Apparatus and method for controlling a satellite

Patent metadata

Field	Value
Publication number	US-9751645-B2
Application number	US-201514955514-A
Country	US
Kind code	B2
Filing date	Dec 1, 2015
Priority date	Sep 10, 2015
Publication date	Sep 5, 2017
Grant date	Sep 5, 2017

Abstract

Provided is an apparatus for controlling an orbiting satellite by sensing a change in a yaw angle of the orbiting satellite and calculating a ground sample distance (GSD) based on the yaw angle. The apparatus may include a sensor configured to sense a yaw angle corresponding to yaw steering of the orbiting satellite, and a processor configured to calculate, based on the yaw angle, a GSD corresponding to a length of a pixel projected onto a planetary surface scanned by the orbiting satellite.

First claim

What is claimed is:

1. An apparatus for controlling an orbiting satellite, the apparatus comprising:
a sensor configured to sense a yaw angle corresponding to yaw steering of the orbiting satellite; and
a processor configured to calculate a ground sample distance (GSD) based on the yaw angle, the GSD corresponding to a length of a pixel projected onto a planetary surface of a planet being scanned by the orbiting satellite;
wherein the processor is configured to:
calculate a major axis and a minor axis of an ellipse corresponding to a trace of the projected pixel based on a change in the yaw angle;
calculate a tilt angle between a direction vector and a line of sight (LOS) vector projected onto the planetary surface; and
calculate the GSD according to the following equation:
GSD =√{square root over ( a 2 cos(ψ+β) 2 +b 2 sin(ψ+β) 2 )}

wherein:
a is a length of the major axis;
ψ is the sensed yaw angle;
β is the calculated tilt angle; and
b is a length of the minor axis.

2. The apparatus of claim 1 , wherein the processor is configured to calculate the length of the major axis and the length of the minor axis based on a radius of the planet, an altitude from the planet to the orbiting satellite, an angle at which a pixel is viewed from a scanning focal point of the orbiting satellite, and an angle between a vertical vector from the orbiting satellite to the planet and a vector from the orbiting satellite to a scanning point at which the planet is scanned.

3. The apparatus of claim 1 , wherein the sensor is configured to sense a roll angle and a pitch angle of the orbiting satellite and the processor is configured to calculate the length of the major axis and the length of the minor axis using the following equation:

a
=

c

cos
⁡

(
θ
)

⁢
cos
⁢

⁢

(
ϕ
)

,

b
=
c

where a denotes the length of the major axis, b denotes the length of the minor axis, φ denotes the roll angle, θ denotes the pitch angle, and c denotes the length of the pixel.

Assignees

• Korea Aerospace Res Inst

Inventors

• Jeon Moon Jin
• Lee Sang Rok
• Kim Hui Kyung
• Kim Eung Hyun
• Lim Seong Bin
• Choi Seok Weon

Classifications

• G05D1/0883

  Physics · mapped topic

• G05D1/0094

  involving pointing a payload, e.g. camera, weapon, sensor, towards a fixed or moving target · CPC title

• B64G1/365 Primary

  using horizon or Earth sensors · CPC title

• B64G1/26

  using jets · CPC title

• B64G1/1021

  Earth observation satellites · CPC title