US5075694A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Airborne surveillance method and system
Assignee: Avion Systems Inc
•
Filing: 1989-12-14
•
Granted: 1991-12-24
•
Expires: 2009-12-14
Abstract
Abstract An airborne surveillance method and system allows an observer aircraft to determine the position and change of position of a multiplicity of target aircraft and thus allows analysis of collision threats from these aircraft. The system uses a phase comparison direction finding antenna to determine direction of nearby ground based SSRs and all target aircraft of interest. The system further makes use of all other available data including Mode C transponder generated altitude information of the target aircraft, the altitude of the observer aircraft, the received signal strength of both the SSR beam and the received transponder signal, the time difference of arrival between the SSR interrogation signal and the response from the target aircraft, and a variety of other factors to determine the position of the target aircraft. The system compensates for the attitude of the observer aircraft and performs optimal Kalman filtering on the input data set to produce an estimate on target position based upon prior estimates and upon information contained in the data set while making estimates of the error magnitude of each measurement and compensating for these errors. The covariance matrix Q of the Kalman filter is adaptively varied so as to optimize the estimate of the degree of correlation between various input values.
Inventors
- 👤 Nicholas C. Donnangelo
- 👤 John T. Abaunza
- 👤 John G. Aiken
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 10:57
CPC Classifications
G; G01; G01S; G01S13/00; G01S13/74; G01S13/76; G01S13/78; G01S13/781; G01S13/88; G01S13/93; G01S13/933; G01S3/00; G01S3/02; G01S3/14; G01S3/46; G01S3/48
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
215 words
In an environment having only a single rotating interrogation signal source within sensing range, a method of locating the position of at least one target object carrying an interrogation signal responsive transponder from an observer object located remotely from the rotating interrogation signal source comprising: a) determining the direction of said interrogation signal source by direction finding on said interrogation signal to develop source direction data; b) determining the direction to a said target object by direction finding on a transponder signal produced by said transponder to develop target direction data; and c) assembling additional available data relevant to relative positions of said objects and/or said interrogation signal source; d) estimating the error of each of said source direction data, target direction data, and additional available data to develop data value error estimates; e) developing a present position estimate of said target object and an associated position error estimate from said data values and data value error estimates; and f) developing a present position value of said target aircraft by using a past position value of the position of said target aircraft to modify the present position estimate including varying the degree of modification based on the position error estimate to optimize the developed position value without use of an observer aircraft active interrogation source.
Claim 2
Dependent Claim
215 words
In an environment having only a single rotating interrogation signal source within sensing range, a method of locating the position of at least one target object carrying an interrogation signal responsive transponder from an observer object located remotely from the rotating interrogation signal source comprising: a) determining the direction of said interrogation signal source by direction finding on said interrogation signal to develop source direction data; b) determining the direction to a said target object by direction finding on a transponder signal produced by said transponder to develop target direction data; and c) assembling additional available data relevant to relative positions of said objects and/or said interrogation signal source; d) estimating the error of each of said source direction data, target direction data, and additional available data to develop data value error estimates; e) developing a present position estimate of said target object and an associated position error estimate from said data values and data value error estimates; and f) developing a present position value of said target aircraft by using a past position value of the position of said target aircraft to modify the present position estimate including varying the degree of modification based on the position error estimate to optimize the developed position value without use of an observer aircraft active interrogation source.
Claim 3
Dependent Claim
35 words
The method of claim 1 further comprising: assembling said direction data and said other available data into vector data packets; said step (e) of developing utilizing said data packets to develop said present position estimates.
Claim 4
Dependent Claim
38 words
The method of claim 2 wherein said step (b) of determining includes direction finding only on said transponder signals received by said observer aircraft having a signal level above a predetermined time after receipt of said interrogation signal.
Claim 5
Dependent Claim
165 words
In an environment having at least one rotating interrogation signal source, a system of locating the position of at least one target object carrying an interrogation signal responsive transponder from an observer aircraft comprising: phase detecting direction finding antenna means for developing a first direction signal representative of the direction of said rotating interrogation signal source and for developing a second direction signal representative of the direction of each target object by detecting the target object's interrogation signal responsive transponder; means for assembling additional data relevant to relative positions of said objects and said interrogation signal source; means, responsive to said first and second direction signals and said additional available data, for developing a present position estimate for the relative position of each said target object; means for storing a past position value of each said target object; and Kalman filtering means for updating the past position value with said estimate of present position to determine a present position value of each said target object.
