Method for calibrating absolute misalignment between linear array image sensor and attitude control sensor

1. A method for estimating and calibrating an absolute misalignment of a satellite or a flight vehicle imaging ground images at high resolution and transmitting the imaged ground images to a ground, the method comprising:

a ground control point imaging and comparing operation in which a plurality of ground control points of which accurate position information is known are each imaged using an image payload using a linear array sensor and position information of the ground control points in a plurality of imaged images and position information of the ground control points which are already known are then compared with each other;

an absolute misalignment estimation value calculating operation of estimating an absolute misalignment value between an attitude control sensor and the image payload by applying a method for estimating the absolute misalignment using an image obtained by a plane image sensor to information obtained by performing the ground control point imaging and comparing operation;

a calibrating operation of calibrating the absolute misalignment by applying the calculated absolute misalignment estimation value to attitude control sensors; and

wherein the information obtained by the ground control point imaging and comparing operation is transformed to have a form of the following Equation 6 by dividing and re-disposing the information into a time-varying term and a time-invariant term

M Body PL {circumflex over (V)} i =Ŵ i   [Equation 6]

V

^

i

=

M

ECI

Body

⁢

M

ECEF

ECI

⁡

[

X

i

-

X

i

S

Y

i

-

Y

i

S

Z

i

-

Z

i

S

]

ECEF

wherein

W

^

i

=

[

0

Y

i

f

]

Image

and it is assumed that all vectors are normalized.

2. The method of claim 1 , wherein a method for calculating an attitude of the plane image sensor using an image of a target obtained by the plane image sensor is any one of a DAVENPORT algorithm and a QUEST algorithm among methods for minimizing an objective function defined as the following Equation 2

J

⁡

(

A

)

=

1

2

⁢

∑

i

=

1

N

⁢

⁢



W

^

i

-

A

⁢

V

^

i



2

[

Equation

⁢

⁢

2

]

wherein J(A) is an objective function, A is a coordinate transformation matrix of the plane image sensor, N is the number of targets in the imaged image, and Ŵ i is a position vector of the imaged image, and {circumflex over (V)} i is a direction vector in an inertia coordinate system of the target.

3. The method of claim 1 , wherein the absolute misalignment estimation value M Body PL is calculated by the Equation 6 and new attitudes of the attitude control sensors are calculated by the following Equation 10

M Body S (new)= M Body S (old)( M Body PL ) T   [Equation 10]

wherein a superscript S shows the attitude control sensor.