US3981013A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Non-jammable plural frequency radar system
Assignee: United States Department of the Navy
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Filing: 1966-08-31
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Granted: 1976-09-14
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Expires: 1986-08-31
Abstract
Abstract A radar system for transmitting and receiving a plurality of signals of derent frequency simultaneously to prevent the possibility of jamming the system. Two signals of different frequency are produced comprising the upper and lower sidebands of a carrier frequency. These signals are simultaneously radiated and upon reflection are received in two receiver channels centered on frequencies identical with the transmitted frequencies. The received signals are then mixed to produce an intermediate frequency which is again mixed with a local oscillator signal whereupon range and tracking information may be derived.
Inventors
- 👤 James L. Christensen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 09:38
CPC Classifications
G; G01; G01S; G01S13/00; G01S13/02; G01S13/06; G01S13/08; G01S13/10; G01S13/106; G01S7/00; G01S7/02; G01S7/36
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
145 words
A radar system comprising: a first oscillator providing a first carrier frequency; means for deriving from said first carrier frequency simultaneous signals of different frequency respectively comprising upper and lower sideband signals of said first carrier frequency; a first selector means receiving said sideband signals and providing an output signal at only one of said different frequencies; a second oscillator providing a second carrier frequency; means combining said output signal wih said second carrier frequency for producing a plurality of signals of different frequency to be simultaneously radiated, which signals comprise upper and lower sidebands of said second carrier frequency; means simultaneously radiating said upper and lower sidebands of said second carrier frequency; and means receiving said second carrier frequency upper and lower sideband signals after reflection from reflecting objects and providing range information about said objects only in the presence of simultaneous signal reflections.
Claim 2
Dependent Claim
145 words
A radar system comprising: a first oscillator providing a first carrier frequency; means for deriving from said first carrier frequency simultaneous signals of different frequency respectively comprising upper and lower sideband signals of said first carrier frequency; a first selector means receiving said sideband signals and providing an output signal at only one of said different frequencies; a second oscillator providing a second carrier frequency; means combining said output signal wih said second carrier frequency for producing a plurality of signals of different frequency to be simultaneously radiated, which signals comprise upper and lower sidebands of said second carrier frequency; means simultaneously radiating said upper and lower sidebands of said second carrier frequency; and means receiving said second carrier frequency upper and lower sideband signals after reflection from reflecting objects and providing range information about said objects only in the presence of simultaneous signal reflections.
Claim 3
Dependent Claim
41 words
A radar system as recited in claim 1 wherein said means for deriving simultaneous signals from said first carrier frequency comprises: a source of signals; and mixer means for mixing the output of said first oscillator and said source of signals.
Claim 4
Dependent Claim
65 words
A radar system as recited in claim 1 wherein said means receiving said second carrier frequency upper and lower sideband signals comprises: means providing an intermediate frequency signal only in the presence of said simultaneous second carrier frequency upper and lower sideband signal reflections; and means for applying said intermediate frequency signal to a receiver and range tracker for providing range information about said object.
Claim 5
Dependent Claim
53 words
A radar system as recited in claim 3 wherein said means providing an intermediate frequency signal includes: means separating said simultaneous second carrier frequency upper and lower sideband signal reflections into discrete signals; and means mixing said discrete signals for providing an intermediate frequency equal to the frequency difference of said discrete signals.
Claim 6
Dependent Claim
34 words
A radar system as recited in claim 4 wherein said means for applying comprises: heterodyning means receiving said intermediate frequency and providing an output at another intermediate frequency for said receiver and range tracker.
Claim 7
Dependent Claim
69 words
A radar system as recited in claim 4 wherein said means separating said reflected second carrier frequency upper and lower sideband signals comprises: first and second filter means receiving said reflected signals and passing substantially unattenuated signals having a frequency within the bandpasses thereof; and mixer means combining said unattenuated signals and providing an intermediate frequency output signal only in the presence of simultaneous signals from said filter means.
Claim 8
Dependent Claim
24 words
A radar system as recited in claim 6 further comprising: receiver means operatively connected to said mixer means for providing target range tracking information.
Claim 9
Dependent Claim
62 words
A radar system as recited in claim 1 wherein said means for combining said output signal with said second carrier frequency includes: first and second mixer means receiving said selector output signal and said second carrier frequency and providing upper and lower sideband output signals thereof; and second and third selector means each selectively passing only one of said sideband output signals.
References Cited (Backward Citations)
US3302161A
Cited
US3082418A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-09-14 | 1980-03-15 | 1980-09-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-09-14 | 1984-03-15 | 1984-09-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-09-14 | 1988-03-15 | 1988-09-14 | $7700.00 | Window Closed / Lapsed |