Subchirp processing method
US5898399A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 10, 1996 |
| Grant date | Apr 27, 1999 |
| Priority date | — |
| Expiry date | May 10, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S13/904
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method of performing the computer-intensive initial steps of the range migration algorithm, or RMA, produces radar imagery of higher quality than the current polar format (PF) processing approach, while operating faster and more efficiently than the standard RMA. The new method is advantageous when the synthetic aperture length required to achieve azimuth resolution is significantly larger than the azimuth extent of the processed scene. The method subdivides the signal history into a plurality of non-overlapping subapertures, adds a low bandwidth azimuth chirp across each subaperture and applies a fast Fourier transform separately to each subaperture. The results are coherently combined, after which the remaining steps of the conventional RMA may be completed with minor modifications to the subsequent two-dimensional phase compensation. The invention is applicable to spotlight, stripmap and scan-mode SAR image formation, and the separate, subaperture Fourier transformations may be performed simultaneously.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.