| Co-Investigator(Kenkyū-buntansha) |
NITTA Ryuzo Shinshu Univ., Faculty of Agriculture, Prof., 農学部, 教授 (50273074)
KITAZAWA Shuji Shinshu Univ., Faculty of Agriculture, Prof., 農学部, 教授 (40021084)
NAKAGAWA Shinji Shinshu Univ., Faculty of Engineering, Asst. (20252067)
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| Research Abstract |
Applicability of simple hand-held type GPS (Global Positioning System) receiver to positioning of field data which concern with problems of environmental change and disaster was investigated. Through field observation and collected data analysis, the following results are summarised.
1) Differential GPS technique (DGPS) is a valid procedure to demarcate the suffered area by disaster or environmental catastrophe. Plane figure of the suffered area can be clearly represented on a map by the process constructed in this investigation.
2) For field data acquisition of snow avalanche disaster, usefulness of hand-held GPS receiver was examined at Tsugaike plateau and Mt.Fuji. At Tsugaike observation, importance of DOP (Dilution of Precision) was experienced by selection of catching GPS-satellites. At Fuji observation, the boundary shape of debris carried by snow-slush-avalanche was clearly and effectively surveyed by the DGPS procedure. This is the first time to use the DGPS technique for field
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reconnaissance of snow avalanche disaster in Japan.
3) Mobile DGPS was tried for surveying of road plan. In Japan, revising cycle of 1/25,000 map is five or more years. Thus, newly constructed road and reconstructed road can not timely be shown on the map. The mobile DGPS procedure can avoid such inconvenience for map users who necessitate the newest road information. Analyzing the positioning data collected by GPS receiver mounted on a car, we obtain the locus of the car drived on the road to survey. How to complement the map by this mobile DGPS procedure was experimentally studied, and how to do it was constructed. Through this study, it can be said that the simple hand-held GPS receiver is valid for complement of map whose scale is smaller than 1/25,000.
4) By the study of mobile DGPS,a new analytic method was found. Series of road positional data, collected by mobile DGPS,can be used to find the road line characteristics such as radius of circular curve, boundary point between straight line and curved line, beginning and end of transition curve, clothoid parameter, etc. They are analytically computed by least square method devised in this investigation. Field experimental study for practicability of this method is necessary to continue. Less
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