Automotive Radar- und Lidarsensoren werden in den letzten Jahren als Steuersignalequelle für Systeme wie Autonomous Intelligent Cruise Control (AICC) und Collision Mitigation (CM) verstärkt eingesetzt. Diese Sensoren operieren im Millimeterwellen- und Infrarotbereich, so dass ihre Performanz bei schlechten Wetterverhältnisse signifikant degradiert werden kann. Dem muss geeignetes Design entgegenwirken. Besonders wichtig für Millimeterwellen-basierte Automotiveradarsensoren ist die automatische Erkennung von der Wasserfilmen auf der Antennenoberfläche und von Regen im Übertragungsmedium, um die Degradation von Radarsichtweite und -detektionsvermögen dynamisch zu unterdrücken bzw. zu vermeiden. In dieser Dissertationsarbeit werden neuartigen Wasserfim- und Regenindikatoren vorgestellt, die kostengünstig mit dem am Markt vertretenden Automotiveradarsensor von Bosch demonstriert sind und während dieser Arbeit auf Serientauglichkeit untersucht wurden. Ferner wird ein Performanzoptimierungsverfahren zur Gewährleistung der Radarsensorverfügbarkait bei schlechtem Wetter präsentiert.

    In recent years vehicle radar and lidar sensors are widely used as sources of control signals for Autonomous Intelligent Cruise Control and Collision Mitigation systems. These devices are operating in the millimeter wave and infrared range in which their performance may be degraded by adverse weather conditions. Currently available information regarding the signal interaction with fog, rain, snow and spray make clear that millimeter-wave radar sensors are far less affected by adverse weather conditions than infrared based sensors. However, when automotive radar sensors are particularly designed for safety-oriented systems, the effects of critical issues (such as water film and heavy rains) on the sensor performance become of the uttermost importance. In this thesis, an analysis of the effects of water film and rain on millimeterwave propagation is presented. Based on the fundamental formulation of wave propagation and scattering in stratified as well as random media, physical parameters describing the wave interaction with the water film and rains are studied and assessed. It is shown that both significantly attenuate millimeter-wave signals, and may exert an adverse influence on detection performance of millimeter-wave radar sensors. Consequently, water-film and rain indicators are derived from returned signals to convey for the first time wet-antenna and rain informa- tion to the radar sensor system, where they could be employed for monitoring the radar detection performance. Methods are also worked out in detail for low-cost measure- ment of water-film and rain indicators in the radar system. Experimental investigations are exhibited to be able to satisfactorily implement these indicators in production. Finally, techniques are introduced to show how detection performance could be optimized. The presented findings emphasize the importance of identification of water film and rain and of being able to optimize detection performance in order to assure availability of automotive radar senors in adverse weather conditions. Results should also be significant for all kinds of millimeter-wave radar sensors where wave interactions with water film on the surface of the radar antenna or its protecting radome as well as with rains in the radar beams are the key issue.


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    Titel :

    Indicators for the signal degradation and optimization of automotive radar sensors under adverse weather conditions


    Beteiligte:


    Erscheinungsdatum :

    2007


    Format / Umfang :

    145 Seiten, Bilder, Tabellen, 88 Quellen




    Medientyp :

    Hochschulschrift


    Format :

    Print


    Sprache :

    Deutsch