CN105005310A - Attitude adjusting method in imaging along oblique strip - Google Patents

Abstract

The invention provides an attitude adjusting method in imaging of an oblique strip. The attitude adjusting method has high practicability in high-resolution imaging tasks for imaging sub-satellite point tracks such as roads, coast lines, border lines which are not parallel along an oblique strip. The invention aims at a problem of no dynamic attitude adjusting method in imaging along the oblique strip, and provides the attitude adjusting method in which the sliding speed of a photographing point along a preset oblique strip is set and then imaging is performed through dynamically tracking the sliding of the photographing point through the satellite attitude and finally drift angle compensation is performed, thereby realizing imaging along a preset target oblique strip. The attitude adjusting method of the invention can satisfy a requirement of satisfying different imaging tasks through changing the sliding speed of the photographing point along the oblique strip, such as quick push-broom imaging which can realize an emergency imaging task and slow push-broom imaging with prolonged exposure time for improving an imaging quality.

Description

A kind of attitude adjusting method along the imaging of slanted bar band

Technical field

The present invention relates to spacecraft attitude adjustment technology field, particularly a kind of attitude adjusting method along the imaging of slanted bar band, for adjusting along the attitude maneuver realizing camera carrier in given slanted bar band imaging process.

Background technology

Traditional static imaging causes primarily of orbital motion owing to pushing away speed of sweeping the floor, and its imaging track thinks parallel sub-satellite track, and one section of track is called a band, the joining image-forming that can realize rectangular area by strips mosaic.But, highway, shore line, boundary line etc. are moved towards to the high-resolution imaging task of not parallel sub-satellite track, traditional static imaging is due to the necessary parallel sub-satellite track of band, the acquisition that could realize complete image need be repeatedly observed to target area, cannot meet the demand of target area image Real-time Obtaining, imaging usefulness is lower.

Along with the further enhancing of small satellite attitude control ability, satellite can by attitude maneuver break traditions quiescent imaging time strictly rely on orbital motion to push away the constraint of sweeping, thus realize ground push-scanning image more flexibly, imaging band no longer needs parallel sub-satellite track, even can be formed the imaging of vertical sub-satellite track by attitude maneuver.The band formed an angle with sub-satellite track is referred to as slanted bar band.In traditional static imaging, for the imaging band of given a certain parallel sub-satellite track, the side-sway angle of satellite keeps constant, and the attitude in imaging process is without the need to planning; But time in attitude maneuver along given slanted bar band imaging, the three-axis attitude of satellite needs real-time change, need to plan the attitude in imaging process.

The motor-driven middle imaging technique of quick satellite, refer to that satellite carries out imaging in the motor-driven middle unlatching optics useful load of three-axis attitude, in imaging process, adjustment optical axis points to realize complicated imaging task over the ground in real time.The Pleiades-HR passing of satelline attitude maneuver of France can realize the push-scanning image of vertical sub-satellite track, and obtain the 0.7m high-definition picture of the 350km × 20km of east-west direction, single imaging can obtain wide cut high-definition picture.In dynamic, the yellow group east of imaging pattern has a detailed description in " attitude points to image motion velocity calculating when being constantly changing into picture over the ground " of the 12nd phase in 2012 " optical precision engineering ", current motor-driven middle imaging technique lacks the motor-driven middle formation method to given target trajectory, cannot realize along the attitude planning in slanted bar band imaging process, do not carry out the compensation of imaging drift angle in its attitude adjusting method, be difficult to the image quality ensureing motor-driven middle imaging yet.

Summary of the invention

The object of the invention is to overcome the deficiencies in the prior art, a kind of attitude adjusting method along the imaging of slanted bar band is provided, the method first plans that photography point is along the sliding speed of given slanted bar band and position, then the attitude adjusting camera carrier makes camera follow shot point carry out imaging, thus achieve edge to the slanted bar band imaging that sets the goal, relative to traditional quiescent imaging method, the method is for highway, shore line, the high-resolution imaging task that boundary line etc. move towards not parallel sub-satellite track has good practicality, and wide cut high-definition picture can be obtained by the imaging of vertical sub-satellite track.

