Signaling and sensing with rotating magnet sources have both Terrestrial and Extraterrestrial applications. The dual spinning magnet unit presented in this paper is a simple, lightweight solution to help understand soil densities and locate water and ice pockets, for example, on Mars. Traditional magnetic telemetry systems that use energy-inefficient large induction coils and antennas as sources and receivers are not practical for extraterrestrial and remote field sensing applications. The recent proliferation of strong rare-earth permanent magnets and high-sensitivity magnetometers enables alternative magnetic telemetry system concepts with significantly more compact formats and lower energy consumption. There are also terrestrial applications, for example, subterranean objects such as underground infrastructure and unexploded ordnances (UXO) that are often unmapped and difficult to find on Earth. Current ground penetrating radar units are expensive, large, and heavy. The research presented explores the viability and possibility to develop a unit that will induce an oscillating magnetic field with controllable shape to reliably locate buried ferromagnetic and non-ferromagnetic objects while remaining lightweight and cost effective. A Dual Rotating Magnet (DRM) design is presented. Experiments and numerical simulations assess the system for terrestrial and extraterrestrial detection of: 1) differences in soil densities, 2) water and ice pockets at shallow depths in the subsurface, and 3) subterranean ferromagnetic and non-ferromagnetic objects of interest.

Thin layers (layers that are not resolvable in terms of GPR wavelengths) are very common in sedimentary deposits. To better understand ground penetrating radar (GPR) wave behavior in sequences of thin layers with contrasting electromagnetic parameters, 1D FDTD simulations are run for simple layer distributions. Laminated (mm-scale) sequences can produce reflected energy with 10-20% of the amplitude of reflections from equivalent isolated contacts. Amplitude spectra from laminae packages are shifted toward higher frequencies. Such spectral shifts in radar profiles may potentially be used as indicators of fine-scale laminations. A comparative study of GPR records and models generated from core data from Waites Island, South Carolina, a Holocene barrier island, suggest that magnetite-rich laminae contribute significantly to radar profiles, but that some features in the radar traces cannot be associated with lithologic changes seen in vibracores.