US4438439A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Self-survey means
Assignee: United States Department of the Army
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Filing: 1981-04-29
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Granted: 1984-03-20
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Expires: 2001-04-29
Abstract
Abstract A method and apparatus for a passive station to locate itself relative to atationary or moving transmitting station transmitting a narrow pulsed scanning beam by utilizing reception of pulses directly from the transmitting station and reception of reflected pulses from a set of scatterers. A method and means for determining a bearing from the transmitting station and a method and means for determining a range to the transmitting station is disclosed utilizing a set of differential times, the times for a pulse from the transmitting station to travel to each scatterer and then to the passive station, a set of angles lying between a line connecting the transmitting station and passive station and a set of lines connecting the transmitting station and the set of scatterers and a set of angles lying between a link connecting the passive station and the transmitting station and the set of lines connecting the passive station and the set of scatterers.
Inventors
- 👤 James S. Shreve
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 20:01
CPC Classifications
G; G01; G01S; G01S5/00; G01S5/02; G01S5/12; G01S13/00; G01S13/003
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
408 words
A method for a passive station to locate itself relative to a transmitting station transmitting a narrow pulsed scanning beam by utilizing reception of pulses directly from the transmitting station and reception of reflected pulses from a set of scatterers S i , comprising the steps of: determining a bearing of said transmittingg station from said passive station by rotating a direction finding antenna in azimuth until a first null position is indicated by said direction finding antenna; measuring a set of differential times t i , each member of said set of differential times being the difference in time measured between reception of a pulse directly from said transmitting station and reception of said pulse via reflectin from a member of said set of scatterers; determining a set of angles θ i , said set of angles lying between a line connecting said transmitting station and said passive station and the set of lines connecting said transmitting station with said set of scatterers; determining a set of angles ψ i , said set of angles, ψ i , lying between a line connecting said passive station and said transmitting station and the set of lines connecting said passive station and said set of scatterers; and calculating a set of ranges r i , utilizing said sets of differential times t i , said angles θ i , and said angles ψ i , by calculating a first set of values, ν i , each member of said first set of values obtained by multiplying the speed of light, the corresponding member of said set of differential times, t i , and the sine of the sum of the corresponding member of said set of angles, θ i , and the corresponding member of said set of angles, ψ i , calculating a second set of values, χ i , each member of said second set of values obtained by summing the sine of the corresponding member of said set of angles, θ i , and the same of the corresponding member of said set of angles, χ i , and subtracting the sine of the sum of the corresponding members of said sets of angles, θ i and ψ i , and calculating said set of ranges, r i , by dividing the corresponding members of said first set of values, ν i , by the corresponding members of said second set of values, χ i .
Claim 2
Independent Claim
408 words
A method for a passive station to locate itself relative to a transmitting station transmitting a narrow pulsed scanning beam by utilizing reception of pulses directly from the transmitting station and reception of reflected pulses from a set of scatterers S i , comprising the steps of: determining a bearing of said transmittingg station from said passive station by rotating a direction finding antenna in azimuth until a first null position is indicated by said direction finding antenna; measuring a set of differential times t i , each member of said set of differential times being the difference in time measured between reception of a pulse directly from said transmitting station and reception of said pulse via reflectin from a member of said set of scatterers; determining a set of angles θ i , said set of angles lying between a line connecting said transmitting station and said passive station and the set of lines connecting said transmitting station with said set of scatterers; determining a set of angles ψ i , said set of angles, ψ i , lying between a line connecting said passive station and said transmitting station and the set of lines connecting said passive station and said set of scatterers; and calculating a set of ranges r i , utilizing said sets of differential times t i , said angles θ i , and said angles ψ i , by calculating a first set of values, ν i , each member of said first set of values obtained by multiplying the speed of light, the corresponding member of said set of differential times, t i , and the sine of the sum of the corresponding member of said set of angles, θ i , and the corresponding member of said set of angles, ψ i , calculating a second set of values, χ i , each member of said second set of values obtained by summing the sine of the corresponding member of said set of angles, θ i , and the same of the corresponding member of said set of angles, χ i , and subtracting the sine of the sum of the corresponding members of said sets of angles, θ i and ψ i , and calculating said set of ranges, r i , by dividing the corresponding members of said first set of values, ν i , by the corresponding members of said second set of values, χ i .
