APPARATUS AND METHOD FOR DETERMINING ORBIT OF GEOSTATIONARY SATELLITE

• US 20140055299A1
• Filed: 03/14/2013
• Published: 02/27/2014
• Est. Priority Date: 08/24/2012
• Status: Active Grant

• Current Assignee: Electronics and Telecommunications Research Institute
• Original Assignee: Electronics and Telecommunications Research Institute
• Inventors: HWANG, Yoo La, LEE, Byoung Sun
• Granted Patent: US 8,972,184 B2
• Time in Patent Office: Days
• US Class Current: 342/357.25
• CPC Class Codes: G01S 19/14 specially adapted for specific applications
• CPC Class Codes: G01S 19/42 Determining position

Abstract

An apparatus and method for determining an orbit of a geostationary satellite is provided. The orbit of the geostationary satellite may be determined using at least one pseudo-range of the geostationary satellite calculated based on an orbit and a position of at least one global positioning system (GPS) satellite, position information of the geostationary satellite, and an angle between the geostationary satellite and each GPS satellite.

Claims

1. An apparatus for determining an orbit of a geostationary satellite, the apparatus comprising:

a data calculating unit to calculate an orbit and a position of at least one global positioning system (GPS) satellite;

a measuring unit to measure position information of a geostationary satellite relative to a ground station;

an angle calculating unit to calculate an angle between the geostationary satellite and each of the at least one GPS satellite;

a pseudo-range calculating unit to calculate at least one pseudo-range of the geostationary satellite using the orbit and the position of the at least one GPS satellite, the position information of the geostationary satellite, and the angle between the geostationary satellite and each of the at least one GPS satellite; and

a position determining unit to determine an orbit of the geostationary satellite using the pseudo-range.

2. The apparatus of claim 1, wherein the position information of the geostationary satellite comprises a distance, an azimuth angle, and an elevation angle of the geostationary satellite relative to the ground station.

3. The apparatus of claim 1, wherein the measuring unit measures the position information of the geostationary satellite through antenna tracking from the ground station.

4. The apparatus of claim 1, wherein the data calculating unit calculates an ephemeris of a GPS satellite matching a time interval involved in measuring the position information of the geostationary satellite, among the at least one GPS satellite.

5. The apparatus of claim 1, wherein the measuring unit calculates an elevation difference between the geostationary satellite and each of the at least one GPS satellite relative to the ground station.

6. The apparatus of claim 1, wherein the angle calculating unit calculates the angle θ

between the geostationary satellite and each of the at least one GPS satellite through Equation 1;

θ

=cos<sup>−

1</sup>(cos Δ

α

cos Δ

α

)  

 

[Equation 1]

where Δ

α

denotes an azimuth difference between the geostationary satellite and each of the at least one GPS satellite, and Δ

θ

denotes an elevation difference between the geostationary satellite and each of the at least one GPS satellite.

7. The apparatus of claim 1, wherein the pseudo-range calculating unit calculates the at least one pseudo-range r_i through Equation 2:

r_i=√

{square root over ((R_is)²+r²−

2r(R_is)cos θ

_i )}{square root over ((R_is)²+r²−

2r(R_is)cos θ

_i )}

where θ

_i denotes an angle between the geostationary satellite and each of the at least one GPS satellite, r_i denotes a distance between the ground station and the geostationary satellite, and R_is corresponds to a distance between the ground station and each of the at least one GPS satellite.

8. The apparatus of claim 1, wherein the pseudo-range calculating unit calculates the at least one pseudo-range r_i through Equation 3:

r_i=squrt((X−

x_i)̂

2+(Y−

y_i)̂

2+(Z−

z_i)̂

2)  

 

[Equation 3]

where X, Y, and Z denote location coordinates of the geostationary satellite, and x_i, y_i, and z_i correspond to location coordinates of each of the at least one GPS satellite.

9. The apparatus of claim 8, wherein the pseudo-range calculating unit calculates a matrix A_i for a relationship between the geostationary satellite and each of the at least one GPS satellite through Equation 4:

10. The apparatus of claim 9, wherein the position determining unit determines location coordinates X of the geostationary satellite through Equation 5:

X=(A_i^TWA_i)<sup>−

1</sup>A_i^Tr_i  

 

[Equation 5]

where W denotes a weight value for geometric dilution of precision (GDOP), and r_i corresponds to the at least one pseudo-range.

11. A method of determining an orbit of a geostationary satellite, the method comprising:

calculating an orbit and a position of at least one global positioning system (GPS) satellite;

measuring position information of a geostationary satellite relative to a ground station;

calculating an angle between the geostationary satellite and each GPS satellite;

calculating at least one pseudo-range of the geostationary satellite using the orbit and the position of the at least one GPS satellite, the position information of the geostationary satellite, and the angle between the geostationary satellite and each GPS satellite; and

determining an orbit of the geostationary satellite using the pseudo-range.

12. The method of claim 11, wherein the position information of the geostationary satellite comprises a distance, an azimuth angle, and an elevation angle of the geostationary satellite relative to the ground station.

13. The method of claim 11, further comprising:

calculating an ephemeris of a GPS satellite matching a time interval involved in measuring the position information of the geostationary satellite, among the at least one GPS satellite.

14. The method of claim 11, further comprising:

calculating an elevation difference between the geostationary satellite and each of the at least one GPS satellite relative to the ground station.

15. The method of claim 11, wherein the calculating of the angle between the geostationary satellite and each of the at least one GPS satellite comprises calculating the angle θ

between the geostationary satellite and each of the at least one GPS satellite through Equation 6;

θ

=cos<sup>−

1</sup>(cos Δ

α

cos Δ

θ

)  

 

[Equation 6]

where Δ

α

denotes an azimuth difference between the geostationary satellite and each of the at least one GPS satellite, and Δ

θ

denotes an elevation difference between the geostationary satellite and each of the at least one GPS satellite.

16. The method of claim 11, wherein the calculating of the at least one pseudo-range comprises calculating the at least one pseudo-range r_i through Equation 7:

r₁=√

{square root over ((R_is)²+r²−

2r(R_is)cos θ

_i)}{square root over ((R_is)²+r²−

2r(R_is)cos θ

_i)}

where θ

_i denotes an angle between the geostationary satellite and each of the at least one GPS satellite, r_i denotes a distance between the ground station and the geostationary satellite, and R_is corresponds to a distance between the ground station and each of the at least one GPS satellite.

17. The method of claim 11, wherein the calculating of the at least one pseudo-range comprises calculating the at least one pseudo-range r_i through Equation 8:

r_i=sqrt((X−

x_i)̂

2+(Y−

y_i)̂

2+(Z−

z_i)̂

2)  

 

[Equation 8]

where X, Y, and Z denote location coordinates of the geostationary satellite, and x_i, y_i, and z_i correspond to location coordinates of each of the at least one GPS satellite.

18. The method of claim 17, wherein the calculating of the at least one pseudo-range further comprises calculating a matrix A_i for a relationship between the geostationary satellite and each of the at least one GPS satellite through Equation 9:

19. The method of claim 18, wherein the determining of the orbit of the geostationary satellite comprises determining location coordinates X of the geostationary satellite through Equation 10:

X=(A_i^TWA_i)<sup>−

1</sup>A_i^Tr_i  

 

[Equation 10]

where W denotes a weight value for geometric dilution of precision (GDOP), and r_i corresponds to the at least one pseudo-range.