US4881077A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Radar arrangement
Assignee: Telefunken Systemtechnik AG
•
Filing: 1987-06-09
•
Granted: 1989-11-14
•
Expires: 2007-06-09
Abstract
Abstract A radar arrangement which is particularly useful for the terrain following radar of an aircraft avoids disturbances from rain echoes by utilizing an antenna arrangement with a transmitting/receving directional antenna which is circularly polarized. A supplementary receiving antenna of orthogonally-circularly polarized type is used in conjunction with the directional antenna. From a comparison of the signal level distinctions is made between a target and a rain echo. The rain echo can thus be suppressed to give a truer target signal.
Inventors
- 👤 Franz Jehle
- 👤 Martin Konig
- 👤 Erwin Wolfle
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 02:15
CPC Classifications
G; G01; G01S; G01S7/00; G01S7/02; G01S7/28; G01S7/2813; G01S13/00; G01S13/88; G01S13/93; G01S13/933; G01S13/935; G01S7/024; G01S7/026
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
184 words
A radar arrangement comprising, transmitter means for supplying a circularly polarized signal being circularly polarized in a first direction, a directional antenna connected to said transmitter means for receiving said signal and transmitting a circularly polarized directional pattern which is circularly polarized in the first direction, a supplementary non-directional antenna which is sensitive to circularly polarized signals in an opposite direction to said circularly polarized signals being polarized in a first direction, said directional antenna being more sensitive to circularly polarized signals in the first direction than to circularly polarized signals in the opposite direction, a level comparator means connected to said directional antenna and said supplementary antenna for comparing the level of the signals of the directional antenna and the level of the signals from the supplementary non-directional antenna to each other for determining if the ratio of the level of the signals of the directional antenna to level of the signals of the supplementary non-directional antenna differs from a predetermined ratio of the directional antenna sensitivity to the supplementary non-directional sensitivity providing n indication of echo signals which are due to rain.
Claim 2
Dependent Claim
184 words
A radar arrangement comprising, transmitter means for supplying a circularly polarized signal being circularly polarized in a first direction, a directional antenna connected to said transmitter means for receiving said signal and transmitting a circularly polarized directional pattern which is circularly polarized in the first direction, a supplementary non-directional antenna which is sensitive to circularly polarized signals in an opposite direction to said circularly polarized signals being polarized in a first direction, said directional antenna being more sensitive to circularly polarized signals in the first direction than to circularly polarized signals in the opposite direction, a level comparator means connected to said directional antenna and said supplementary antenna for comparing the level of the signals of the directional antenna and the level of the signals from the supplementary non-directional antenna to each other for determining if the ratio of the level of the signals of the directional antenna to level of the signals of the supplementary non-directional antenna differs from a predetermined ratio of the directional antenna sensitivity to the supplementary non-directional sensitivity providing n indication of echo signals which are due to rain.
Claim 3
Dependent Claim
60 words
A radar arrangement according to claim 1, including an additional non-directional antenna connected to said level comparator, said additional antenna being more sensitive to said circularly polarized signals in said first direction than said circularly polarized signal in said opposite direction with said circularly polarized signal of said opposite direction being supplied by said supplementary antenna to said level comparator.
Claim 4
Dependent Claim
17 words
A radar arrangement according to claim 2, wherein said supplementary and said additional antennae comprise horn radiators.
Claim 5
Dependent Claim
19 words
A radar arrangement according to claim 2, wherein said supplementary and said additional antennae comprise open hollow waveguide radiators.
Claim 6
Dependent Claim
53 words
A radar arrangement according to claim 2, wherein said transmitter means includes means for causing said directional pattern of said directional antenna to scan vertically from an upper line to a lower line with an acute angle formed between said upper and lower lines, whereby said directional antenna is useful in following terrain.
Claim 7
Independent Claim
169 words
A method for providing an indication of echo signals which are due to rain comprising the steps of: supplying a circularly polarized signal by a directional antenna, said circularly polarized signal being circularly polarized in a first direction; receiving signals, by a supplementary non-directional antenna which is sensitive to circularly polarized signals in an opposite direction to said circularly polarized signals being circularly polarized in a first direction; receiving signals by the directional antenna which is more sensitive to circularly polarized signals in the first direction than to circularly polarized signals in the opposite direction; comparing the circularly polarized signals received by the directional antenna and the signals received by the supplementary non-directional antenna and determining if the ratio between the level of the signals received by the directional antenna to the level of the signals received by the supplementary non-directional antenna differs from a predetermined ratio of the directional antenna sensitivity to the supplementary non-directional antenna sensitivity providing an indication of echo signals which are due to rain.
