Henke, DanielDanielHenkeFrioud, MaxMaxFrioudFagir, JulianJulianFagirGuillaume, SébastienSébastienGuillaumeMeindl, MichaelMichaelMeindlGeiger, AlainAlainGeigerSieger, StefanStefanSiegerJanssen, DanielDanielJanssenKlöppel, FrankFrankKlöppelCaris, MichaelMichaelCarisStanko, StephanStephanStankoRenker, MatthiasMatthiasRenkerWellig,PeterWellig2022-03-142022-03-142019https://publica.fraunhofer.de/handle/publica/41032810.1109/IGARSS.2019.8897902Technological advances in frequency-modulated continuous-wave (FMCW) synthetic aperture radar (SAR) and the associated miniaturization and energy efficiency make it increasingly possible to transfer SAR systems from traditional airborne platforms to small UAVs. An important factor to successfully achieve high-quality imaging from SAR systems mounted on small drones is the precise knowledge of the platform's navigation data in best case by avoiding the use of an expensive and heavy inertial measurement unit (IMU). In this paper, we test different concepts and discuss the impact on SAR image quality using FHR's FMCW MIRANDA35 sensor. To compare several methods simultaneously on one platform and to have an IMU as reference, first preparatory steps were carried out on an airborne platform. Specifically, we present and evaluate solutions based on SAR autofocus, moving baseline differential GPS and optical structure-from-motion-based localization. SAR autofocus shows the best performance in our preliminary investigations.en621conference paper