Ralph W Hudson

US Patent:

7307580, Dec 11, 2007

Filed:

Jan 17, 2006

Appl. No.:

11/333497

Inventors:

Jon H. Sherman - Los Angeles CA, US
John P. Kilkelly - San Pedro CA, US
Helen L. Sun - Rancho Palos Verdes CA, US
Ralph E. Hudson - Los Angeles CA, US

Assignee:

Raytheon Company - Waltham MA

International Classification:

G01S 13/90

US Classification:

342 58, 342 25 D, 342196

Abstract:

Provided is a non-statistical method for compressing and decompressing complex SAR data derived from reflected energy. The method includes selecting a first FFT to provide a target ratio of pixel spacing to resolution. A second FFT is then selected which is smaller than the first FFT. The data is zero-padded to fill the second FFT and transformed to provide at least one transfer frequency. This transfer frequency is then transferred to the at least one remote site. At the remote site the second FFT is inverted to restore the data from the received transfer frequency. The restored data is then zero-padded again to fill the first FFT. The first FFT is then used to transform the zero-padded restored data to provide a data set of points with the target ratio of pixel spacing to resolution.

US Patent:

7714768, May 11, 2010

Filed:

Sep 28, 2007

Appl. No.:

11/904715

Inventors:

Jon H. Sherman - Los Angeles CA, US
John P. Kilkelly - San Pedro CA, US
Helen L. Sun - Rancho Palos Verdes CA, US
Ralph E. Hudson - Los Angeles CA, US

Assignee:

Raytheon Company - Waltham MA

International Classification:

G01S 13/90

US Classification:

342 58, 342 25 D, 342196

Abstract:

Provided is a non-statistical method for compressing and decompressing complex SAR data derived from reflected energy. The method includes selecting a first FFT to provide a target ratio of pixel spacing to resolution. A second FFT is then selected which is smaller than the first FFT. The data is zero-padded to fill the second FFT and transformed to provide at least one transfer frequency. This transfer frequency is then transferred to the at least one remote site. At the remote site the second FFT is inverted to restore the data from the received transfer frequency. The restored data is then zero-padded again to fill the first FFT. The first FFT is then used to transform the zero-padded restored data to provide a data set of points with the target ratio of pixel spacing to resolution.

US Patent:

49242326, May 8, 1990

Filed:

Oct 31, 1988

Appl. No.:

7/265079

Inventors:

Ralph E. Hudson - Los Angeles CA
Stanley O. Aks - Cerritos CA
Peter P. Bogdanovic - Los Angeles CA
David D. Lynch - Northridge CA

Assignee:

Hughes Aircraft Company - Los Angeles CA

International Classification:

G01S 740

US Classification:

342174

Abstract:

The method and system for reducing phase error of phased array radar beam steering controllers having digitally controlled phase shifters includes the monitoring of individual digitally controlled phase shifter elements, determining an additive phase correction to reduce the number of failed phase shifter elements, determining whether said additive phase correction is achievable by comparing the stuck bit state at each said failed changers element with said additive phase correction and adjusting the phase commands to the nearest values which can be achieved if the additive phase correction is unachievable.

US Patent:

47807180, Oct 25, 1988

Filed:

Jun 17, 1985

Appl. No.:

6/745729

Inventors:

Ralph E. Hudson - Los Angeles CA
Yoji G. Niho - Rancho Palos Verdes CA

Assignee:

Hughes Aircraft Company - Los Angeles CA

International Classification:

G01S 1389

US Classification:

342 25

Abstract:

A technique is disclosed for encoding SAR image data to achieve data compression. In the image encoding stage, the SAR image is transformed into a list of high reflectivity radar discretes and a small array of frequency filters. In the target list, the location data and intensity levels above the local average background clutter are tabulated for a predetermined number of the highest intensity radar discretes. The array of frequency filters is divided into three zones; the inner, middle, and higher frequency zones relative to the d. c. filter. Only the inner and middle zones of filters are retained and the outer filters are discarded, thus acheiving the desired data reduction. The inner zone filters are quantized to a higher level of precision than the middle zone of filters. The saturation levels of the filters are determined adaptively. In the decoding stage, the original SAR image is reconstructed from the radar discrete list and the small array of frequency filters.

