventive method can obtain the closed loop high precision tracking to cooperative target.

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

Claims (1)

1. the attitude of satellite maneuver tracking method of following the tracks of based on the closed loop mode cooperative target is characterized in that step is as follows:

(1) obtain the x time of cooperative target, theoretical flight path data, and satellite is in the orbital data of cooperative target x time;

(2) calculate the relative position relation between satellite and cooperative target on ground; Described relative position relation adopts the target optical axis under the satellite orbit coordinate system to mean, the target optical axis points to cooperative target by satellite, and the direction vector of the target optical axis means with the position angle under the satellite orbit coordinate system and the angle of pitch;

(3), within the time period to the cooperation target following of drafting, determine not that the theory of described target optical axis direction vector is in the same time pointed to and decomposed to obtain take target optical axis bearing data and the pitch angle data that time t is variable; Described target optical axis bearing data and pitch angle data adopt the form of following the tracks of matched curve to mean, described tracking matched curve at least comprises that cooperative target is moved in advance, the cooperative target situation of setting in motion, cooperative target time delay campaign in scope at the appointed time;

(4) the cubic polynomial matching is carried out respectively in tracking matched curve step (3) obtained, and obtains the fitting coefficient of cubic polynomial, and fitting coefficient should make the data fitting error minimum in whole tracking time section;

(5) fitting coefficient step (4) obtained, and satellite start to follow the tracks of cooperative target time, follow the tracks of the form of concluding time by data block and start front upper notes to satellite at tracking time, ground will be annotated to satellite on the orbital data of satellite simultaneously;

(6) before the cooperative target emission, satellite is according to the orbital data of self, the Z axis that utilizes satellite to point to control method control satellite body overlaps with the target optical axis of cooperative target x time, then according to the fitting coefficient of annotating on ground, the Z axis of adjusting satellite body overlaps with the cooperative target flight target optical axis constantly, realizes the attitude maneuver of cooperative target is followed the tracks of;

(7) the emission situation of ground Real-Time Monitoring cooperative target, if zero-time at the appointed time in error range, is not intervened, satellite is followed the tracks of the matched curve target following of cooperating according to former acquiescence; If ground-level finding target first motion time delays or leading, switch to the immediate tracking matched curve of cooperative target x time satellite by instruction and followed the tracks of;

(8), after having followed the tracks of, satellite returns to the state of flight of following the tracks of between cooperative target.

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