Ground Penetrating Radar
Ground Penetrating Radar (GPR) Detection in Oregon (Eugene & Portland) and Washington State (Everett, Renton, Seattle, & Tacoma)
RADAR (Radio Detection and Ranging) is a technology primarily used to detect above-ground objects such as aircrafts, ships, vehicles, birds, and rainstorms. In contrast, ground penetrating radar (GPR) antennas transmit an electromagnetic pulse into the ground, and when this pulse encounters a change in material or an object, it echoes back and is captured by the antenna’s receiver. The software used for ground penetrating radar utilizes the frequency and time delay of the transmitted pulses and received echoes to generate information about the target. The depth range and resolution depend on various factors such as radar frequency, transmitted power, the ground material’s dielectric/conductive properties, and the targets’ shape and characteristics.
There are three ways to perform a Dielectric Calibration:
Changes in dielectric cannot be accounted for because only one dielectric value can be entered into the system at a time. Concrete tends to stay consistent, and soil can change horizontally and vertically.
GPR profiles were taken parallel and perpendicular to the drainage in the figures above, revealing a gradual increase in pipe depth from right to left of approximately 3ft (1m). The concrete storm drain’s top and bottom reflections were detected, indicating no metallic structure. Based on the reflection depths and assuming it was an air-filled pipe, the diameter was estimated to be 36 inches. The entire process of locating, marking, tracking depth, and diameter estimation took around 10 minutes.
GPR images can be color-coded using a specific color palette to assist identifying reflections of GPR signals, since some reflections can be more easily identified in different color palettes. Multiple color palettes are available for displaying the image, with some palettes providing better visualization of the target than others. (See Examples Below)