Abstract: Range-compressed data are determined by range-compressing echo data, and are set as first data to be decomposed by first decomposition. Starting from n=1, iteration is performed as follows. nth data to be decomposed are up-sampled. nth decomposition is performed on the up-sampled data. Dependency on slant ranges between a reference point and sub-apertures before and after synthesis is determined. nth azimuth-synthesized data are acquired by performing, according to the dependency on the slant ranges, nth azimuth synthesis on data acquired by the nth decomposition. The nth azimuth-synthesized data are set as (n+1)th data to be decomposed by (n+1)th decomposition. The n is increased by 1. A next iteration is performed until the n reaches a positive integer N greater than 1. A focused image is acquired by performing azimuth focusing on the Nth azimuth-synthesized data by BP.

Abstract: Range-compressed data are determined by range-compressing echo data, and are set as first data to be decomposed by first decomposition. Starting from n=1, iteration is performed as follows. nth data to be decomposed are up-sampled. nth decomposition is performed on the up-sampled data. Dependency on slant ranges between a reference point and sub-apertures before and after synthesis is determined. nth azimuth-synthesized data are acquired by performing, according to the dependency on the slant ranges, nth azimuth synthesis on data acquired by the nth decomposition. The nth azimuth-synthesized data are set as (n+1)th data to be decomposed by (n+1)th decomposition. The n is increased by 1. A next iteration is performed until the n reaches a positive integer N greater than 1. A focused image is acquired by performing azimuth focusing on the Nth azimuth-synthesized data by BP.