CN103886208A - High-resolution optical satellite maneuvering imaging drift angle correction method - Google Patents

Abstract

The invention discloses a high-resolution optical satellite maneuvering imaging drift angle correction method. A drift angle correction model under a maneuvering imaging mode is set up according to a satellite attitude maneuver scheme, a method for calculating a drift angle is derived based on the satellite position and ground point position coordinates, and a scheme for installing a drift angle correction device at the focal plane position is provided. Thus, a satellite can have the imaging capacity on a target strip deviating from the flying direction, the observation range and the observation efficiency of the satellite are greatly improved, and meanwhile, the satellite can have the dynamic pushing and blooming imaging capacity in the vertical direction of a sub-satellite point. Large-width imaging of a sub-satellite point area is achieved in a multi-strip splicing manner, and the requirement for the TDICCD camera width is lowered.

Description

The motor-driven imaging drift angle of a kind of high-resolution optical satellite modification method

Technical field

The invention belongs to Optical remote satellite imaging field, relate to a kind of motor-driven imaging drift angle of high-resolution optical satellite modification method of taking load TDICCD camera.

Background technology

TDICCD realizes time delay integration based on same target is carried out to multiexposure, multiple exposure, has greatly strengthened luminous energy collection, has improved signal to noise ratio (S/N ratio), is therefore widely used on high-resolution optical remote sensing satellite.But simultaneously, due to this special working method of TDICCD, require same each pixel listing to same target exposure integration, the basic premise of its normal work is that the transfer of photogenerated charge bag and the motion of focal plane epigraph keep synchronizeing, and any matching error all will cause image blurring.

Current most satellite all adopts and passes through in advance attitude maneuver, camera light stabilizer shaft is pointed to behind target area, motion via satellite realizes the push-scanning image (see figure 1) of TDICCD camera to target, under this imaging pattern, the attitude of satellite remains unchanged, TDICCD camera object-image relation is stable, image blurring main source is that earth rotation the satellite flight direction and the TDICCD camera actual imaging direction that cause are inconsistent, angle between the two is drift angle, the horizontal picture that drift angle can cause camera to produce image in integration imaging process moves, and affects camera imaging quality.Therefore, drift angle being regulated is a vital task in TDICCD camera image shift compensation system.

Aerospace optical remote sensing technical development is in recent years rapid, satellite rapid attitude maneuver ability promotes greatly, there is the quick satellite of the high resolving power that there is flexible attitude maneuver ability and there is higher ground resolution, if the traditional observation mode shown in employing Fig. 1 is observed target, for having the target stripe region of certain angle with heading, if satellite TDICCD camera fabric width is limited, once push away to sweep and do not cover target overall picture, need by mission planning, by the multi-ribbon splicing of different rails, can realize the complete observation to target area.

For the feature of the powerful attitude maneuver ability of quick satellite, people begin one's study and regulate in real time and realize having in the target stripe sensing process in real time of certain angle with heading in attitude, and TDICCD camera carries out the Novel work pattern of imaging---motor-driven imaging (seeing accompanying drawing 2).Under this pattern, because the attitude of satellite constantly changes in time, the source of drift angle is just earth rotation impact not, is also subject to the impact of the motor-driven scheme of the attitude of satellite, and under the motor-driven imaging pattern of research satellite, the computing method of drift angle and modification method are the prerequisites that realizes motor-driven imaging.

Domestic existing satellite in orbit, not yet has the precedent of motor-driven imaging, the computing method of drift angle in attitude change procedure is had to certain research, but do not carry out full link research in conjunction with the motor-driven imaging pattern of satellite.In at present external data, the Pleiades satellite of France, the IKONOS satellite of the U.S. are the quick satellite with fast reserve ability, can realize flexibly strips mosaic imaging, three-dimensional imaging and region point target imaging etc., the imaging pattern providing according to Pleiades satellite and IKONOS-2 satellite, infer that Pleiades and IKONOS-2 should also have motor-driven imaging capability, but concrete implementation method, does not have data to consult.

Summary of the invention

The technical matters that the present invention solves is: overcome the deficiencies in the prior art, the motor-driven imaging drift angle of a kind of high-resolution optical satellite modification method is provided, under the motor-driven imaging pattern of satellite, for different attitude maneuver schemes, obtain drift angle computation model in motor-driven imaging process, propose, at focal plane, image motion compensation device is installed for drift angle model and carry out the real-time correction-compensation of drift angle.

