Recently DLR has developed and constructed a new experimental radar instrument for various applications like radar signature collection, SAR/ISAR imaging, motion detection, tracking, etc., where high performance and high flexibility have been the key drivers for system design. Consequently a multi-purpose and multi-channel radar called GigaRad is operated in X band and allows an overall bandwidth of up to 6 GHz, resulting in a theoretical range resolution of up to 2.5 cm. Hence, primary obligation is a detailed analysis of various possible error sources, being of no or less relevance for low-resolution systems. A high degree of digital technology enables advanced signal processing and error correction to be applied. The paper outlines technical main features of the radar, the basic error correction strategy and illustrates some first imaging results.