Above-mentioned purpose of the present invention is realized by following scheme:

Along an attitude adjusting method for slanted bar band imaging, specific implementation step is as follows:

(1), by imaging starting point M to imaging end point N work with the earth's core be the circular arc in the center of circle, and the center line using described circular arc as imaging slanted bar band; The location parameter of slanted bar band under ECEF coordinate system is calculated according to spherical geometry; Described location parameter comprises the angle i of slanted bar band center line and the equatorial plane, the longitude Ω of slanted bar band center line and equatorial plane intersection point, and slanted bar band center line and equatorial plane intersection point are to the sphere argument f of starting point;

(2), under ECEF coordinate system, according to the location parameter of slanted bar band under ECEF coordinate system that step (1) calculates, and the photography spot speed size variation function v of setting _dt (), calculates velocity V when photography point slides into position D along slanted bar band center line _dwith position vector R _d; Wherein position D is between imaging starting point M to imaging end point N;

(3), according to the camera carrier positions of setting function S (t) is changed, and the photography point position vector R that step (2) is determined _d, calculate the pose adjustment parameter of the airborne body of camera carrier optical axis follow shot point motion phase; Described adjustment parameter comprises roll angle pitching angle theta and crab angle β, and axis of rolling angular velocity omega _xwith pitch axis angular velocity omega _y;

(4) the pose adjustment parameter of the camera carrier, according to step (3) calculated, the three-axis attitude of adjustment camera carrier.

The above-mentioned attitude adjusting method along the imaging of slanted bar band, in step (1), calculate the location parameter of slanted bar band under ECEF coordinate system according to spherical geometry, circular is as follows:

(1a), first the warp of imaging end point N and the angle C of slanted bar band center line place disc are appeared in calculating:

$\cot C=\frac{{\mathrm{tan\δ}}_M{\mathrm{cos\δ}}_N-{\mathrm{sin\δ}}_{N}cos({\mathrm{\α}}_N-{\mathrm{\α}}_M)}{sin({\mathrm{\α}}_N-{\mathrm{\α}}_M)};$

Wherein: α _m, δ _mbe respectively longitude and the latitude of the imaging starting point M of setting; α _n, δ _nbe respectively longitude and the latitude of the imaging end point N of setting;

(1b) the angle C, calculated according to step (1a) is by the angle i of following formula determination slanted bar band center line and the equatorial plane:

cosi＝sin(π-C)cosδ _N；

(1c) the longitude Ω of slanted bar band center line and equatorial plane intersection point, is obtained by following formulae discovery:

tan(α _N-Ω)＝sinitan(π-C)；

(1d), slanted bar band center line and the equatorial plane intersection point sphere argument f to starting point is obtained by following formulae discovery:

$\sin f=\frac{\sin i}{{\mathrm{sin\δ}}_M}.$

The above-mentioned attitude adjusting method along the imaging of slanted bar band, in step (2), under ECEF coordinate system, calculates velocity V when photography point slides along slanted bar band center line _dwith position vector R _dconcrete steps as follows:

(2a), first according to photography spot speed size variation function v (t) of setting, photography point is calculated along spherical angle when slanted bar band center line sliding into position D

(2b), photography spot speed vector V is obtained by following formulae discovery _dwith position vector R _d:

$V_D=v_D\left[\begin{array}{c}-sin(f+\mathrm{\μ})cos\mathrm{\Ω}-cos(f+\mathrm{\μ})sin\mathrm{\Ω}\cos i\\ -sin(f+\mathrm{\μ})sin\mathrm{\Ω}+cos(f+\mathrm{\μ})cos\mathrm{\Ω}\cos i\\ cos(f+\mathrm{\μ})\sin i\end{array}\right];$

$R_D=R_e\left[\begin{array}{c}\cos (f+\mathrm{\μ})cos\mathrm{\Ω}-\sin (f+\mathrm{\μ})sin\mathrm{\Ω}\cos i\\ \cos (f+\mathrm{\μ})sin\mathrm{\Ω}+\sin (f+\mathrm{\μ})cos\mathrm{\Ω}\cos i\\ \sin (f+\mathrm{\μ})\sin i\end{array}\right];$

Wherein, v _dfor velocity magnitude value during photography point in-position D; R _efor earth radius.

