The first semi-annual progress report contains a summary of the problem that is being addressed in this project, a summary of the work that is now in progress, a list of personnel who are participating in this project, and a summary of project-related activities. The goal of this project is to formulate and investigate new approaches for forming images of radar/sonar targets from spotlight-mode, delay-doppler measurements. Initially, we are studying a particular processing motivated by an approach used in radionuclide imaging. Out longer term goal is to develop new processing based upon a realistic model for the data acquired with a radar-imaging system. Inverse synthetic-aperture imaging (ISAR) in radar and sonar relies upon the relative motion between the transmitter, target, and receiver. In the usual approach, the target is illuminated by a series of transmitted pulses. The return for each pulse is a superposition of reflections from various locations on the target, with each location affecting the pulse by introducing both a delay and doppler shift. The returns are processed to produce an image of the target.