A special purpose synthetic aperture sonar (SAS) system has been developed and built by Hughes Aircraft Co. and Dynamics Technology, Inc. The main features of the system are a 3.2-m-long, 32-element linear array, and a data acquisition system capable of recording the elemental data in real time while preserving the phase and amplitude fidelity required by SAS processing. High-resolution, large (1002 m2) and small (32 m2) SAS images of various objects will be presented that demonstrate resolutions of 20 cm at 1000 m. The innovation of the work is that resolution achievable only with short-range, high-frequency sonar has been demonstrated at ranges obtainable only with a low-frequency sonar. [Work supported by DARPA.]