Atmospheric Effects on Radar Target Identification and Imaging

The Advanced Study Institute (ASI) under discussion was initiated by the "Special Programme Panel on Radio­ meteorology" of the Scientific Affairs Division of NATO. The domain of this panel - and consequently the topics of their former ASI-~rogrammes - is the influ­ ence of the non-ionized atmosphere on electromagnetic wave propagation, its prediction and its use as a re­ mote sensing technique. It is the final goal to inform radio and radar engineers about the various defects caused by the propagation medium atmosphere. Today there exist high-sensitive radar systems which can pro­ vide identification and produce images of distant ob­ jects very accurately by measuring a) the effect of the target on the shape of a short radar pulse, or b) the wave front (phase and amplitude distribution) and its orientation in space. But usuallv the radar-to-target path is through the inhomogeneous and turbulent atmo­ sphere and so the absolut limits of the system are very often determined by this atmosphere. It was the plan of this ASI to arrange an interdisciplinary information exchange between radar experts and propagation specia­ lists in order to get a better understanding of the susceptibility to atmospheric effects and to develope new methods that will reduce or correct these errors. The lectures given and especially the intensive dis­ cussions during the workshop sessions contributed to this aim.

Inhalt

I Target Characteristics and their Determination Modern Radar Techniques.- Short-Pulse Target Characteristics.- Signal Properties and Target Models in the View of Target Classification at a Surveillance Radar.- On the Polarization Transforming Power of Radar Targets.- Short-Pulse and Wide-Bandwidth High-Resolution Radars.- Side-Looking Radar.- Azimuth Compression Processing of Real Slar Data.- Synthetic Aperture Radar.- On the Evaluation of Doppler Spectra for Radar Cross Section Analysis and Target Recognition.- On Some Parallelisms between Radar and Sonar Transmission Channels.- II Atmospheric Influences.- Atmospheric Effects: Some Theoretical Relations and Ample Measurements.- Distortion of Radar Pulses by Atmospheric Layers.- Measurements of Wave-Front Distortion.- On the Influence of Atmospheric Refractive Index Irregularities on the Resolution Performance of a Radar.- Propagation Effects Due to Specific Atmospheric Structures.- Useful Meteorological Parameters for Predicting Signal Behavior.- New Developments in the Detection of Atmospheric Structures.- Integrated Refractive Effects Prediction System (IREPS).- The Effects of Precipitation on Radar Target Identification and Imaging.- Some Polarization Effects for Millimeter Wave Propagation in Rain.- Radar Echoes from Birds and their Effects on Radar Performance.- III Workshop Reports.- Statistical Description of Targets and Environment Including Atmospheric Effects.- Short Pulse, FM/CW and Chirp Radars.- Synthetic Aperture Radar.- Influence of Atmospheric Propagation Effects on Holographic Imaging Techniques.