|FREELAND, ROBERT - University Of Tennessee|
|Martinez, Luis - Rene|
|JONES, BRIAN - Geophysical Survey Systems, Inc|
|MCCOY, EDWARD - The Ohio State University|
Submitted to: Journal of Environmental & Engineering Geophysics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/25/2016
Publication Date: 6/1/2016
Citation: Freeland, R.S., Allred, B.J., Martinez, L.R., Gamble, D.L., Jones, B.R., McCoy, E.L. 2016. Performance of hybrid and single-frequency impulse GPR antennas on USGA sporting greens. Journal of Environmental & Engineering Geophysics. 21(2):57-65.
Interpretive Summary: This project evaluated the performance characteristics of various ground penetrating radar (GPR) antenna frequencies in resolving the subsurface features of an artificially constructed subsurface. The study demonstrated the utility of using a standardized subsurface of an outdoor USGA-specified putting green as a common geophysical test bed. Greens management staff may have concerns regarding damage to high-value turf from geophysical survey trafficking. It was suggested that geophysical surveyors employ wide, soft-pneumatic, smooth-tread tires on any equipment carts that must traverse high-value putting greens. Hard, thin, treaded tires from conventional GPR utility-survey carts impacted surface playability and greens aesthetics. Surveys trafficking upon high-value sports turf should not be conducted on frost, during frozen or dry soil conditions, or following sand top dressing. The research demonstrated that a general “all-purpose” antenna for routine profiling of turf putting greens fell within the 400- to 800 -MHz range. Other frequencies also performed well for a specific target or task, such as profiling sub-grade depths and mapping relative spatial distributions of surface compaction and moisture. Results are presented using a hybrid antenna and fixed-frequency antennas; both center frequencies of the hybrid antenna performed well for the entire subsurface range of a USGA-specified green.
Technical Abstract: The utility of employing ground-penetrating radar (GPR) technologies for environmental surveys can vary, depending upon the physical properties of the site. Environmental conditions can fluctuate, altering soil properties. Operator proficiency and survey methodology will also influence GPR findings. Therefore, GPR equipment performance evaluation involves standardized tests that are frequently conducted indoors within laboratory-controlled environments. This study uses outdoor United States Golf Association (USGA) putting greens as a structure for standardized GPR testing. These USGA putting greens provide a controlled environment, because many golf courses and sports turf fields adhere to strict USGA construction guidelines. Past studies on numerous USGA greens show that GPR provided precise and accurate profiles of root-mixture depth, gravel-blanket thickness, and drain-tile layout. Results are independent of locale, as all USGA putting greens are essentially identical. The performance of various GPR antenna frequencies on USGA greens was assessed. This research determined that a general “all-purpose” antenna for routine profiling of turf putting greens is in the 400- to 800 -MHz range. Other frequencies also performed well for a specific target or task, such as for profiling sub-grade depths and mapping relative spatial distributions of surface compaction and moisture. The study also compared the performance of a hybrid-antenna design with the performance of fixed-frequency antennas, and found that the hybrid frequencies fit well for profiling turf greens. It is noted that greens management staff may have concerns regarding damage to high-value turf from geophysical survey trafficking. Surveying practices and procedures that help lessen these concerns are proposed.