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7 General Findings and Overall Recommendations In this report, the panel takes a comprehensive look at naval communications, focusing principally on space communications including UHF, SHF, and EHF systems. The panel discusses the changing world environment and its impact on the national security, the military strategy, and in turn on naval strategy for the next 10 to 20 years. The panel notes that this new naval strategy (i.e., From the Sea1) represents a fundamental shift from open-ocean warfighting to regional conflicts involving littoral warfare. The panel notes the need for a robust C3 system to support these strategies at all levels of command and points out the need for survivable global communications and the role of satellite communications systems to support this need. The panel characterizes naval communications requirements at the global through joint tactical command levels and observes that coverage around the globe is necessary but is primarily significant in the mid-latitudes. The degree of robustness is shown to vary from a hard-core warfighting capability with sufficient protection and security to unprotected general- purpose communications. A range of services to both fixed and mobile users is identified, including voice, data, facsimile, video, and imagery transmission, with data rates that extend from less than roughly 10 kbps (LDR) to upward of several hundred Mbps (VHDR), depending upon the specific user. The panel notes that interoperable communications systems are a necessity to support joint operations and activities involving allied and coalition forces. Finally, to support future power projection and precision strike operations, the panel notes that communications volumes and capacities can become very high (> 1 Mbps) for most tactical circuits, and that time to establish necessary circuits is severely compressed (generally less than a few seconds). The panel recommends that a continuing analysis of communications requirements be maintained, particularly in light of the changing tactical and strategic environments, and that these data be incorporated in DOD requirements documents (i.e., the Integrated Satellite Communications Requirements Document (ISRD) and be used to support necessary Navy engineering development efforts and programmatic decisions. The panel has taken a broad look at current and planned military, civil, and commercial satellite communications capabilities and concludes that selected combinations of these systems could meet most identified requirements. There are some exceptions, however. The panel believes that an abundance of technology exists and could be applied to resolve these remaining issues. The panel observes that current Navy satellite communications is highly structured, with little flexibility to dynamically shift or reconfigure resources. Overall, the current systems have limited throughput capacity and are vulnerable to unintentional interference and jamming. The panel observes, however, that the Navy has strong programs at UHF and EHF in terms of both on-orbit and planned systems and terminal development efforts. The panel notes, lFrom the Sea, Navy and Marine Corps strategy document, Secretary of the Navy, September 28, 1992 (unclassified).

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also, that the Navy has taken dramatic steps to improve its throughput capacity by making greater use of SHF systems on its principal command and combat (Tomahawk-capable) ships. Finally, the panel observes that the Navy makes only limited use of commercial satellite communications services, but the panel recognizes that careful consideration of a number of factors is necessary before any large-scale use is made of commercial capabilities. These factors include (1) coverage—commercial systems provide only limited oceanic coverage and are driven more by the market potential over landmasses, (2) frequency assignments and compatibility with existing Navy terminals, (3) shipboard electromagnetic interference from local high-power transmitters, (4) throughput capacity available to military users, (5) cost of service, and (6) treaty restrictions on military use. The panel concludes that the "ideal" or goal naval communications architecture (NAVSATCOM-21) should reflect a multilayered structure of interconnecting networks that are geographically dispersed, employ differing topographies (mesh, hub-spoke), and allow point-to- point as well as broadcast services to network users. The architecture should include a global, high-capacity (> 1 Gbps) backbone network, with both fixed and mobile gateways to selected task force elements and tactical units. High-capacity (several Mbps) tactical networks should be used to provide connectivities between and among selected platforms and should interface directly with the platform's local area network. The architecture should permit dynamic network management and control and interoperable operations with joint, allied, and coalition forces using terminals that are adaptable to specific user need (in terms of size and performance). For those links that provide connectivity to selected fixed but predominately mobile users, the links should be implemented using integrated UHF, SHF, and EHF military capabilities and heavily augmented by commercial systems, where practicable. The panel recommends that the Navy maintain and reinforce continued investment in EHF as the principal hard-core and soft-core satellite communications resource. The Navy should add an MDR capability to LDR and EHF terminals and investigate the cost and schedule feasibility of an MDR engineering change to the UFO satellites. The Navy should continue its efforts at SHF, particularly the demand assignment multiple access (DAMA) activity to increase the use of available SHF channels. Also recommended is Navy investment in a low-cost multiple-frequency shipboard terminal (C-, X-, and Ku-bands) for increased access to services at SHF. Particularly important to the realization of this multifrequency terminal is a suitable antenna system. The panel endorses Navy efforts to develop a multimission, multi-user broadband antenna (MMBA) to achieve a robust SHF capability with minimal space and weight requirements. The panel acknowledges the Navy's expansive use of UHF as a general-purpose service and recommends that the capacity of these UHF systems be enhanced with more efficient modems to achieve roughly a tenfold increase in information throughput at relatively low cost. The panel recommends the expanded use of GPS in all communications nodes as a straightforward way to improve control and operation of all Navy satellite communications in terms of unproved positional knowledge (especially for mobile users) and timing synchronization. The panel concludes that a robust satellite communications capability would have a significant role in all expanded strike operations and significant impact on the effectiveness of these operations. (See Table 5.1, which summarizes the principal features of the 81

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NAVSATCOM-21 goal architecture and relates these features to naval operations today with future operational capabilities enabled if the architecture is implemented.) New tactical missions involving littoral strike operations against hard-to-find relocatable targets will require a mix of both line-of-sight and satellite relay links to support concepts involving advanced airborne sensor platforms and new applications of cruise missiles (including battle damage assessment and health and status reporting) and remotely piloted vehicles. It is noted that these missions will severely compress timelines for data and imagery transmission and greatly increase the volume of data to be transmitted. A judicious tradeoff of cost and achievable performance is recommended to the Navy for resolution of issues concerning airborne versus satellite relay for these applications. The panel notes that ongoing joint exercises, such as Tandem Thrust '92 and '93 and Ocean Venture '93 would provide the opportunity to demonstrate many of the satellite communications concepts identified by NAVSATCOM-21. For example, the panel specifically urges the Navy to devote at least a portion of these exercises to assessing the vulnerability of selected circuits to intentional jamming in order to more accurately specify the degree of jamming protection actually required. In comparing the NAVSATCOM-21 architecture with Copernicus/CSS, the panel concludes that many features discussed in NAVSATCOM-21 are similar to the planned objectives of Copernicus/CSS. The panel notes, however, that the Copernicus architecture does not fully address tactical information exchange at the unit level and should be extended accordingly. The panel recognizes that the CSS effort has begun to introduce an engineering approach for dynamic routing and resource management that is totally consistent with NAVSATCOM-21 and should continue to do so, but CSS will also expand efforts to more fully integrate GPS into all existing and planned communications elements for enhanced control and management of these resources. 82