Design and development of a multi-channel radar depth sounder.

摘要

Over the past 5 years global climate change has rapidly become one of the world's greatest environmental concerns. An atypical warming trend in the global climate has both the scientific and political communities on edge. One of the largest concerns of this warming trend is its effect on polar ice sheets and sea level rise. The scientific community is tirelessly researching and modeling the mass balance of the ice sheets, and trying to predict how future melt of the ice sheets could affect sea level rise. One key component in modeling the mass balance of the ice sheets is the determination of an ice sheet's thickness.; At the University of Kansas, the Remote Sensing Laboratory (RSL) and Center for Remote Sensing of Ice Sheets (CReSIS) have successfully implemented a variety of depth sounding radars to attempt to make this thickness measurement. However, previous depth sounding radars, both at KU and around the world, have failed to measure the ice sheet thickness in certain areas where high attenuation of the radar signal occurs. In an effort to provide the missing thickness information, CReSIS has developed a Multi-Channel Radar Depth Sounder (MCRDS).; MCRDS is an airborne system that alternately transmits a 3- mu s then 10- mus linearly chirped pulse across a 5-element linear antenna array at 800 W peak power. The bandwidth of MCRDS is 20 MHz, at frequencies of 140-160 MHz. MCRDS uses quarter-wave folded dipoles as both the transmit and receiver antenna elements. MCRDS utilizes 5 individual receivers that have a noise figure of 3.9 dB and a loop sensitivity of 217 dB. A thorough co-simulation of the MCRDS PCB boards and components has been performed, and accurately predicts/replicates the system performance. MCRDS has been field tested in Northeast Canada and in Greenland from May-June 2006, and has successfully provided the first depth sounding of the Jacobshavn glacier within 90 km of the calving front, to a depth of 800 m [13].