FPD'17

D1P2 - TRP - Study of Multi-Channel Ka-Band SARs for Moving Target Indication - DLR (Germany), Airbus Defence and Space (Germany), ISEL (Portugal)

14 Feb 2017, 11:20

50m

Newton 1 & 2 (ESA/ESTEC)

Speaker

Dr Stefan Baumgartner (German Aerospace Center (DLR), Microwaves and Radar Institute)

Description

The major objective of the ESA-funded TRP Activity was to design a spaceborne multi-channel Ka-band SAR optimized for detecting targets moving on land and ocean surfaces, and for estimating their position and motion parameters with high accuracy. A further objecitve was to investigate the capability of the system for ocean surface current measurements. The study was organized in four tasks: 1. Review and trade-off of state-of-the-art multi-channel techniques,algorithms and instruments for moving target indication (MTI) and ocean current measurement. 2. Preliminary system concepts definition, trade-off and performance assessment. 3. Detailed instrument definition and performance assessment. 4. Technology roadmap and way forward. Task 1 started with a comprehensive review of state-of-the-art MTI techniques, algorithms and instruments. Also methods for measuring ocean currents were investigated. Single-channel as well as multichannel algorithms were reviewed. As output a comprehensive overview document was obtained which can be used as a reference for future air- and spaceborne MTI activities. In this document also figure of merits were defined, potential scenarios and applications were suggested and requirements for land and ocean MTI were proposed. Preliminary system concepts were defined and discussed in Task 2. For the concepts the MTI performance was assessed using a state-of-the-art performance model based on Post-Doppler Space-Time Adaptive Processing (STAP). The advantage of the short wavelength of Ka-band is that shorter along-track baselines can be used for achieving a good MTI detection and parameter estimation performance. Thus, a number of along-track channels can be accommodated at the same SAR platform which has an overall length small enough to fit in a VEGA launcher. During the investigations in Task 2 it also carried out, that especially for Ka-band MTI rather high PRFs are needed if state-of-the-art MTI algorithms shall be applied and if the velocities and geographical positions of targets moving with high velocities shall be estimated unambiguously. In the frame of a Contract Change Notice (CCN) Task 2 was significantly extended for developing and investigating novel low PRF MTI algorithms. In total we have developed three novel algorithms whose performance was evaluated by Monte-Carlo simulations as well as by a Post-Doppler STAP model. With the novel low PRF algorithms MTI and high-resolution wide-swath (HRWS) SAR imaging can be performed simultaneously without the need of a separate high PRF system operation mode. However, even with the introduction of the novel HRWS-MTI algorithms high technical effort and hardware complexity is needed for achieving swath widths beyond 33 km with the investigated Ka-band systems, even if the stringent requirements on MTI performance and NESZ are relaxed. For Task 3 ESA wanted us to investigate a kind of multi-purpose system which additionally can be used for across-track interferometry (XTI). This system called "Architecture #9" was originally proposed in the frame of a different study ("Study into Ka-Band SAR," ESA Contract No. 4000102378) for high-resolution XTI applications, but not for MTI. In Task 3 a detailed MTI performance assessment and additionally a sensitivity analysis for the expected most critical non-calibrateable errors was carried out for "Architecture #9". Finally, in Taks 4 designing guidlines for spaceborne SAR-MTI systems were written and critical system and technology aspects were sketched.

Short Speaker Information

Stefan V. Baumgartner received the Dipl.-Ing. (M.S.) degree (with honors) in electrical engineering and communication technology from the Graz University of Technology, Graz, Austria, in 2004 and the Dr.-Ing. (Ph.D.) degree (with honors) in electrical engineering and communication technology from the Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany, in 2014.

Since 2004, he has been with the Microwaves and Radar Institute, German Aerospace Center (DLR), Oberpfaffenhofen, Germany. He is currently with
the Radar Concepts Department, where his field of activity is the development of ground moving target indication (GMTI) and parameter estimation algorithms for future traffic-monitoring applications using multichannel air and spaceborne synthetic aperture radars.

His current research interests include SAR along-track interferometry, space–time adaptive processing, digital beamforming on receive, time–frequency analysis, and other advanced signal and image processing techniques.