Distributed Network Opportunistic Positioning (DiNO) 2012 Joint Navigation Conference Session B7: Collaborative Navigation Techniques Dr. Alison K. Brown, Cayle Stickler, and Jarrett Redd NAVSYS Corporation DFARS 252.227-7018 (June 1995)) SBIR Data Rights Contract Number: W91-CRB011-C-0005 NAVSYS Corporation, 14960 Woodcarver Road, Colorado Springs, CO 80921 Expiration of SBIR Data Rights Period: Expires five years after completion of project work for this or any other follow-on SBIR contract, whichever is later. The Government s rights to use, modify, reproduce, release, perform, display, or disclose technical data or computer software marked with this legend are restricted during the period shown as provided in paragraph (b)(4) of the Rights in Noncommercial Technical Data and Computer Software Small Business Innovative Research (SBIR) Program clause contained in the above identified contract. No restrictions apply after the expiration date shown above. Any reproduction of technical data, computer software, or portions thereof marked with this legend must also reproduce the markings. (End of legend) The views expressed are those of the authors and do not reflect the official policy or position of the Department of Defense or the U.S. Government DISTRIBUTION A. Approved for public release; distribution is unlimited
GPS Issues to be Overcome GPS signals may be attenuated when operating under foliage, in an urban canyon, or inside a building to the extent that they cannot be detected by a conventional GPS receiver. GPS signals can be denied when in close proximity to a GPS jammer or interference source The GPS signals can be corrupted with multipath when operating in urban canyons GPS navigation is not possible without sufficient satellites to provide good geometry (PDOP) GPS Outage GPS Degraded by Multipath and Signal Blockage GPS Network Assistance GPS Denied
GPS + Cross-link Ranging Distributed Network Solution Combines GPS observations and intra-network net ranges from a sparse network Calculates ensemble network location solution even when no units have complete GPS observability SVs in use TOA Range
DiNO Positioning with Signals of Opportunity (SoOP) Space-Based SoOP Wideband SoOP Narrowband SoOP GPS Satellite W-CDMA Cell WLAN Digital TV Analog TV GSM Cell AM/FM Radio Software Defined Radios Intra-Network Ranges Software Defined Radios Distributed DiNO Network Network Assistance Positioning (DiNO) Server
SDR Enabling Capabilities for collecting DiNO observations Multi-band operation Channels can be tuned to scan for SoOP and collect signal samples for DiNO processing Common channel reference clock Common clock for GPS and SoOP channels reduce to DiNO solution solving for common Bu offset for each unit (4-states per unit) Network communications Can be used for messaging g and intra-channel ranging
DiNO SDR Test Bed
Ettus Universal Software Radio Peripheral (USRP ) USRP Software Open source GNU Radio GNU Radio Companion N210 Radio Spartan-3A 3400 DSP Transceiver daughterboards USRP WBX transceiver daughterboard Full-duplex 50MHzto22GHz 2.2 14 bits A/D
USRP DAE to HyperX
DiNO Signals of Opportunity Desired Features DTV Broadband modulation Frequency separation Strong received signal DiNO Processing Geolocates SoOP using TDOA observations (note does not require detailed knowledge of signal structure) Uses TDOA dpr obs to augment network positioning 300-750 Mz 6 MHz BW, >1000 kw PCS 1930-1990 MHz 1.23 MHz BW, 100-500W WiMax 2.3, 2.5, 3.6 GHz 3.5-20 MHz BW, 100 W
DTV DPR Observations Cross-correlation of two samples in DTV band provides D-PR observations
GPS Jammers as SoOP Example jammer signals collected at WSMR TDOA cross-correlation provides dpr observations DiNO algorithm associates dpr with each jammer node and solves for location
Jammer-Assisted Collaborative Navigation Solution
DiNO Navigation Example Interior units have intra-network network ranges (e.g. SRW) DiNO App captures snapshots from selected SoOP on all units (e.g. DTV and/or GPS jammer) DiNO network service calculates all distributed networked units locations and also locations of SoOP Solution can be calculated with no GPS observations through addition of two anchor units at known location with precise local clock
DiNO Simulation TOA Obs Insufficient TOA observation geometry to compute solution without any GPS obs
TOA + GPS Jammer Assistance TOA + Jammer dpr obs relative to anchor units provides sufficient geometry for solving for jammer and network participant locations
GPS Timing Testing GPS snapshot collected from two SDRs GPS time of transmission i extracted to mark start time of samples [m] GPS Synchronous Snapshots, Correlation Results: Tau Offset Mean: 1.318 [m] Standard Deviation: 0.966 [m] 4 3 2 1 0-1 Test data collected with common clock used to -2 20 40 60 80 100 120 Snapshot observe accuracy Time Differences were accurate to within 1 m (1-sigma) FOUO
GPS/DTV Observation Accuracies Synchronous Snapshots, Correlation Results: Tau Offset GPS Mean: 1.318 [m], Standard Deviation: 0.966 [m] DTV Mean: 0.690 [m], Standard Deviation: 0.002 [m] GPS and DTV snapshots 4 GPS-GPS were collected using two DTV-DTV 3 channels on SDR 2 SDR clock offset 1 determined from GPS observations 0 DTV dpr observation -1 created using GPS -2 20 40 60 80 100 120 Snapshot corrected SDR clock offset DTV dpr observations were accurate to within 2 mm (1-sigma) [m]
Conclusion Distributed Network Opportunistic Positioning (DiNO) provides robust collaborative positioning in an urban environment where GPS satellite visibility is occluded DiNO leverages GPS + RF Ranging Network assistance to allow positioning of users in an environment where GPS is partially denied DiNO leverages RF Ranging + SoOP (including GPS Jammer Assistance) to allow positioning of users in an environment where GPS is completely denied DiNO provides back-up navigation capability to GPS as an embedded SDR and Network application Lab and field testing planned with GDAP test bed under US Army contract with DARPA SBIR funding