The $240 High Resolution X-Band Linear Rail SAR Imaging System

ABSTRACT

Using a discarded garage door opener, an old cordless drill, and a collection of surplus microwave parts, a high resolution X-band linear rail synthetic aperture radar (SAR) imaging system was developed for approximately $240 material cost.  Entry into the field of radar cross section measurements or SAR algorithm development is often difficult due to the cost of high-end precision pulsed IF or other precision radar test instruments.  The low cost system that will be presented is a frequency modulated continuous wave radar utilizing a homodyne radar architecture.  Transmit chirp covers 8 GHz to 12.4 GHz with 15 dBm of transmit power.  Due to the fairly wide transmit bandwidth of 4.4 GHz, this radar is capable of approximately 1.4 inches of range resolution.  The dynamic range of this system was measured to be 60 dB thus providing high sensitivity.  The radar system traverses a 96 inch automated linear rail, acquiring range profiles at any user defined spacing.  SAR imaging algorithms developed for this system include the Polar Format Algorithm (PFA), a range stacking algorithm, and the Range Migration Algorithm (RMA).  Downrange and cross range motion compensation (MOCOMP) algorithms have been developed.  An autofocus algorithm has also been developed.  SAR imaging results prove that this system could easily image objects as small as pushpins and 4.37 mm diameter steel spheres.  This machine is the latest in a series of small radar systems developed in an effort to understand SAR imaging and apply that technology to the eventual application of through lossy dielectric imaging.

News & Blogs

M. Szczys, ‘More continuous wave radar fun,’ Hackaday, November 20, 2012.

Make Magazine Blog, ‘How-to: Build a synthetic aperture radar from $240 of junk.’

Hack a Day, ‘X-Band linear rail SAR imaging,' June 17, 2010.

Slashdot, ‘DIY Synthetic Aperture Radar.’

Popular Science, ‘A DIY Synthetic Aperture Radar system for $250.’

Publications

• 'Radar Imaging In Your Garage: Synthetic Aperture Radar.' Hackaday, March 17, 2014.

• T. S. Ralston, G. L. Charvat, S. G. Adie, B. J. Davis, S. Carney, S. A. Boppart.  "Interferometric synthetic aperture microscopy, microscopic laser radar."  Optics and Photonics News, June 2010, Vol. 21, No. 6, pp. 32-38.

• G. L. Charvat.  “Build a high resolution synthetic aperture radar imaging system in your backyard,”  MIT Haystack Observatory, May 12, 2010.

• G. L. Charvat.  "Low-Cost, High Resolution X-Band Laboratory Radar System for Synthetic Aperture Radar Applications."  Austin Texas:  Antennas Measurement Techniques Association conference, October 2006.

• PPT slides from AMTA ’06 in Austin Texas

• G. L. Charvat, L. C. Kempel.  “Low-Cost, High Resolution X-Band Laboratory Radar System for Synthetic Aperture Radar Applications.”  East Lansing, MI:  IEEE Electro/Information Technology Conference, May 2006.

• PPT slides from IEEE EIT Conference at MSU, May 2006

• G. L. Charvat, “Low-cost, high-resolution, X-band laboratory radar system for synthetic aperture radar applications,” Michigan State University Chapter of the IEEE, January 31, 2007

• Seminar for PhD Interview Process, Fall ’06

Engineering Notes

$240 Rail SAR Engineering Notes and Schematics

Rev. 2 of video amplifier

X-band Sweep Module Performance Data

Range profiles were acquired on a cold Michigan February day, where the radar sensor was directed toward a row of 1” tall 3/4” wide pipes placed in a row in the snow.  High clutter was present in the data, however it did clearly show that the radar sensor was working.  This proved that it was a worth while investment to take the project to the next level of SAR imaging.

Shown here you will find SAR imagery of various target scenes and the experimental setup itself.  Most notably pushpins and 4.3mm diameter metal spheres.  These images show the sensitivity of this radar system.  The imagery of model aircraft, a 5.0 Mustang, and a Cannondale M300 mountain bike are good examples of high resolution imagery resulting from this radar system.