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Session: Exploring the Frontier of Environmental Processes using Fiber-optic Sensing [Poster]

Type: Poster

Date: 10/9/2024

Time: 07:00 AM

Room: Stanley Park Ballroom

Characterizing Environmental Noise in Hypersonic Object Detection: Insights from a Fiber Optic Cable Deployment

Infrasonic and seismic signals generated by hypersonic objects transiting Earth’s atmosphere provide critical information to classify the arriving object as natural or anthropogenic. Historically, these sound waves have been recorded by permanent arrays of widely separated seismometers and infasound instruments. During the 24 September 2023 reentry of the OSIRIS-REx space capsule, a total of 12 km of fiber optic cable was deployed at two sites in Nevada, which each sampled the capsule’s acoustic wavefield with high spatiotemporal resolution by utilizing Distributed Acoustic Sensing (DAS) technology. A straight-line cable array and a T-shaped array were deployed during the span of a few days directly onto the surface, exposing the cable to environmental forcings which may have induced signal distortion. Three separate Interrogator Units (IU’s) were used to capture DAS data, and multiple seismometers and infrasound sensors were co-located along the cable to inform our interpretation of DAS data and environmental noise sources. Here, we sample portions of the dataset recorded prior to the capsule arrival to investigate environmental sources affecting signals in the 5-100 Hz range which vary with the time of day, such as temperature, solar exposure, and wind speed. We quantify the signal distortion frequency range, intensity, and triggering factors to identify which noise sources may have impacted the spectral signature of the capsule arrival data. Finally, we compare the variations in noise captured by the three IU’s to determine which systems performed best given the most significant noise sources. Our results have implications for mitigating the impact of environmental noise sources in DAS datasets to better constrain target signals. Characterization of these noise sources will also aid in efforts to advance future design and operation of DAS in remote and extreme environments where large temperature and wind variations affect signal acquisition.

Presenting Author: Elisa

Additional Authors