Session S14: Safeguards Needs at Geological Repositories and Encapsulation Facilities Secure and Reliable Wireless Communications for Geological Repositories and Nuclear Facilities Richard E. Twogood Dirac Solutions Inc. TECHNOLOGY We are developing a new class of ultra-wideband communications system with the potential to meet challenging applications Ultra-wideband pulses Frequencies, pulse bandwidths in 100 s of MHz Novel modulation scheme Pulses penetrate unlike narrowband Prototypes built R&D system (left - 2013) Commercial prototype (right-2014) Voiced comms now 250 KHz bandwidth scalable up Data, texts, imaging if needed Subsystems optimized UWB antenna (left) Advanced pulsers APPLICATIONS Ship-based communications Very challenging environment Excellent results; very promising Mines and waste repositories Initial results at US DOE WIPP Very promising Further work planned 2015 Urban settings; first-responders Good initial results May need higher power variants Need broader testing results Based on the promising experimental results, we are investigating tailored and optimized systems for numerous areas such as nuclear waste facilities, other mining operations, first-responder needs, on-ship communications, and others.
Narrow RF pulses for communications in UWB technology significantly differentiate their performance over conventional narrowband systems Ultra-wideband systems use narrow pulses (subnano second duration, with low power, ultra-wide frequency band ) to transmit and receive information Power Traditional RF systems use Narrowband signaling (Continuous waveforms, with high power and narrow frequency band) to transmit/receive information. Noise floor BW= GHz Frequency Key disadvantages of narrowband signaling: Vulnerable to signal jamming and spoofing Limited penetrability in harsh environments Easy to detect Low channel capacity (data rate) Low Precision Needs sophisticated encryption techniques Complex hardware architecture Limitations in worldwide operation Key advantages of UWB signaling are: Resistant to signal jamming and tampering Good penetration properties of signal in harsh environments Secure transmission by pulse coding High channel capacity (data rate) Accurate ranging and geolocation Inherently encrypted by pulse coding Simple architecture small form-factor, low cost Unlicensed spectrum Global operations
We have built R&D prototypes and now commercial prototypes of the UWB walkie-talkie Since 2011, Dirac Solutions Inc. has partnered with the US DOE Lawrence Livermore National Laboratory to conduct joint R&D in UWB comms technology and related subsystems such as wideband pulsers, wideband antennas, and software-defined radios. Scalable from 10 s MHz to 10 GHz Propagation through cracks Resilience to multipath reflections Resistant to intentional and unintentional jamming Potentially low cost Low power, scalable up Small form factor and light weight R&D prototype (2013) Commercial prototype (2014)
DSI s custom UWB Antennas enhance performance We developed a new class of UWB Vivaldi-type antennas with excellent wideband performance tunable to our application needs Frequency response excellent: no ringing Excellent gain, circa 6dB Low cost and light weight Small form factor, particularly in 3rd dimension Patent filed jointly with LLNL This antenna is the widest bandwidth antenna system known. Initial commercial prototype has been developed; first sales began February 2013. In addition to use with the UWB walkie-talkie DSI is considering other applications of this antenna technology.
Experiments on Cape Orlando showed reliable communications using UWB walkie-talkie Existing ultra-wideband walkie-talkie s performance was tested against a commercial radio currently used by Marine Corps on Cape Orlando ship in Alameda, CA DSI s walkie-talkie was able to clearly transfer voice data in the following scenarios where the commercial radio experienced significant dropouts Full length of the ship (1200 ft) 200 ft behind a closed hatch 3 levels down in engine room Currently working towards longer range communications (Km) Next phase will focus on MIMO design for higher data bandwidth (video rate) UWB (left) transceiver is much more robust than narrowband to interference effects (red signal and blue signal correspond to 5 inch position change of receiver) 5
We are investigating UWB walkie-talkie performance in tunnels and storage areas for nuclear waste One of our early experiments with the hardware walkie-talkies shown was conducted at the U.S. Department of Energy s Waste Isolation Pilot Plant (WIPP) in Carlsbad, New Mexico in 2011. WIPP is the world s largest underground repository for the storage of transuranic waste products. The experiments were very successful. Line-of-sight communications were effective at a distance of 2000 feet. Non-line-of-sight communications were successful to a range of approximately 1000 feet in tests where the transmitter and receiver were separated by an L-shaped tunnel and a U-shaped tunnel configuration. Attempts to communicate down the >2000 foot vertical shaft were not successful, although we are optimistic that can be overcome with a higher power version of our system and/or use of better antennas. The left photo is a long underground tunnel and the right photo is deep vertical shaft. WIPP officials are keenly interested in further tests with our improved systems discussed above, and further experiments are being planned for the early-2015 time frame.
Preliminary results of UWB performance in urban environments for emergency response are encouraging Goal - determine the performance of UWB system in a harsh RF environment, typical of challenges faced by first responders. Two types of tests were performed at the Transamerica building in San Francisco (height of about 260 meters and 48 floors). Test 1: Audio quality for inside-the-building: One walkie-talkie stays stationary and talks to another person with the matching communications system while walking in different none-line-of-sight (NLOS) paths inside the structure until the communications fail. The range of the systems is measured and recorded as well as the audio quality at every stage. Test 2: Audio quality for outside-to-inside: One person with one of the communication systems stays stationary outside the structure and talks to another person with the matching communications system inside the structure to test the communications capability from inside to outside. Two variations were tried: a) using a pair of hand-held units both mobile with small stub antenna, and b) one stationary unit attached to a large Vivaldi antenna on one end and second unit mobile with small stub antenna. Important our walkie-talkies have average power of only about 20 mw (4% of a cell phone and 0.4% of a typical narrowband walkie-talkie). We can increase the transmitter power (and still meeting regulatory requirements) for greater performance. The results show significant promise for a new generation of advanced UWB systems for emergency response applications. The most significant observation was that we could talk from the street (with a large antenna) to the hand-held (small antenna) unit on the 48th floor. The implication is that we can establish a direct communication link between the command-and-control unit at the street level with a first responder anywhere in a tall structure with just a hand held UWB radio. Such long-range communication through a harsh environment is difficult with conventional walkie-talkies without many repeaters.
Conclusions and Future Directions We have developed a novel UWB walkie-talkie system with: Unique signal modulation Unique hardware architecture and subsystems Excellent performance in several initial tests in harsh environments Based on the results to date, we are optimistic there are numerous application areas where this technology can have impact. We are pursuing: Applications where our UWB walkie-talkie can have impact Tailored solutions where we can adapt this technology Potential non-voiced applications of this technology Broader uses of the unique subsystems developed 8