Claim 3
Dependent Claim
96 words
A method, as recited in claim 1, wherein the step of measuring a set of differential times, t i , is accomplished by: observing a first time of reception at said passive station of a pulse directly from said transmitting station; observing a second time of reception at said passive station of said pulse after being reflected from a member of said set of scatterers, S i ; and calculating each member of said set of differential times by comparing said second time with said first time observed for each member of said set of scatterers.
Claim 4
Dependent Claim
106 words
A method, as recited in claim 2, wherein the step of determining a set of angles, θ i , is accomplished by: determining a scanning rate, ω 1 , of said transmitting station; determining a set of coarse times, T i , each member of said set of coarse times being the elapsed time between reception of said reflected pulse from a member of said set of scatterers and passage of said scanning beam across said passive station; and calculating each member of said set of angles, θ i , by multiplying each member of said set T i by said scanning rate ω 1 .
Claim 5
Dependent Claim
83 words
A method, as recited in claim 3, wherein the step of determining a set of angles, ψ i , is accomplished by: rotating said direction finding antenna in azimuth and recording positions of second and subsequent null positions, each of said second and subsequent null positions indicating the direction of each member of said scatterers from said passive station; and determining said set of angles, ψ i , by comparing each of said second and subsequent null positions with said first null position.
Claim 6
Dependent Claim
17 words
A method, as recited in claim 1, further comprising the step of averaging said set of ranges.
Claim 7
Dependent Claim
24 words
A method, as recited in claim 5, further comprising the step of applying a weighted value to each member of said set of ranges.
Claim 8
Independent Claim
420 words
An apparatus for enabling a passive station to locate itself relative to a transmitting station transmitting a narrow pulsed scanning beam which utilizes reception of pulses directly from the transmitting station and reception of reflected pulses from a set of scatterers S i , comprising: means for receiving said pulses, including a rotating direction finding antenna with a null position and an omni-directional antenna; means for determining a bearing of said transmitting station from said passive station; means for measuring a set of differential times, t i , each member of said set of differential times being the difference in time measured between reception of a pulse directly from said transmitting station and reception of said pulse via reflection from a member of said set of scatterers; means for determining a set of angles,, θ i , said set of angles lying between a line connecting said transmitting station and said passive station and the set of lines connecting said transmitting station with said set of scatterers; means for determining a set of angles, ψ i , said set of angles lying between a line connecting said passive station and said transmitting station and a set of lines connecting said passive station and said set of scatterers; and means for calculating a set of ranges r i , utilizing said set of differential times t i , said set of angles θ i , and said set of angles ψ i , comprising means for calculating a first set of values ν i , each member of said first set of values obtained by multiplying the speed of light, the corresponding member of said set of differential times, t i , and the sine of the sum of the corresponding member of said set of angles, θ i , and the corresponding member of said set of angles, ψ i , means for calculating a second set of values, χ i , each member of said second set of values obtained by summing the sine of the corresponding member of said set of angles, θ i , and the sine of the corresponding member of said set of angles, ψ i , and subtracting the sine of the sum of the corresponding members of said sets of angles, θ i and ψ i , and calculating said set of ranges, r i , by dividing the corresponding members of said first set of values, ν i , by the corresponding members of said second set of values, χ i .
