Patent US5923293A successfully refreshed from Google Patents.
US5923293A
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Method and apparatus for accomplishing extended range TCAS using a dual bandwidth receiver
Assignee: L3 Technologies Inc
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Filing: 1997-09-30
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Granted: 1999-07-13
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Expires: 2017-09-30
Abstract
Abstract A Traffic Alert and Collision Avoidance System (TCAS) uses a dual bandwidth receiver to achieve extended range operation. During normal operations TCAS radio signals are filtered by a bandpass filter which passes all TCAS radio signals of interest. When extended range operation is desired the TCAS radio signals are filtered by a more narrow bandpass filter. The narrower filter passes only selected TCAS radio signals and improves the signal to noise ratio and thus allows detection of selected TCAS radio signals at extended range. The TCAS system switches between the normal mode and the extended range mode to detect and track aircraft at both near and far distances.
Inventors
- 👤 Mark D. Smith
- 👤 Lyle Alan Fajen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 18:04
CPC Classifications
G; G01; G01S; G01S13/00; G01S13/88; G01S13/93; G01S13/933; G01S13/74
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
131 words
An extended range Traffic Alert and Collision Avoidance System (TCAS) comprising: a) a dual bandwidth receiver suitable for processing transponder spontaneous transmissions and replies, said receiver including, 1) a normal bandwidth filter capable of passing frequencies containing transponder spontaneous transmission and reply signals and attenuating other frequencies, and, 2) a narrow bandwidth filter capable of passing a more narrow band of frequencies than said normal bandwidth filter such that desired transponder spontaneous transmissions and reply signals are passed and other frequencies are attenuated; b) said filters selectable such that said spontaneous transmissions and replies are filtered by said normal bandwidth filter and not filtered by said narrow bandwidth filter in normal TCAS operation and said spontaneous transmissions and replies are filtered by said narrow bandwidth filter in extended range TCAS operation.
Claim 2
Dependent Claim
131 words
An extended range Traffic Alert and Collision Avoidance System (TCAS) comprising: a) a dual bandwidth receiver suitable for processing transponder spontaneous transmissions and replies, said receiver including, 1) a normal bandwidth filter capable of passing frequencies containing transponder spontaneous transmission and reply signals and attenuating other frequencies, and, 2) a narrow bandwidth filter capable of passing a more narrow band of frequencies than said normal bandwidth filter such that desired transponder spontaneous transmissions and reply signals are passed and other frequencies are attenuated; b) said filters selectable such that said spontaneous transmissions and replies are filtered by said normal bandwidth filter and not filtered by said narrow bandwidth filter in normal TCAS operation and said spontaneous transmissions and replies are filtered by said narrow bandwidth filter in extended range TCAS operation.
Claim 3
Dependent Claim
43 words
The extended range Traffic Alert and Collision Avoidance System (TCAS) according to claim 1 wherein said narrow bandwidth filter is continuously switched into and out of the receive path to achieve both normal and extended range functionality are available simultaneously to an operator.
Claim 4
Dependent Claim
63 words
The extended range Traffic Alert and Collision Avoidance System (TCAS) according to claim 1 wherein said filters are selected in accordance with a predetermined algorithm such that as air traffic density increases said TCAS system spends more time filtering said transmissions and replies through said normal bandwidth filter only and spends less time filtering said transmissions and replies through said narrow bandwidth filter.
Claim 5
Dependent Claim
65 words
A Traffic Alert and Collision Avoidance System (TCAS) comprising: a) a dual bandwidth receiver for processing TCAS radio signals, said receiver including, 1) a narrow bandwidth filter; b) said filter being selectable such that when extended range operation is desired said TCAS radio signals are filtered by said narrow bandwidth filter whereby the signal to noise ratio is improved and extended range operation is achieved.
Claim 6
Dependent Claim
65 words
A Traffic Alert and Collision Avoidance System (TCAS) comprising: a) a dual bandwidth receiver for processing TCAS radio signals, said receiver including, 1) a narrow bandwidth filter; b) said filter being selectable such that when extended range operation is desired said TCAS radio signals are filtered by said narrow bandwidth filter whereby the signal to noise ratio is improved and extended range operation is achieved.
