Communication system, communication receiving device and communication terminal in the system

• US 6,695,259 B1
• Filed: 12/23/1999
• Issued: 02/24/2004
• Est. Priority Date: 05/21/1997
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Ito, Masahiro, Ikeda, Masahiko, Maeda, Toshihide, Owada, Masataka, Nakamura, Shigeki, Yabutani, Takashi, Hamano, Nobuo, Yoshida, Tomiharu
• Primary Examiner(s): Eldred, J. Woodrow
• Application Number:
  US09/471,503
• Time in Patent Office: 1,524 Days
• Field of Search: 244/158.R, 455/427, 455/429, 455/430
• US Class Current: 244/158.4
• CPC Class Codes: B64G 1/1007 Communications satellites
• CPC Class Codes: B64G 1/1085 Swarms and constellations
• CPC Class Codes: B64G 1/242 Orbits and trajectories
• CPC Class Codes: H04B 7/18539 Arrangements for managing radio, resources, i.e. for establishing or releasing a connection
• CPC Class Codes: H04B 7/195 Non-synchronous stations

Abstract

A communication line not affected by artificial structures and plants is established between mobile objects and stationary stations surrounded with skyscrapers, and economical artificial satellite service capable of efficiently performing satellite broadcast, mobile satellite communication, satellite-to-satellite communication and earth surveillance is provided using the communication line and by constructing the system with a small number of satellites.

Six orbital elements 7-12 of a plurality of artificial satellites at reference time 5 are determined, and a plurality of elliptical orbits corresponding to the determined six orbital elements are combined, and then each of the satellites is appropriately arranged on each of the orbits to form a group of artificial satellites. Satellite communication or satellite broadcast is performed using the group of artificial satellites.

Claims

1. A communication system comprising a plurality of artificial satellites each having a communication unit traveling on elliptical orbits with an orbital period of 24 hours, each of the orbits is formed one of (a) so that an orbital inclination angle is in a range of larger than 37 degrees and smaller than 44 degrees and an eccentricity is not larger than 0.24 and (b) so that an orbital inclination angle is in a range of larger than 40 degrees and smaller than 44 degrees and an eccentricity is in a range of larger than 0.24 and smaller than 0.35.

3. A communication system according to any one of claim 1 and claim 2, wherein arguments of perigee are set to values with a predetermined allowance in a setting process of said artificial satellites.

32. A communication system according to claim 1, wherein the plurality of artificial satellites comprise at least three artificial satellites.

2. A communication system comprising a group of artificial satellites each having a communication unit, wherein a plurality of elliptical orbits of which an apogee is located above a specified service target area are set so that an angle between right ascensions of north-bound node become a predetermined value, each of the satellites traveling on each of the elliptical orbits, the group of artificial satellites being arranged on said elliptical orbits so that at least one of the artificial satellite having the communication unit is always visible within a predetermined elevation angle with respect to a zenith direction from said service target area, wherein

said group of artificial satellites travel with an orbital period of 24 hours on the elliptical orbits, each of the orbits being formed one of (a) so that an orbital inclination angle is in a range of larger than 37 degrees and smaller than 44 degrees and an eccentricity is not larger than 0.24 and (b) so that an orbital inclination angle is in a range of larger than 40 degrees and smaller than 44 degrees and an eccentricity is in a range of larger than 0.24 and smaller than 0.35.

4. A communication system comprising a group of artificial satellites, wherein a plurality of elliptical orbits are set so that each apogee is located above a specified service target area and the orbits projected on the ground nearly agree with one another;

each of the artificial satellites having a communication unit and traveling on the elliptical orbit with an orbital period of 24 hours being arranged on each of the orbits;

right ascensions of north-bound node of said orbits being separated by an angle of 360 degrees divided by number of the satellites;

said artificial satellites being arranged so that at least one of said artificial satellites is always visible at a higher angle position than a maximum elevation angle of a stationary satellite as seen from said service target area;

said artificial satellites being arranged so that when one of said artificial satellites is at the perigee on the orbit, true anomalies of the others of said artificial satellites are separated by an angle corresponding to a time period of the orbital period divided by the number of the satellites;

said group of artificial satellites traveling on the elliptical orbits with the-orbital period of 24 hours have each of the orbits formed one of (a) so that an orbital inclination angle is in a range of larger than 37 degrees and smaller than 44 degrees and an eccentricity is not larger than 0.24 and so that an orbital inclination angle is in a range of larger than 40 degrees and smaller than 44 degrees and an eccentricity is in a range of larger than 0.24 and smaller than 0.35.

