1.  INTRODUCTION

Burst-mode or ScanSAR data collection is used in several SAR systems, such as Radarsat and ENVISAT, and a phase-preserving processing algorithm is needed if this data is to be used for interferometry [1].

For efficiency reasons, the SPECtral ANalysis (SPECAN) algorithm [2] is usually recommended for processing burst-mode data. SPECAN can be made to be phase preserving at the peak of the impulse response. However, the azimuth sample spacing is a function of the azimuth FM rate.

The Range Doppler (RD) algorithm [3] is well proven for its efficiency and accuracy, including its ability to preserve phase. In this paper we describe a modification to the RD algorithm to allow it to process burst-mode data with accurate phase.