Claim 7
Dependent Claim
47 words
The Traffic Alert and Collision Avoidance System (TCAS) according to claim 4 wherein said narrow bandwidth filter is selected in accordance with a predetermined algorithm such that as air traffic density increases said TCAS system spends less time filtering TCAS radio signals through said narrow bandwidth filter.
Claim 8
Dependent Claim
82 words
A Collision Avoidance apparatus comprising: a) receiver means for detecting data in TCAS radio signals, said receiver means including, 1) dual filter means for processing radio frequency signals in at least two modes, said filter means passing substantially all transponder spontaneous transmission and reply frequencies and attenuating other frequencies when in a first mode and said filter means passing a more narrow band of frequencies when in a second mode thereby increasing the signal to noise ratio for selected TCAS radio signals.
Claim 9
Dependent Claim
82 words
A Collision Avoidance apparatus comprising: a) receiver means for detecting data in TCAS radio signals, said receiver means including, 1) dual filter means for processing radio frequency signals in at least two modes, said filter means passing substantially all transponder spontaneous transmission and reply frequencies and attenuating other frequencies when in a first mode and said filter means passing a more narrow band of frequencies when in a second mode thereby increasing the signal to noise ratio for selected TCAS radio signals.
Claim 10
Dependent Claim
41 words
The Collision Avoidance Apparatus according to claim 6 wherein said filter means is continuously switched between said first mode and said second mode according to a predetermined algorithm such that both normal TCAS tracking and extended range tracking are achieved simultaneously.
Claim 11
Independent Claim
172 words
A method of accomplishing extended range TCAS, said method comprising the steps of: a) providing a TCAS system having a dual bandwidth receiver for processing TCAS radio signals, said receiver including, 1) a normal bandwidth filter capable of passing frequencies containing transponder spontaneous transmission and reply signals and attenuating other frequencies, and, 2) a narrow bandwidth filter capable of passing a more narrow band of frequencies than said normal bandwidth filter, said narrow bandwidth filter being selectable such that said TCAS radio signals are filtered by said narrow bandwidth filter when desired; b) filtering, for a first time period, said TCAS radio signals through said normal bandwidth filter and not through said narrow bandwidth filter so that all transponder spontaneous transmissions and replies are received and processed by said TCAS system; and, c) filtering, for a second time period, said TCAS radio signals through said narrow bandwidth filter such that the signal to noise ratio is improved for desired transponder spontaneous transmissions and the effective range of said TCAS system is increased.
Claim 12
Independent Claim
172 words
A method of accomplishing extended range TCAS, said method comprising the steps of: a) providing a TCAS system having a dual bandwidth receiver for processing TCAS radio signals, said receiver including, 1) a normal bandwidth filter capable of passing frequencies containing transponder spontaneous transmission and reply signals and attenuating other frequencies, and, 2) a narrow bandwidth filter capable of passing a more narrow band of frequencies than said normal bandwidth filter, said narrow bandwidth filter being selectable such that said TCAS radio signals are filtered by said narrow bandwidth filter when desired; b) filtering, for a first time period, said TCAS radio signals through said normal bandwidth filter and not through said narrow bandwidth filter so that all transponder spontaneous transmissions and replies are received and processed by said TCAS system; and, c) filtering, for a second time period, said TCAS radio signals through said narrow bandwidth filter such that the signal to noise ratio is improved for desired transponder spontaneous transmissions and the effective range of said TCAS system is increased.
Claim 13
Dependent Claim
29 words
The method according to claim 8 wherein said filters are selected in accordance with a predetermined algorithm such that as air traffic density increases said first time period increases.
Claim 14
Dependent Claim
29 words
The method according to claim 8 wherein said filters are selected in accordance with a predetermined algorithm such that as air traffic density increases said second time period decreases.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2002-07-12 | 2003-01-11 | 2003-07-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-07-12 | 2007-01-11 | 2007-07-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-07-12 | 2011-01-11 | 2011-07-13 | $7700.00 | Window Closed / Lapsed |