8. A communication system according to any one of claims 4, 5, 6, and 7, wherein number of said artificial satellites arranged is three or four.

5. A communication system comprising a group of artificial satellites, wherein a service target area is one of (a) an area set by latitudes and longitudes of four positions of a northernmost end, a southernmost end, a westernmost end and a easternmost end of said service target area and (b) a polygonal area including the service target area set by latitudes and longitudes other than those of said four positions when said service target area is not completely included in a quadrangle having apices of said four positions;

a plurality of elliptical orbits being set so that each apogee is located above said service target area and the orbits projected on the ground nearly agree with one another;

each of the artificial satellites having a communication unit and traveling on the elliptical orbit with an orbital period of 24 hours being arranged on each of the orbits;

right ascensions of north-bound node of said orbits being separated by an angle of 360 degrees divided by number of the satellites;

said artificial satellites being arranged so that at least one of said artificial satellites is always visible at a higher angle position than a maximum elevation angle of a stationary satellite as seen from said service target area;

said artificial-satellites being arranged so that when one of said artificial satellites is at the perigee on the orbit, true anomalies of the others of said artificial satellites are separated by an angle corresponding to a time period of the orbital period divided by the number of the satellites;

said group of artificial satellites traveling on the elliptical orbits with the orbital period of 24 hours have each of the orbits formed one of (a) so that an orbital inclination angle is in a range of larger than 37 degrees and smaller than 44 degrees and an eccentricity is not larger than 0.24 and (b) so that an orbital inclination angle is in a range of larger than 40 degrees and smaller than 44 degrees and an eccentricity is in a range of larger than 0.24 and smaller than 0.35.

6. A communication system comprising a group of artificial satellites, wherein a service target area is an area selected from the whole world within a range from latitude approximately 70 degrees north to latitude approximately 70 degrees south;

a plurality of elliptical orbits being set so that each apogee is located above said service target area and the orbits projected on the ground nearly agree with one another;

each of the artificial satellites having a communication unit and traveling on the elliptical orbit with an orbital period of 24 hours being arranged on each of the orbits;

right ascensions of north-bound node of said orbits being separated by an angle of 360 degrees divided by number of the satellites;

said artificial satellites being arranged so that at least one of said artificial satellites is always visible at a higher angle position than a maximum elevation angle of a stationary satellite seeing from said service target area;

said artificial satellites being arranged so that when one of said artificial satellites is at the perigee on the orbit, true anomalies of the others of said artificial satellites are separated by an angle corresponding to a time period of the orbital period divided by the number of the satellites;

an orbital inclination angle and an eccentricity of said elliptical orbit being set to values within corresponding ranges in combination with each other.

7. A communication system comprising a group of artificial satellites, wherein a service target area is an area selected from the whole world within a range from latitude approximately 85 degrees north to latitude approximately 85 degrees south;

a plurality of elliptical orbits being set so that each apogee is located above said service target area and the orbits projected on the ground nearly agree with one another;

each of the artificial satellites having a communication unit and traveling on the elliptical orbit with an orbital period of 24 hours being arranged on each of the orbits;

right ascensions of north-bound node of said orbits being separated by an angle of 360 degrees divided by number of the satellites;

said artificial satellites being arranged so that at least one of said artificial satellites is always visible at a higher angle position than a maximum elevation angle of a stationary satellite seeing from said service target area;

said artificial satellites being arranged so that when one of said artificial satellites is at the perigee on the orbit, true anomalies of the others of said artificial satellites are separated by an angle corresponding to a time period of the orbital period divided by the number of the satellites;

an orbital inclination angle and an eccentricity of said elliptical orbit being set to values within corresponding ranges in combination with each other.

9. A communication system comprising a group of artificial satellites each having a communication unit, wherein a plurality of elliptical orbits of which an apogee is located above a specified service target area are set so that an angle between right ascensions of north-bound node become a predetermined value, each of the satellites traveling on each of the elliptical orbits, the group of artificial satellites being arranged on said elliptical orbits so that at least one of the artificial satellite having the communication unit is always visible within a predetermined elevation angle with respect to a zenith direction from said service target area, wherein said group of artificial satellites are a plurality of artificial satellites of which arguments of perigee are set to values with a predetermined allowance in a setting process of said plurality of artificial satellites.

