Standoff detection of explosives and related threats is a current challenge for the United States government in connection with anti-terrorism operations, urban warfare and homeland defense. A potentially useful and technically feasible area of development is radio frequency (RF) sensors to detect and monitor human activities associated with bomb making and bomb delivery from a standoff distance. RF sensors provide unsurpassed range, 24-7 operation and good penetration through building walls. Human body and limb movements also result in unique "microDoppler" features that can be detected easily. There are a number of ongoing through-wall radar sensing programs funded by the US government. However, a more fundamental examination of the human RF sensing problem is needed to advance the long-term research of this challenging problem. The objective of our research is to explore the "art of the possible" in RF sensing of humans through the development of an end-to-end simulation tool that incorporates sensor physics, propagation and scattering mechanisms, signal processing, feature extraction, image formation and classification.
H. Ling, "MicroDoppler exploitation: data collection and analysis," Naval International Cooperative Opportunities in Science and Technology (NICOP) program on Time-Frequency ISAR and NCTI, London, England, June 7, 2004.
A. Lin and H. Ling, "Human tracking using a two-element antenna array," SPIE Defense and Security Symposium, Radar Sensor Technology IX, vol. 5788, pp. 57-64, Orlando, FL, April 2005.
A. Lin and H. Ling, "Through-wall measurements of a Doppler and direction-of-arrival (DDOA) radar for tracking indoor movers," International IEEE AP-S Symposium, paper no. S099p03a, 4 pp., Washington, DC, July 2005.
H. Ling, "Multiple scattering and microDoppler effects in radar imaging and target recognition," IMA Workshop on Imaging from Wave Propagation, Institute for Mathematics and its Applications, University of Minnesota, Minneapolis, Minnesota, October 20, 2005.
A. Lin and H. Ling, "Frontal imaging of human using a three-element Doppler and direction-of-arrival (DDOA) radar," Elect. Lett., vol. 42, pp. 660-661, May 2006.
A. Lin and H. Ling, "Three-dimensional tracking of humans using a very low-complexity radar," Elect. Lett., vol. 42, pp. 67-68, August 2006.
A. Lin and H. Ling, "Two-dimensional human tracking using a three-element Doppler and direction-of-arrival (DOA) radar," 2006 IEEE Radar Conference, paper no. 7152, 4 pp., Verona, NY, April 2006.
A. Lin and H. Ling, "Location tracking of indoor movers using a two-frequency Doppler and direction-of-arrival (DDOA) radar," International IEEE AP-S Symposium, pp. 1125-1128, Albuquerque, NM, July 2006.
A. Lin and H. Ling, "A Doppler and direction-of-arrival (DDOA) radar for multiple-mover sensing based on a two-element array," IEEE Trans. Aerospace Electronic Syst., vol. AES-43, pp. 1496-1509, October 2007.
S. S. Ram and H. Ling, "Analysis of microDopplers from human gait using reassigned joint time-frequency transform," Elect. Lett., vol. 43, pp., November 2007.
S. S. Ram, Y. Li, A. Lin and H. Ling, "Human tracking using Doppler processing and spatial beamforming," 2007 IEEE Radar Conference, Boston, MA, April 2007.
Y. Kim and H. Ling, "Tracking a moving target with multiple Doppler sensors using artificial neural network," International IEEE AP-S Symposium, Honolulu, HI, June 2007.
Y. Kim and H. Ling, "Bearing estimation of moving targets using an artificial neural network," 2007 North American Radio Science Meeting, Ottawa, Canada, July 2007.
H. Ling, "Low-cost radar sensors for personnel detection and tracking in urban areas," DARPA Force Multiplier Seedling Final Review, Washington, DC, February 23, 2007.
H. Ling, R. Bhalla and J. K. Aggarwal, "Simulating RF signatures of dismounts," DARPA RF Dismount Characterization Workshop, Washington, DC, December 5, 2007.
S. S. Ram and H. Ling, "Through-wall tracking of human movers using joint Doppler and array processing," IEEE Trans. Geosci. Remote Sensing Lett., vol. 5, pp. 537-541, July 2008.
S. S. Ram, Y. Li, A. Lin and H. Ling, "Doppler-based detection and tracking of humans in indoor environments," J. Franklin Institute, special issue on Indoor Imaging, vol. 345, pp. 679-699, September 2008.
S. S. Ram and H. Ling, "Simulation of human microDopplers using computer animation data," 2008 IEEE Radar Conference, Rome, Italy, May 2008. (1st place, student paper contest)
S. S. Ram and H. Ling, "MicroDoppler signature simulation of computer animated human and animal motions," International IEEE AP-S Symposium, San Diego, CA, July 2008.