US Patent:

54955408, Feb 27, 1996

Filed:

Oct 12, 1994

Appl. No.:

8/322117

Inventors:

Robert T. Frankot - Van Nuys CA
Ralph E. Hudson - Los Angeles CA

Assignee:

Hughes Aircraft Company - Los Angeles CA

International Classification:

G06K 932

US Classification:

382294

Abstract:

A method for automatically selecting subareas from reference image data such that registration accuracy is optimized between images. Optimal subarea selection reduces the on-line computation and reference data storage required for multi-subarea correlation or, alteratively, improves its effectiveness. Example results for a synthetic aperture radar (SAR) image are described. The results indicate that the automatic subarea selection method of the present invention reduces on-line computation by a factor of 2 to 3 (relative to random subarea selection) without degradation in accuracy. The present selection method minimizes the predicted total mean squared registration error (MSE). The total MSE is predicted in terms of the position and predicted measurement covariance (derived from local image statistics) of each candidate subarea. Combinatorial optimization procedures select a predetermined number of subareas to minimize total MSE. The present method jointly considers the quality and position for each local measurement, optimally handles any order polynomial model, and includes bounds on the uncertainty of registration parameters.

US Patent:

56106106, Mar 11, 1997

Filed:

May 18, 1988

Appl. No.:

7/195555

Inventors:

Ralph E. Hudson - Los Angeles CA
Howard S. Nussbaum - Los Angeles CA
Ernest Chen - San Pedro CA

Assignee:

Hughes Electronics - Los Angeles CA

International Classification:

G01S 1390

US Classification:

342 25

Abstract:

An inverse synthetic array radar (ISAR) system provides for improving the resolution of an ISAR image by providing compensation for non-uniformity in the magnitude of the angular velocity of a rotating target as the target rotates to generate the synthetic-aperture-angle, and enables use of a larger synthetic-aperture angle, without compromising ISAR image quality with respect to smear. The preferred embodiment records sampled data signals to generate a collected-data matrix indexed in each of two dimensions on the basis of uniform increments of time, and performs data processing to produce a translated data matrix indexed in a dimension on the basis of uniform increments of synthetic-aperture angle. Further processing of the translated data matrix produces data in a buffer for controlling a display device for the ISAR image.

US Patent:

54482410, Sep 5, 1995

Filed:

May 26, 1994

Appl. No.:

8/249488

Inventors:

Gene W. Zeoli - Palos Verdes Estates CA
Ralph E. Hudson - Los Angeles CA
Robert H. Latter - Manhattan Beach CA
Robert T. Frankot - Van Nuys CA

Assignee:

Hughes Aircraft Company - Los Angeles CA

International Classification:

G01S 1390

US Classification:

342 25

Abstract:

A terrain height radar system and processing method comprising a high resolution synthetic aperture radar (SAR) mounted on an air vehicle and a SAR signal processor containing a signal processing algorithm or method for computing terrain height and radar backscatter power. The system contains motion sensing and navigation functions that also provide data to the signal processor to provide motion compensation. Signal processing algorithms in the method compensate for planar motion of the air vehicle for variations of terrain height in the field of view. The algorithms also compensate for nonplanar motion of the radar, and for scatterers in or very near to a reference plane in the field of view. The algorithms exploit defocusing due to displacement from the reference plane to estimate the terrain height above the reference plane. The algorithm is computationally efficient because the bulk of the radar signal processing is common to both the SAR function and the terrain height estimation function.

US Patent:

54883741, Jan 30, 1996

Filed:

Oct 14, 1994

Appl. No.:

8/323414

Inventors:

Robert T. Frankot - Van Nuys CA
Ralph E. Hudson - Los Angeles CA
George H. Senge - Los Angeles CA

Assignee:

Hughes Aircraft Company - Los Angeles CA

International Classification:

G01S 1390

US Classification:

342 25

Abstract:

Apparatus including a multi-scale adaptive filter for smoothing interferometric SAR (IFSAR) data in areas of low signal-to-noise ratio (SNR) and/or coherence while preserving resolution in areas of high SNR/coherence. The multi-scale adaptive filter uses simple combinations of multiple linear filters applied to a complex interferogram. The multi-scale adaptive filter is computationally efficient and lends itself to parallel implementation. A pyramid architecture comprising a plurality of cascaded stages is employed which reduces the computational load and memory required for implementation of the processing algorithm. The multi-scale adaptive filter implements a processing algorithm that may be applied to standard IFSAR data. Its input is a complex interferogram (the conjugate product of two complex images) and its output is a filtered interferogram (A) which is passed to an information extraction processor, that extracts a terrain elevation map, for example. The adaptive filter incorporates linear filters at two or more scales (i. e.

Author:

Ralph F. Hudson

ISBN #:

0918812941