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US6134484A
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Method and apparatus for maintaining the integrity of spacecraft based time and position using GPS
Assignee: General Dynamics Mission Systems Inc
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Filing: 2000-01-28
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Granted: 2000-10-17
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Expires: 2020-01-28
Abstract
Abstract A method and apparatus for maintaining the integrity of spacecraft based time and position using GPS (11) is disclosed. A GPS receiver is provided with a Receiver Autonomous Integrity Monitor (RAIM) processor (12) and a Kalman filter (14). GPS signals are received from at least four GPS satellites and processed in the GPS receiver to provide time and position information. Periodically, an extended fault vector is formed in the Kalman filter with propagated open-loop position and velocity measurements. The extended fault vector is used to isolate and remove failing GPS satellites.
Inventors
- 👤 George Jeffrey Geier
- 👤 Roger Charles Hart
- 👤 Gaylin David Brenchley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 16:14
CPC Classifications
G; G01; G01S; G01S19/00; G01S19/01; G01S19/13; G01S19/20; H; H04; H04B; H04B7/00; H04B7/14; H04B7/15; H04B7/185; H04B7/1851; H04B7/18519
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
109 words
A method for maintaining the integrity of spacecraft based time and position using the Global Positioning System (GPS) comprising the steps of: providing a GPS receiver coupled to a Receiver Autonomous Integrity Monitor (RAIM) processor and a Kalman filter; receiving GPS signals from GPS satellites and processing the GPS signals in the GPS receiver to provide time and position information; periodically forming an extended fault vector in the Kalman filter with propagated open-loop position and velocity measurements; the step of periodically forming the extended fault vector includes inputting a spacecraft acceleration model into the Kalman filter; and using the extended fault vector to isolate and remove failing GPS satellites.
Claim 2
Independent Claim
109 words
A method for maintaining the integrity of spacecraft based time and position using the Global Positioning System (GPS) comprising the steps of: providing a GPS receiver coupled to a Receiver Autonomous Integrity Monitor (RAIM) processor and a Kalman filter; receiving GPS signals from GPS satellites and processing the GPS signals in the GPS receiver to provide time and position information; periodically forming an extended fault vector in the Kalman filter with propagated open-loop position and velocity measurements; the step of periodically forming the extended fault vector includes inputting a spacecraft acceleration model into the Kalman filter; and using the extended fault vector to isolate and remove failing GPS satellites.
Claim 3
Dependent Claim
49 words
A method for maintaining the integrity of spacecraft based time and position using the Global Positioning System (GPS) as claimed in claim 1 wherein the step of periodically forming the extended fault vector includes forming the extended fault vector at intervals which are long relative to Selective Availability (SA).
Claim 4
Dependent Claim
45 words
A method for maintaining the integrity of spacecraft based time and position using the Global Positioning System (GPS) as claimed in claim 1 wherein the step of periodically forming the extended fault vector includes forming the extended fault vector at intervals of approximately 300 seconds.
Claim 5
Independent Claim
132 words
A method for maintaining the integrity of spacecraft based time and position using the Global Positioning System (GPS) comprising the steps of: providing a GPS receiver coupled to a Receiver Autonomous Integrity Monitor (RAIM) processor and a Kalman filter; receiving GPS signals from GPS satellites and processing the GPS signals in the GPS receiver to provide time and position information; computing unit variance in the RAIM processor and using the unit variance to desensitize the Kalman filter to off-nominal conditions; periodically forming an extended fault vector in the Kalman filter with propagated open-loop position and velocity measurements; the step of periodically forming the extended fault vector includes inputting a spacecraft acceleration model into the Kalman filter; and using the extended fault vector to isolate failures of GPS satellites and failing GPS satellites.
Claim 6
Independent Claim
132 words
A method for maintaining the integrity of spacecraft based time and position using the Global Positioning System (GPS) comprising the steps of: providing a GPS receiver coupled to a Receiver Autonomous Integrity Monitor (RAIM) processor and a Kalman filter; receiving GPS signals from GPS satellites and processing the GPS signals in the GPS receiver to provide time and position information; computing unit variance in the RAIM processor and using the unit variance to desensitize the Kalman filter to off-nominal conditions; periodically forming an extended fault vector in the Kalman filter with propagated open-loop position and velocity measurements; the step of periodically forming the extended fault vector includes inputting a spacecraft acceleration model into the Kalman filter; and using the extended fault vector to isolate failures of GPS satellites and failing GPS satellites.
Claim 7
Dependent Claim
49 words
A method for maintaining the integrity of spacecraft based time and position using the Global Positioning System (GPS) as claimed in claim 4 wherein the step of periodically forming the extended fault vector includes forming the extended fault vector at intervals which are long relative to Selective Availability (SA).
Claim 8
Dependent Claim
45 words
A method for maintaining the integrity of spacecraft based time and position using the Global Positioning System (GPS) as claimed in claim 4, wherein the step of periodically forming the extended fault vector includes forming the extended fault vector at intervals of approximately 300 seconds.
Claim 9
Dependent Claim
41 words
A method for maintaining the integrity of spacecraft based time and position using the Global Positioning System (GPS) as claimed in claim 4 wherein the step of computing unit variance includes computing pseudo ranges from the received time and position information.
Claim 10
Dependent Claim
51 words
A method for maintaining the integrity of spacecraft based time and position using the Global Positioning System (GPS) as claimed in claim 4 wherein the step of receiving GPS signals includes receiving carrier phase data and the step of computing unit variance includes computing delta ranges from differenced carrier phase data.
Claim 11
Independent Claim
118 words
An apparatus for maintaining the integrity of spacecraft based time and position using the Global Positioning System (GPS) comprising: a GPS receiver; a Receiver Autonomous Integrity Monitor (RAIM) processor coupled to receive signals from the GPS receiver; a Kalman filter coupled to receive signals from the RAIM processor; a spacecraft acceleration model coupled to provide information to the Kalman filter to generate an extended fault vector; an open loop propagator coupled to receive extended fault vector information from the Kalman filter and supplying open-loop position and velocity measurements to the RAIM processor; and the RAIM processor, Kalman filter, spacecraft acceleration model, and open loop propagator are all functions performed in a single processor embedded in the GPS receiver.
Claim 12
Independent Claim
118 words
An apparatus for maintaining the integrity of spacecraft based time and position using the Global Positioning System (GPS) comprising: a GPS receiver; a Receiver Autonomous Integrity Monitor (RAIM) processor coupled to receive signals from the GPS receiver; a Kalman filter coupled to receive signals from the RAIM processor; a spacecraft acceleration model coupled to provide information to the Kalman filter to generate an extended fault vector; an open loop propagator coupled to receive extended fault vector information from the Kalman filter and supplying open-loop position and velocity measurements to the RAIM processor; and the RAIM processor, Kalman filter, spacecraft acceleration model, and open loop propagator are all functions performed in a single processor embedded in the GPS receiver.
Claim 13
Dependent Claim
36 words
An apparatus for maintaining the integrity of spacecraft based time and position using the Global Positioning System (GPS) as claimed in claim 9 wherein the GPS receiver includes at least four channels for tracking GPS satellites.
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) | 2003-10-17 | 2004-04-17 | 2004-10-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-10-17 | 2008-04-17 | 2008-10-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-10-17 | 2012-04-17 | 2012-10-17 | $7700.00 | Window Closed / Lapsed |