Patent US5077967A successfully refreshed from Google Patents.
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USH1720H
Expired / Lapsed
US
⏱️ 0.0 years remaining
Time frequency processor for radar imaging of moving targets
Assignee: Individual
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Filing: 1997-03-31
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Granted: 1998-04-07
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Expires: 2017-03-31
Abstract
Abstract Conventional radar uses the Fourier transform to generate a radar target image. Constraints on the use of Fourier methods requiring point scatterers to remain in their range cells and requiring Doppler frequency shifts for point scatterers to be stationary are impractical due to a moving object's inherent non-uniform motion and rotation. Time varying motion-induced Doppler frequency shift spectra represented with Fourier transform methods smears radar target image. Representing time-varying Doppler spectrum using joint time-frequency transform methods is desirable. Replacing conventional radar Fourier transform with a high resolution time-frequency transform, a 2-D range-Doppler Fourier image frame becomes a 3-D time-range-Doppler cube. By sampling in time, a time sequence of 2-D range-Doppler images with superior resolution can be viewed. Smears from time-variance of Doppler spectrum may be removed to enhance target image.
Inventors
- 👤 Victor C. Chen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 07:31
CPC Classifications
G; G01; G01S; G01S13/00; G01S13/88; G01S13/89; G01S13/90; G01S13/9021; G01S13/9029
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
151 words
In a radar image signal processing system, an improved method for processing radar target image information comprising: generating a series of pulses for transmission in a target range, receiving target image backscatter information generated from said series of pulses transmitted in said target range by reflecting from a target in said target range, and processing said target image backscatter information received in said receiving step into target information using a series of processing steps comprising: generating frequency domain signatures from said target image backscatter information, range processing said frequency domain signatures and generating first transformed target information, receiving said first transformed target information and generating target range profiles therefrom, performing a Joint Time-Frequency Transform upon said target range profiles and generating second transformed target information, sampling said second transformed target information in the time domain and generating time sampled target information, and displaying a target image using time sampled target information.
Claim 2
Dependent Claim
151 words
In a radar image signal processing system, an improved method for processing radar target image information comprising: generating a series of pulses for transmission in a target range, receiving target image backscatter information generated from said series of pulses transmitted in said target range by reflecting from a target in said target range, and processing said target image backscatter information received in said receiving step into target information using a series of processing steps comprising: generating frequency domain signatures from said target image backscatter information, range processing said frequency domain signatures and generating first transformed target information, receiving said first transformed target information and generating target range profiles therefrom, performing a Joint Time-Frequency Transform upon said target range profiles and generating second transformed target information, sampling said second transformed target information in the time domain and generating time sampled target information, and displaying a target image using time sampled target information.
Claim 3
Dependent Claim
19 words
The method of claim 1, wherein said series of pulses further comprises individual narrow band pulses of increasing frequency.
Claim 4
Dependent Claim
27 words
The method of claim 1, wherein said target image backscatter information further comprises target image backscatter information from a plurality of point scatter sources on said target.
Claim 5
Dependent Claim
31 words
The method of claim 1, wherein said step of range processing further comprises removing a motion component further comprises removing extraneous phase term from a spatial frequency signature of said target.
Claim 6
Dependent Claim
23 words
The method of claim 4, wherein said step of range processing further comprises removing said motion component using an Inverse Discrete Fourier Transform.
Claim 7
Dependent Claim
16 words
The method of claim 1, wherein said first transformed target information further comprises N range profiles.
Claim 8
Dependent Claim
20 words
The method of claim 6, wherein said target range profiles further comprise M target range profiles comprising N range profiles.
Claim 9
Dependent Claim
47 words
The method of claim 1, wherein said step of performing a Joint Time-Frequency Transform upon said target range profiles and generating second transformed target information further comprises performing M Joint Time-Frequency Transforms upon M target range profiles and generating M groups of said second transformed target information.
Claim 10
Dependent Claim
47 words
The method of claim 8, wherein said step of sampling said second transformed target information in the time domain and generating time sampled target information further comprises sampling said M groups of said second transformed target information and generating M frames of said time sampled target information.
Claim 11
Dependent Claim
51 words
The method of claim 9, wherein said step of displaying a target image using time sampled target information further comprises displaying an enhanced target image in the Range Doppler plane, said target image comprising M frames of said time sampled target information displayed on a display over a predetermined time interval.
Claim 12
Dependent Claim
60 words
A radar system comprising: means for generating a plurality of radar bursts, each said burst comprising a plurality of radar pulses; means for receiving echoes of said pulses in said bursts; means for time aligning pulses across said bursts to form an aligned echo data base; and means for transforming said aligned echo database by a preselected joint time-frequency transform.
Claim 13
Dependent Claim
60 words
A radar system comprising: means for generating a plurality of radar bursts, each said burst comprising a plurality of radar pulses; means for receiving echoes of said pulses in said bursts; means for time aligning pulses across said bursts to form an aligned echo data base; and means for transforming said aligned echo database by a preselected joint time-frequency transform.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-04-06 | 2001-10-06 | 2002-04-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-04-06 | 2005-10-06 | 2006-04-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-04-06 | 2009-10-06 | 2010-04-07 | $7700.00 | Window Closed / Lapsed |