Technical scheme of the present invention is: the motor-driven imaging drift angle of a kind of high-resolution optical satellite modification method, and step is as follows:

1), according to real satellite parameter, set up TDICCD camera imaging model on dummy satellite and satellite;

2) according to target location to be observed, determine the motor-driven scheme of the attitude of satellite, generate the real-time attitude maneuver data of satellite, and the dummy satellite obtaining according to step 1) and TDICCD camera imaging model, obtain attitude maneuver process Satellite real time position coordinate and imaging topocentric coordinates

obtain the corresponding time t of satellite real time position coordinate and topocentric coordinates simultaneously;

3) by step 2) the satellite real time position coordinate that obtains

to time t differentiate, calculate and obtain satellite velocity vector ${\stackrel{\→}{V}}_s=(v_{x\_s},v_{y\_s},v_{z\_s}),$ Wherein $\begin{array}{c}{v}_{x\_s}=\frac{\mathrm{dSx}}{\mathrm{dt}};\\ v_{y\_s}=\frac{\mathrm{dSy}}{\mathrm{dt}};\\ v_{z\_s}=\frac{\mathrm{dSz}}{\mathrm{dt}};\end{array}$

4) by step 2) topocentric coordinates that obtains

to time t differentiate, calculate and obtain photography point ground vector ${\stackrel{\→}{V}}_g=(v_{x\_g},v_{y\_g},v_{z\_g}),$ Wherein $\begin{array}{c}{v}_{x\_g}=\frac{\mathrm{dGx}}{\mathrm{dt}};\\ v_{y\_g}=\frac{\mathrm{dGy}}{\mathrm{dt}};\\ v_{z\_g}=\frac{\mathrm{dGz}}{\mathrm{dt}};\end{array}$

5) calculate satellite velocity vector

with ground vector

angle theta (t) on TDICCD camera focal plane between projection vector, i.e. drift angle θ (t);

51) calculate and obtain the projection vector of satellite velocity vector in focal plane

52) calculate and obtain the projection vector of ground vector in focal plane

$\stackrel{\→}{F}=\frac{{\stackrel{\→}{P}}_s-{\stackrel{\→}{P}}_g}{|{\stackrel{\→}{P}}_s-{\stackrel{\→}{P}}_g|}=\frac{(\mathrm{Sx},\mathrm{Sy},\mathrm{Sz})-(\mathrm{Gx},\mathrm{Gy},\mathrm{Gz})}{|(\mathrm{Sx},\mathrm{Sy},\mathrm{Sz})-(\mathrm{Gx},\mathrm{Gy},\mathrm{Gz})}=\frac{((\mathrm{Sx}-\mathrm{Gx}),(\mathrm{Sy}-G_y),(\mathrm{Sz}-G_z))}{\sqrt{{(\mathrm{Sx}-\mathrm{Gx})}^2+{(\mathrm{Sy}-\mathrm{Gy})}^2+{(\mathrm{Sz}-\mathrm{Gz})}^2}},$ Wherein for

between angle;

53) calculate and obtain drift angle $\mathrm{\θ}\left(t\right)=\arcsin d\left(\frac{|{\stackrel{\→}{V}}_{s\_c}\×{\stackrel{\→}{V}}_{g\_c}|}{\left|{\stackrel{\→}{V}}_{s\_c}\right|\×\left|{\stackrel{\→}{V}}_{g\_c}\right|}\right);$

6) under the motor-driven scheme of the attitude of satellite, set up drift angle θ (t) temporal evolution model, adopt focal plane drift angle compensation system that drift angle θ (t) is modified to 0 degree in real time according to this model.

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

The present invention carries out modeling to the motor-driven imaging pattern of high-resolution optical satellite of taking load TDICCD camera, and the implementation process of this Novel work pattern of satellite is simulated.For the motor-driven scheme of the attitude of satellite, set up drift angle correction model under motor-driven imaging pattern, derive the method taking a drift based on satellite position and ground point location coordinate, and propose to install in position of focal plane the scheme of drift angle correcting device.Make satellite possess the imaging capability to departing from heading target stripe, greatly improve range of observation and the observation efficiency of satellite, can make satellite possess along the ability of the dynamic push-scanning imaging of substar vertical direction simultaneously, the mode of splicing by multi-ribbon, realize the large fabric width imaging to substar region, thereby reduce the requirement to TDICCD camera fabric width.

Accompanying drawing explanation

Fig. 1 is general satellite imagery pattern diagram;

Fig. 2 is motor-driven imaging pattern schematic diagram;

Fig. 3 is focal plane rotation compensation device composition;

Fig. 4 is focal plane two-dimension translational compensation system composition;

Fig. 5 is the inventive method process flow diagram.

Embodiment

As shown in Figure 5, the present invention mainly comprises the following steps:

(1) utilize stk simulation software, according to real satellite parameter, set up satellite scene and dummy satellite, and utilize the sensor tool in stk software, under dummy satellite, set up TDICCD camera model, obtain motor-driven imaging basic model;

(2) utilize matlab software, follow the trail of requirement according to target trajectory, determine attitude maneuver scheme (turning order, attitude angle rate variation etc.), the attitude of satellite is carried out to analog computation, obtain the real-time attitude data of each moment satellite, co-ordinates of satellite system, attitude angle are turned order, load moment etc. and stipulate simultaneously, the attitude data form requiring according to stk generates attitude of satellite data file (.a file), be loaded in the basic model that step (1) sets up, to the dynamic imaging process simulation of target trajectory.