The above-mentioned attitude adjusting method along the imaging of slanted bar band, in step (3), the concrete steps calculating the pose adjustment parameter of camera carrier are as follows:

(3a), calculate when camera attitude of carrier adjusts to the airborne body body coordinate system X of optical axis aligning photography point phase _by _bz _btarget three axial vector x _b, y _b, z _b; Wherein, when photography point aimed at by the camera carrier optical axis, Z _baxle points to photography point position D, Y _baxle is perpendicular to Z _baxle and photography spot speed vector V _dthe plane at place, X _bby Z _baxle and Y _baxle is determined according to right-hand rule;

(3b), according to the target three axial vector x that step (1) calculates _b, y _b, z _b, calculate the roll angle of camera attitude of carrier adjustment pitching angle theta and crab angle β; Wherein, described pose adjustment implementation procedure is: orbital coordinate system forwards the camera carrier optical axis to according to 123 turns of sequences and aims at the airborne body body coordinate system X of photography point phase _by _bz _b;

(3c) ground of causing of, according to camera attitude of carrier moving pushes away the speed of sweeping, and calculates axis of rolling angular velocity omega _xwith pitch axis angular velocity omega _y.

The above-mentioned attitude adjusting method along the imaging of slanted bar band, in step (3a), camera carrier body coordinate system X _by _bz _btarget three axial vector x _b, y _b, z _bspecific formula for calculation as follows:

$z_b=\frac{\stackrel{\→}{SD}}{\left|\stackrel{\→}{SD}\right|};$

$y_b=\frac{z_b\×V_D}{\left|z_b\×V_D\right|};$

x _b＝y _b×z _b；

Wherein, for being pointed to the direction vector of photography point position D by camera carrier positions S.

The above-mentioned attitude adjusting method along the imaging of slanted bar band, in step (3b), roll angle the circular of pitching angle theta and crab angle β is as follows:

First by axial vector z _b[Z is expressed as in orbital coordinate system _b] _orbit=[z _bxz _byz _bz] ^t, then roll angle as follows with the computing formula of pitching angle theta:

Do roll pitching motor-driven after the X of camera carrier body coordinate system _baxle and target axial vector x _bangle be crab angle β, namely the computing formula of crab angle β is as follows:

The above-mentioned attitude adjusting method along the imaging of slanted bar band, in step (3c), axis of rolling angular velocity omega _xwith pitch axis angular velocity omega _yconcrete computation process as follows:

(3ca), under orbital coordinate system, calculate the move ground of causing of camera attitude of carrier and push away and sweep speed V _η:

V _η＝V _D+ω _e×R _D-ω _s×R _D；

Wherein, ω _efor the earth rotation speed vector of setting; ω _sfor the camera carrier rack of setting runs angular velocity vector;

(3cb), axis of rolling angular velocity omega is obtained by following formulae discovery _xwith pitch axis angular velocity omega _y:

${\mathrm{\ω}}_x=-\frac{V_{\mathrm{\η}}\·y_b}{L};{\mathrm{\ω}}_y=\frac{V_{\mathrm{\η}}\·x_b}{L}$

Wherein, L is the distance of camera carrier position to photography point position.The present invention's advantage is compared with prior art:

(1), the attitude adjusting method of the inventive method achieves the imaging along given slanted bar band: the imaging band of traditional static imaging can only parallel sub-satellite track, the imaging mode of the inventive method can realize the slanted bar band formed an angle with sub-satellite track, high-resolution imaging task highway, shore line, boundary line etc. being moved towards to not parallel sub-satellite track has good practicality, and can obtain wide cut high-definition picture by the imaging of vertical sub-satellite track;

(2), first the inventive method is planned the sliding speed of photography point on slanted bar band, then adopt the slip of the motor-driven real-time follow-up photography point of camera carrier body coordinate system three-axis attitude to realize the pose adjustment of imaging process, thus complete the imaging task along slanted bar band.This attitude maneuver method of adjustment of being moved by follow shot point proposes first, and different imaging tasks can be met by changing the sliding speed programme of photography point on slanted bar band, imaging task is planned more flexible, such as can to the control of the quick push-scanning image of realization of goal and push-scanning image at a slow speed, quick push-scanning image can meet emergent imaging task, and push-scanning image can increase the camera exposure time and reaches good image quality at a slow speed;

(3), the inventive method in camera attitude of carrier parameter calculation procedure, achieved the compensation of drift angle by yaw steering, ensure that image quality; The drift angle of motor-driven middle imaging is produced jointly by satellite orbit motion, earth rotation and attitude maneuver, has bigger difference with the drift angle of traditional static imaging, and existing motor-driven middle imaging model does not carry out drift angle adjustment.Further, because satellite three-axis attitude is simultaneously motor-driven in real time, the motor-driven adjustment to yaw axis of the axis of rolling and pitch axis has coupling, considers this impact in the drift angle compensation of the inventive method.

