Development of a Practical Under-Snow Radar System for Searching Victims by Snwoslide and Lost Articles in Accumulated Snow

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An experimental system of holographic radar was constructed in order to develop a practical radar system for searching victims by snowslide and lost articles in accumurated snow and experiments on imaging targets buried in accumurated snow were conducted. For realizing a practical radar system. following research items were investigated: (1) real-time system, (2) small-sized system. (3) system with high resolution. Concerning item (1). a quasi-real-time signal processing was achieved by using a recently developed DSP ( Digital Signal Processor ). Since in the first half stage of the research. a transmitting and receiving antenna was mechanically scanned over two-dimensional surface of accumurated snow. it took much time to obtain sufficient data for reconstruction of radar images. To overcome this difficulty a rotating linear antenna array with 16 array elements was constructed in the final research year. The experimental result of the array system showed the possibility of achieving a … More real-time radar system. Concerning item (2). microcomputers were used to collect radar signals and to process them, resulting in the small-sized experimental system. Concerning item (3). advantages of a holographic imaging radar with respect to the resolution was investigated, where three-dimensional (3-D) radar images were reconstructed. Diagnosis of radar images was done with radar data collected by field experiments in snow seasons, where the projected 3-D radar images onto 2-D CRT scope were observed by changing the point of view of an abserver. By this diagnosis technique radar images equivalent to those of high-resolution can be obtained even in a system of low resolution, resulting in confirmation of the effectiveness of the technique for practical use. Since a memory system of large capacity is necessary to store and to display 3-D radar image, a special memory system was design and constructed. This memory system was implemented in the experimental radar system and usefulnes of the memory system was demonstrated. Less