Subsurface Communications System for Robotics (DHS002)

Underground cross-border tunnels of all sizes and shapes are an increasingly important threat
to our National security. Finding cross-border tunnels is a challenging task and once found, an
additional challenge is mapping the entire underground tunnel. Manned entry into these
dangerous underground environments is a risky endeavor. The use of robotics offers a great
improvement over human entry into these tunnels. To function effectively, tunnel robots require
a wireless communications link. This proposal describes a research program to successfully
develop a flexible and highly adaptable electromagnetic (RF) communications link for
underground robotics. The link will be bi-directional and have a range of at least 500 m. What
we are proposing in this proposal is an adaptive parametric signal processing scheme where
the relationship between data rate, communications range, power, covertness, etc. can be
optimized for a given communications link because the underground electromagnetic
propagation environments can greatly vary from site to site. By using a software defined radio
approach this optimization can be user-adjusted or automatically optimized in the field. We call
this method the Parametric Underground Communications System (PUCS). Frequencies will
range from several kHz to several MHz. Data rates will be sufficient to transmit slow scan
imagery. This effort will implement, test and finally conduct a field demonstration of the PUCS
method at a local underground test site.