Dieter Klement

An autonomous, non-cooperative, wide-area traffic monitoring system using space-based radar (TRAMRAD)

To meet the challenges of ever increasing road traffic and the associated economic and sociological impacts, new techniques and technologies for better traffic management are needed. The TRAMRAD project (Traffic Monitoring with space-based Radar) aims to profit from research and development in earth observation and advances in radar remote sensing techniques to define a future space-based sensor system for the wide-area monitoring of road traffic. The paper describes the requirements for the system and the concepts being investigated. In particular, it discusses the complex detection conditions, the requirements on the radar instrument and the methods for processing the data. Possible system concepts are described and their capabilities are discussed.

Computation and validation of bistatic RCS in the upper-middle and high frequency region

Two computer codep have been developed at DLR in order to calculate bistatic RCSs. The first code treats the high frequency case and is based on the physical optics (PO) method. The second one is suited for objects with dimensions comparable to the wavelength and is based on the finite-difference time-domain (FDTD) method. For test objects with perfectly conducting surfaces (a sphere and an elliptical cylinder) numerical results of the codes are compared and validated with those of the IEM-code NEC-2, analytical solutions and experimental results achieved by measurements at 94 GHz.

Bistatic RCS Computations by FDTD and Comparison with other Rigorous Methods and Experiments

Der bistatische Streuquerschnitt von Testobjekten wird mit Hilfe von Rechenprogrammen basierend auf der Methode der Finiten Differenzen im Zeitbereich (FDTD) und der Integralgleichungsmethode (IEM) berechnet und experimentell validiert.

Edge-diffraction effects in RCS predictions and their importance in systems analysis

In developing RCS prediction codes a variety of physical effects such as the edge diffraction effect have to be considered with the consequence that the computer effort increases considerably. This fact limits the field of application of such codes, especially if the RCS data serve as input parameters for system simulators which very often need these data for a high number of observation angles and/or frequencies. Vice versa the issues of a system analysis can be used to estimate the relevance of physical effects under system viewpoints and to rank them according to their magnitude. This paper tries to evaluate the importance of RCS predictions containing an edge diffracted field for systems analysis. A double dihedral with a strong depolarizing behavior and a generic airplane design containing many arbitrarily oriented edges are used as test structures. Data of the scattered field are generated by the RCS computer code SIGMA with and without including edge diffraction effects. These data are submitted to the code DORA to determine radar range and radar detectibility and to a SAR simulator code to generate SAR imagery. In both cases special scenarios are assumed. The essential features of the computer codes in their current state are described, the results are presented and discussed under systems viewpoints.