Claim 9
Independent Claim
420 words
An apparatus for enabling a passive station to locate itself relative to a transmitting station transmitting a narrow pulsed scanning beam which utilizes reception of pulses directly from the transmitting station and reception of reflected pulses from a set of scatterers S i , comprising: means for receiving said pulses, including a rotating direction finding antenna with a null position and an omni-directional antenna; means for determining a bearing of said transmitting station from said passive station; means for measuring a set of differential times, t i , each member of said set of differential times being the difference in time measured between reception of a pulse directly from said transmitting station and reception of said pulse via reflection from a member of said set of scatterers; means for determining a set of angles,, θ i , said set of angles lying between a line connecting said transmitting station and said passive station and the set of lines connecting said transmitting station with said set of scatterers; means for determining a set of angles, ψ i , said set of angles lying between a line connecting said passive station and said transmitting station and a set of lines connecting said passive station and said set of scatterers; and means for calculating a set of ranges r i , utilizing said set of differential times t i , said set of angles θ i , and said set of angles ψ i , comprising means for calculating a first set of values ν i , each member of said first set of values obtained by multiplying the speed of light, the corresponding member of said set of differential times, t i , and the sine of the sum of the corresponding member of said set of angles, θ i , and the corresponding member of said set of angles, ψ i , means for calculating a second set of values, χ i , each member of said second set of values obtained by summing the sine of the corresponding member of said set of angles, θ i , and the sine of the corresponding member of said set of angles, ψ i , and subtracting the sine of the sum of the corresponding members of said sets of angles, θ i and ψ i , and calculating said set of ranges, r i , by dividing the corresponding members of said first set of values, ν i , by the corresponding members of said second set of values, χ i .
Claim 10
Dependent Claim
36 words
An apparatus, as recited in claim 7, wherein said means for determining a bearing of said transmitting station from said passive station comprises means for determining when said null position is pointed towards said transmitting station.
Claim 11
Dependent Claim
94 words
An apparatus, as recited in claim 8, wherein said means for measuring a set of differential times, t i , comprises: means for determining a first time of reception at said passive station of a pulse directly from said transmitting station; means for determining a second time of reception at said passive station of said pulse after being reflected from a member of said set of scatterers; and means for calculating said differential times, t i , by comparing said second time with said first time for each member of said set of scatterers.
Claim 12
Dependent Claim
114 words
An apparatus, as recited in claim 9, wherein said means for determining a set of angles, θ i , comprises: means for determining a scanning rate, ω 1 , of said transmitting station; means for determining a set of coarse times, T i , each member of said set of coarse times being the elapsed time between reception of said reflected pulse from a member of said set of scatterers and passage of said scanning beam across said passive station; and means for calculating each member of said set of angles, θ i , by multiplying each member of said set of coarse times, T i , by said scanning rate ω 1 .
Claim 13
Dependent Claim
78 words
An apparatus, as recited in claim 10, wherein said means for determining a set of angles, ψ i , comprises: means for determining second and subsequent null positions of said direction finding antenna wherein said second and subsequent null positions each indicate a direction to a member of said set of scatterers; and means for calculating said set of angles, ψ i , by comparing each of said second and subsequent null positions with said first null position.
Claim 14
Dependent Claim
16 words
An apparatus, as recited in claim 7, further comprising means for averaging said set of ranges.
Claim 15
Dependent Claim
23 words
An apparatus, as recited in claim 12, further comprising means for applying a weighted value to each member of said set of ranges.
Claim 16
Independent Claim
249 words
A method for a passive station to locate itself relative to a transmitting station transmitting a narrow pulsed scanning beam, comprising; receiving pulses transmitted from the transmitting station to an omni-directional antenna at the passive station; determining which of said received pulses are direct pulses transmitted directly from the transmitting station to the passive station and which are reflected pulses reflected from a set of scatterers S i ; determining the direction of said transmitting station and said set of scatterers from said passive station by rotating a direction finding antenna in azimuth; measuring a set of differential times t i , each member of said set of differential times being the difference in time measured between reception of a pulse directly from said transmitting station and reception of said pulse via reflection from a member of said set of scatterers; determining a set of angles, θ i , said set of angles lying between a line connecting said transmitting station and said passive station and the set of lines connecting said transmitting station with said set of scatterers; determining a set of angles ψ i , said set of angles, ψ i , lying between a line connecting said passive station and said transmitting station and the set of lines connecting said passive station and said set of scatterers; and calculating a set of ranges, r i , utilizing said sets of differential times, t i , said angles, θ i , and said angles, ψ i .