10. A communication system comprising a group of artificial satellites, wherein a service target area is an area set by latitudes and longitudes of four positions of a northernmost end, a southernmost end, a westernmost end and a easternmost end of said service target area, or a polygonal area including the whole service target area set by latitudes and longitudes other than those of said four positions when said service target area is not completely included in said quadrangle having apices of said four positions;

a plurality of elliptical orbits being set so that each apogee is located above said service target area and the orbits projected on the ground nearly agree with one another;

each of the artificial satellites having a communication unit and traveling on the elliptical orbit with an orbital period of 12 hours or 24 hours being arranged on each of the orbits;

right ascensions of north-bound node of said orbits being separated by an angle of 360 degrees divided by number of the satellites;

said artificial satellites being arranged so that at least one of said artificial satellites is always visible at a higher angle position than a maximum elevation angle of a stationary satellite seeing from said service target area;

said artificial satellites being arranged so that when one of said artificial satellites is at the perigee on the orbit, true anomalies of the others of said artificial satellites are separated by an angle corresponding to a time period of the orbital period divided by the number of the satellites;

an orbital inclination angle and an eccentricity of said elliptical orbit being set to values within corresponding ranges in combination with each other;

said group of artificial satellites being a plurality of artificial satellites of which arguments of perigee are set to values with a predetermined allowance in a setting process of said plurality of artificial satellites.

13. A communication system according to any one of claims 9, 10, 11 and 12, wherein number of said artificial satellites arranged is three or four.

14. A communication system according to any one of claims 9, 10, 11 and 12, wherein said setting range of argument of perigee is 210 to 290 degrees.

15. A communication system according to any one of claims 9, 10, 11 and 12, wherein an initial value on the orbit to said setting range of argument of perigee is not larger than 270 degrees.

11. A communication system comprising a group of artificial satellites, wherein a service target area is an area selected from the whole world within a range from latitude approximately 70 degrees north to latitude approximately 70 degrees south;

a plurality of elliptical orbits being set so that each apogee is located above said service target area and the orbits projected on the ground nearly agree with one another;

each of the artificial satellites having a communication unit and traveling on the elliptical orbit with an orbital period of 12 hours or 24 hours being arranged on each of the orbits;

right ascensions of north-bound node of said orbits being separated by an angle of 360 degrees divided by number of the satellites;

said artificial satellites being arranged so that at least one of said artificial satellites is always visible at a higher angle position than a maximum elevation angle of a stationary satellite seeing from said service target area;

said artificial satellites being arranged so that when one of said artificial satellites is at the perigee on the orbit, true anomalies of the others of said artificial satellites are separated by an angle corresponding to a time period of the orbital period divided by the number of the satellites;

an orbital inclination angle and an eccentricity of said elliptical orbit being set to values within corresponding ranges in combination with each other;

said group of artificial satellites being a plurality of artificial satellites of which arguments of perigee are set to values with a predetermined allowance in a setting process of said plurality of artificial satellites.

12. A communication system comprising a group of artificial satellites, wherein a service target area is an area selected from the whole world within a range from latitude approximately 85 degrees north to latitude approximately 85 degrees south;

a plurality of elliptical orbits being set so that each apogee is located above said service target area and the orbits projected on the ground nearly agree with one another;

each of the artificial satellites having a communication unit and traveling on the elliptical orbit with an orbital period of 12 hours or 24 hours being arranged on each of the orbits;

right ascensions of north-bound node of said orbits being separated by an angle of 360 degrees divided by number of the satellites;

said artificial satellites being arranged so that at least one of said artificial satellites is always visible at a higher angle position than a maximum elevation angle of a stationary satellite seeing from said service target area;

said artificial satellites being arranged so that when one of said artificial satellites is at the perigee on the orbit, true anomalies of the others of said artificial satellites are separated by an angle corresponding to a time period of the orbital period divided by the number of the satellites;

an orbital inclination angle and an eccentricity of said elliptical orbit being set to values within corresponding ranges in combination with each other;

said group of artificial satellites being a plurality of artificial satellites of which arguments of perigee are set to values with a predetermined allowance in a setting process of said plurality of artificial satellites.

16. An orbit arranging method for artificial satellites, wherein a plurality of artificial satellites are arranged so that four elements of a semi-major axis, an eccentricity, an argument of perigee and an orbital inclination angle of the artificial satellite traveling on an orbit are set to nearly equal values among the artificial satellites, and said value of argument of perigee is set with a predetermined allowance.

17. An orbit arranging method for artificial satellites, wherein a plurality of artificial satellites are arranged so that four elements of a semi-major axis, an eccentricity, an argument of perigee and an orbital inclination angle of the artificial satellite traveling on an orbit are set to nearly equal values among the artificial satellites and so as to be spaced a true anomaly of nearly 360 degrees/N (N is number of the satellites), and said value of argument of perigee is set with a predetermined allowance.

