Common Mid-Point (Cmp) Surveys - Sensors & Software pulseEKKO Product Manual

Surveying Techniques & Tips

11.6 Common Mid-Point (CMP) Surveys

A Common Mid Point (CMP) survey is performed to measure GPR velocity in the survey area.
A CMP survey is best done in an area with flat lying reflectors and relies on changing the
antenna separation to increase the signal path length from the mid-point reflector (Figure 11-5 &
Figure 11-6).
Figure 11-5: Illustration of a CMP Survey
Figure 11-6: Actual CMP Survey
The resulting data can then be processed using a semblance analysis routine to extract average
GPR velocities to the reflectors (Figure 11-7). The extracted velocities are used for adding an
accurate depth axis for other GPR survey lines collected in the area of the CMP.
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