← Back to Patent Explorer
US4724439A Expired / Lapsed US ⏱️ 0.0 years remaining

Microwave radiometer using fanbeam inversion

Assignee: The AT&T MVPD Group LLC
•
Filing: 1987-02-12
•
Granted: 1988-02-09
•
Expires: 2007-02-12
📄 Original PDF 🌐 Google Patents 🔄 Sync Now

Abstract

Abstract A microwave radiometer reconstructs images by fanbeam inversion. True time delay (100), frequency (600, 700) and mechanical scanning systems (200) are disclosed. The mechanically scanning radiometer includes a fanbeam antenna (210) to scan a scene so that the antenna output is a projection of the scene taken along the direction of scan. The mechanical scanning motion is provided by a rocking motor (254) controlled by a computer (214). Projections are obtained for successive orientations as the antenna is rotated by another motor (212). By application of an inverse Radon transform, the scene scanned is reconstructed by the computer. In one frequency scanning system (600), a filter bank spectrometer is implemented to obtain the projections, and in the other frequency scanning system (700), a transform spectrometer implemented. In the delay scanning system (100), a beam forming computer is used in the reconstruction process. A modification of the Radon transform is disclosed which compensates for the conicity of electronically scanning fanbeams.

Inventors

  • 👤 Carl A. Wiley
  • 👤 Charles R. Edelsohn

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-25 12:57
CPC Classifications
G; G01; G01K; G01K11/00; G01K11/006

Claims Analysis

Total Claims: 10
Claim 1
Independent Claim 136 words
A radiometer for determining the mircrowave radiation distribution of a scene comprising: an antenna for providing an output as a function of microwave radiation received along fanbeams; said fanbeams collectively spanning said scene, said fanbeams having predetermined relative positions around an axis parallel to the antenna; means for moving said fanbeams; around a line of sight from the antenna to the scene an orientation sensor for providing an output as a function of the rotation orientation of said fanbeams; means for tranforming said outputs from said antenna and said orientation sensor into one-dimensional radiation functions, each of said radiation functions having a respective rotational orientation; and computing means for reconstructing the microwave radiation distribution of the scene from said radiation functions and their respective rotational orientations, wherein a two dimensional image of the scene are produced.
Claim 2
Dependent Claim 136 words
A radiometer for determining the mircrowave radiation distribution of a scene comprising: an antenna for providing an output as a function of microwave radiation received along fanbeams; said fanbeams collectively spanning said scene, said fanbeams having predetermined relative positions around an axis parallel to the antenna; means for moving said fanbeams; around a line of sight from the antenna to the scene an orientation sensor for providing an output as a function of the rotation orientation of said fanbeams; means for tranforming said outputs from said antenna and said orientation sensor into one-dimensional radiation functions, each of said radiation functions having a respective rotational orientation; and computing means for reconstructing the microwave radiation distribution of the scene from said radiation functions and their respective rotational orientations, wherein a two dimensional image of the scene are produced.
Claim 3
Dependent Claim 23 words
The radiometer of claim 1 further characterized in that said radiation function is a spatial frequency spectrum of radiation received from the scene.
Claim 4
Dependent Claim 21 words
The radiometer of claim 1 further characterized in that said radiation function is a projection of radiation received from the scene.
Claim 5
Dependent Claim 19 words
The radiometer of claim 1 further characterized in that said computing means includes means for correcting for beam shape.
Claim 6
Dependent Claim 29 words
The radiometer of claim 4 further characterized in that said fanbeams are conical sheets and said means for correcting for beam shape corrects for the conicity of said fanbeams.
Claim 7
Dependent Claim 16 words
The radiometer of claim 5 further characterized in that said antenna is adapted for frequency scanning.
Claim 8
Dependent Claim 16 words
The radiometer of claim 5 further characterized in that said antenna is adapted for delay scanning.
Claim 9
Dependent Claim 16 words
The radiometer of claim 4 further characterized in that said antenna is adapted for mechanical scanning.
Claim 10
Dependent Claim 21 words
The radiometer of claim 8 further characterized in that said means for correcting beam shape corrects for side-lobes and beam thickness.

References Cited (Backward Citations)

US3482244A Cited
US3808596A Cited
US4178100A Cited
US4509048A Cited
US4553145A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1991-02-08 1991-08-10 1992-02-09 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1995-02-08 1995-08-10 1996-02-09 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1999-02-08 1999-08-10 2000-02-09 $7700.00 Window Closed / Lapsed

Assigned Categories & Tags

No categories assigned to this patent yet.

Assign Category Tag