Claim 6
Dependent Claim
165 words
In an environment having at least one rotating interrogation signal source, a system of locating the position of at least one target object carrying an interrogation signal responsive transponder from an observer aircraft comprising: phase detecting direction finding antenna means for developing a first direction signal representative of the direction of said rotating interrogation signal source and for developing a second direction signal representative of the direction of each target object by detecting the target object's interrogation signal responsive transponder; means for assembling additional data relevant to relative positions of said objects and said interrogation signal source; means, responsive to said first and second direction signals and said additional available data, for developing a present position estimate for the relative position of each said target object; means for storing a past position value of each said target object; and Kalman filtering means for updating the past position value with said estimate of present position to determine a present position value of each said target object.
Claim 7
Dependent Claim
21 words
The system of claim 4 further comprising means for storing relevant data including target object positions to record object position information.
Claim 8
Dependent Claim
246 words
In an environment having at least one rotating interrogation signal source, a system of locating the position of at least one target object carrying an interrogation signal responsive transponder from an observer object positioned remotely from the rotating interrogation signal source comprising: phase detecting direction finding antenna means for developing a first direction signal representative of the direction of said rotating interrogation signal source and for developing a second direction signal representative of the direction of each target object by detecting the target object's interrogation signal responsive transponder; means for assembling additional data elements relevant to relative positions of said objects and said interrogation signal source; means for developing an estimate of the error of each of said first and second direction signals as well as each of said additional data elements to produce data value error estimates; means, responsive to said first and second direction signals, said additional available data, and said data value error estimates, for developing a present position estimate for the relative position of each said target object as well as a related position error estimate; means for storing a past position value of each said target object; and optimal filtering means for developing a present position value of said target by using the past position value to modify the estimate of present position to determine a present position value of each said target object, the degree of modification being based on the position error estimate to optimize the developed position value.
Claim 9
Dependent Claim
246 words
In an environment having at least one rotating interrogation signal source, a system of locating the position of at least one target object carrying an interrogation signal responsive transponder from an observer object positioned remotely from the rotating interrogation signal source comprising: phase detecting direction finding antenna means for developing a first direction signal representative of the direction of said rotating interrogation signal source and for developing a second direction signal representative of the direction of each target object by detecting the target object's interrogation signal responsive transponder; means for assembling additional data elements relevant to relative positions of said objects and said interrogation signal source; means for developing an estimate of the error of each of said first and second direction signals as well as each of said additional data elements to produce data value error estimates; means, responsive to said first and second direction signals, said additional available data, and said data value error estimates, for developing a present position estimate for the relative position of each said target object as well as a related position error estimate; means for storing a past position value of each said target object; and optimal filtering means for developing a present position value of said target by using the past position value to modify the estimate of present position to determine a present position value of each said target object, the degree of modification being based on the position error estimate to optimize the developed position value.
Claim 10
Dependent Claim
15 words
The system of claim 6 wherein said data value error estimates form a covariance matrix.
Claim 11
Independent Claim
60 words
A method of determining the orientation of an observer object comprising: a) providing previous orientation information; b) sensing rate information related to the present state of the observer object; c) multiplying said previous orientation information with said rate information to obtain the present orientation rate of said observer object; d) integrating the present orientation rate to develop updated orientation information.
Claim 12
Independent Claim
60 words
A method of determining the orientation of an observer object comprising: a) providing previous orientation information; b) sensing rate information related to the present state of the observer object; c) multiplying said previous orientation information with said rate information to obtain the present orientation rate of said observer object; d) integrating the present orientation rate to develop updated orientation information.
Claim 13
Dependent Claim
15 words
The method of claim 8 further comprising correcting said rate information to compensate for bias.
Claim 14
Dependent Claim
12 words
The method of claim 8 wherein the observer object is an aircraft.
References Cited (Backward Citations)
US3959793A
Cited
US4027307A
Cited
US3895382A
Cited
US4188630A
Cited
US4196434A
Cited
US4380050A
Cited
US4642648A
Cited
US4782450A
Cited
US4768036A
Cited
US4733241A
Cited
US4839658A
Cited
US4910526A
Cited
US4789865A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-12-23 | 1995-06-24 | 1995-12-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-12-23 | 1999-06-24 | 1999-12-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-12-23 | 2003-06-24 | 2003-12-24 | $7700.00 | Window Closed / Lapsed |