Communications: directive radio wave systems and devices (e.g. – Directive – Including a satellite
Reexamination Certificate
2000-12-22
2002-01-22
Issing, Gregory C. (Department: 3662)
Communications: directive radio wave systems and devices (e.g.,
Directive
Including a satellite
C342S387000
Reexamination Certificate
active
06340947
ABSTRACT:
TECHNICAL FIELD
This invention relates to methods and systems for determining a position of a transceiver unit, such as employed on an aircraft, utilizing two-way ranging in a polystatic satellite configuration including a ground radar.
BACKGROUND ART
Current Automatic Dependent Surveillance (ADS) technology, such as Global Positioning System (GPS), Wide Area Augmentation System (WAAS) or GLONASS, provides positioning information utilizing satellite transmissions. For example, the GPS, developed and deployed by the U.S. Department of Defense, consists of 24 satellites orbiting the earth twice a day at an altitude of 12,000 miles, as well as five ground stations to monitor and manage the satellite constellation. Using atomic clocks and location data, GPS satellites transmit continuous time more satellites at once to determine the user's position. By measuring the time interval between the transmission and the reception of a satellite signal, the GPS receiver calculates the distance between the user and each satellite, and then uses the distance measurements of at least three satellites to arrive at a position.
Such systems, however, utilize one-way ranging in which an accurate, synchronized clock is required at each station. Any synchronization error or error regarding the location of one of the satellites results in an error in the determined position of the target vehicle. Thus, there is a need to provide very accurate position and velocity information with a high degree of integrity and reliability.
DISCLOSURE OF THE INVENTION
It is thus a general object of the present invention to provide a method and system for determining a location of an object with a high degree of integrity and reliability utilizing two-way ranging in a polystatic satellite configuration to derive independent estimates of the transceiver's state vectors including position and velocity.
In carrying out the above object and other objects, features, and advantages of the present invention, a method is provided for determining position of an object. The method includes the steps of transmitting a first ranging signal from a first known ground location to the object and transmitting a second ranging signal in response to the first ranging signal to the first known ground location. The method also includes the steps of transmitting a third ranging signal in response to the first ranging signal to a second known location and transmitting a fourth ranging signal in response to the third ranging signal to a third known location. The method further includes the step of determining a first delay corresponding to a time difference between transmission of the first ranging signal and receipt of the second ranging signal. The method also includes the step of determining a second delay corresponding to a time difference between transmission of the first ranging signal and receipt of the third ranging signal. Still further, the method includes the step of determining a third delay corresponding to a time difference between transmission of the first ranging signal and receipt of the fourth ranging signal. The method finally includes the step of determining the position of the object based on the first, second, and third known locations and the first, second and third delays.
In further carrying out the above object and other objects, features, and advantages of the present invention, a system is also provided for carrying out the steps of the above described method. The system includes a ground transceiver at a first known ground location for providing a bidirectional communication path between the ground transceiver and the object wherein the ground transceiver transmits a first ranging signal to the object and the object transmits a second ranging signal to the ground transceiver in response to the first ranging signal. The system also includes a first communication transceiver at a second known location for providing a first unidirectional communication path between the first communication transceiver and the object wherein the first communication transceiver performs one of transmitting a third ranging signal to the object and receiving a third ranging signal from the object in response to the first ranging signal. The system further includes a second communication transceiver at a third known location for providing a second unidirectional communication path between the second communication transceiver and the object wherein the second communication transceiver performs one of transmitting a fourth ranging signal to the object and receiving a fourth ranging signal from the object in response to the first ranging signal. Finally, the system includes a signal processor for determining a first path length corresponding to a first time length of the bidirectional communication path, determining a second path length corresponding to a second time length of the first unidirectional communication path, determining a third path length corresponding to a third time length of the second unidirectional communication path, and determining the position of the object based on the first, second, and third known locations and the first, second, and third path lengths.
The above object and other object, features and advantages of the present invention are readily apparent from the following detailed description of the best mode for carrying out the invention when taken in connection with the accompanying drawings.
REFERENCES:
patent: 2470787 (1949-05-01), Nosker
patent: 2763857 (1956-09-01), Valley, Jr.
patent: 2821704 (1958-01-01), O'Day
patent: 3384891 (1968-05-01), Anderson
patent: 3544995 (1970-12-01), Bottenberg et al.
patent: 3665464 (1972-05-01), Meilander
patent: 3668403 (1972-06-01), Meilander
patent: 4161730 (1979-07-01), Anderson
patent: 4161734 (1979-07-01), Anderson
patent: 4359733 (1982-11-01), O'Neill
patent: 4613864 (1986-09-01), Hofgen
patent: 4897661 (1990-01-01), Hiraiwa
patent: 4994809 (1991-02-01), Yung et al.
patent: 5006855 (1991-04-01), Braff
patent: 5099245 (1992-03-01), Sagey
patent: 5111209 (1992-05-01), Toriyama
patent: 5126748 (1992-06-01), Ames et al.
patent: 5387916 (1995-02-01), Cohn
patent: 5410314 (1995-04-01), Frush et al.
patent: 5444450 (1995-08-01), Olds et al.
patent: 5525995 (1996-06-01), Benner
patent: 5739785 (1998-04-01), Allison et al.
patent: 5944770 (1999-08-01), Enge et al.
patent: 5945948 (1999-08-01), Buford et al.
patent: 5969674 (1999-10-01), Von der Embse et al.
patent: 0 335 558 (1989-04-01), None
patent: 2 271 902 (1993-10-01), None
patent: 2 306 827 (1997-05-01), None
patent: 2-28580 (1990-01-01), None
patent: 3-291584 (1991-12-01), None
patent: 07146995 (1995-06-01), None
patent: 08015405 (1996-01-01), None
patent: 09026328 (1997-01-01), None
patent: 09113600 (1997-05-01), None
patent: 10090391 (1998-04-01), None
K.-H. Bethke, B. Rode, M. Schneider & A. Schroth, “A Novel Noncooperative Near-Range Radar Network for Traffic Guidance and Control on Airport Surfaces” IEEE Transactions on Control Systems Technology, vol. 1, No. 3, Sep. 1993.
Doc 9524, FANS/4-WP/76, International Civil Aviation Organization, Special Committee on Future Air Navigation Systems, Fourth Meeting, Montreal, May 2-20, 1988, pp. 3.2B-2 & 3.2B-3.
Teles J et al: “Overview of TDRSS” Orbit Determination and Analysis. PSD Meeting, Cospar Technical Panel on Satellite Dynamics, 13thCospar Scientific Assembly, Hamburg, Germany, Jul. 11-21, 1994, Advances in Space Research, pp. 67-76.
Bricker,P. et al. “Integrated Receiver for NASA Tracking and Data Relay Satellite System”, MILCOM 90. A New Era. 1990 IEEE Military Communications Conference, Monterey CA, USA, Sep. 30-Oct. 3, 1990, pp. 1-5.
Dunham, J. B., et al.: “Onboard Orbit Estimation with Tracking and Data Relay Satellite System Data”, Journal of Guidance, Control, and Dynamics, Jul.-Aug. 1983, USA, vol. 6, NR. 4, pp. 292-301.
Chang Donald C. D.
Goliff William
Novak, III John I.
Yung Kar W.
Duraiswamy V. D.
Hughes Electronics Corporation
Issing Gregory C.
Sales M. W.
LandOfFree
Method and system for determining a position of a... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and system for determining a position of a..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and system for determining a position of a... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2836837