Karl-Heinz Bethke

A novel noncooperative near-range radar network for traffic guidance and control on airport surfaces

The concept of a novel modular structured near-range primary radar network (NRN) for guidance and control of airport surface traffic is presented. Several autonomously operating modules comprising of four radar stations cover all relevant airport areas or, alternatively, are integrated in a complex structured surveillance system by data fusion; then only selected areas have to be covered. Each sensor of a single module illuminates a common area of surveillance by a fixed, non-rotating antenna and measures range echo profiles. For the utilization within a planning and alert system the target locations inside a module are derived from multilateration of echo ranges, measured by multiple distributed sensors. Target velocity vectors are evaluated from the time history of several range echo profiles at least at two stations; target classification is obtained from microwave imaging techniques. In order to demonstrate the performance of the location technique and its flexibility in adapting to different airport scenarios, simulation results are presented. The location simulations are based on high-resolution radar cross-section measurements of a downscaled A-310 aircraft model. >

Ground Based Polarimetric Radar Imaging at DLR, an Overview.

The paper gives an overview about the activities at DLR in the field of ground based polarimetric radar imaging. Some features of the measurement equipment are given. The basic principle of the generation of complex target microwave images from scattered fields is outlined, and the derivation of target characteristic parameters as well as target characteristic polarizations is described. Special emphasis is given to the analysis of localized scattering centers. Two methods for studying bistatic scattering effects on a monostatic range are introduced. The physics of radar backscatter from randomly distributed targets is explained especially with respect to the measurement of scattering matrix time series. Further, the determination of signal degradations on Earth-satellite paths by means of the DLR weather radar is dealt with.

High Resolution Polarimetric Radar Imaging and Applications.

The basic principle of the generation of high resolution complex target microwave images from scattered fields is outlined, and the derivation of so-called target characteristic parameters as well as target characteristic polarizations is described. Special emphasis is given to the analysis of localized scattering centres. A fast procedure for the generation of two-dimensional microwave images under real-time conditions is explained in detail. Finally, two methods for stuying bistatic scattering effects on a monostatic measurement range are introduced.