Accompanying drawing explanation

Fig. 1 is the attitude adjusting method process flow diagram along the imaging of slanted bar band of the present invention;

Fig. 2 is slanted bar band geometric model schematic diagram in the present invention;

Fig. 3 is the schematic diagram that in the present invention, photography point slides along slanted bar band center line;

Fig. 4 is the imaging attitude maneuver model schematic that in the present invention, band driftage compensates;

Fig. 5 is that the three-axis attitude when camera carrier optical axis is aligned to picture point in the present invention points to schematic diagram;

Fig. 6 is along the roll angle of vertical substar imaging and angle of pitch result of calculation schematic diagram in embodiment;

Fig. 7 is the crab angle result of calculation schematic diagram along vertical substar imaging in embodiment;

Fig. 8 is the Attitude Tracking angular speed calculation result schematic diagram along vertical substar imaging in embodiment;

Fig. 9 is the STK simulating scenes schematic diagram along vertical substar imaging in embodiment.

Embodiment

Below in conjunction with the drawings and specific embodiments, the present invention is described in further detail:

Method flow diagram as shown in Figure 1, the present invention is directed to along the imaging of slanted bar band, at planning photography point along on the basis of sliding speed on slanted bar band, by being created as picture attitude maneuver model realization, the tracking of photography point and the drift angle of imaging are compensated, obtain along camera carrier (satellite, the spacecraft etc.) three-axis attitude in slanted bar band imaging process and Attitude Tracking angular velocity, achieve the pose adjustment along the imaging of given slanted bar band in attitude maneuver.

(1), slanted bar band geometric parameter is determined

Setting up slanted bar band model as shown in Figure 2, on slanted bar band, is the circular arc in the center of circle with the earth's core by imaging starting point M to imaging end point N work, the center line using this circular arc as imaging slanted bar band.This slanted bar band center line is in the great circle crossing the earth's core, the geometric parameter of this slanted bar band can be calculated according to spherical geometry under ECEF coordinate system, wherein, earth centered fixed coordinate frame is that initial point is in the earth's core, X-axis points to the intersection point of zero degree warp and the equatorial plane, Z axis points to the arctic along earth's axis, and XYZ becomes right hand rectangular coordinate system.

The slanted bar band geometric parameter calculated in the present invention comprises: the angle i of slanted bar band center line and the equatorial plane, the longitude Ω of slanted bar band center line and equatorial plane intersection point, and slanted bar band center line and equatorial plane intersection point are to the sphere argument f of starting point.Circular is as follows:

(1a), first the warp of imaging end point N and the angle C of slanted bar band center line place disc are appeared in calculating:

$\cot C=\frac{{\mathrm{tan\δ}}_M{\mathrm{cos\δ}}_N-{\mathrm{sin\δ}}_{N}cos({\mathrm{\α}}_N-{\mathrm{\α}}_M)}{sin({\mathrm{\α}}_N-{\mathrm{\α}}_M)};$

Wherein: α _m, δ _mbe respectively longitude and the latitude of the imaging starting point M of setting; α _n, δ _nbe respectively longitude and the latitude of the imaging end point N of setting;

(1b) the angle C, calculated according to step (1a) is by the angle i of following formula determination slanted bar band center line and the equatorial plane:

cosi＝sin(π-C)cosδ _N；

(1c) the longitude Ω of slanted bar band center line and equatorial plane intersection point, is obtained by following formulae discovery:

tan(α _N-Ω)＝sinitan(π-C)；

(1d), slanted bar band center line and the equatorial plane intersection point sphere argument f to starting point is obtained by following formulae discovery:

