InSar

This memo describes the ASCE Geotechnical Meeting that took place at the Crown Plaza on October 1, 2014

This memo describes the ASCE Geotechnical Meeting that took place at the Crown Plaza on October 1, 2014.

Meeting Description          

Bruce Macdonald from Tre Canada presented a lecture about InSAR^TM technology his firm uses to measure surface Deformation.  Interferometric synthetic aperture radar, abbreviated InSAR or IfSAR, is a radar technique used in geodesy and remote sensing.  He began the lecture with a image of a satellite that orbits the earth.  The satellite is position at one place, a point on the earth’s meridian.  It gathers information.  The earth rotates. 

DInSAR^TM is differential InSAR^TM.  DInSAR^TM has a precision in Centimeters.  It is capable of gathering information of a 3m x 3m earth surface.  Previous image provides 2321/Km² points density.  The new image provides 17,000/Km² resolution.  As advertised on the http://treuropa.com/technique/squeesar/ website, SqueeSAR^TM has identified many more ground points.  This increases the overall understanding of surface displacement occurring in an area of interest.  SqueeSAR^TM uses algorithm that offers significantly increased coverage of ground points especially over non-urban areas.   

Applications

Tre Canada mines the data from different government agency satellites.  The satellites are not their own.  However, obtaining the data and correlating the data to the specific client need is a highly time consuming and technically difficult task.  Deformation of the earth surface is a serious issue for the environment and the safety of the community.  Oil companies have to be monitored by the government to meet the safety standards as they mine the surface of the earth which causes deformation.  This technology is also used

to monitor landslide activities hazardous areas.  The whole country of Italy has been monitored by satellites for their frequent and ongoing land deformation, inventory of existing cases of landslides and stabilizing program monitoring.            

Lessons Learned

I learned a great deal of information during Bruce’s presentation.  Improvements are rapid.  TRE introduced SqueeSAR^TM in 2010.  There are companies that mine these free satellite data to make a great profit.  The cost for monitoring a small plot of land of 3m x 3m can in as much as $100,000 USD.  The data needs to be processed.  Alogorithms are used to make sense of the data and organized into coherent presentations that are useful to the client.   

Conclusion

The field of GIS and satellite imaging is fascinating.  The presentation display multi disciplines and techniques.  There is a bit of math in the algorithms, a bit of geography, surveying, environmental, geotechnical and business.  Engineering field is comprehensive and complex.  Computer technology has provided new techniques to better understand the planet earth.  The future will benefit more from these improvements and hopefully lower the costs of these satellite monitoring to provide us information for studying the earth’s surface and provide a safer living environment.        

Attachments

Attachment A – Figure 1

Attachment A.  

Figure 1 shows a schematic representation of the PSInSAR approach. 

ΔR=λ/2π

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