This paper discusses several in-hull RF propagation studies on board one decommissioned and several active Naval ships in the 0.8-2.5 GHz range. During these tests, it was repeatedly demonstrated that radio signals will propagate from one compartment to another even when the watertight doors (hatches) are shut and sealed. In fact, signals have been received across several bulkheads. Results indicate approximately 20 dB of attenuation is associated with transmission through a bulkhead/watertight door. It has also been found that the wireless channel aboard Naval vessels does not show good correspondence with a Ricean channel. Finite element modeling of a shipboard compartment has been performed and supports the hypothesis that rubber door gaskets and other non-conductive structures may be the source of bulkhead penetratiotieakage. For comparison, ultra-wideband channel measurements within the hull of a ship have also been taken. These measurements will be used to characterize the propagation within a single compartment as well as through a sealed bulkhead/watertight door. Receiver, Huntsville AL, Time Domain Corporation, 2000.

Subject Terms Document Classification unclassified Classification of SF298 unclassified Classification of Abstract unclassified Limitation of Abstract unlimited Number of Pages 130 REPORT DOCUMENTATION PAGE Form Approved OMB No. 074-0188Public reporting burden for this collection of information is estimated to average 1 hour per response, including g the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Assessment of radio frequency propagation in a naval shipboard environment AUTHOR(S)Estes, Daniel R.J. FUNDING NUMBERS PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION REPORT NUMBER SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSORING/MONITORING AGENCY REPORT NUMBER US Naval Academy Annapolis, MD 21402Trident Scholar project report no. (2001) SUPPLEMENTARY NOTES 12a. DISTRIBUTION/AVAILABILITY STATEMENTThis document has been approved for public release; its distribution is UNLIMITED. 12b. DISTRIBUTION CODE ABSTRACT:The Navy, in an effort to reduce costs and operate within future budgetary constraints, is planning to reduce the manning on combat ships. To support this reduction in manning, several wireless technologies are being considered, including wireless LANs and a wireless sensor system augmented by a computer-controlled log keeping system. The internal volume of a combat ship is a generally un-studied wireless environment. While a preliminary study demonstrated that radio energy can be radiated and received from compartment to compartment (room to room) within a ship, a detailed analysis of this environment has not been done. In this project, data was collected aboard decommissioned and active ships to characterize the wireless channel on combat ships and to attempt to determine the effect of bulkheads (walls) and hatches (doors) on the information path. Both narrowband and ultrawideband techniques have been used to demonstrated and measure transmissions through the shipboard environment. Each bulkhead attenuated the test signal roughly 20dB. Computer modeling of the bulkhead supported the hypothesis that the radio energy is propagating through the non-conductive structures within the bulkhead -hatch seals, for example -rather than through the steel. AbstractThe Navy, in an effort to reduce costs and operate within the budgetary constraints of the near future, is planning to reduce the manning on combat ships. To accomplish this without reducing the readiness or capability of these ships, the remaining personnel must work more efficiently. To support this required increase in efficiency, several wireless technologies are being considered, including wireless LANs and a wireless sensor system augmented by a computer-controlled log keeping system.The internal volume of a combat ship is a generally un-studied wireless environment. While a preliminary study demonstrated that radio energy can be radiated and received from compartment to compartmen...