18. A communication system comprising a group of artificial satellites each having a communication system composed of three or four artificial satellites traveling on different three or four elliptical orbits, wherein

each of said artificial satellites is arranged on each of said elliptical orbits;

a semi-major axis among orbital elements of each of the artificial satellites being set so that an orbital period becomes 24 hours, the orbit on which each of the artificial satellites travels being formed one of (a) so that an orbital inclination angle is in a range of larger than 37 degrees and smaller than 44 degrees and an eccentricity is not larger than 0.24 and (b) so that an orbital inclination angle is larger than 40 degrees and smaller than 44 degrees and an eccentricity is larger than 0.24 and smaller than 0.35;

orbital configuration of each of the artificial satellites is formed so that four elements of a semi-major axis, an eccentricity, an argument of perigee and an orbital inclination angle of the artificial satellite traveling on an orbit are set to nearly equal values among the artificial satellites, and said value of argument of perigee is set with a predetermined allowance.

19. A tracking and controlling facility for tracking and controlling an artificial satellite, wherein

an artificial satellite to be tracked and controlled is (1) an artificial satellite traveling on an elliptical orbit with an orbital period of 24 hours, the orbit is formed so that an orbital inclination angle is larger than 37 degrees and smaller than 44 degrees and an eccentricity is not larger than 0.24, or so that an orbital inclination angle is larger than 40 degrees and smaller than 44 degrees and an eccentricity is larger than 0.24 and smaller than 0.35;

or

(2) an artificial satellite traveling on an elliptical orbit, wherein an argument of perigee is set to a value with a predetermined allowance in a setting process of said artificial satellite;

or

(3) an artificial satellite traveling on an orbit derived from the orbit arranging method according to any one of claims 18 and 19, or

a group of artificial satellites to be tracked and controlled are (4) a group of artificial satellites composed of three or four artificial satellites traveling on different three or four elliptical orbits, wherein each of said artificial satellites is arranged on each of said elliptical orbits;

a semi-major axis among orbital elements of each of the artificial satellites being set so that an orbital period becomes 24 hours, the orbit on which each of the artificial satellites travels being formed so that an orbital inclination angle is larger than 37 degrees and smaller than 44 degrees and an eccentricity is not larger than 0.24, or so that an orbital inclination angle is larger than 40 degrees and smaller than 44 degrees and an eccentricity is larger than 0.24 and smaller than 0.35;

or

(5) a group of artificial satellites composed of three or four artificial satellites traveling on different three or four elliptical orbits, wherein an argument of perigee is set to a value with a predetermined allowance in a setting process of each of said group of artificial satellites.

20. A satellite broadcast system comprising an artificial satellite, a satellite broadcast terminal for receiving satellite broadcast through said artificial satellite, and a base station for performing broadcast to the satellite broadcast terminal through said artificial satellite, wherein

said artificial satellite is (1) an artificial satellite traveling on an elliptical orbit with an orbital period of 24 hours, the orbit is formed so that an orbital inclination angle is larger than 37 degrees and smaller than 44 degrees and an eccentricity is not larger than 0.24, or so that an orbital inclination angle is larger than 40 degrees and smaller than 44 degrees and an eccentricity is larger than 0.24 and smaller than 0.35;

or

(2) an artificial satellite traveling on an elliptical orbit, wherein an argument of perigee is set to a value with a predetermined allowance in a setting process of said artificial satellite;

or

(3) an artificial satellite traveling on an orbit derived from the orbit arranging method according to any one of claims 18, and 19, or

a group of artificial satellites to be tracked and controlled are (4) a group of artificial satellites composed of three or four artificial satellites traveling on different three or four elliptical orbits, wherein each of said artificial satellites is arranged on each of said elliptical orbits;

a semi-major axis among orbital elements of each of the artificial satellites being set so that an orbital period becomes 24 hours, the orbit on which each of the artificial satellites travels being formed so that an orbital inclination angle is larger than 37 degrees and smaller than 44 degrees and an eccentricity is not larger than 0.24, or so that an orbital inclination angle is larger than 40 degrees and smaller than 44 degrees and an eccentricity is larger than 0.24 and smaller than 0.35;

or

(5) a group of artificial satellites composed of three or four artificial satellites traveling on different three or four elliptical orbits, wherein an argument of perigee is set to a value with a predetermined allowance in a setting process of each of said group of artificial satellites.

21. A satellite broadcast terminal used in the satellite broadcast system described in claim 20, which comprises

means for receiving satellite broadcast through the artificial satellite and means for receiving an electromagnetic wave from a ground broadcast station.