$\sin f=\frac{\sin i}{{\mathrm{sin\δ}}_M}.$

(2) velocity put and slide along slanted bar band of, photographing and position vector calculate

When along the imaging of slanted bar band, photography point slides on slanted bar band center line, and the camera carrier optical axis needs the motion of follow shot point, thus realizes real time imagery.Therefore, the present invention realizes the planning of the attitude of satellite by the sliding speed of planning photography point.In imaging process, camera carrier positions along with Changing Pattern S (t) of time given, the optical axis of this camera carrier at any time all will to aligning photography point, therefore, when carrying out the adjustment of camera attitude of carrier, need first to determine that photography point is along slanted bar band slip rule D (t).

As shown in Figure 3, point is photographed with velocity V at moment t _dslide into position D, the earth's core is R to the vector of this position D _d, this position D is between imaging starting point M to imaging end point N.The present invention under ECEF coordinate system according to slanted bar band geometry of position parameter, and setting photography spot speed size variation function v _dt (), calculates velocity V when photography point slides into position D along slanted bar band center line _dwith position vector R _d, concrete calculation procedure is as follows:

(2a), first according to photography spot speed size variation function v (t) of setting, photography point is calculated along spherical angle when slanted bar band center line sliding into position D

(2b), photography spot speed vector V is obtained by following formulae discovery _dwith position vector R _d:

$V_D=v_D\left[\begin{array}{c}-sin(f+\mathrm{\μ})cos\mathrm{\Ω}-cos(f+\mathrm{\μ})sin\mathrm{\Ω}\cos i\\ -sin(f+\mathrm{\μ})sin\mathrm{\Ω}+cos(f+\mathrm{\μ})cos\mathrm{\Ω}\cos i\\ cos(f+\mathrm{\μ})\sin i\end{array}\right];$

$R_D=R_e\left[\begin{array}{c}cos(f+\mathrm{\μ})cos\mathrm{\Ω}-sin(f+\mathrm{\μ})sin\mathrm{\Ω}\cos i\\ \cos (f+\mathrm{\μ})sin\mathrm{\Ω}+sin(f+\mathrm{\μ})cos\mathrm{\Ω}\cos i\\ sin(f+\mathrm{\μ})\sin i\end{array}\right];$

Wherein, v _dfor velocity magnitude value during photography point in-position D; R _efor earth radius.

Spot speed size variation of photographing in the present invention function v _dt the programme of () has multiple, different imaging tasks can be met by changing the sliding speed programme of photography point on slanted bar band, imaging task is planned more flexible, such as can to the control of the quick push-scanning image of realization of goal and push-scanning image at a slow speed, quick push-scanning image can meet emergent imaging task, and push-scanning image can increase the camera exposure time and reaches good image quality at a slow speed.The simplest scheme of one is provided to explain: the slanted bar band imaging programme adopting constant ground velocity in the present embodiment, photography point slides on given slanted bar band with the speed of constant size, namely any time photography point sliding speed size keeps constant, and photography point moves along oblique strip direction in ground level.The sliding speed size v of photography point on slanted bar band _d=k ω _sr _e, wherein: ω _sfor satellite runs angular velocity around the earth; R _efor earth radius; K is velocity coefficient, and the sliding speed of k larger photography point on slanted bar band is larger, by realizing sweeping soon or sweeping slowly target slanted bar band to the planning of k.

(3), camera attitude of carrier parameter calculates

Imaging model as shown in Figure 4; the motor-driven imaging process of camera carrier is as follows: satellite S orbiting; realize Attitude Tracking thus make the optical axis point to SD sliding along landing ground slanted bar band track by the axis of rolling and the motor-driven of pitch axis; diagram slanted bar band becomes η angle with sub-satellite track, makes the vertical tiltedly strip direction in linear array direction by driftage compensation.Wherein V _sthe ground caused for orbital motion pushes away the speed of sweeping, V _efor earth rotation speed, V _rollsweep the ground caused push away the speed of sweeping, V for roll angle pushes away _pitchsweep the ground caused and push away for the angle of pitch pushes away the speed of sweeping.

