Integrated combat systems

Sea Power, Jan 2003 by Walsh, Edward J

Aegis Combat System

The Aegis combat system, fielded to Ticonderoga-class guidedmissile cruisers and Arleigh Burke-class guided-missile destroyers, consists of three primary elements: the SPY-1 phased-array radar, the Aegis weapons control system (WCS), and the command and decision (C&D) system. The system elements function in a highly integrated manner to provide area-wide surveillance, detection, and engagement of airborne threats.

The AN/SPY-1 is a computer-controlled, four-faced, phased-array radar that rapidly transitions detections into tracks and passes them to the C&D system element for engagement decisions and further processing. The SPY1A and SPY-1B Aegis radars use two transmitters linked to four phasedarray antennas, each of which emits an electronically controlled beam across a 110-degree field.

The SPY-1A, the first variant, was fielded to Baseline 1 (CGs 47 to 51) and Baseline 2 (CGs 52 to 58) ships. Baseline 3 (CGs 59 to 64) and Baseline 4 (CGs 65 to 73) cruisers received the SPY-1B, which incorporates improved antennas and electronic countercountermeasures and improves performance against low-flying antiship missiles (ASMs).

The SPY-1D, installed on DDG 51, is virtually identical to the SPY-1 B, but has only one transmitter. The SPY-1D(V) radar, a littoral upgrade to the SPY-1 D, adds a new repertoire of clutter-cancellation waveforms and better sensitivity to allow better low-flyer detection and clutter suppression.

The Aegis weapon system has been upgraded regularly to incorporate new weapons, sensors, and threat profiles. A critical Navy priority in recent years has been the upgrading of fleet defense capabilities against ASMs approaching at sea-skimming altitudes.

The Aegis program office, PMS-400, under the Program Executive Officer Ships, has initiated an effort to shift the Aegis weapon system from the Navyunique computer architecture to commercial-off-the-shelf (COTS) technology.

The COTS insertion begins with Baseline 6 Phase 1, which introduces the UYQ-70 advanced processing and display system. Baseline 6 Phase 1 also marks the transition from a traditional point-to-point architecture to an architecture based on local area networks (LANs); the Aegis Mk6 display system will be configured in a LAN architecture.

Baseline 6 Phase 1 is being fielded in three variants. One variant has been installed aboard the cruisers USS Hue City and USS Vicksburg to support integration testing with the cooperative engagement capability (CEC). The second variant, fielded to DDGs 79 and 80, incorporates the UYQ-70 display console for the command table in the CIC (combat information center). Version 3 of Baseline 6 Phase 1, which introduces a full-up architecture of UYQ70s, is fielded to DDGs 81 through 84.

Beginning with DDG 81, Baseline 6 Phase 1 ships will be fitted out with the Navy's latest naval surface fire-support capability. Baseline 6 Phase 3 (DDGs 85-90) was expected to introduce CEC, the Evolved SeaSparrow Missile (ESSM), and a new variant of the SQQ-89 surface-ship undersea warfare (USW) system.

Baseline 7 phase 1, for DDGs 91-107, eliminates the Navy-unique computers from the Aegis system and replaces them with COTS-based microprocessors. Baseline 7 Phase 1 DDGs will be fitted out with the SPY-1D(V) radar, which has been designed for enhanced detection over land and littoral waters and in high jamming environments. Baseline 7 Phase 1 ships also will receive the SOO-89(V)15, a fully COTS variant, and a range of other new warfighting enhancements.

The Aegis program is pursuing an "open architecture" (OA) initiative to transition the Aegis system to a single common baseline that will replace the mix of baseline configurations now in the fleet. The OA work will be derived primarily from technology insertion opportunities for the UYQ-70 processor. The introduction of new object-oriented software is expected to eliminate the need for continuous insertions of new combat system code to accommodate system upgrades. The OA effort also builds on previous efforts to move toward a common command and decision architecture that would encompass both Aegis and the ship self-defense system (SSDS) being fielded to aircraft carriers and Waspclass amphibious ships.

Cooperative Engagement Capability

"Cooperative engagement" will allow large numbers of CEC-equipped surface ships and aircraft to participate in an air-defense network that would enable them to share fire-control-quality radar target measurements in real time.

The CEC system features two primary components-a cooperative-- engagement processor (CEP) and a data-distribution system (DDS), which acts as the CEC communications relay-and a series of modifications to already-fielded combat systems. The CEP and DDS both are built by Raytheon Systems Company.

In CEC operations, radar measurement information on airborne targets is passed from shipboard air-search radars to the CEP, which reformats the data and sends it to the DDS. The DDS then encrypts and transmits the data to other ships (referred to as CUs) participating in the CEC network. In a fraction of a second, the DDS receives all other CU data and forwards it to the CEP. The CEP combines all of the unprocessed sensor-measurement data into one air picture, identical for all platforms in the network. The same picture then is available for display and use by each individual platform's sensor and engagement systems.