The Mk 15 Phalanx Close-In Weapon System (CIWS - pronounced "sea-whiz") is a stand-alone, quick-reaction time defense system that provides final defense against incoming air targets. CIWS will automatically engage anti-ship missiles and high-speed, low-level aircraft that penetrate the ship's primary defenses. As a stand-alone weapon system, CIWS automatically searches for, detects, tracks, evaluates for threat, fires at, and assesses kills of targets. A manual override function allows the operator to disengage a target, if necessary.

The search and track radar antennas are enclosed in a radome mounted on top of the gun assembly (see

Figure 2-14.-Mk 92 Fire Control System on PERRY class frigate.

Figure 2-15.-WMEC-910 Coast Guard Cutter Thetis with Mk 92 CAS.

figure 2-16). All associated electronics for radar operations are enclosed within either the radome or the Electronics Enclosure (called the ELX). CIWS is operated remotely from either a Local Control Panel (LCP) or the Remote Control Panel (RCP) located in the Combat Information Center (CIC). It has two primary modes of operation: automatic and manual. In the automatic mode, the computer program determines the threat target, automatically engages the target, and performs the search-to-kill determination on its own. In the manual mode, the operator fires the gun after CIWS has identified the target as a threat and has given a "recommend fire" indication.

CIWS was developed in the late 1970's to defend against anti-ship cruise missiles. However, as the sophistication of cruise missiles increased, so did the sophistication of CIWS. Major changes to CIWS are referred to as "Block" upgrades. The first upgrade, known as "Block 0", incorporated a standard rotating search antenna. Limitations of elevation in Block 0 lead to the next upgrade, Block 1. Block 1 provided improved elevation coverage and search sensitivity by using a phased-array antenna. A minor upgrade to Block 1, known as Block IA, improved the processing power of the computer by incorporating a new high-order language. This upgrade gave CIWS the ability to (1) track maneuvering targets and (2) work with multiple weapons coordination. The next upgrade, Block 113, enabled CIWS to engage surface targets. This upgrade is known as the Phalanx Surface Mode (PSUM). A special radar, Forward-Looking Infrared Radar (FLIR), was added to CIWS to detect small surface targets (i.e., patrol/torpedo boats) and low, slow, or hovering aircraft (i.e., helicopters). This radar is mounted on the side of the radome structure. FUR can also help the radar system engage anti-ship cruise missiles. To detect targets day or night, CIWS Block 1B uses a thermal imager and advanced electro-optic angle tracking.

Figure 2-16. -CIWS radome with search and track radar.

SHIP SELF-DEFENSE SYSTEM (SSDS)

The principal air threat to US naval surface ships is a variety of highly capable anti-ship cruise missiles (ASCMs)(figure 2-17). These include subsonic (Mach 0.9) and supersonic (Mach 2+), and low altitude ASCMs. Detection, tracking, assessment, and engagement decisions must be made rapidly to defend against these threats, since the time from when an ASCM is initially detected until it is engaged is less than a minute. SSDS is designed to accomplish these defensive actions.

SSDS, consisting of software and commercial off-the-shelf (COTS) hardware, integrates and coordinates all of the existing sensors and weapons systems aboard a non-AEGIS ship to provide Quick Reaction Combat Capability (QRCC). (It will eventually be installed on board most classes of non-AEGIS ships.) SSDS (fig. 2-18), by providing a Local Area Network (LAN), LAN access units (LAUs), special computer programs, and operator stations, automates the defense process, from the

Figure 2-17.-Missile launch from an AEGIS class cruiser.

detect sequence through the engage sequence. This provides a quick response, multi-target engagement capability against anti-ship cruise missiles.

The entire combat system, including the sensors and weapons, is referred to as Quick Reaction Combat Capability (QRCC), with SSDS as the integrating element. Although SSDS broadens the ship's defensive capability, it is not intended to improve the performance of any sensor or weapon beyond its stand-alone performance. The primary advantage SSDS brings to the combat systems suite is the ability to coordinate both hard kill (gun and missile systems) and soft kill (decoys such as chaff) systems and to use them to their optimum tactical advantage.

The following systems represent the SSDS interfaces for a non-AEGIS ship:

AN/Air Search Radar

AN/Surface Search Radar

AN/Electronic Warfare System

Centralized Identification Friend or Foe (CIFF)

Rolling Airframe Missile (RAM)

Figure 2-18. -Ship Self-Defense System.

Phalanx Close-in Weapon System (CIWS)

Mk 36 Decoy Launching System (DLS)

SSDS options range from use as a tactical decision aid (up to the point of recommending when to engage with specific systems) to use as an automatic weapon system. SSDS will correlate target detections from individual radars, the electronic support measures (ESM) system, and the identification-friend or foe (IFF) system, combining these to build composite tracks on targets while identifying and prioritizing threats. Similarly, SSDS will expedite the assignment of weapons for threat engagement. It will provide a "recommend engage" display for operators or, if in automatic mode, will fire the weapons, transmit ECM, deploy chaff or a decoy, or provide some combination of these.

Q2. What classes of ship use the AN/SPY-1 radar system?

Q3. In the Mk 99 MFCS, the terminal guidance phase of a SM-2 missile is controlled by what illuminating radar?

Q4. Name the three modes of operation of the ANISPQ-9 radar?

Q5. The NATO SEASPARROW missile is controlled by what fire control system?

Q6. What class of ship uses the Combined Antenna System (CAS) and the Separate Target Illumination Radar (STIR)?

Q7. What type of ships, in general, are being upgraded with the Ship Self-Defense System (SSDS)?