The present invention is according to the position vector R of camera carrier positions change function S (t) of setting with photography point position D _d, when calculating the some motion of camera carrier optical axis follow shot, the pose adjustment parameter of camera carrier: comprise roll angle pitching angle theta and crab angle β, and axis of rolling angular velocity omega _xwith pitch axis angular velocity omega _y.Concrete calculation procedure is as follows:

(3a), calculate when camera attitude of carrier adjusts to the airborne body body coordinate system X of optical axis aligning photography point phase _by _bz _btarget three axial vector x _b, y _b, z _b; Wherein, when photography point aimed at by the camera carrier optical axis, Z _baxle points to photography point position D, Y _baxle is perpendicular to Z _baxle and photography spot speed vector V _dthe plane at place, X _bby Z _baxle and Y _baxle is determined according to right-hand rule.Wherein:

$z_b=\frac{\stackrel{\→}{SD}}{\left|\stackrel{\→}{SD}\right|};$

$y_b=\frac{z_b\×V_D}{\left|z_b\×V_D\right|};$

x _b＝y _b×z _b；

Wherein, for being pointed to the direction vector of photography point position D by camera carrier positions S, can according to known camera carrier positions along with Changing Pattern S (t) of time and the position vector of position D calculate.

(3b) roll angle of attitude of satellite adjustment, is calculated pitching angle theta and crab angle β; Wherein, described pose adjustment implementation procedure is: orbital coordinate system forwards the satellite optical axis to according to 123 turns of sequences and aims at satellite body coordinate system X when photography is put _by _bz _b, namely first rotate around the axis of rolling angle, then around pitch axes θ angle, finally rotate γ angle around yaw axis and arrive predetermined attitude in Fig. 5.Wherein, orbit coordinate is: z-axis points to substar direction, and x-axis points to spacecraft velocity reversal, and y-axis is determined by right hand Normal rule.

Circular is as follows: first by axial vector z _b[Z is expressed as in orbital coordinate system _b] _orbit=[z _bxz _byz _bz] ^t, then roll angle as follows with the computing formula of pitching angle theta: do roll pitching motor-driven after the X of camera carrier body coordinate system _baxle and target axial vector x _bangle be crab angle β, namely the computing formula of crab angle β is as follows:

The attitude of carrier parameter calculated according to above method has carried out drift angle compensation.

(3c) ground of, causing according to Satellite Attitude Movement pushes away the speed of sweeping, calculating axis of rolling angular velocity omega _xwith pitch axis angular velocity omega _y.Concrete computation process is as follows:

(3ca), under orbital coordinate system, the ground that calculating Satellite Attitude Movement causes pushes away sweeps speed V _η:

V _η＝V _D+ω _e×R _D-ω _s×R _D；

Wherein, ω _efor the earth rotation speed vector of setting; ω _sfor the satellite orbit of setting runs angular velocity vector;

(3cb), axis of rolling angular velocity omega is obtained by following formulae discovery _xwith pitch axis angular velocity omega _y:

${\mathrm{\ω}}_x=-\frac{V_{\mathrm{\η}}\·y_b}{L};{\mathrm{\ω}}_y=\frac{V_{\mathrm{\η}}\·x_b}{L}$

Wherein, L is the distance of satellite position to photography point position.

Then according to the pose adjustment parameter of the camera carrier calculated, the three-axis attitude of adjustment camera carrier.

Embodiment:

The present embodiment to be imaged as example to the slanted bar band of vertical sub-satellite track, and adopts the sliding speed programme of constant ground velocity to carry out the three-axis attitude adjustment of satellite, and the velocity coefficient k of employing is 0.5,1 and 1.5.When calculating vertical sub-satellite track imaging, satellite needs the roll angle of adjustment, the angle of pitch, crab angle and axis of rolling angular velocity and pitch axis angular velocity, and result is as shown in Fig. 6, Fig. 7, Fig. 8.

In the present embodiment, the major parameter of vertical substar imaging is as shown in table 1, wherein: the imaging that can realize about 700km when velocity coefficient is 1, obtains high resolving power and to hold concurrently the remotely-sensed data of large fabric width.In vertical sub-satellite track imaging process, rate of roll pushes away for what offset orbital motion speed of sweeping the floor, and rate of pitch determines the speed of push-scanning image, and during k=1.5, rate of pitch maximal value reaches 1.267 °/s.By the attitude of satellite

Control ability limits, and needs control rate coefficient to push away sweep angular velocity to reduce required attitude during imaging.

