Study On Monopulse Radar Forward-looking Imaging Algorithm And Its Hardware Implementation

In radar imaging, doppler beam sharpening (DBS), synthetic aperture radar (SAR) and inverse synthetic aperture radar (ISAR) with relatively high resolution in range and azimtuh are widely used for years. However, DBS and SAR technology fail when imaging for the front view district (the so called blind area), and ISAR totally depends on the target’s rotation relative to the radar plat, which unfortunately limit these techniques in some practical applications. Via comparing echo signals received simulately by two or more independent receiving circuits, monopulse radar can obtain accurate information of the target angular position. This method has a high measurement precision, lower data rate, stronger anti-interference, so it’s widely used in the field of radar detection.Beginning with the principle of monopulse angle measurement, this paper foucus on two imaging algorithms, i.e., one-dimensional scanning monopulse imaging algorithm that effectively improves the azimuth resolution and two-dimensional scanning monopulse imaging algorithm for the down-looking area imaging. Besides, one-dimensional scanning monopulse imaging algorithm is successfully implemented on a general digital signal processing system to process groups of measured data collected by an airborne X-band monopulse radar. The remainder of this paper is organized as follows.In chapter I, the research background of the monopulse imaging technology is analysed, following by a brief review concerning the current research status on monopulse angle measurement and monopulse imaging technology is provided. At last, the applications of digital signal processor (DSP) in radar signal processing area are introduced and the full-text content is outlined.In chapter II, the principle of monopulse radar angle measurement including the concept of monopulse recovery ratio is introduced. The two main monopulse technologies, i.e., amplitude comparison monopulse technology and phase comparison monopulse technology are discussed with detailed analysis on the factors that affect the angular accuracy.In chapter III, a monopulse imaging algorithm based on phaseΣ-Δmonopulse theoretical model is investigated. This algorithm effectively improves the azimuth resolution accuracy of the image by take advantages of the accurate angle measurement characteristic of the monopulse technology. Simulation results are employed in this section to verify its effectiveness. At last, from the point of airborne radar imaging principle, some brief discussions on the application conditions of monopulse imaging.Aiming at the imaging for some specific environments, Chapter IV introduces a two-dimensional scanning monopulse imaging, and verifies is effectiveness via simulations. In chapter V Transtech Company’s common digital signal processing hardware and software resources are depicted first, which are based on TigerSHARC 101S DSP processing chips. After that, the algorithms are implemented to parallelly poccess several sets of measured data collected by an airborne monopulse radar.Chapter VI summarizes the work of the full paper, and points out problems for further study.