Patent US4099180A successfully refreshed from Google Patents.
US4099180A
Expired / Lapsed
US
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Geographic gain time control
Assignee: CARDION Inc A DE CORP
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Filing: 1977-03-02
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Granted: 1978-07-04
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Expires: 1997-03-02
Abstract
Abstract Apparatus is provided for modifying a conventional target locating system in which targets respond to an interrogation signal by transmitting a reply, and the target location is deduced from the azimuth from which a reply is received and the delay between the interrogation signal and the reply. The improvement includes a controllable attenuator coupling the receiving antenna to the target locating system which is controlled to selectively discriminate against selected range cells at selected azimuths. In a preferred embodiment, digital circuitry is relied upon to control the attenuator, and the identication of the range cells to be discriminated against is stored in a digital memory.
Inventors
- 👤 Murray Kupersmith
- 👤 Curtis W. Symansky
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 19:39
CPC Classifications
G; G01; G01S; G01S13/00; G01S13/74; G01S13/76; G01S13/78
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
148 words
In an interrogator transponder system for locating targets carrying a transponder, triggered into operation by receipt of interrogation signals, with a receiver coupled to an antenna for determining target position as a function of range and azimuth as the locus of transmission of said interrogation signals is changed, an improvement to reduce the ability of multi-path effects to generate spurious target positions comprising: a controllable attenuator coupled to said receiver in a signal path from said antenna, memory means with a plurality of storage locations corresponding to a plurality of range cells, each of said storage locations storing a quantity related to the ability of multi-path effects to generate a spurious reply at a corresponding range cell, addressing means for addressing different storage locations of said memory means, and memory output means for controlling said controllable attentuator in accordance with a quantity read from an addressed storage location.
Claim 2
Dependent Claim
148 words
In an interrogator transponder system for locating targets carrying a transponder, triggered into operation by receipt of interrogation signals, with a receiver coupled to an antenna for determining target position as a function of range and azimuth as the locus of transmission of said interrogation signals is changed, an improvement to reduce the ability of multi-path effects to generate spurious target positions comprising: a controllable attenuator coupled to said receiver in a signal path from said antenna, memory means with a plurality of storage locations corresponding to a plurality of range cells, each of said storage locations storing a quantity related to the ability of multi-path effects to generate a spurious reply at a corresponding range cell, addressing means for addressing different storage locations of said memory means, and memory output means for controlling said controllable attentuator in accordance with a quantity read from an addressed storage location.
Claim 3
Dependent Claim
41 words
The apparatus of claim 1 which includes means for transmitting an interrogation signal sweeping in azimuth as a function of time and in which said addressing means addresses different storage locations in synchronism with the changing azimuth of said interrogation signal.
Claim 4
Dependent Claim
23 words
The apparatus of claim 1 in which the said addressing means includes means to address different storage locations as a function of time.
Claim 5
Dependent Claim
73 words
The apparatus of claim 1 in which said interrogation signals interrogate different range cells as a function of time at a given azimuth and in which said interrogation signals are swept in azimuth in which said addressing means includes means to address storage locations corresponding to different range cells at a given azimuth as a function of time, and to address different storage locations in synchronism with different azimuths of said interrogation signal.
Claim 6
Dependent Claim
128 words
In an interrogator-transponder system including an interrogation signal transmitter sweeping a search volume at different azimuths with a receiver detecting target position as a function of azimuth of a reply and time delay after transmission of an interrogation signal which is subject to generation of spurious target positions due to multi-path effects, a method of reducing such multi-path effects comprising the steps of: providing a controllable attenuator in a signal path to said receiver, providing a memory storing, in locations corresponding to different range cells, quantities related to detected ability for generation of spurious target positions at said range cells, reading locations of said memory in accordance with azimuthal position of said interrogation signal, and controlling said attenuator to provide attenuation corresponding to quantities read from said memory.
Claim 7
Dependent Claim
128 words
In an interrogator-transponder system including an interrogation signal transmitter sweeping a search volume at different azimuths with a receiver detecting target position as a function of azimuth of a reply and time delay after transmission of an interrogation signal which is subject to generation of spurious target positions due to multi-path effects, a method of reducing such multi-path effects comprising the steps of: providing a controllable attenuator in a signal path to said receiver, providing a memory storing, in locations corresponding to different range cells, quantities related to detected ability for generation of spurious target positions at said range cells, reading locations of said memory in accordance with azimuthal position of said interrogation signal, and controlling said attenuator to provide attenuation corresponding to quantities read from said memory.
Claim 8
Dependent Claim
30 words
The method of claim 5 in which said reading step comprises reading different storage locations of said memory as a function of time subsequent to transmission of said interrogation signal.
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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) | 1981-07-03 | 1982-01-02 | 1982-07-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-07-03 | 1986-01-02 | 1986-07-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-07-03 | 1990-01-02 | 1990-07-04 | $7700.00 | Window Closed / Lapsed |