The major parameter of the vertical substar imaging of table 1

Fig. 9 is STK imaging simulation result: the vertical sub-satellite track of slanted bar band of imaging meets imaging task requirement; Sweep known the pushing away of track from CCD linear array and sweep direction pushing away of ground and maintain along oblique strip direction, having carried out goes off course compensates; Satellite body axle points to along oblique strip direction all the time, and three-axis attitude maneuver mode is correct, meets imaging Gesture.

The above; be only the present invention's embodiment, but protection scope of the present invention is not limited thereto, is anyly familiar with those skilled in the art in the technical scope that the present invention discloses; the change that can expect easily or replacement, all should be encompassed within protection scope of the present invention.

The content be not described in detail in instructions of the present invention belongs to the known technology of professional and technical personnel in the field.

Claims (7)

1. along an attitude adjusting method for slanted bar band imaging, it is characterized in that: specific implementation step is as follows:

(1), by imaging starting point M to imaging end point N work with the earth's core be the circular arc in the center of circle, and the center line using described circular arc as imaging slanted bar band; The location parameter of slanted bar band under ECEF coordinate system is calculated according to spherical geometry; Described location parameter comprises the angle i of slanted bar band center line and the equatorial plane, the longitude Ω of slanted bar band center line and equatorial plane intersection point, and slanted bar band center line and equatorial plane intersection point are to the sphere argument f of starting point;

(2), under ECEF coordinate system, according to the location parameter of slanted bar band under ECEF coordinate system that step (1) calculates, and the photography spot speed size variation function v of setting _dt (), calculates velocity V when photography point slides into position D along slanted bar band center line _dwith position vector R _d; Wherein position D is between imaging starting point M to imaging end point N;

(3), according to the camera carrier positions of setting function S (t) is changed, and the photography point position vector R that step (2) is determined _d, calculate the pose adjustment parameter of the airborne body of camera carrier optical axis follow shot point motion phase; Described adjustment parameter comprises roll angle pitching angle theta and crab angle β, and axis of rolling angular velocity omega _xwith pitch axis angular velocity omega _y;

(4) the pose adjustment parameter of the camera carrier, according to step (3) calculated, the three-axis attitude of adjustment camera carrier.

2. a kind of attitude adjusting method along the imaging of slanted bar band according to claim 1, is characterized in that: in step (1), and calculate the location parameter of slanted bar band under ECEF coordinate system according to spherical geometry, circular is as follows:

(1a), first the warp of imaging end point N and the angle C of slanted bar band center line place disc are appeared in calculating:

$\cot C=\frac{{\mathrm{tan\δ}}_M{\mathrm{cos\δ}}_N-{\mathrm{sin\δ}}_N\cos ({\mathrm{\α}}_N-{\mathrm{\α}}_M)}{\sin ({\mathrm{\α}}_N-{\mathrm{\α}}_M)};$

Wherein: α _m, δ _mbe respectively longitude and the latitude of the imaging starting point M of setting; α _n, δ _nbe respectively longitude and the latitude of the imaging end point N of setting;

(1b) the angle C, calculated according to step (1a) is by the angle i of following formula determination slanted bar band center line and the equatorial plane:

cosi＝sin(π-C)cosδ _N；

(1c) the longitude Ω of slanted bar band center line and equatorial plane intersection point, is obtained by following formulae discovery:

tan(α _N-Ω)＝sinitan(π-C)；

(1d), slanted bar band center line and the equatorial plane intersection point sphere argument f to starting point is obtained by following formulae discovery:

$\sin f=\frac{\sin i}{{\mathrm{sin\δ}}_M}.$

3. a kind of attitude adjusting method along the imaging of slanted bar band according to claim 1, is characterized in that: in step (2), under ECEF coordinate system, calculates velocity V when photography point slides along slanted bar band center line _dwith position vector R _dconcrete steps as follows:

(2a), first according to photography spot speed size variation function v (t) of setting, photography point is calculated along spherical angle when slanted bar band center line sliding into position D

(2b), photography spot speed vector V is obtained by following formulae discovery _dwith position vector R _d:

