Migration (GPR)
Definition
A processing algorithm that collapses hyperbolic reflections back to their true point positions. Migration requires a velocity model; with the correct velocity it sharpens subsurface images; with an incorrect velocity it can introduce artefacts or under-collapse the hyperbolas.
- Function
- Collapses hyperbolic reflections to true positions
- Requirement
- Velocity model of the subsurface
- Correct velocity effect
- Sharper, accurately positioned image
- Incorrect velocity effect
- Artefacts or under-collapsed hyperbolas
Common questions
How is the velocity model for migration usually obtained?+
It is commonly estimated by fitting the curvature of known hyperbolas in the data itself, by measuring reflector depth at a known test point, or from published velocity values for the local soil type, then refined until reflections collapse cleanly.
Is migration always applied to GPR data in forensic search?+
No, it is one optional processing step among several; some searches interpret raw or only lightly filtered hyperbolic data directly, reserving migration for cases where precise positioning of a target below the surface is required.
Related terms
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- Cheetham 2005 Framework
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- De-Striping
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- Interpolation and Gridding
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- Zero-Time Correction
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