Patent US3750168A successfully refreshed from Google Patents.
US3750168A
Expired / Lapsed
US
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Apparatus for aiding a pilot in avoiding a midair collision between aircraft
Assignee: National Aeronautics and Space Administration
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Filing: 1972-04-07
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Granted: 1973-07-31
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Expires: 1992-04-07
Abstract
Abstract This invention is an apparatus for aiding a pilot in avoiding a midair collision between aircraft. A protected aircraft carries a transmitter, a transponder, a receiver and a data processor; and an intruding cooperating aircraft carries a transponder. The transmitter of the protected aircraft continuously transmits a signal to the transponders of all intruding aircraft. The transponder of each of the intruding aircraft adds the altitude of the intruding aircraft to the signal and transmits it back to the receiver of the protected aircraft. The receiver selects only the signal from the most hazardous intruding aircraft and applies it to the data processor. From this selected signal the data processor determines the closing velocity between the protected and intruding aircraft, the range between the two aircraft, their altitude difference and the time to a possible collision. Also, the bearing of the intruding aircraft can be determined.
Inventors
- 👤 J Schrader
- 👤 R Couch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:39
CPC Classifications
G; G01; G01S; G01S13/00; G01S13/88; G01S13/93; G01S13/933
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
131 words
Apparatus for aiding a pilot in avoiding a midair collision between aircraft comprising: transmitter means mounted on a protected aircraft for transmitting a single continuous wave signal; said transmitter means including means for frequency modulating said single continuous wave signal with a code that is unique to said transmitter means; transponder means mounted on each possible intruding aircraft for receiving said modulated single continuous wave signal; each of said transponder means including means for repeating said signal and retransmitting it; receiver means mounted on said protected aircraft for receiving said retransmitted signal; said receiver means including means for selecting only signals which are replies to signals transmitted by the transmitter on said protected aircraft and means for selecting only the retransmitted signal from the transponder on the most hazardous intruding aircraft.
Claim 2
Dependent Claim
131 words
Apparatus for aiding a pilot in avoiding a midair collision between aircraft comprising: transmitter means mounted on a protected aircraft for transmitting a single continuous wave signal; said transmitter means including means for frequency modulating said single continuous wave signal with a code that is unique to said transmitter means; transponder means mounted on each possible intruding aircraft for receiving said modulated single continuous wave signal; each of said transponder means including means for repeating said signal and retransmitting it; receiver means mounted on said protected aircraft for receiving said retransmitted signal; said receiver means including means for selecting only signals which are replies to signals transmitted by the transmitter on said protected aircraft and means for selecting only the retransmitted signal from the transponder on the most hazardous intruding aircraft.
Claim 3
Dependent Claim
61 words
Apparatus for aiding a pilot in avoiding a midair collision according to claim 1 wherein said means for modulating said single continuous wave signal with a code that is unique to said transmitter comprises a pseudorandom noise generator; means for generating a continuous wave signal; and means for frequency modulating said continuous wave signal with the signal from said noise generator.
Claim 4
Dependent Claim
49 words
Apparatus for aiding a pilot in avoiding a midair collision according to claim 1 wherein said transponder includes means for producing a signal proportional to the altitude of the intruding aircraft; and means for phase modulating said repeated signal with said altitude signal before the repeated signal is retransmitted.
Claim 5
Dependent Claim
51 words
Apparatus for aiding a pilot in avoiding a midair collision according to claim 1 wherein said means for selecting only signals transmitted by the transmitter on said protected aircraft includes means for converting the signal received by the receiver to an intermediate frequency by mixing it with said modulated transmitter signal.
Claim 6
Dependent Claim
95 words
Apparatus for aiding a pilot in avoiding a midair collision according to claim 1 wherein said transponder means includes means for generating a signal proportional to the altitude of the intruding aircraft; means receiving said altitude signal for producing an altitude subcarrier signal; means for generating an offset frequency signal; means for phase modulating said offset frequency signal with said altitude subcarrier signal; means for converting the received modulated single continuous wave signal to an IF frequency; means for converting said IF frequency back to the frequency band of said modulated single continuous wave signal.
Claim 7
Dependent Claim
73 words
Apparatus for aiding a pilot in avoiding a midair collision according to claim 1 wherein said means for selecting only thE retransmitted signal from the transponder on the most hazardous intruding aircraft includes; means for accepting signals from approaching aircraft and rejecting signals from receding aircraft; and means for introducing a transfer characteristic to said accepted signal such that the strongest resultant signal provides a reasonable estimate of the most hazardous intruding aircraft.
Claim 8
Dependent Claim
40 words
Apparatus for aiding a pilot in avoiding a midair collision according to claim 1 including means for producing a signal to the closing velocity between the protected aircraft and the intruding aircraft from the signal produced by said receiver means.
Claim 9
Dependent Claim
38 words
Apparatus for aiding a pilot in avoiding a midair collision according to claim 1 including means for producing a signal related to the range between the protected and intruding aircraft from the signal produced by said receiver means.
Claim 10
Dependent Claim
41 words
Apparatus for aiding a pilot in avoiding a midair collision according to claim 1 including means for producing a signal related to the time to possible collision of the protected and intruding aircraft from the signal produced by said receiver means.
Claim 11
Dependent Claim
39 words
Apparatus for aiding a pilot in avoiding a midair collision according to claim 1 including means for producing a signal related to the altitude difference between the protected and intruding aircraft from the signal produced by said receiver means.
Claim 12
Dependent Claim
41 words
Apparatus for aiding a pilot in avoiding a midair collision according to claim 1 including means for producing a signal related to the bearing of the intruding aircraft relative to the protected aircraft from the signal produced by said receiver means.
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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) | 1976-07-30 | 1977-01-29 | 1977-07-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-30 | 1981-01-29 | 1981-07-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-30 | 1985-01-29 | 1985-07-31 | $7700.00 | Window Closed / Lapsed |