Electromagnetic (EM) locating and Ground-Penetrating Radar (GPR) locating use different frequency ranges to detect and map underground utilities, each tailored to the specific capabilities and applications of the technologies:
EM Locating Frequency Ranges:
Low Frequency: Below 1 kHz, used for long-distance tracing and deep utility locating with less susceptibility to interference.
Medium Frequency: 1 kHz to 33 kHz, offers a balance between depth penetration and resolution, suitable for general utility locating.
High Frequency: Above 33 kHz, up to 400 kHz or higher, provides high conductivity for locating of utilities, but has limited depth penetration.
EM locating frequencies are chosen based on the type of utility, the required depth of detection, and the need to minimize interference from other nearby metallic utilities or structures.
GPR Locating Frequency Ranges:
Low Frequency: Approximately 100 MHz to 250 MHz, allows for deep penetration (up to 10 meters or more) but with lower resolution.
Medium Frequency: 250 MHz to 600 MHz, offers a balance between penetration depth and resolution, suitable for a wide range of applications.
High Frequency: 600 MHz to 2.6 GHz or higher, provides high-resolution images of subsurface objects at shallow depths (less than 3 meters).
GPR frequencies are selected based on the depth of penetration needed and the desired resolution of the image.
Lower frequencies are used for deeper utility locating with less detail, while higher frequencies are chosen for detailed imaging of shallow utilities.
Both EM locating and GPR technologies are essential for accurately identifying and mapping underground utilities, with the choice of frequency range being critical to their effectiveness in different conditions and applications.