4.1 SUBMARINE ANTENNA INTRODUCTION
Submarines require a suite of antennas to provide the necessary communications, navigation,
and Identification, Friend or Foe (IFF) capabilities. Submarine antennas, as compared to surface
ship antennas, are unique in design, shape, materials, and performance due to a submarine’s
space and weight limitations, extreme environmental conditions, and stealth considerations. The
NUWC Division Newport, under the Submarine Integrated Antenna System (SIAS) program, is
the primary design agent for submarine antennas. The following sections summarize the current
SIAS program and future antenna concepts. Appendix A provides a detailed Submarine
Antenna Program Plan, listing both existing capabilities and current and planned SIAS
acquisition and research and development programs.
4.2 OVERVIEW OF CURRENT SUBMARINE INTEGRATED ANTENNA SYSTEM
The current antenna development efforts include: the Submarine SHF/EHF HDR SATCOM
antenna, an Improved AN/BRA-34 antenna, the upgrade to the AN/BST-1 SSBN emergency
buoy, the ADS, and antenna systems engineering. Ongoing antenna systems engineering
include: GBS, SOF connectivity, Global Maritime Distress and Safety System (GMDSS),
JTIDS, and a Maritime Cellular Information Exchange System (MCIXS) cellular telephone
capability. Table 4-1 and the following sections summarize the capabilities provided by each
4.2.1 SHF/EHF High Data Rate Satellite Communications Antennas
The Submarine HDR antenna effort is focused on providing submarines with antennas that have
the bandwidth, gain, and flexibility to meet the stated COMSUBLANT/COMSUBPAC
requirements for HDR communications in the SHF and EHF frequency bands. Antenna
development is concentrating on multiband antennas which support military SHF (Defense
Satellite Communications System [DSCS]), commercial SHF, and EHF MDR communications
at data rates up to 1544 kbps (T1). A near-term SHF capability at 128 kbps and a minimum EHF
MDR capability of 64 kbps is required. These capabilities will be achieved using existing
technology and a COTS/GOTS/NDI approach. The far-term (FY06) requirement is to achieve
data rates up to T-1 as antenna and satellite technology matures. Anticipated technologies
include multi-band antennas and the use of conformal arrays. Ongoing submarine technology
base efforts sponsored by the Office of Naval Research will be leveraged and transitioned into
the SIAS program at the appropriate time.
4.2.2 Improved AN/BRA-34
The Improved AN/BRA-34 (or AN/OE-XXX) program began in June 1989 to increase reliability
and improve the antenna’s multifunction (communications, navigation, and IFF) capabilities
while retaining the existing radome. The program has since been restructured to optimize
support for Fleet UHF DAMA requirements. A low band very high frequency (VHF) capability
(30-88 MHz) has been added to support interoperability with SOF. Technical and Operational
Evaluation (TECHEVAL/OPEVAL) is to be conducted in FY96 with a Milestone III decision
expected in late FY96.
4.2.3 Antenna Distribution System
The objective of the ADS program is to replace the existing manually operated antenna RF patch
panels. Manual patching prevents the rapid reconfiguration of communications circuits required
to support submarine operations in a Joint or Battle Group environment. The ADS will allow
highly flexible and automated routing of signals and information between the radio room and
various antenna systems. The ADS will be under the technical control of the SCSS INM, using
an industry standard SNMP running on a single TAC-X based operator workstation. The ADS
will replace the point-to-point wiring of radio frequency (RF) and control lines that exist on
current submarines. As discussed in Section 3.2.1, a prototype version of the ADS, supporting
RF switching in the high frequency (HF) and ultra high frequency (UHF) bands, is being fielded
as part of the SCSS BBS Phase Prototype and will be demonstrated and evaluated at sea in
FY96. Following IOC in FY98, ADS installations will continue during the SCSS SARR phase.
Production ADS units will be OSA-based, using the VXI standard and, wherever possible,
COTS components. All future antennas will be designed with an ADS interface to provide for
automatic control and operation. The antenna designer will be required to provide a plug-in card
for the ADS controller that will contain all information regarding the capabilities and operation
of the antenna. The antenna system design will require an RF plug-in unit that conforms to the
ADS interface standard. The ADS will provide RF and Intermediate Frequency (IF) interfaces
for SOF communications equipment.
4.2.4 AN/BST-1 Upgrade
The AN/BST-1, a submarine emergency communications transmitter (SECT) system, has been
deployed on SSBNs since 1972. A system upgrade providing a long-life battery, increased
reliability, and reduced operating costs is under consideration. The upgrade program would be
applicable to TRIDENT class submarines and consists of a launch control system (LCS),
launcher subsystem, buoy subsystem, and test set subsystem. The LCS would upgrade the
launch control unit, release unit, depth sensing unit, and signal unit while using existing cables
and hull penetrators, as well as add Built-in Test/Built-in Test Equipment (BIT/BITE) circuitry.
CJCSI 3150.3, Joint Reporting Structure Event and Incident Reports require a system be in place
for immediate notification to the National Military Command Center (NMCC) and CINCs of any
incident or event where national level interest is indicated. Without notification, the loss or
destruction of a TRIDENT submarine would significantly degrade the ability of the CINC to
manage strategic forces in a crisis. The AN/BST-1 system currently provides for immediate and
reliable loss reporting capability. Until a new system that meets the current requirements is
developed, the AN/BST-1 should be maintained and remain reliable.
4.3 ANTENNA SYSTEMS ENGINEERING
The SIAS program will continue to concentrate on the development of a system of antennas,
new SHF/EHF HDR antennas, and technology enhancements to meet the evolving needs
identified by the submarine force. In particular, the SIAS program will continue to concentrate
on addressing the specific antenna requirements identified in the
COMSUBLANT/COMSUBPAC requirements letter (see Appendix E). Figure 4-1 describes the
future transitions in submarine antennas and antenna switching. The related programs,
commencing in FY96 and discussed in detail in Appendix A, include:
- A GBS capable antenna to support the Joint GBS program and its planned capability
to provide high data rate (up to 23 Mbps), receive only satellite communications.
- VHF antennas to support current and future SOF communications requirements.
- Backup UHF DAMA antennas to support removal of AN/BRA-34 on SSN 688 class
submarines with the introduction of the SHF/EHF multiband antenna.
- Continuing antenna investigations to evaluate alternative approaches to meet the joint
COMSUBLANT/COMSUBPAC requirements for GMDSS, JTIDS, and MCIXS.