Dual frequency Radars in the Very High Frequency (VHF) and Ultra High Frequency (UHF) ranges have been flown on the NASA P3 aircraft to successfully perform interferometric cross-track ice-thickness measurements. VHF/UHF radar can provide ground level information of areas obscured by vegetation coverage, monitor variations in biomass of forested ecosystems, and study the impact of global warming. To expand the operational use of VHF/UHF tomography and extend this technology for biomass and ice-sheet imaging, a dedicated tomographic radar design that includes highly configurable radar electronics, antennas, calibration procedures, and field-proven processing tools are needed. Low-Frequency, All Digital Radar (ADR) can be a key component for NASA Phased-array and tomographic Radar systems spanning multiple earth-science measurement objectives. One of the key attractions of ADR is hardware re-use for different scenarios. IAI proposes the design of an ADR system that will build upon IAI's Software Defined Radio/Radar (SDR) design expertise. State-of-the-art technologies in the design of data conversion devices like Analog-to-Digital Converters (ADC), Digital-to-Analog Converters (DAC), Direct Digital Synthesizers (DDS) and reconfigurable logic devices like Field Programmable Gate Arrays (FPGA) MMIC make it possible to realize the concept of ADR with low SWaP and low-cost goals. IAI's approach is modular and scalable and meets NASA's goals of multi-channel, coherent altimeters along the cross track to obtain high resolution in the cross track direction. A highly programmable, common Radar platform that supports Global Biomass and Ice-Sheet investigations will enable the development of novel data processing schemes with a robust, routine procedure for processing the tomographic data into science-quality products, within a short acceptable time frame.