The attitude data file layout that Stk requires is specific as follows:

Data line	Content
		1	Stk?Version
2	BEGIN?Attitude
		3	NumberOfAttitudePoints
4	BlockingFactor
		5	InterpolationOrder

6	CentralBody
		7	ScenarioEpoch
8	CoordinateAxes
		9	Sequence
10	AttitudeTimeEulerAngles
		11	Attitude?data
12	END?Attitude

(3) satellite real time position coordinate during the middle dynamic imaging of output step (2)

and the camera optical axis points to and ground intersecting point coordinate

export the time t that real time position coordinate and topocentric coordinates are corresponding simultaneously;

Wherein, coordinate of the satellite position and topocentric coordinates all adopt coordinate under the fixed coordinate system of the earth's core, coordinate origin O be the earth's core and with the earth synkinematic coordinate system that connects firmly that spins, its x axle points to the intersecting lens of the equatorial plane and Greenwich meridian ellipse, z axle points to the arctic, equator, and y axle and z, x diaxon form right hand orthonormal system.

(4) coordinate of the satellite position, to time differentiate, obtains satellite velocity vector

$v_{x\_s}=\frac{\mathrm{dSx}}{\mathrm{dt}};$

$v_{y\_s}=\frac{\mathrm{dSy}}{\mathrm{dt}};$

$v_{z\_s}=\frac{\mathrm{dSz}}{\mathrm{dt}};$

(5) topocentric coordinates, to time differentiate, obtains photography point ground vector

$v_{x\_g}=\frac{\mathrm{dGx}}{\mathrm{dt}};$

$v_{y\_g}=\frac{\mathrm{dGy}}{\mathrm{dt}};$

$v_{z\_g}=\frac{\mathrm{dGz}}{\mathrm{dt}};$

(6) calculate satellite velocity vector

with ground vector

angle theta (t) on TDICCD camera focal plane between projection vector, is drift angle θ (t);

A. satellite pushes away and sweeps the projection vector computing method of velocity in TDICCD camera focal plane:

The installation that is connected of most TDICCD cameras and satellite body, TDICCD camera optical axis is consistent with z axle, and focal plane is perpendicular to optical axis, sweeps velocity at the projection vector of focal plane therefore satellite pushes away:

B. ground vector is in the projection vector computing method of focal plane

According to vector principle, the unit normal vector of a known plane

ask known vector projection vector in this plane can calculate as follows:

obtain vector to the distance b of plane;

obtain the long vector perpendicular to plane for b of mould;

be

projection vector in the plane.

According to upper, ground vector is as follows in the projection vector computing method of focal plane:

Focal plane unit normal vector can be calculated by following formula:

$\stackrel{\→}{F}=\frac{{\stackrel{\→}{P}}_s-{\stackrel{\→}{P}}_g}{|{\stackrel{\→}{P}}_s-{\stackrel{\→}{P}}_g|}=\frac{(\mathrm{Sx},\mathrm{Sy},\mathrm{Sz})-(\mathrm{Gx},\mathrm{Gy},\mathrm{Gz})}{|(\mathrm{Sx},\mathrm{Sy},\mathrm{Sz})-(\mathrm{Gx},\mathrm{Gy},\mathrm{Gz})|}=\frac{((\mathrm{Sx}-\mathrm{Gx}),(\mathrm{Sy}-G_y),(\mathrm{Sz}-G_z))}{\sqrt{{(\mathrm{Sx}-\mathrm{Gx})}^2+{(\mathrm{Sy}-\mathrm{Gy})}^2+{(\mathrm{Sz}-\mathrm{Gz})}^2}},$

?

be projected as in focal plane:

${\stackrel{\→}{V}}_{g\_c}={\stackrel{\→}{V}}_g-({\stackrel{\→}{V}}_g\·\stackrel{\→}{F})\×\stackrel{\→}{F}$

Wherein:

for ${\stackrel{\→}{V}}_g,\stackrel{\→}{F}$ Between angle.

C. drift angle computing method

Known vector

with

ask angle between the two can utilize following formula to calculate:

$|{\stackrel{\→}{V}}_{s\_c}\×{\stackrel{\→}{V}}_{g\_c}|=\left|{\stackrel{\→}{V}}_{s\_c}\right|\×\left|{\stackrel{\→}{V}}_{g\_c}\right|\×\sin d\left(\mathrm{\θ}\left(t\right)\right)\⇒$

$\mathrm{\θ}\left(t\right)=\arcsin d\left(\frac{|{\stackrel{\→}{V}}_{s\_c}\×{\stackrel{\→}{V}}_{g\_c}|}{\left|{\stackrel{\→}{V}}_{s\_c}\right|\×\left|{\stackrel{\→}{V}}_{g\_c}\right|}\right)$

(7) calculate in gained attitude of satellite real-time change situation according to step (6), the real-time numerical value of drift angle, increases drift angle compensation system at focal plane, can adopt two schemes as shown in Figure 3 and Figure 4.

