Evaluation of Low Altitude Rocket Dropsondes for Shipboard Atmospheric Profilingand Electromagnetic Propagation Assessment

摘要

A study was performed on two measurement systems used to obtain profiles ofrefraction from a ship; the radiosonde and the rocketsonde. Refractive conditions measured by the Marwin Rawinsonde Set (MRS) utilizing radiosondes launched from U.S. Navy ships can yield misleading modified refractivity (M) versus height profiles. MRS obtained M unit profiles, when incorporated in propagation loss models such as Radio Physical Optics (RPO), also may produce unrepresentative propagation loss assessments. Rocketsonde obtained environmental parameters (temperature, relative humidity, pressure) are measured away from the ships influence. The ship can modify the environmental parameters and affect temperatures by as much as 3 deg C. Rocketsonde obtained data yield improved fine scale vertical resolution. Resolution approaching 5m obtained via rocketsondes is found to most closely resemble the actual environment. Rocketsonde data is available down to the near surface whereas there is a distinct lack of data from the surface to the launch point when utilizing balloon launched radiosondes. Inaccuracies in initial surface data drastically impact refractive profiles. Rocketsondes can be used regardless of sea state or wind conditions onboard ship and require no specific ship maneuvering to safely launch. It is found that the rocketsonde can obtain the requisite environmental parameters for refractive assessment on demand in less than half the time required to prepare and launch a balloon guided radiosonde.