US4847624A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Coordinate system transformation apparatus for a high resolution radar
Assignee: Northrop Grumman Corp
•
Filing: 1987-12-30
•
Granted: 1989-07-11
•
Expires: 2007-12-30
Abstract
Abstract The present invention includes an apparatus that prebiases a transmitted radar signal. The prebiasing of the transmit signal automatically aligns the return signals in one dimension or dimensionally transforms the return signals thereby removing the need for one of the dimensional processing operations of a conventinal two dimensional return signal interpolator. A map function generator produces small frequency (phase) changes in the transmitted signal during each pulse over the entire integration or exposure period. The map function generator produces a parabolic frequency change control signal applied during the integration period. The control signal is divided into segments where each segment controls a single transmit pulse. The control signal modifies a linear frequency modulation control signal. conventionally produced by high resolution radar systems.
Inventors
- 👤 Francis W. Hopwood
- 👤 Jerry A. Kane
- 👤 George A. Ioannidis
- 👤 Martin J. Decker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 08:36
CPC Classifications
G; G01; G01S; G01S13/00; G01S13/02; G01S13/06; G01S13/08; G01S13/10; G01S13/26; G01S13/28; G01S13/282; G01S13/88; G01S13/89; G01S13/90; G01S13/904
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
99 words
A signal transformation apparatus for a radar system that controls transmit frequency of each radar pulse with a phase shifter, said apparatus comprising: modulation means for providing a modulation control signal; preinterpolation means for providing a biasing control signal eliminating a dimension of processing of a received signal by causing dimensional transformation of the transmitted and received signal so that the received signal is aligned in one dimension with one axis of the received signal image mapping coordinates; and combining means for combining the biasing control signal and the modulation control signal as an output to the phase shifter.
Claim 2
Dependent Claim
99 words
A signal transformation apparatus for a radar system that controls transmit frequency of each radar pulse with a phase shifter, said apparatus comprising: modulation means for providing a modulation control signal; preinterpolation means for providing a biasing control signal eliminating a dimension of processing of a received signal by causing dimensional transformation of the transmitted and received signal so that the received signal is aligned in one dimension with one axis of the received signal image mapping coordinates; and combining means for combining the biasing control signal and the modulation control signal as an output to the phase shifter.
Claim 3
Dependent Claim
23 words
An apparatus as recited in claim 1, wherein said preinterpolation means provides a parabolic shaped biasing control signal during an image integration period.
Claim 4
Dependent Claim
63 words
An apparatus as recited in claim 1, wherein said modulation means comprises a first linear frequency modulation synchronizer provided with an initial condition setting for linear modulation, said preinterpolation means comprises a second linear frequency modulation synchronizer with a changeable slope and initial condition output and said combining means comprises an accumulator connected to said first and second synchronizers and the phase shifter.
Claim 5
Dependent Claim
69 words
An apparatus as recited in claim 1, wherein said combining means produces a signal D 0 (J)=D 0 (0)+J*(D 1 (0)-D 2 (0)/2)+J 2 *D 2 (0)/2, where D 0 (0) is the initial condition of the parabolic bias signal for each radar pulse, D 1 (0) and D 2 (0) are initial conditions of the frequency modulation control signal and J is the value of a reference clock.
Claim 6
Dependent Claim
104 words
A radar system, comprising: waveform generator means for producing radar signals with a phase being controlled by a signal D 0 (J)=D 0 (0)+J*(D 1 (0)-D 2 (0)/2)+J 2 *D 2 (0)/2, where D 0 (0) is an initial condition of a parabolic bias signal for each radar pulse, D 1 (0) and D 2 (0) are initial conditions of a linear frequency modulation control signal and J is a value of a reference clock; trasmit/receive means for transmitting the radar signals and receiving return signals; interpolator means for one dimensionally interpolating the return signals; and display means for displaying the interpolated return signals.
Claim 7
Dependent Claim
104 words
A radar system, comprising: waveform generator means for producing radar signals with a phase being controlled by a signal D 0 (J)=D 0 (0)+J*(D 1 (0)-D 2 (0)/2)+J 2 *D 2 (0)/2, where D 0 (0) is an initial condition of a parabolic bias signal for each radar pulse, D 1 (0) and D 2 (0) are initial conditions of a linear frequency modulation control signal and J is a value of a reference clock; trasmit/receive means for transmitting the radar signals and receiving return signals; interpolator means for one dimensionally interpolating the return signals; and display means for displaying the interpolated return signals.
Claim 8
Dependent Claim
85 words
A signal transformation apparatus for a radar system that controls transmit frequency of each radar pulse with a phase shifter, said apparatus comprising: modulation means for providing a modulation control signal; preinterpolation means for providing a biasing control signal eliminating a dimension of processing of a received signal, where said preinterpolation means provides a parabolic shaped biasing control signal curing an image integration period; and combining means for combining the biasing control signal and the modulation control signal as an ouptut to the phase shifter.
Claim 9
Dependent Claim
85 words
A signal transformation apparatus for a radar system that controls transmit frequency of each radar pulse with a phase shifter, said apparatus comprising: modulation means for providing a modulation control signal; preinterpolation means for providing a biasing control signal eliminating a dimension of processing of a received signal, where said preinterpolation means provides a parabolic shaped biasing control signal curing an image integration period; and combining means for combining the biasing control signal and the modulation control signal as an ouptut to the phase shifter.
References Cited (Backward Citations)
US3216013A
Cited
US4321601A
Cited
US3992707A
Cited
US4002827A
Cited
US4186397A
Cited
US4160958A
Cited
US4310907A
Cited
US4245250A
Cited
US4386529A
Cited
US4611208A
Cited
US4724418A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-07-10 | 1993-01-09 | 1993-07-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-07-10 | 1997-01-09 | 1997-07-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-07-10 | 2001-01-09 | 2001-07-11 | $7700.00 | Window Closed / Lapsed |