Artificial satellite and method of controlling the same

Patent metadata

Field	Value
Publication number	US-11155369-B2
Application number	US-201816027705-A
Country	US
Kind code	B2
Filing date	Jul 5, 2018
Priority date	Aug 16, 2017
Publication date	Oct 26, 2021
Grant date	Oct 26, 2021

Abstract

Provided are an artificial satellite and a method of controlling the same. The artificial satellite includes a main body flying along an orbit of a planet, an optical payload arranged on the main body to photograph a ground surface of the planet, and a pair of solar cell panels rotatably arranged on both sides of the main body in a first direction, wherein the first direction and a flight direction of the main body form an acute angle with each other.

First claim

What is claimed is:

1. An artificial satellite comprising:
a main body flying along an orbit of a planet;
an optical payload arranged on the main body to photograph a ground surface of the planet;
a pair of solar cell panels rotatably arranged on both sides of the main body in a first direction;
a rotation driver rotating the pair of solar cell panels on a rotation axis of the first direction with respect to the main body; and
a controller configured to control the rotation driver to rotate the pair of solar cell panels by a rotation angle θ,
wherein the controller determines the rotation angle θ based on a latitude φ where the artificial satellite is currently located, a beta angle β between a star direction u x and an orbital plane of an orbit where the artificial satellite is currently rotating, and an angle (90-ψ) between the first direction and a flight direction of the main body, and controls the rotation driver to rotate the pair of solar cell panels by the determined rotation angle θ,
wherein the angle (90-ψ) between the first direction and the flight direction is an acute angle.

2. The artificial satellite of claim 1 , wherein the optical payload comprises a linear image sensor comprising pixels arranged in a line in a second direction perpendicular to the flight direction.

3. The artificial satellite of claim 1 , wherein the optical payload comprises a line scan camera photographing the ground surface in such a manner as to scan a line region in a second direction perpendicular to the flight direction on a line-by-line basis along the flight direction.

4. An artificial satellite comprising:
a main body flying along an orbit of a planet;
a pair of solar cell panels rotatably arranged on both sides of the main body in a first direction;
a linear image sensor arranged on the main body and comprising pixels arranged in a line in a second direction, the second direction forming an acute angle with the first direction;
a rotation driver rotating the pair of solar cell panels on a rotation axis of the first direction with respect to the main body; and
a controller configured to control the rotation driver to rotate the pair of solar cell panels by a rotation angle θ,
wherein the controller determines the rotation angle θ based on a latitude φ where the artificial satellite is currently located, a beta angle β between a star direction u x and an orbital plane of an orbit where the artificial satellite is currently rotating, and an angle ψ between the first direction and the second direction or an angle (90-ψ) between the first direction and the flight direction, and controls the rotation driver to rotate the pair of solar cell panels by the determined rotation angle θ.

5. The artificial satellite of claim 4 , wherein the artificial satellite flies on the orbit of the planet in a flight direction perpendicular to the second direction.

6. The artificial satellite of claim 4 , wherein an angle between the first direction and the flight direction or the second direction is about 30 degrees to about 60 degrees.

7. The artificial satellite of claim 4 , wherein an angle between the first direction and the flight direction or the second direction is about 45 degrees.

8. The artificial satellite of claim 4 , wherein a normal direction of the pair of soar cell panels is perpendicular to the rotation axis.

9. The artificial satellite of claim 4 , wherein a center of mass of the pair of solar cell panels is located on an extension line of the rotation axis regardless of the rotation of the pair of solar cell panels.

10. The artificial satellite of claim 4 , wherein the rotation angle θ is an angle of a normal direction S 2 of the pair of solar cell panels with respect to a vertical direction S 1 from the ground surface to the artificial satellite.

11. The artificial satellite of claim 10 , wherein the controller calculates the rotation angle θ as θ=cos −1 ({right arrow over (S 1 )}·{right arrow over (S 2 )}), where a first vector {right arrow over (S 1 )} is a unit vector of the vertical direction S 1 and a second vector {right arrow over (S 2 )} is a unit vector of the normal direction S 2 .

12. The artificial satellite of claim 11 , wherein the controller calculates the first vector {right arrow over (S 1 )} as

S
1

→

=

[

cos
⁡

(
β
)

⁢

cos
⁡

(
ϕ
)

sin
⁡

(
β
)

⁢

cos
⁡

(
ϕ
)

sin
⁡

(
ϕ
)

]

based on the latitude φ and beta angle β.

13. The artificial satellite of claim 11 , wherein the controller calculates the second vector {right arrow over (S 2 )} as {right arrow over (S 2 )}=a({right arrow over (Y b )}+b{right arrow over (u x )}) based on a unit vector {right arrow over (Y b )} of the first direction and a unit vector {right arrow over (u x )} of the star direction, where “a” is a normalization constant and “b” is a constant determined such that the second vector {right arrow over (S 2 )} and the unit vector {right arrow over (Y b )} of the first direction are perpendicular to each other.

14. The artificial satellite of claim 13 , wherein the controller calculates the unit vector {right arrow over (Y b )}, of the first direction as

Y
b

→

=

[

Y
bx

Assignees

• Korea Aerospace Res Inst

Inventors

• JEON Moon-Jin
• Choi Seok-Weon
• Lim Seong-Bin

Classifications

• H04N25/701

  Line sensors · CPC title

• B64G1/244

  Spacecraft control systems · CPC title

• B64G1/26

  using jets · CPC title

• H10F19/00

  Integrated devices, or assemblies of multiple devices, comprising at least one photovoltaic cell covered by group H10F10/00, e.g. photovoltaic modules · CPC title

• B64G1/105 Primary

  Space science · CPC title