The Boeing Company

Robert Irving Ridgway

Ryon Christopher Warren

Charles H Hightower

Eric David Haugse

A radar tracking system extracts moving target content from a single radar pulse stream. The radar tracking system has a single phase center antenna for receiving the radar pulse stream. The tracking system further includes a signal processing system for converting the radar pulse stream into a plurality of SAR images. Each image has a corresponding moving target content and a corresponding clutter content. The tracking system also includes a targeting system for canceling identical clutter content between the images. The signal processing system includes a synthetic subaperture system for generating a plurality of synthetic subapertures and defining a common reference point. The common reference point has known slant ranges with respect to the plurality of synthetic subapertures. A deramping module uses a unique deramping function to compute a deramped signal for each synthetic subaperture based on the known slant ranges. The signal processing system further includes an imaging system for generating SAR images for the deramped signals. The processing of a radar pulse stream from a single antenna allows antenna size to be reduced by a factor of two or more, and allows tracking of slowly moving targets.

Subaperture processing for clutter reduction in synthetic aperture radar images of ground moving targets

A deformation compensation system for use with a large phased-array antenna system to electronically compensate for surface deformations occurring on the phased-array antenna which would otherwise compromise antenna performance. In one embodiment, a plurality of strain gauges are disposed on or integrally formed in structure forming the phased-array antenna. The strain gauges are placed at those locations on the antenna structure, where, through prior structural modeling and testing, it has been determined that high strains associated with the expected deformation of the phased-array antenna are expected to occur to a significant degree. The strain gauges output signals to a data acquisition system which uses a strain-to-displacement algorithm to produce displacements corresponding to the estimated, deformed shape of the phased-array antenna. These displacements are input to a beam steering controller which is used to generate phase shift or time delay commands used for electronically compensating, in real time, for the overall estimated, deformed shape of the phased-array antenna. The invention eliminates the need for heavy and large structural supports or trusses which have traditionally been required to maintain surface planarity of a large, phased-array antenna, and further enables the use of even larger phased-array antennas in space-based applications. The invention enables surface deformation to be compensated for in a non-intrusive manner which does not significantly increase the overall complexity of the phased-array antenna system.

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San Jose, CA, United States of America

Robert Irving Ridgway