Synthetic Aperture Radar Design for a High-Altitude Platform

As part of an integrated joint project, the German Aerospace Center (DLR) is developing a stratospheric glider called High-Altitude Platform alpha (HAP-alpha), which can be stationed almost permanently at an altitude of between 15 km and 25 km for months. This enables permanent observation of a certain region of interest for a wide variety of applications. In staring time, either the high-resolution optical camera (MACS) or the synthetic aperture radar (SAR) system HAPSAR will be operated as payload sensors. The environmental and marginal conditions require a system that is specially adapted to the circumstances. Furthermore, the applications requiring different radar operating modes. This paper presents the basic concept of the HAPSAR instrument on HAP-alpha with the different operating modes, the structural design and the radar concept.