FY2010 - Oak Ridge National Laboratory

Director’s R&D Fund—
National Security Science and Technology
paradigm in reliable, low-power, low-cost INS units. All these components, plus advanced signal
modeling and simulation, will be used to assemble a laboratory demonstration of the integrated TPS/INS
navigation system. Our overall research and development (R&D) focus is on the next-generation user
navigation unit, including the RF receivers, signal processing, and INS and timing modules.
Mission Relevance
A major concern in the tracking of personnel by agencies, such as the Department of Defense (DOD),
Department of Homeland Security (DHS), and the Department of Justice, and assets by DOE, the
National Nuclear Security Administration (NNSA), and the DOD is the heavy dependence on GPS for
accurate position information in the field. However, the use of GPS is at times unreliable (typically only
~85% coverage) and even subject to “spoofing” by an adversary. The obvious consequences of inaccurate
(or no) position information can be severe, up to and including injury or death of personnel or loss of key
assets (i.e., special nuclear materials). Although autonomous INS units have been proposed as short-term
backups to GPS reception during outages, these units are too costly (>$5K), heavy, bulky, inaccurate, and
power hungry to be deployed except in a few specialized applications. For most venues, a much more
robust, inexpensive technique is needed, especially where GPS outages occur due to jamming or foliated
terrain and in buildings and underground scenarios. This project directly addresses this need. Specific
U.S. Government agencies that could benefit from applications of this technology include DOE (research
facilities, electrical distribution, and environmental monitoring), NNSA (production-plant assets and
materials transportation), DOD/DHS (personnel/vehicle tracking, combat and emergency operations, plus
logistics), and the Department of Transportation/Federal Aviation Administration (reliable navigation
and timing).
Results and Accomplishments
We have thus far continued the R&D of a new, patentable high-performance version of TPS, a
terrestrially based RF backup for GPS, compatibly operating in the existing worldwide
90–110 kHz LORAN-C radionavigation band. A new variant of this system developed this year replaces
the existing LORAN format (discontinued by the U.S. Government in February 2010) with a new
specialized spread-spectrum signal that will greatly improve the accuracy, range, and robustness of the
old LORAN protocol. The new signal’s format design has been largely completed, and detailed
performance simulations are under way; a patent disclosure is also in preparation. In addition, a U.S.
patent was issued on TPS (December 1, 2009) and two more patents allowed (October–November 2010).
Further, we continued the R&D of a next-generation combined seven-oscillator quartz-based timing
system and INS to determine the user’s location and orientation; the unit should vastly outperform current
INS units [based on optical and microelectromechanical (MEMS) systems technologies] in accuracy,
stability, size, weight, power, and cost. A key electronic advancement we have achieved is the use of
tightly balanced, fully differential oscillator circuitry to convert DC bias drifts to common-mode effects,
thus drastically reducing the long-term phase noise in the differential output signals. Coupled with
advanced auto-zeroing techniques, we have demonstrated nearly a factor-of-100 improvement over
standard quartz oscillator units and radically better long-term overall stabilities. In addition, we have
pioneered a novel dual-mode compensated oscillator architecture using a 5th-overtone crystal mode to
correct for quartz temperature drifts; a U.S. Patent application is being currently prepared. We have also
continued R&D of a novel three-dimensional antenna/magnetometer unit for improved TPS reception,
providing receiver location and orientation information, which will facilitate integrating the TPS and
INS subsystems into a highly reliable, self-calibrating, user-friendly navigation device ideal for GPSdenied
environments.
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