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trace for each transmission pulse, so a single trace or scan composed of 512 samples requires 512 transmit pulses. An RTS system digitizes the entire scan at one time, requiring only a single transmit pulse for each scan or trace. This significantly improves the signal to noise ratio in the data allowing deeper resolution and also allows for increase in data collection speed. For this application an ImpulseRadar PinPointR is the best option for depth and resolution, which operates at both 400 and 800 MHz simultaneously and is shown in Figure 2 from a previous survey. An analog 400 MHz antenna has a depth of penetration of up to 12 feet, while the 400 MHz real time sampling antenna can penetrate between 0 to 20+ feet, depending on site conditions (penetration is deepest in dry, sandy soils with low conductivity but is severely limited in moist, clay soils with high conductivity). All GPR penetration depths are highly site dependent due to the attenuation at the site which is a function of clay content, soil type, and moisture content. The positioning will utilize a GNSS receiver capable of approximately 1 ft accuracy as that is typically standard for pavement surveys. The GPR data will be post -processed with an appropriate GPR analysis program designed for large surveys employing GPS positioning. The primary deliverable for this project will be a map showing the extents of potential underlying ground rubber tire layer as well as profiles of the asphalt pavement thickness and ground rubber tire layer thickness where applicable. The geophysical data will be briefly analyzed during field testing to ensure data quality. The data will be fully analyzed at our office and a report prepared with the final detailed results. The final results will include Google Earth KMZ maps of the site that show the start and end location of each profile. Each road segment will be presented as a standard GPR profile with the distance along the profile noted along the x-axis as well as the GPS coordinates at regular intervals. We will pick the base of the asphalt in the profiles and provide data files with coordinates and thicknesses that will also be shown graphically as colored dots indicating the thickness of the asphalt. If requested, Olson can also provide GPS positioned heat maps of the asphalt thickness and ground tire fill presence overlain on available public imagery (e.g. Google Earth). Figure 2: Picture of Impulse Radar PinPointR GPR instrument with an EMLID Reach RS2 RTK GNSS receiver mounted on a pole from a previous survey Olson Proposal No. P2023149.1 GP Page 3