1. Introduction
The more attention is paid to the radar forward-looking imaging, which is of great significance for the military field and civilian field. Now high resolution of side-looking and oblique side-looking can be realized by many matured approaches. However, the forward-looking problem is still existed. Although the real aperture imaging can be obtained by scanning radar, the antenna aperture limits the application of scanning radar. The virtual aperture can not be synthesized in the forward-looking area. It is necessary to propose the signal processing method to improve the angular resolution of scanning radar.