In 2022, Eka Hospital BSD will plan development in its hospital area, in the BSD area, Tangerang. At the pre-construction stage, an overview of the distribution of existing utilities is needed. This data is used during the construction process to minimize damage to existing utilities. One method that can be used for subsurface utility mapping is GPR.
Ground Penetrating Radar (GPR) also known as Georadar. It is method from geophysical engineering that use the propagation of electromagnetic waves that respond to changes in electromagnetic properties of the medium below the surface. The speed of electromagnetic wave propagation is the main controlling factor in the occurrence of reflection events, which are highly determined by the contrast in relative permittivity values between the background medium (embedding media) and buried/target object, or can be a contrast between layers.
The GPR method works by having a frequency range from 25 MHz to 2 GHz (2000 MHz). There are several option for antenna frequency. It varies according to the purpose of the survey or investigation. Selection of an antenna with a higher frequency allows better resolution results, but the target depth is shallower. On the other hand, selecting an antenna with a lower frequency allows for a deeper target depth, but with a less good resolution.
GPR survey activities at the Eka Hospital BSD, it was carried out to mapping existing utilities at their area. So it is necessary to investigate the utilities at shallower area with best resolution data. This survey activity requires a GPR antenna that has a medium frequency at so that the depth and data obtained can be more optimal. An antenna with a frequency of 450 MHz has been selected to mapping the utilities with depth targets of less than six meters. Data collection is carried out gridded with space between lines in 2.5m. Total Station was used to positioning start and end of line GPR on each lines.