Claim 17
Independent Claim
249 words
A method for a passive station to locate itself relative to a transmitting station transmitting a narrow pulsed scanning beam, comprising; receiving pulses transmitted from the transmitting station to an omni-directional antenna at the passive station; determining which of said received pulses are direct pulses transmitted directly from the transmitting station to the passive station and which are reflected pulses reflected from a set of scatterers S i ; determining the direction of said transmitting station and said set of scatterers from said passive station by rotating a direction finding antenna in azimuth; measuring a set of differential times t i , each member of said set of differential times being the difference in time measured between reception of a pulse directly from said transmitting station and reception of said pulse via reflection from a member of said set of scatterers; determining a set of angles, θ i , said set of angles lying between a line connecting said transmitting station and said passive station and the set of lines connecting said transmitting station with said set of scatterers; determining a set of angles ψ i , said set of angles, ψ i , lying between a line connecting said passive station and said transmitting station and the set of lines connecting said passive station and said set of scatterers; and calculating a set of ranges, r i , utilizing said sets of differential times, t i , said angles, θ i , and said angles, ψ i .
Claim 18
Independent Claim
265 words
An apparatus for enabling a passive station to locate itself relative to a transmitting station transmitting a narrow pulsed scanning beam, comprising: omni-directional antenna means for receiving pulses transmitted from the transmitting station to the passive station; threshold means for determining which of said received pulses are direct pulses transmitted directly from the transmitting station to the passive station and which are reflected pulses reflected from a set of scatterers S i ; means for determining the direction of said transmitting station and said set of scatterers S i from said passive station, including a rotating direction finding antenna means; means for measuring a set of differential times t i , each member of said set of differential times being the difference in time measured between reception of a pulse directly from said transmitting station and reception of said pulse via reflection from a member of said set of scatterers; means for determining a set of angles, θ i , said set of angles lying between a line connecting said transmitting station and said passive station and the set of lines connecting said transmitting station with said set of scatterers; means for determining a set of angles, ψ i , said set of angles lying between a line connecting said passive station and said transmitting station and the set of lines connecting said passive station and said set of scatterers; and means for calculating a set of ranges, r i , utilizing said set of differential times, t i , said set of angles, θ i , and said set of angles, ψ i .
Claim 19
Independent Claim
265 words
An apparatus for enabling a passive station to locate itself relative to a transmitting station transmitting a narrow pulsed scanning beam, comprising: omni-directional antenna means for receiving pulses transmitted from the transmitting station to the passive station; threshold means for determining which of said received pulses are direct pulses transmitted directly from the transmitting station to the passive station and which are reflected pulses reflected from a set of scatterers S i ; means for determining the direction of said transmitting station and said set of scatterers S i from said passive station, including a rotating direction finding antenna means; means for measuring a set of differential times t i , each member of said set of differential times being the difference in time measured between reception of a pulse directly from said transmitting station and reception of said pulse via reflection from a member of said set of scatterers; means for determining a set of angles, θ i , said set of angles lying between a line connecting said transmitting station and said passive station and the set of lines connecting said transmitting station with said set of scatterers; means for determining a set of angles, ψ i , said set of angles lying between a line connecting said passive station and said transmitting station and the set of lines connecting said passive station and said set of scatterers; and means for calculating a set of ranges, r i , utilizing said set of differential times, t i , said set of angles, θ i , and said set of angles, ψ i .
References Cited (Backward Citations)
US2971190A
Cited
US3895385A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-03-20 | 1987-09-19 | 1988-03-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-03-20 | 1991-09-19 | 1992-03-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-03-20 | 1995-09-19 | 1996-03-20 | $7700.00 | Window Closed / Lapsed |