|dc.description.abstract||Improved capability to model and forecast atmospheric effects on electromagnetic (EM) spectrum propagation in the battle-space has broad application throughout Navy and Department of Defense functional areas. Many Naval systems utilize the EM energy, active or passive, for applications in remote sensing (radar), communications (radio), and optical (high energy laser) systems. Refraction is an atmospheric property that bends EM energy from a straight-line path and is caused by spatial variations in temperature, humidity, and pressure. Meanwhile, small perturbations of the refraction index significantly impact free-space optical and high energy laser (HEL) weapon performance. These effects need to be quantified and predicted for all weather conditions.
The Liquid Robotics Wave Glider, known as the Sensor Hosting Autonomous Remote Craft (SHARC) for Navy applications, is a slow-moving platform that can be deployed for extended missions. With adequate sensors onboard SHARC, environmental data can be collected in data sparse regions or hazardous environments. The standard SHARC is instrumented with a default meteorological station (Airmar PB200) that samples air pressure, temperature, wind speed and wind direction at 1.12 m above the water surface. The SHARC automatically transmits 10-minute averaged data through an Iridium satellite link. To maximize SHARC utilization in future Navy-relevant applications, NPS Meteorology Department partnered with the NPS Physics Department and engaged in integration and testing efforts to evaluate the default Airmar PB200 and sought optimal sensors for air-sea interaction and EM propagation studies. In this effort, we developed two SHARC payloads, the 'NPS Met� and �NPS Turbulence� systems. NPS Met payload measures pressure, air temperature, wind, SST, and relative humidity. This SHARC payload package was deployed three times in the Monterey Bay, along with a collocated drifting buoy (Marine Air-Sea Flux buoy, or MASFlux) with proven flux, mean, wave, and SST measurement for comparison and validation. NPS Met was augmented with a 3-D ultrasonic wind anemometer sensor and became the NPS Turbulence payload. Addition of the 20-Hz turbulence sampling required considerable modifications to the data acquisition and power management components.
The NPS-owned Liquid Robotics WaveGlider SV2 (previously Mako, now named Thresher) was deployed with the turbulence payload during the Coupled Air-Sea Processes and EM ducting Research east coast field campaign (CASPER-East). Data collected from Thresher in CASPER-East were limited due to water ingress and salt corrosion inside the meteorological sensors and data acquisition system. The sensor payload configuration for Thresher was redesigned for the CASPER west coast field campaign (CASPER-West) to ensure continuous data collection during its deployment, while maintaining minimal flow distortions. In this presentation, we will showcase the Thresher payload design iterations, present example results from the met and turbulence payloads, and relate those results to the environmental impact on Navy operations using EM spectrum for sensing, communication, and weapon systems.||