EVALUATING THE EFFECTIVENESS OFHYPERSTACKING
FOR GPR SURVEYS
SAGEEP 2016
Dr. Jeffrey Feigin and Dr. David Cist
Geophysical Survey Systems Inc.Nashua, NH
Objective:
Compare performance in data quality of
Equivalent time sampling (ETS)
Hyperstacking (HS)
Defining terms:
Conventional Equivalent time sampling (ETS)One data sample per Transmit Pulse.
Hyperstacking (HS):A variant of Real Time Sampling (RTS)Many samples per Transmit Pulse.
Equivalent Time Sampling (ETS)
Defining terms:
Conventional Equivalent time sampling (ETS)One data sample per Transmit Pulse.
Hyperstacking (HS):A variant of Real Time Sampling (RTS)Many samples per Transmit Pulse.
Real Time Stacking (RTS)
How is HS different from RTS?
HS is a subclass of RTS which incorporates Dithering
Spreads energy to make full use of FCC limits.
Benefits:
Reduced System noise
Reduced Broadcast noise.
Operates at a faster rate than standard RTS
Now can operate at high PRFs and still comply
Cost effective
Test Method:
Collect data from ETS and HS systems over the same profile line using the same cart and using similar frequencies (400MHz) Same processing
Collect these data in different locations Low Loss soils High Loss soils High noise environment
Compare the images qualitatively
Low Loss Soils
ETS HS
ETS HS
Shallow Depth (High resolution)
HS “350”ETS at 800 MHz
High Loss SoilsHSETS
High Loss SoilsHSETS
ETS HS
High Noise EnvironmentSurveying close to a cell tower.
High Noise EnvironmentSurveying close to a cell tower.
ETS HS
High Noise EnvironmentSurveying close to a cell tower.
ETS HS
Conclusions
Low Loss soils• HS penetrates significantly more deeply than ETS systems.• Weak target reflections are brought out of the noise.
High Loss soilsHS performs about the same as ETS.
High Interference(Broadcast, Cellular, etc.) is randomized and Averaged Out.
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