Feature referenced error correction apparatus

Claim 2

A feature referenced error correction apparatus comprising in combination: a first and second stage processing means to process signal data from a synthetic aperture radar, said first stage processing means receiving said signal data from said synthetic aperture radar, said second stage processing means operatively connected to said first stage processing means to recevie the output signal therefrom, and means for preprocessing said signal data from said first stage processing means, said signal data comprising multiple images of a given frame from said synthetic aperture, said multiple images establishing positional shift errors in said signal data, said preprocessing means operatively conected to the output of said first stage processing means to receive the output signal therefrom, said preprocessing means measuring the errors in said signal data from said first stage processing means, said preprocessing means providing an error correction signal in response to the measured error in said signal data, said preprocessing means applying said error correction signal to said second stage processing means.

Claim 3

A feature referenced error correction apparatus as described in claim 1 wherein said preprocessing means comprises in combination: means for measuring error in said signal data from said first stage processing means, said error measuring means providing a measured error signal, and means for correcting error operatively connected to said error measuring means to receive said measured error signal therefrom, said error correcting means providing an error correction signal in response to said measured error signal to said second stage processing means.

Claim 4

A feature referenced error correction apparatus as described in claim 1 wherein said preprocessing means comprises in combination: means for processing key features operatively connected to said first stage processing means, said key feature processing means receiving said signal data which comprises a plurality of interstage sub-aperture images, said key feature processing means extracting the key features from each image of said plurality of interstage sub-aperture images, said synthetic aperture radar comprising a plurality of sub-aperture segments, each sub-aperture segment having a sub-frame image associated therewith, each sub-frame image comprising a sub-aperture image, means for sub-frame registration operatively connected to said key feature processing means, said sub-frame registration means receiving said key features for each of said sub-frame images, said sub-frame registration means measuring the positional displacements of said key features in said sub-frame images, said sub-frame registration means generating a positional error signal in response to said positional displacements in said sub-frame images, and means for generating an error function operatively connected to said sub-frame registration means, said error generating means receiving said positional error signal from said sub-frame registration means and generating an error correction signal in response thereto, said error generating means applying said error correction signal to said second stage processing means.

Claim 5

A feature referenced error correction apparatus as described in claim 3 further including a bulk memory means operatively connected to said first stage processing means to receive said signal data therefrom, and means for combining signals operatively connected to said bulk memory means to receive said signal data therefrom, said signal combining means receiving said error correction signal from said error generating means, said signal combining means combining said signal data with said error correction signal to provide a corrected data signal to said second stage processing means.