Double pulse envelope radar

Abstract

Radio Echo Sounding (RES) technique is used in glaciology, to perform the study of the properties of glaciers and ice [Bogorodsky, 1985]. It is based on the use of radar techniques, mainly to obtain information about the thickness of glaciers and polar ice caps. The RES instrumentation also allows the study of interglacial stratification and identification of areas of inhomogeneity of the ice, the exploration of subglacial lakes and physical characterization of the ice - bedrock interface [Cafarella, 2006; Frezzotti, 2000; Forieri, 2003; Mancini, 2003; Tabacco, 2000; Tabacco, 2003; Zirizzotti, 2010]. Simplifying RES instrumentation, it is a radar system mainly constituted by two main components: a radio frequency transmitter and a receiver connected to an antenna [Plewes, 2001]. A short electromagnetic pulse is transmitted through an antenna and the receiver detects the transmitted pulse and all the pulses reflected from the ice. The reflecting surfaces are surfaces of discontinuity in the electromagnetic characteristics of the medium. In the case of the ice we have: air-ice surface, the layers of ice or “internal layers” due to annual ice stratifications, the rocky “bedrock” (ice-rock interfaces) and subglacial lakes (liquid water present at the bedrock interface) all those are thus seen as electromagnetic discontinuity (figure 1). From measurements of the delay times of the received pulses, knowing the speed of electromagnetic waves propagation in the ice, it is possible to determine the distance to these surfaces. The radio waves have different speeds depending on the media in which they propagate: in the air it is the light speed (300 m / µs), while in the ice it is about 168 m /µs [Glen, 1975]. Moreover, from...