Improving the sensitivity and phased array response of FMCW radar for imaging avalanches

Radar has proved to be a valuable tool for gathering velocity measurements of flowing avalanches. Geodar, a recently developed FMCW, phased array radar, successfully improved upon existing avalanche radar measurements and has to date provided the community with high-quality avalanche measurements over several winter seasons. Indeed, Geodar has recorded measurements of flowing avalanches in two-spatial dimensions for the first time. Following the success of Geodar, the authors are now redesigning the system to improve its performance in terms of sensitivity and array response. This paper summarises the issues encountered with the original design and describes how these issues have been addressed with the new design. This includes a drastic change to the receiver design, shifting the deramp processing onto the antenna board, and printing the antenna array and its associated RF receiver circuitry on a single PCB. The design is shown to dramatically improve the array sidelobe performance, and enhance the sensitivity of the receiver by reducing the transmission line losses in the RF chain.