$V_D=v_D\left[\begin{array}{c}-sin(f+\mathrm{\μ})cos\mathrm{\Ω}-cos(f+\mathrm{\μ})sin\mathrm{\Ω}\cos i\\ -\sin (f+\mathrm{\μ})sin\mathrm{\Ω}+cos(f+\mathrm{\μ})cos\mathrm{\Ω}\cos i\\ cos(f+\mathrm{\μ})\sin i\end{array}\right];$

$R_D=R_e\left[\begin{array}{c}cos(f+\mathrm{\μ})cos\mathrm{\Ω}-sin(f+\mathrm{\μ})sin\mathrm{\Ω}\cos i\\ cos(f+\mathrm{\μ})sin\mathrm{\Ω}+sin(f+\mathrm{\μ})cos\mathrm{\Ω}\cos i\\ sin(f+\mathrm{\μ})\sin i\end{array}\right];$

Wherein, v _dfor velocity magnitude value during photography point in-position D; R _efor earth radius.

4. a kind of attitude adjusting method along the imaging of slanted bar band according to claim 1, is characterized in that: in step (3), and the concrete steps calculating the pose adjustment parameter of camera carrier are as follows:

(3a), calculate when camera attitude of carrier adjusts to the airborne body body coordinate system X of optical axis aligning photography point phase _by _bz _btarget three axial vector x _b, y _b, z _b; Wherein, when photography point aimed at by the camera carrier optical axis, Z _baxle points to photography point position D, Y _baxle is perpendicular to Z _baxle and photography spot speed vector V _dthe plane at place, X _bby Z _baxle and Y _baxle is determined according to right-hand rule;

(3b), according to the target three axial vector x that step (1) calculates _b, y _b, z _b, calculate the roll angle of camera attitude of carrier adjustment pitching angle theta and crab angle β; Wherein, described pose adjustment implementation procedure is: orbital coordinate system forwards the camera carrier optical axis to according to 123 turns of sequences and aims at the airborne body body coordinate system X of photography point phase _by _bz _b;

(3c) ground of causing of, according to camera attitude of carrier moving pushes away the speed of sweeping, and calculates axis of rolling angular velocity omega _xwith pitch axis angular velocity omega _y.

5. a kind of attitude adjusting method along the imaging of slanted bar band according to claim 4, is characterized in that: in step (3a), camera carrier body coordinate system X _by _bz _btarget three axial vector x _b, y _b, z _bspecific formula for calculation as follows:

$z_b=\frac{\stackrel{\→}{SD}}{\left|\stackrel{\→}{SD}\right|};$

$y_b=\frac{z_b\×V_D}{\left|z_b\×V_D\right|};$

x _b＝y _b×z _b；

Wherein, for being pointed to the direction vector of photography point position D by camera carrier positions S.

6. a kind of attitude adjusting method along the imaging of slanted bar band according to claim 4, is characterized in that: in step (3b), roll angle the circular of pitching angle theta and crab angle β is as follows:

First by axial vector z _b[Z is expressed as in orbital coordinate system _b] _orbit=[z _bxz _byz _bz] ^t, then roll angle as follows with the computing formula of pitching angle theta:

Do roll pitching motor-driven after the X of camera carrier body coordinate system _baxle and target axial vector x _bangle be crab angle β, namely the computing formula of crab angle β is as follows:

7. a kind of attitude adjusting method along the imaging of slanted bar band according to claim 4, is characterized in that: in step (3c), axis of rolling angular velocity omega _xwith pitch axis angular velocity omega _yconcrete computation process as follows:

(3ca), under orbital coordinate system, calculate the move ground of causing of camera attitude of carrier and push away and sweep speed V _η:

V _η＝V _D+ω _e×R _D-ω _s×R _D；

Wherein, ω _efor the earth rotation speed vector of setting; ω _sfor the camera carrier rack of setting runs angular velocity vector;

(3cb), axis of rolling angular velocity omega is obtained by following formulae discovery _xwith pitch axis angular velocity omega _y:

${\mathrm{\ω}}_x=-\frac{V_{\mathrm{\η}}\·y_b}{L},{\mathrm{\ω}}_y=\frac{V_{\mathrm{\η}}\·x_b}{L}$

Wherein, L is the distance of camera carrier position to photography point position.