US3858211A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Proximity indication with range and bearing measurements
Assignee: Litchstreet Co
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Filing: 1973-06-20
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Granted: 1974-12-31
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Expires: 1993-06-20
Abstract
Abstract Proximity indication and evaluation for aircraft, using only the signals emitted by secondary surveillance radar and cooperating transponders, to detect intrusion in a monitored proximity volume and determine slant range and relative bearing to the intruder.
Inventors
- 👤 G Litchford
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 05:06
CPC Classifications
G; G01; G01S; G01S13/00; G01S13/74; G01S13/76; G01S13/78; G01S13/781; G01S13/88; G01S13/93; G01S13/933
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
159 words
A method of determining at an own transponder station the bearing angle phi of said own station from a selected secondary surveillance radar (SSR) that omniazimuthally transmits a reference signal as the main radar beam sweeps through a standardized reference direction, such as magnetic North, said method comprising the steps of: a. receiving said reference signals, b. receiving interrogation signals from said radar as the main beam sweeps by the own location, c. measuring the time interval between successive reception of one of said reference and said interrogation signals and producing a quantitative first representation of the main beam rotation inverval, d. measuring and producing a quantitative second representation of the time interval between reception of a reference signal and reception of the next subsequently received interrogation signal, e. dividing the value of said second representation by that of said first representation to produce the quotient of said values, and f. producing a quantitative representation phi of said quotient.
Claim 2
Independent Claim
159 words
A method of determining at an own transponder station the bearing angle phi of said own station from a selected secondary surveillance radar (SSR) that omniazimuthally transmits a reference signal as the main radar beam sweeps through a standardized reference direction, such as magnetic North, said method comprising the steps of: a. receiving said reference signals, b. receiving interrogation signals from said radar as the main beam sweeps by the own location, c. measuring the time interval between successive reception of one of said reference and said interrogation signals and producing a quantitative first representation of the main beam rotation inverval, d. measuring and producing a quantitative second representation of the time interval between reception of a reference signal and reception of the next subsequently received interrogation signal, e. dividing the value of said second representation by that of said first representation to produce the quotient of said values, and f. producing a quantitative representation phi of said quotient.
Claim 3
Dependent Claim
149 words
Apparatus for determining at an own transponder station the bearing angle phi of said own station from a selected azimuthally scanning radar that omnidirectionally transmits a reference signal when its directional beam points in a standard reference direction, such as North, said apparatus comprising: a. means for receiving said reference signal and for receiving the normal interrogation transmission signals of said radar as the radar beam sweeps by the own location, b. a first interval timer for measuring the interval between successive reception of one of said reference and said normal transmission signals and producing a quantitative representation N of said interval, c. a second interval Timer for measuring and producing a quantitative representation M of the interval between reception of a reference signal and a normal transmission signal, d. divider means for computing the quotient M/N, and e. means for producing a quantitative representation phi of said quotient.
Claim 4
Dependent Claim
149 words
Apparatus for determining at an own transponder station the bearing angle phi of said own station from a selected azimuthally scanning radar that omnidirectionally transmits a reference signal when its directional beam points in a standard reference direction, such as North, said apparatus comprising: a. means for receiving said reference signal and for receiving the normal interrogation transmission signals of said radar as the radar beam sweeps by the own location, b. a first interval timer for measuring the interval between successive reception of one of said reference and said normal transmission signals and producing a quantitative representation N of said interval, c. a second interval Timer for measuring and producing a quantitative representation M of the interval between reception of a reference signal and a normal transmission signal, d. divider means for computing the quotient M/N, and e. means for producing a quantitative representation phi of said quotient.
Claim 5
Dependent Claim
125 words
A method as in claim 1 for additionally producing at said own transponder station a representation of the angular relationship between the bearing of said own transponder station from said selected SSR and the bearing from said selected SSR of another transponder station within a common azimuthal sector with said own transponder station, including the further steps of: g. receiving at said own transponder station reply signals transmitted by said other transponder station in response to said interrogation signals as said main beam sweeps by said other transponder station, h. determining the time relationship between said interrogation signals and said reply signals, and i. producing, in accordance with said time relationship, a representation of said angular relationship between said bearing angles from said selected SSR.
Claim 6
Dependent Claim
56 words
The method according to claim 3 wherein step (i) comprises the steps of: j. producing a lead signal in response to the prior occurence of said interrogation signals immediately subsequent to said reference signals, and k. producing a lag signal in response to the prior occurrence of said reply signals immediately subsequent to said reference signals.
Claim 7
Dependent Claim
127 words
Apparatus according to claim 2 for additionally producing at said own transponder station a representation of the angular relationship between the bearing of said own transponder station from said selected SSR and the bearing from said selected SSR of another transponder station within a common azimuthal sector with said own transponder statin, further comprising; f. means for receiving at said own transponder station reply signals transmitted by said other transponder station in response to said interrogation signals as said main beam sweeps by said other transponder station, g. means for determining the time relationship between said interrogation signals and said reply signals, and h. means for producing, in accordance with said time relationship, a representation of said angular relationship between said bearing angles from said selected SSR.
Claim 8
Dependent Claim
57 words
Apparatus according to claim 5 wherein the means (h) comprises: i. means for producing a lead signal in response to the prior occurrence of said interrogation signals immediately subsequent to said reference signals, and j. means for producing a lag signal in response to the prior occurrence of said reply signals immediately subsequent to said reference signals.
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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) | 1977-12-30 | 1978-07-01 | 1978-12-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-30 | 1982-07-01 | 1982-12-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-30 | 1986-07-01 | 1986-12-31 | $7700.00 | Window Closed / Lapsed |