Platforms:Two ship classes in the United States Navy currently field the AEGIS radar and weapons package- Ticonderoga-class guided missile cruisers and Arliegh Burke-class guided missile destroyers. Additionally, the Japanese Kongo-class destroyers and Spanish F-100 frigates also house the AEGIS system. Cooperation with allies will be an integral part of sea-based global missile defense as our ships will have to cruise far from home in the littoral waters surrounding possible hostile states armed with ballisitic missiles to enable boost phase intercepts. For more information on AEGIS platforms or to become involved in promoting one of the Navy's most capable platforms, visit the AEGIS Industrial Alliance and become a member.
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Guided Missile Cruiser (AEGIS) (CG) Displacement: 9450 Tons |
Guided Missile Destroyer (AEGIS) (DDG) Displacement: 9300 tons |
Missiles: The STANDARD Missile
In order to meet the NTW and the Sea-Based Global Missile Defense roles, the Standard Missile will have to be modified. One such modification, increasing the speed of the missile, will be easily achieved as the current deployed version of the Standard has been intentionally slowed-down so that it does not risk violating the restrictions of the ABM treaty. See this PDF file to see modifications that will have to be made to upgrade the Standard.
SM-II The Standard Missile is the Navy’s prime fleet-area air defense weapon and was developed to replace first generation Talos, Tartar and Terrier air defense missiles. It is a solid propellant-fueled, tail-controlled, surface to air missile fired by surface ships. The SM homes in on high-altitude anti-ship missiles during its terminal phase of flight by utilizing the Aegis Radar system and mid-course guidance with radar illumination of the target by the ship. The Standard Missile family plays a paramount role in the theater ballistic missile defense. There are several versions of the Standard Missile: Developed in 1967 as the first generation Standard Missile, the SM-1 served as the primary missile of the U.S. Navy and several other navies. It is a home-all-the-way missile in medium and extended range versions designed for anti-air, anti-missile, and anti-ship warfare.
The latest generation of Standard Missile, SM-2, utilizes an imaging infrared seeker in terminal phase of flight. It maximizes advanced signal processing, communication techniques, and propulsion improvements to provide substantial increases in intercept range, high and low altitude intercept capability, and performance against advanced threats. The SM-2 employs a vertical launch system, Command Midcourse Guidance, an ECM resistant monopulse receiver for semi-active radar terminal guidance, and a blast fragmentation warhead. The SM-2 provides medium range defense for Ticondergoa-class AEGIS cruisers, Arleigh Burke-class AEGIS destroyers, California and Virginia-class nuclear cruisers and some Kidd-class destroyers.
Radars and Sensors:
Offboard cueing is the key to efficient radar management and early detection. In 2005, cueing to Aegis will be primarily a function of the U.S. Space Command. The joint force maritime component commander, or JFMCC, will therefore have to bear in mind that "as friendly operations shift in time and place, the T[B]MD planner must . . . effect continual coordination with USSPACECOM to obtain [sensor] coverage."
SPY-1D Phased Array Radar
The backbone of the AEGIS Weapons System is the SPY-1D phased array radar. SPY-1D is the most technologically advanced radar in the world, able to track marble-sized targets in excess of 100 miles. All the targets tracked by the SPY radar are monitored by the ship's Command and Decision system. If a target is determined to be a threat, the ship's crew can issue orders through the Weapons Control System, and engage the target with missiles, guns, and/or CIWS.Significant funding is being allocated by the US Navy to upgrade or modify existing SPY-1D Aegis systems aboard the US Navy's CG-47 guided missile cruisers and DDG-51 destroyers to accomplish the TBMD function to meet US Navy requirements. These upgrades to the Aegis system consist of improved or new missiles, improved and new radars, and significant modifications to the software. SPY-1D is the only radar being considered by the US Navy today for upgrade to accommodate a TBMD capability.Sensors The primary sensor for naval TBMD active defense will be the Aegis SPY radar. Its TBM-tracking capabilities are being explored and expanded through the use of new computer software that will produce a TBMD-capable Aegis system. Thus altered, SPY radars have "demonstrated the ability to track TBMs at ranges well in excess of 500km."
As with any radar, tracking range is highly dependent on the radar cross-section (RCS) of the target, and SPY autonomous ranges against TBMs with challengingly small cross-sections will decrease accordingly. Here, battlespace (i.e., distance, and therefore time) can be regained through cooperative tracking by two Aegis ships: the forward "picket" transmits track data to a consort downrange until the second ship can acquire the target. This capability has been demonstrated in several TBMD Extended Tracking Exercises, including Joint Task Force (JTF 95) demonstrations of the new "cooperative engagement capability," the present-day precursor to the "joint fire control network" postulated for 2005.
Cooperative tracking against low-RCS targets can also be improved by not stationing ships directly under the threat trajectory. The TBM is thus illuminated from several angles by the SPY radars of more than one ship. What might be a very small target head-on may give a useful return from the side. The composite data shared via cooperative engagement takes advantage of this phenomenon and thus provides all platforms in the network the best possible track of the target.
Battlespace can be increased not only through sharing track data between radars but also by using the transmitted energy of any given radar more efficiently. The SPY must search for and detect a TBM before the Aegis system can compute a track. If radar waveforms and anticipated search volumes can be "fine-tuned" early for TBM detection, SPY can acquire and Aegis can track the target much faster, thus gaining all-important time.
A significant limitation of national overhead sensors is their inability to gather data on any TBM after its boost phase, that is, when the hot plume of the rocket motor no longer exists. Without post-boost information, it may be possible to perform search-volume limitation and waveform selection for the SPY but not to meet criteria for an optimum single-beam cue--"an uncertainty volume small enough to be covered by a single beam of a [fire control radar] system."
The importance of post-boost phase sensors to allow single-beam cueing has been clear to the Navy for several years, as shown by studies advocating infrared search and track (IRST) equipment for the E-2C early-warning aircraft. Airborne infrared systems can continue to track a TBM after its motor burns out, by sensing skin heating of the missile body caused by the friction of its passage through the atmosphere. The E-2C/IRST concept, known as Gatekeeper, is currently unfunded.
Battle Management, Command and Control:
Regulated by treaty, battle management and command and control capablities remain the key obstacle in transforming Navy Theater Wide into home defense. The lack of an improvement over the Defense Support Program [DSP] sattelite constelation leaves the tracking capabilities of deployed AEGIS ships in jeopardy while treaty constraints against networked sensor capabilites either through other AEGIS ships or the proposed SBIRS satellite system leaves gaps in the ability of Sea-Based BMD. BMC2 problems have also forced the recent delay of the Navy's projected 2004 deployment of NTW capable platforms for 20 additional months.
