The Center for Oldest Ice Exploration (COLDEX) project is exploring Antarctica to find a continuous ice record from the present to 1.5 million years ago and document the midPleistocene transition, which occurred similar to 1 million years ago. The current longest ice record is 800,000 years old. This work describes a new 600-900 MHz UHF radar to help address this challenge with a 1) much larger, 22.8 m or 57-wavelength, cross-track antenna array and 2) higher transmit power, than prior renditions. Survey flights on a Basler aircraft were conducted from the South Pole in 2022-2023 and in 2023-2024. In this work, we provide an overview of the design requirements, the radar system architecture, and antenna array implementation. We also present preliminary results from aerial surveys conducted in Antarctica.

This paper presents a reconfigurable, low-cost ultra-wideband microwave radar front-end and radar demonstrator designed for nadir-looking measurements of layered media (e.g. snow or vegetation) from either a fast-moving ground-based platform or a C-3 class unmanned aerial system (UAS). The radar demonstrator uses a frequency modulated continuous-wave (FMCW) architecture and can be configured to operate in either the 2-8 GHz or in the 12-18 GHz range, providing fine vertical resolution while offering a significantly reduced weight, size, and power consumption with respect to prior implementations. We have demonstrated the operation of the system in the 2-8 GHz and 12-18 GHz bands in the laboratory; in the 2-8 GHz band using a surface-based setup in Antarctica; and in the 2.6-7 GHz band on local flight tests onboard an Aurelia X6 Pro UAS equipped with 3-D printed antennas. This paper provides an overview of the radar front-end and demonstrator design and implementation, and a summary of the different tests completed to document their performance.

We developed a multi-channel, ultra-wideband, microwave radar for swath mapping of snow layers on land, sea ice and ice sheets. The system operates in the 2-18 GHz band (up to 16-GHz bandwidth) with two nadir-looking transmitters and six receivers; and a dual-polarized, forward-looking transmitter/receiver pair. The system addresses the limitations in cross-track resolution found in prior single-channel instruments and will help improve snow thickness retrieval in areas of complex surface topography. This paper presents an overview of the radar electronics and antenna system and their installation on the NASA P-3B aircraft. We also present initial results from a short field campaign conducted in Greenland in the spring of 2022.

This work describes the design and development of a radar receiver with a large dynamic range by means of carefully designed compression. The receiver is designed for ice sounding applications on the Antarctic and Greenland ice sheets and is designed to be usable over a large frequency range (VHF and UHF) and with multiple analog-to-digital converters with only minor modifications. We present the receiver design, in which we have implemented an RF-power limiting feature so that the output power is monotonically increasing with respect to the input power over a large dynamic range. This allows the receiver to operate in the non-linear region to compress the high-power returns into the dynamic range of the analog to digital converter while still achieving good sensitivity (low noise figure) for low power signals. We discuss design considerations, hardware description, initial lab test results, the architecture of the design and results from recent field deployments. Lastly, we discuss the future work on the decompression mechanism to recover the uncompressed signals.