期刊名称：ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences
印刷版ISSN：2194-9042
电子版ISSN：2194-9050
出版年度：2008
卷号：XXXVII-B8
页码：837-842
出版社：Copernicus Publications
摘要：Snow covered crevasses are of great danger for mountain tourists, especially if the snow cover is rather thin in late spring or early winter. This was the motivation to investigate methods and techniques for crevasse detection with the future aim to establish a .secure navigation system" for mountain tourists. Ground penetrating radar (GPR) is a promising tool for the detection of snow covered crevasses, since the transition from snow to ice can easily be detected due to the change of several material parameters, like density, water content and most important the dielectricity. The feasibility and reliability of GPR crevasse detection was investigated by a field study. During the summer season a number of open crevasses were surveyed by differential GPS. In late winter a thick snow cover obscured these "test crevasses" and provided a secure crossing. The surveyed crevasses were marked on the snow surface and afterwards crossed by GPR in different directions. A regular profiling was carried out, as well as crossings in different traversing angles. After the usual processing steps to synchronize and enhance the reflected signals, the anomalies in case of an occurring crevasse can be seen clearly: - the reflection horizon from the snow/ice boundary is non continuous - internal snow layers above a detected crevasse show curvatures towards the crevasse - diffraction from the walls of the crevasse appear as hyperbolas The results from the combined application of GPR and GPS suggest that a system for safe glacier travel on alpine glaciers could be developed, based on clear crevasse detection combined with high accuracy positioning. So called "safe tracks" are monitored using a GPR system and differential GPS for reliable profile localization. The safe tracks are surveyed by GPS and the coordinates are made available to mountain tourists via download from the internet. These tracks can be utilized in the tourist′s GPS navigator in order to guide them on safe tracks
