Patent US1003190A successfully refreshed from Google Patents.
Patent US3955199A successfully refreshed from Google Patents.
US3955199A
Expired / Lapsed
US
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Method of and apparatus for ground testing doppler navigation sets-a doppler radar simulator
Assignee: United States Department of the Navy
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Filing: 1974-08-21
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Granted: 1976-05-04
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Expires: 1994-08-21
Abstract
Abstract A doppler/range simulator for use in testing aircraft systems based on therinciple that an ionized gas absorbs microwave radiation and thus becomes raised to higher energy levels, and when falling back to the original energy state the ionized gas re-radiates the absorbed microwave energy. A frequency control simulates a doppler or velocity signal. A voltage or current control simulates the time delay or altitude range signal. The test set is in the form of a light-weight anechoic chamber lined on the inside with energy absorbant material except for the top. Within the enclosure there are positioned near the open top a plurality of parallel - arranged flurescent tubes adapted to be energized with pulsating d.c. to produce a flow of ions in the tubes which flow from one end of the tube to the other. The tubes are excited in parallel so that the ion flow is always in the same direction. The enclosure is provided with means for easily attaching and detaching the chamber to the underside structure of the aircraft at a location immediately beneath and close to the transmitting and receiving antennas of the radome.
Inventors
- 👤 Robert W. Hutzelman
- 👤 Everitt E. Fairbanks
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 18:46
CPC Classifications
G; G01; G01S; G01S7/00; G01S7/02; G01S7/40; G01S7/4004; G01S7/4021
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
157 words
A method for testing a doppler velocity/altimeter radar with an antenna situated in an aircraft comprising the steps of: attaching to the aircraft an anechoic chamber to absorb microwave energy, said chamber having closed sides and bottom and an open top with a plurality of parallel arranged flourescent tubes set within the chamber facing the open top so that the open top of the chamber faces the antenna; pulsing said flourescent tubes in paralel with a direct current so that groups of ions travel in one direction through said plurality of tubes at a speed determined by the frequency of said pulsing; transmitting microwave energy from the antenna, which energy is absorbed by the traveling groups of ions, raising said ions to a higher energy level; and re-radiating the energy absorbed by the ions to the antenna as the ions return to their normal energy state after a delay determined by the amplitude of said direct current.
Claim 2
Independent Claim
157 words
A method for testing a doppler velocity/altimeter radar with an antenna situated in an aircraft comprising the steps of: attaching to the aircraft an anechoic chamber to absorb microwave energy, said chamber having closed sides and bottom and an open top with a plurality of parallel arranged flourescent tubes set within the chamber facing the open top so that the open top of the chamber faces the antenna; pulsing said flourescent tubes in paralel with a direct current so that groups of ions travel in one direction through said plurality of tubes at a speed determined by the frequency of said pulsing; transmitting microwave energy from the antenna, which energy is absorbed by the traveling groups of ions, raising said ions to a higher energy level; and re-radiating the energy absorbed by the ions to the antenna as the ions return to their normal energy state after a delay determined by the amplitude of said direct current.
Claim 3
Dependent Claim
76 words
A doppler/range simulator for testing an aircraft doppler velocity/altimeter radar having an antenna comprising: means for absorbing microwave energy; a source of ionizable gas mounted within said absorbing means; means for exciting said source of gas to create a traveling ionized field to simulate a moving target whereby energy transmitted by said antenna is absorbed by said gas and re-radiated to said antenna to provide an indication of the velocity and distance from the simulated target.
Claim 4
Dependent Claim
76 words
A doppler/range simulator for testing an aircraft doppler velocity/altimeter radar having an antenna comprising: means for absorbing microwave energy; a source of ionizable gas mounted within said absorbing means; means for exciting said source of gas to create a traveling ionized field to simulate a moving target whereby energy transmitted by said antenna is absorbed by said gas and re-radiated to said antenna to provide an indication of the velocity and distance from the simulated target.
Claim 5
Dependent Claim
16 words
A doppler/range simulator as recited in claim 2 wherein said absorbing means comprises an anechoic chamber.
Claim 6
Dependent Claim
31 words
A doppler/range simulator as recited in claim 3 wherein said source of ionizable gas comprises a plurality of flourescent tubes arranged in a planar parallel array mounted within said anechoic chamber.
Claim 7
Dependent Claim
62 words
A doppler/range simulator as recited in claim 4 wherein said exciting means comprises a pulsating D.C. power supply to provide precise voltage levels and frequency levels, wherein the voltage determines the time delay between absorption and re-radiation by said ionized field to simulate target distance, and wherein the frequency of the pulses determines the speed of said field to simulate target motion.
Claim 8
Dependent Claim
51 words
A doppler/range simulator as recited in claim 5 wherein said power supply is connected to said tubes so that one end of said tubes is always positive relative to the opposite end of said tubes, and said power supply excites any pair of said tubes in phase one with the other.
Claim 9
Dependent Claim
45 words
A doppler/range simulator as recited in claim 6 wherein said simulator further comprises means for placing said simulator in proximity to said antenna so that said antenna can transmit microwave energy to, and receive microwave energy from, said flourescent tubes situated within said anechoic chamber.
Claim 10
Dependent Claim
35 words
A doppler/range simulator as recited in claim 7 wherein said anechoic chamber comprises: an enclosure open at the top; and a lining of microwave energy absorbent material along all sides and bottom of said enclosure.
Claim 11
Dependent Claim
22 words
A doppler/range simulator as recited in claim 8 wherein said plurality of flourescent tubes are relatively long with respect to said antenna.
Claim 12
Dependent Claim
88 words
A doppler/range simulator as recited in claim 9 wherein said placing means comprises: a radome having a bump, said radome being mounted on said aircraft and enclosing said antenna; a plurality of fixed hooks positioned on the sides of and around said bump; and a plurality of swivelling hooks fitted to the exterior of said anechoic chamber suitably positioned to engage said fixed hooks on said radome whereby said simulator is securely held in proximity to said antenna so that the opening of said enclosure faces said antenna.
Claim 13
Dependent Claim
21 words
A doppler/range simulator as recited in claim 10 wherein said enclosure comprises sheet aluminum, and said lining comprises graphite-loaded sponge material.
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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) | 1979-05-04 | 1979-11-03 | 1980-05-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-05-04 | 1983-11-03 | 1984-05-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-05-04 | 1987-11-03 | 1988-05-04 | $7700.00 | Window Closed / Lapsed |