Claim 8
Independent Claim
169 words
A method for providing an indication of echo signals which are due to rain comprising the steps of: supplying a circularly polarized signal by a directional antenna, said circularly polarized signal being circularly polarized in a first direction; receiving signals, by a supplementary non-directional antenna which is sensitive to circularly polarized signals in an opposite direction to said circularly polarized signals being circularly polarized in a first direction; receiving signals by the directional antenna which is more sensitive to circularly polarized signals in the first direction than to circularly polarized signals in the opposite direction; comparing the circularly polarized signals received by the directional antenna and the signals received by the supplementary non-directional antenna and determining if the ratio between the level of the signals received by the directional antenna to the level of the signals received by the supplementary non-directional antenna differs from a predetermined ratio of the directional antenna sensitivity to the supplementary non-directional antenna sensitivity providing an indication of echo signals which are due to rain.
Claim 9
Dependent Claim
47 words
A method according to claim 6, further comprising: causing said directional pattern of said directional antenna to scan vertically from an upper line to a lower line with an acute angle formed between said upper and lower lines, whereby the directional antenna is useful in following terrain.
Claim 10
Dependent Claim
273 words
An automatic rain echo suppression radar system for use with terrain following radar systems comprising: transmitter means supplying a circularly polarized signal being circularly polarized in a first direction; a directional antenna connected to said transmitter means, said antenna receiving said signal and transmitting a particularly polarized directional pattern which is circularly polarized in the first direction, the directional antenna being more sensitive to circularly polarized signals in the first direction than to circularly polarized signals in a direction orthogonal to the first direction for receiving echo signals reflected to the directional antenna circularly polarized in the first direction; first level means for receiving echo signals reflected to the directional antenna and for outputing the level of the signal reflected to the directional antenna; a supplementary non-directional antenna which is sensitive to circularly polarized signals in a direction orthogonal to the first direction for receiving echoes signals circularly polarized orthongonally to the first direction; the second level means for receiving the signals reflected to the non-directional antenna and outputing the level of the signal reflected to nondirectional antenna; means for scaling the level signal of said non-directional antenna signal by a factor equal to the ratio of said sensitivities of said directional antenna to said nondirectional antenna; comparator means for comparing the nondirectional signals to the directional signals as an indication of a rain echo signal; and, gate means receiving said signal from said comparator for allowing the passage of the signal from said directional antenna when no rain echo signal is present and blocking the passage the signal from the directional antenna when there is an indication of a rain echo signal.
Claim 11
Dependent Claim
273 words
An automatic rain echo suppression radar system for use with terrain following radar systems comprising: transmitter means supplying a circularly polarized signal being circularly polarized in a first direction; a directional antenna connected to said transmitter means, said antenna receiving said signal and transmitting a particularly polarized directional pattern which is circularly polarized in the first direction, the directional antenna being more sensitive to circularly polarized signals in the first direction than to circularly polarized signals in a direction orthogonal to the first direction for receiving echo signals reflected to the directional antenna circularly polarized in the first direction; first level means for receiving echo signals reflected to the directional antenna and for outputing the level of the signal reflected to the directional antenna; a supplementary non-directional antenna which is sensitive to circularly polarized signals in a direction orthogonal to the first direction for receiving echoes signals circularly polarized orthongonally to the first direction; the second level means for receiving the signals reflected to the non-directional antenna and outputing the level of the signal reflected to nondirectional antenna; means for scaling the level signal of said non-directional antenna signal by a factor equal to the ratio of said sensitivities of said directional antenna to said nondirectional antenna; comparator means for comparing the nondirectional signals to the directional signals as an indication of a rain echo signal; and, gate means receiving said signal from said comparator for allowing the passage of the signal from said directional antenna when no rain echo signal is present and blocking the passage the signal from the directional antenna when there is an indication of a rain echo signal.
References Cited (Backward Citations)
US3566403A
Cited
US4010469A
Cited
US3357013A
Cited
US2851681A
Cited
US2942260A
Cited
US3001193A
Cited
US3614787A
Cited
US4044359A
Cited
US3947848A
Cited
US3268891A
Cited
US3540045A
Cited
US3918055A
Cited
US4075633A
Cited
US3978483A
Cited
US4106015A
Cited
US4329687A
Cited
US4283795A
Cited
US4295140A
Cited
US4739327A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-11-13 | 1993-05-15 | 1993-11-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-11-13 | 1997-05-15 | 1997-11-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-11-13 | 2001-05-15 | 2001-11-14 | $7700.00 | Window Closed / Lapsed |