A low-cost through-the-wall FMCW radar for stand-off operation and activity detection

In this paper we present a new through-wall (TW) FMCW radar system. The architecture of the radar enables both high sensitivity and range resolutions of <1.5 m. Moreover, the radar employs moving target indication (MTI) signal processing to remove the problematic primary wall reflection, allowing higher signal-to- noise and signal-to-interference ratios, which can be traded-off for increased operational stand-off. The TW radar operates at 5.8 GHz with a 200 MHz bandwidth. Its dual-frequency design minimises interference from signal leakage, and permits a baseband output after deramping which is digitized using an inexpensive 24-bit off-the-shelf sound card. The system is therefore an order of magnitude lower in cost than competitor ultrawideband (UWB) TW systems. The high sensitivity afforded by this wide dynamic range has allowed us to develop a wall removal technique whereby high-order digital filters provide a flexible means of MTI filtering based on the phases of the returned echoes. Experimental data demonstrates through-wall detection of individuals and groups of people in various scenarios. Target positions were located to within ±1.25 m in range, allowing us distinguish between two closely separated targets. Furthermore, at 8.5 m standoff, our wall removal technique can recover target responses that would have otherwise been masked by the primary wall reflection, thus increasing the stand-off capability of the radar. Using phase processing, our experimental data also reveals a clear difference in the micro-Doppler signatures across various types of everyday actions

[1]  Hugh Griffiths,et al.  Multistatic micro-Doppler radar signatures of personnel targets , 2010 .

[2]  Hao Ling,et al.  Simulation and Analysis of Human Micro-Dopplers in Through-Wall Environments , 2010, IEEE Transactions on Geoscience and Remote Sensing.

[3]  Alessio Balleri,et al.  Classification of personnel targets by acoustic micro-Doppler signatures , 2011 .

[4]  Wesley D. Boyer,et al.  A Diplex, Doppler Phase Comparison Radar , 1963, IEEE Transactions on Aerospace and Navigational Electronics.

[5]  M. Aftanas,et al.  Throughwall imaging of the objects scanned by M-sequence UWB radar system , 2008, 2008 18th International Conference Radioelektronika.

[6]  Matthew Ritchie,et al.  A New Multistatic FMCW Radar Architecture by Over-the-Air Deramping , 2015, IEEE Sensors Journal.

[7]  R.J. Fontana,et al.  Recent system applications of short-pulse ultra-wideband (UWB) technology , 2004, IEEE Transactions on Microwave Theory and Techniques.

[8]  John B. Shoven,et al.  I , Edinburgh Medical and Surgical Journal.

[9]  Odile Picon,et al.  A Study of UWB FM-CW Radar for the Detection of Human Beings in Motion Inside a Building , 2009, IEEE Transactions on Geoscience and Remote Sensing.

[10]  Kamal Sarabandi,et al.  Special Issue on Remote Sensing of Building Interior , 2009, IEEE Trans. Geosci. Remote. Sens..

[11]  Allan R. Hunt,et al.  Use of a Frequency-Hopping Radar for Imaging and Motion Detection Through Walls , 2009, IEEE Transactions on Geoscience and Remote Sensing.

[12]  Moeness G. Amin,et al.  Dual-frequency Doppler radars for indoor range estimation: Cramer-Rao bound analysis , 2010 .

[13]  G. G. Stokes "J." , 1890, The New Yale Book of Quotations.

[14]  Greg Barrie,et al.  UWB Impulse Radar Characterization and Processing Techniques , 2004 .

[15]  Gregory L. Charvat,et al.  Through-Wall Imaging Radar , 2012 .

[16]  Sana Salous,et al.  Through-The-Wall Detection With Gated FMCW Signals Using Optimized Patch-Like and Vivaldi Antennas , 2015, IEEE Transactions on Antennas and Propagation.

[17]  V. Chen,et al.  Radar Micro-Doppler signatures : processing and applications , 2014 .

[18]  Graeme E. Smith,et al.  Through-the-Wall Sensing of Personnel Using Passive Bistatic WiFi Radar at Standoff Distances , 2012, IEEE Transactions on Geoscience and Remote Sensing.

[19]  Kyle Jamieson,et al.  ThruMapper: Through-Wall Building Tomography with a Single Mapping Robot , 2017, HotMobile.