Auto-focusing correction for rotational acceleration effects on inverse synthetic aperture radar images
US5343204A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 29, 1993 |
| Grant date | Aug 30, 1994 |
| Priority date | — |
| Expiry date | Jul 29, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S13/9019
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Inverse synthetic aperture radar imaging systems that are used to image targets that undergo rotational accelerations are enhanced by signal processing techniques which provide correction factors to reduce the frequency-shift and frequency-stretch errors that occur due to such accelerations. A target scan is subdivided into a number of sub-apertures and a Fast Fourier Transfer (FFT) is performed on the data for each sub-aperture to provide associated frequency sub-images. The FFT is then subdivided in "sub-swaths" of amplitude versus frequency for a plurality of frequency bands. The change-of-frequency, or frequency shift, data between prominent scattering points of each sub-image are processed to provide a phase correction factor that incorporates range changes and translational acceleration distortions for additional scattering points other than the most prominent scattering point. A frequency-stretch correction factor that compensates for rotational acceleration distortion is also provided.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.