22. A satellite broadcast terminal used in the satellite broadcast system described in claim 20, which comprises

means for receiving satellite broadcast through the artificial satellite and means for sending information to the base station by a communication means not through the artificial satellite.

23. A mobile object comprising the satellite broadcast terminal described in any one of claims 20 to 21.

24. A satellite communication system comprising at least an artificial satellite, a for performing satellite communication through said artificial satellite and a base station for performing communication with the satellite communication send and receive apparatus through said artificial satellite, wherein

said artificial satellite is (1) an artificial satellite traveling on an elliptical orbit with an orbital period of 24 hours, the orbit is formed so that an orbital inclination angle is larger than 37 degrees and smaller than 44 degrees and an eccentricity is not larger than 0.24, or so that an orbital inclination angle is larger than 40 degrees and smaller than 44 degrees and an eccentricity is larger than 0.24 and smaller than 0.35;

or

(2) an artificial satellite traveling on an orbit derived from the orbit arranging method according to any one of claims 18 and 19, or

a group of artificial satellites to be tracked and controlled are (3) a group of artificial satellites composed of three or four artificial satellites traveling on different three or four elliptical orbits, wherein each of said artificial satellites is arranged on each of said elliptical orbits;

a semi-major axis among orbital elements of each of the artificial satellites being set so that an orbital period becomes 24 hours, the orbit on which each of the artificial satellites travels being formed so that an orbital inclination angle is larger than 37 degrees and smaller than 44 degrees and an eccentricity is not larger than 0.24, or so that an orbital inclination angle is larger than 40 degrees and smaller than 44 degrees and an eccentricity is larger than 0.24 and smaller than 0.35;

or

(4) a group of artificial satellites composed of three or four artificial satellites traveling on different three or four elliptical orbits, wherein an argument of perigee is set to a value with a predetermined allowance in a setting process of each of said group of artificial satellites.

25. A satellite communication send and receive apparatus used in the satellite communication system described in claim 24, which comprises

means for performing satellite communication through the artificial satellite;

and a measuring means for measuring at least its own position by receiving an electromagnetic wave from a GPS satellite.

26. A satellite communication send and receive apparatus used in the satellite communication system described in claim 24, which comprises

means for performing satellite communication through the artificial satellite;

and a measuring means for measuring a consumed amount with regard to at least one of electricity, city gas and city water.

27. A satellite communication send and receive apparatus used in the satellite communication system described in claim 24, which comprises

means for performing satellite communication through the artificial satellite;

and means for collecting and relaying information on an information network.

28. A satellite communication send and receive apparatus used in the satellite communication system described in claim 24, which comprises

means for performing satellite communication through the artificial satellite;

and means for monitoring environment.

29. A satellite communication send and receive apparatus used in the satellite communication system described in claim 24, which comprises

means for performing satellite communication through the artificial satellite;

and means for detecting an abnormality.

30. A mobile object comprising the satellite communication send and receive apparatus described in any one of claims 25 to 29.

31. A survey ground station for receiving a survey result transmitted from an artificial satellite mounting an earth survey unit, wherein

a satellite communication system comprising at least an artificial satellite, a for performing satellite communication through said artificial satellite and a base station for performing communication with the satellite communication send and receive apparatus through said artificial satellite, wherein

said artificial satellite is (1) an artificial satellite traveling on an elliptical orbit with an orbital period of 24 hours, the orbit is formed so that an orbital inclination angle is larger than 37 degrees and smaller than 44 degrees and an eccentricity is not larger than 0.24, or so that an orbital inclination angle is larger than 40 degrees and smaller than 44 degrees and an eccentricity is larger than 0.24 and smaller than 0.35;

or

(2) an artificial satellite traveling on an orbit derived from the orbit arranging method according to any one of claims 18 and 19, or

a group of artificial satellites to be tracked and controlled are (3) a group of artificial satellites composed of three or four artificial satellites traveling on different three or four elliptical orbits, wherein each of said artificial satellites is arranged on each of said elliptical orbits;

a semi-major axis among orbital elements of each of the artificial satellites being set so that an orbital period becomes 24 hours, the orbit on which each of the artificial satellites travels being formed so that an orbital inclination angle is larger than 37 degrees and smaller than 44 degrees and an eccentricity is not larger than 0.24, or so that an orbital inclination angle is larger than 40 degrees and smaller than 44 degrees and an eccentricity is larger than 0.24 and smaller than 0.35;

or

(4) a group of artificial satellites composed of three or four artificial satellites traveling on different three or four elliptical orbits, wherein an argument of perigee is set to a value with a predetermined allowance in a setting process of each of said group of artificial satellites.