US4958788A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Orbit control system for a satellite
Assignee: NEC Corp
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Filing: 1989-10-16
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Granted: 1990-09-25
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Expires: 2009-10-16
Abstract
Abstract A system for controlling the orbit of a satellite by operating a plurality of thrusters is disclosed. In the system, an actual attitude of the satellite is sensed, an evaluation is set up on the basis of the sensed attitude and compared with a threshold which is adequately changing, and the ON-OFF condition of the firing of the thrusters is based on the relationship between the evaluation value and the threshold.
Inventors
- 👤 Takakazu Namera
- 👤 Naoto Ogura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 12:56
CPC Classifications
B; B64; B64G; B64G1/00; B64G1/22; B64G1/24; B64G1/244
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
158 words
A system for controlling orbit of a satellite which has a plurality of gas jet thrusters, comprising: a sensing means for sensing an attitude of the satellite; a setting means for setting up a predetermined evaluation value in response to an output of said sensing means; OFF control means for turning OFF an orbital control thruster when, at least during a predetermined period of time after the initiation of orbit control, the evaluation value exceeds a given value of a threshold A which is sequentially varied to prevent an attitude error angle of the satellite from becoming excessively high; and ON control means for turning ON said orbital control thruster when, at least during said predetermined period of time, the evaluation value after said orbital control thruster has been turned OFF becomes smaller than a given value of a threshold B which is sequentially varied to prevent an attitude error angle of the satellite from becoming excessively high.
Claim 2
Independent Claim
158 words
A system for controlling orbit of a satellite which has a plurality of gas jet thrusters, comprising: a sensing means for sensing an attitude of the satellite; a setting means for setting up a predetermined evaluation value in response to an output of said sensing means; OFF control means for turning OFF an orbital control thruster when, at least during a predetermined period of time after the initiation of orbit control, the evaluation value exceeds a given value of a threshold A which is sequentially varied to prevent an attitude error angle of the satellite from becoming excessively high; and ON control means for turning ON said orbital control thruster when, at least during said predetermined period of time, the evaluation value after said orbital control thruster has been turned OFF becomes smaller than a given value of a threshold B which is sequentially varied to prevent an attitude error angle of the satellite from becoming excessively high.
Claim 3
Dependent Claim
18 words
A system as claimed in claim 1, wherein the thresholds A and B are equal to each other.
Claim 4
Dependent Claim
18 words
A system as claimed in claim 1, wherein the thresholds A and B are different from each other.
Claim 5
Dependent Claim
23 words
A system as defined in claim 1, wherein the predetermined evaluation value is a function of an attitude error angle of the satellite.
Claim 6
Dependent Claim
19 words
A system as defined in claim 4, wherein the predetermined evaluation value is proportional to the attitude error angle.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-09-24 | 1994-03-26 | 1994-09-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-09-24 | 1998-03-26 | 1998-09-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-09-24 | 2002-03-26 | 2002-09-25 | $7700.00 | Window Closed / Lapsed |