For scheme shown in Fig. 3, the index request of electric rotating machine is calculated as follows:

Dynamic range: θ (t) _min～θ (t) _max

Maximum angular speed:

For scheme shown in Fig. 4, the index request that contraposition moves adjusting part is calculated as follows:

Linear array direction displacement adjusting part:

Dynamic range: L-L × cosd (θ (t))

Regulating frequency: (L-L × cosd (θ (t)))/dt

Progression direction displacement adjusting part:

Dynamic range: L-L × sind (θ (t))

Regulating frequency: (L-L × sind (θ (t)))/dt

Wherein, L is TDICCD half-breadth value.

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

Claims (1)

1. the motor-driven imaging drift angle of a high-resolution optical satellite modification method, is characterized in that step is as follows:

1), according to real satellite parameter, set up TDICCD camera imaging model on dummy satellite and satellite;

2) according to target location to be observed, determine the motor-driven scheme of the attitude of satellite, generate the real-time attitude maneuver data of satellite, and the dummy satellite obtaining according to step 1) and TDICCD camera imaging model, obtain attitude maneuver process Satellite real time position coordinate

and imaging topocentric coordinates

obtain the corresponding time t of satellite real time position coordinate and topocentric coordinates simultaneously;

3) by step 2) the satellite real time position coordinate that obtains to time t differentiate, calculate and obtain satellite velocity vector ${\stackrel{\→}{V}}_s=(v_{x\_s},v_{y\_s},v_{z\_s}),$ Wherein $\begin{array}{c}{v}_{x\_s}=\frac{\mathrm{dSx}}{\mathrm{dt}};\\ v_{y\_s}=\frac{\mathrm{dSy}}{\mathrm{dt}};\\ v_{z\_s}=\frac{\mathrm{dSz}}{\mathrm{dt}};\end{array}$

4) by step 2) topocentric coordinates that obtains

to time t differentiate, calculate and obtain photography point ground vector ${\stackrel{\→}{V}}_g=(v_{x\_g},v_{y\_g},v_{z\_g}),$ Wherein $\begin{array}{c}{v}_{x\_g}=\frac{\mathrm{dGx}}{\mathrm{dt}};\\ v_{y\_g}=\frac{\mathrm{dGy}}{\mathrm{dt}};\\ v_{z\_g}=\frac{\mathrm{dGz}}{\mathrm{dt}};\end{array}$

5) calculate satellite velocity vector

with ground vector angle theta (t) on TDICCD camera focal plane between projection vector, i.e. drift angle θ (t);

51) calculate and obtain the projection vector of satellite velocity vector in focal plane

52) calculate and obtain the projection vector of ground vector in focal plane

$\stackrel{\→}{F}=\frac{{\stackrel{\→}{P}}_s-{\stackrel{\→}{P}}_g}{|{\stackrel{\→}{P}}_s-{\stackrel{\→}{P}}_g|}=\frac{(\mathrm{Sx},\mathrm{Sy},\mathrm{Sz})-(\mathrm{Gx},\mathrm{Gy},\mathrm{Gz})}{|(\mathrm{Sx},\mathrm{Sy},\mathrm{Sz})-(\mathrm{Gx},\mathrm{Gy},\mathrm{Gz})}=\frac{((\mathrm{Sx}-\mathrm{Gx}),(\mathrm{Sy}-G_y),(\mathrm{Sz}-G_z))}{\sqrt{{(\mathrm{Sx}-\mathrm{Gx})}^2+{(\mathrm{Sy}-\mathrm{Gy})}^2+{(\mathrm{Sz}-\mathrm{Gz})}^2}},$ Wherein

for ${\stackrel{\→}{V}}_g,\stackrel{\→}{F}$ Between angle;

53) calculate and obtain drift angle $\mathrm{\θ}\left(t\right)=\arcsin d\left(\frac{|{\stackrel{\→}{V}}_{s\_c}\×{\stackrel{\→}{V}}_{g\_c}|}{\left|{\stackrel{\→}{V}}_{s\_c}\right|\×\left|{\stackrel{\→}{V}}_{g\_c}\right|}\right);$

6) under the motor-driven scheme of the attitude of satellite, set up drift angle θ (t) temporal evolution model, adopt focal plane drift angle compensation system that drift angle θ (t) is modified to 0 degree in real time according to this model.

Images