Y. Kim and H. Ling, "Human activity classification based on micro-Doppler signatures using an artificial neural network," International IEEE AP-S Symposium, San Diego, CA, July 2008.
H. Ling, "Tracking human activities for countering IED threats - RF sensor analysis, design and optimization," National Science Foundation EXP Program Grantee's Conference, Washington, DC, January 17, 2008.
L. Du, J. Li, P. Stoica, H. Ling and S. S. Ram, "Doppler spectrogram analysis of the human gait via an iterative adaptive approach," Elect. Lett., vol. 45, pp. 186-188, January 2009.
Y. Kim and H. Ling, "Human activity classification based on microDoppler signatures using a support vector machine," IEEE Trans. Geosci. Remote Sensing, special issue on Indoor Imaging, vol. 47, pp. 1328-1337, May 2009.
Y. Kim and H. Ling, "Through-wall human tracking with multiple Doppler sensors using an artificial neural network," IEEE Trans. Antennas Propagat., vol. AP-57, pp. 2116-2122, July 2009.
S. S. Ram, C. Christianson and H. Ling, "Simulation of high range resolution profiles for humans behind walls," 2009 IEEE Radar Conference, Pasadena, CA, May 2009. (1st place, student paper contest)
S. S. Ram, R. Bhalla and H. Ling, "Simulation of human radar signatures in the presence of ground," 2009 International IEEE AP-S Symposium, Charleston, SC, June 2009.
S. S. Ram and H. Ling, "Human motion animation using microDoppler signatures from multiple Doppler sensors," 2009 International IEEE AP-S Symposium, Charleston, SC, June 2009.
S. S. Ram and H. Ling, "MicroDoppler signatures of anomalies in human gait," 2009 International Symposium on Electromagnetic Compatibility, Kyoto, Japan, July 2009.
S. S. Ram, C. Christianson, Y. Kim and H. Ling, "Simulation and analysis of human microDopplers in through-wall environments," IEEE Trans. Geosci. Remote Sensing, vol. 48, pp. 2015-2023, April 2010.
Y. Kim and H. Ling, "Direction of arrival estimation of humans with a small sensor array using an artificial neural network," Progress in Electromag. Research B, vol. 27, pp. 127-149, 2011.
S. T. Yang and H. Ling, "Design of a microstrip leaky wave antenna for two-dimensional bearing tracking," IEEE Antennas Wireless Propagat. Lett., vol. 10, pp. 784-787, 2011.
S. T. Yang and H. Ling, "Design of a leaky wave antenna for two-dimensional bearing tracking of moving targets," 2011 URSI National Radio Science Meeting, Spokane, WA, July 2011.
T. Mijares, H. Ling and K. Jennings, "A new development in sensory enhancing technology: scientific developments, operational challenges, and legal questions," 2011 Annual Meeting of the Southwestern Association for Criminal Justice, College Station, TX, October 2011.
T. Mijares, H. Ling and K. Jennings, "A new development in sensory enhancing technology: scientific developments, operational challenges, and legal questions," J. Global Homeland Security Education Network, vol. 1, pp. 89-104, March 2012.
S. T. Yang and H. Ling, "Range-azimuth tracking of humans using a microstrip leaky wave antenna," 2012 International IEEE AP-S Symposium, Chicago, IL, July 2012.
S. T. Yang and H. Ling, "RCS of a microstrip leaky wave antenna," 2012 URSI National Radio Science Meeting, Chicago, IL, July 2012.
H. Ling, "Radar signatures of humans," 2012 Mini-Symposium on Wireless and Microwave Circuits and Systems, Baylor University, Waco, TX, March 23, 2012.
S. T. Yang and H. Ling, "RCS of a microstrip leaky wave antenna," IEEE Antennas Wireless Propagat. Lett., vol. 12, pp. 35-38, 2013.
S. T. Yang and H. Ling, "Application of a microstrip leaky wave antenna for range-azimuth tracking of humans," IEEE Trans. Geosci. Remote Sensing Lett., vol. 10, pp. 1384-1388, November 2013.
T. Mijares, K. Jennings and H. Ling, "Tactical applications of sensory enhancing technology: new developments," 2013 Annual Meeting of the Academy of Criminal Justice Sciences, Dallas, TX, March 2013.
S. T. Yang and H. Ling, "Frontal imaging of a human using two microstrip leaky wave antennas," 2013 URSI National Radio Science Meeting, Orlando, FL, July 2013.
H. Ling, Computational electromagnetics of time-varying structures," 2013 Workshop on Electromagnetic Theory, Modeling and Simulations, Chengdu, China, June 9, 2013.