SBIR-STTR Award

This proposal investigates a novel technique for determining whether an HF signal is arriving via ground wave propagation and is therefore emanating from within the tactical area or whether the wave is propagating via sky wave and is therefore emanating from the strategic area of interest. The technique makes use of an electrically spinning loop antenna combined with a signal processor to differentiate vertically polarized ground waves arriving over sea water from elliptically polarized sky waves. The technique exploits differences between the characteristics of skywave propagation and waves propagating via ground wave over a good ground.

In Phase I of this program, we showed a new link protocol to be capable of increasing the throughput of data transmission with maritime disadvantaged UHF SATCOM users experiencing severe sea-state induced fading. This protocol can achieve reliable throughput with less overhead than other protocols. We demonstrated that this protocol combined with selected CPM signaling could further increase performance for transmission over DASA or dedicated UHF SATCOM channels. In Phase II, we will implement and demonstrate the protocol using COTS DAMA/DASA radios and selected marine antennas operating over a UHF SATCOM link to validate these performance improvements and to refine the protocol parameters for optimal performance. Variable channel fading conditions will be reproduced using a radio channel simulator. Phase II option tasks include following the initial demonstration by an end-to-end demonstration with equipment installed in a UUV testbed. We will develop a system for collecting and distributing UUV intelligence data throughout the NMCI in compliance with Net-Centric Warfare to expedite transition to Phase III, as well as developing approaches to support increasing bandwidth requirements in support of UUV mission planning in order to ensure scalability. Plans for Phase III implementation of the protocol as a JTRS module will be developed. Benefit Specific military interest for the use of this protocol has been identified. The proposed data-link-control protocol will greatly improve network performance in both existing and emerging satellite networks that may be subject to fading. It can be applied to a wide range of satellite communications, such as submarine communications, corporate satellite networks, remote satellite telemetry, network control data, intelligence data, image transmission, and digital video, as well as to corporate branch offices, and utility data networks. The protocol is also suitable for adaptation to improve performance of digital mobile radio networks. Keywords LMRS, DAMA, NCW, DASA, UUV, Data Communications, data link protocol, Satellite Communications