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AN/SPS-48G

 
Description
The AN/SPS-48G is a long-range, three-dimensional (3D), air search radar that is progressively being installed on CVN, LHA, LHD and LPD classes of ships, replacing the AN/SPS-48E. The program of record is to backfit the existing AN/SPS-48E population with the AN/SPS-48G variant from 2011 through 2021, and to keep this system operational through the year 2050. As of the end of 2016, the AN/SPS-48G is already installed or in the process of installation aboard CVNs 68-72, CVNs 74-76, LHDs 1-3, LHD 7, LHA 7 and LPDs 26-27.

The AN/SPS-48G is used to provide full volumetric detection data for the Ship Self Defense System (SSDS) via the Cooperative Engagement Capability (CEC) or the SYS-2 tracker; Air Intercept Control; Anti-Ship Cruise Missile detection including low elevation and high diver targets; backup aircraft marshalling; and the new Hazardous Weather Detection and Display Capability.

Long-term obsolescence, reliability, maintainability, and availability (RM&A) issues have reduced the AN/SPS-48E radar's effectiveness in the Fleet and increased system and lifecycle support costs. The AN/SPS-48G program responds to these issues through a system redesign that improves the radar's RM&A through technology improvements, open architecture (OA) design and improved logistics processes to accommodate future obsolescence avoidance while reducing lifecycle cost.

The improvements introduced by the AN/SPS-48G only affect the layout of the below-deck units. The antenna and pedestal remain the same as in the AN/SPS48E. The AN/SPS-48G replaces the current 1st and 2nd stage radio frequency (RF) amplifiers (Unit 1) with a solid state transmitter and combines the existing receiver (Unit 9), processor (Unit 10) and auxiliary detection processor (Unit 15) cabinets into a single commercial off the shelf (COTS) processing equipment cabinet. All of this provides an 87% reduction in the number of lowest replaceable units. Mean Time Between Critical Failure of the AN/SPS-48G is also improved over the AN/SPS-48E by 104% based on 18 years of historical AN/SPS-48E data, and with associated improvements in both operational availability and capability.

OA design concepts are being implemented that will ensure the sustainment of the COTS radar processor computing environment through a cost effective tech-refresh program. The objective is for maintainability and supportability improvements to result from an improved maintenance system, which is centered on a more intuitive and interactive Built-in-Test (BIT), embedded technical data and embedded maintenance and operator training. The maintenance system is integrated with a Technical Integrated Digital Environment (TIDE) that stores and makes available all radar technical, engineering and logistics data; facilitates remote monitoring and distance support; and ensures accurate and timely configuration management. The training curriculum, supply support and maintenance philosophy aspects of the AN/SPS-48G program were changed correspondingly with implementation of the system. Training is now delivered in a two-week course, which is reduced from twenty-one weeks for the AN/SPS-48E, and consists of eleven concentrated training days developed, delivered and maintained by the In-Service Engineering Agent (ISEA). Time is split between instructor-led, classroom discussions (38%) and hands-on lab (62%) with technical training equipment in a simulated work center environment. The curriculum covers radar component functions, system operation, preventive and corrective maintenance and safety; and reinforces basic electronics and radar training received at advanced technical training and Class A schools.
 
Features
The AN/SPS-48G radar is employed on U.S. Navy ships and provides 3D volume air surveillance. Once installed on the ship, the radar is no longer transportable and becomes shipboard permanent equipment until removed. The radar is integrated with a track management system, such as the CEC or the AN/SYS-2 Integrated Automated Detection and Tracking system, to provide air search information to the Combat Information Center watch team.

The radar set is comprised of 30 individual units that combine to form four major functional areas: Transmitter, Receiver/Processor, Antenna and Ancillary. These functional areas combined with computer software components provide the key radar hardware and system parameters described below.

The processor functional area utilizes a digital receiver to provide filtering and decimation of nine independent time aligned beams of narrowband digital data processing described in the key parameters paragraphs below.

The antenna, Unit 14, is comprised of two separate antennas: main and reference. The main antenna radiates radio frequency (RF) and receives return RF in a beam pattern whose position is determined vertically by its radiated frequency and horizontally by mechanical position of the antenna. As system RF is being routed to the main antenna it passes through two RF filters: Unit 48, a high pass filter and Unit 47, a band pass filter. These filters eliminate amplified harmonics from being radiated into the atmosphere. The reference antenna is used to sample the RF noise level existing in the radiating environment.

The processor supports contact processing rates of non-coherent and coherent detections per 4-second scan. Doppler filtering is utilized to make coherent detections. The radar has been designed to function in two separate scan modes: Low Elevation (LOW-E) and Equal Angle Coverage (EAC) mode. LOW-E is designed to detect and track low flying anti-ship missiles utilizing Moving Target Indicator (MTI). EAC mode is designed for high angle volume search and to track both high and low altitude targets. Either scan mode can be selected for all 360 degrees in azimuth coverage (Background Mode) or can be entered as scan mode gates in sectors not smaller than 5.6 degrees and as large as 360 degrees.
 
Background
The AN/SPS-48E variant of the radar was originally developed as part of the New Threat Upgrade (NTU) Program onboard destroyers to support the SM-2 Launch On Search capability by providing accurate and precise position data, allowing mid-course guidance of missiles fired from own ship or (under some circumstances) fired from other ships. Beginning in FY93, refurbishment of decommissioned assets replaced procurement of new AN/SPS-48E Radars and began installations onboard CVN, LHA and LHD ship classes. The AN/SPS-48E Radar was developed under the Navy Decision Coordinating Paper, SO-188-AA/SO-964-AA of 24 February 1981, which identified a requirement to upgrade the AN/SPS-48C Radar for the NTU Program.

The AN/SPS-48G Program, referred to as Radar Obsolescence and Availability Recovery (ROAR), is a Reliability, Maintainability and Availability (RM&A) improvement to the AN/SPS-48E Radar that resolves known system readiness issues and addresses Unable to Procure concerns throughout its extended lifecycle. The RM&A and Operating & Support Cost improvements for AN/SPS-48G allow it to be supported in the Fleet through 2050 and beyond with a performance equivalent to that of the AN/SPS-48E.

AN/SPS-48G kits are produced by Exelis, Inc., A Wholly Owned Subsidiary of Harris Corporation (Formerly ITT Gilfillan) under a Fixed Price plus Incentive Fee contract. Refurbishment of the AN/SPS-48E components is completed by Exelis, Inc. under a CPFF/FFP NAVSEA Basic Ordering Agreement contract. Both contracts are covered under the AN/SPS-48 Radar Acquisition Plan (AP) #94-003 (Revision 8 approved July 14, 2014). The AN/SPS-48G unique components passed MIL-S-901D shock and environmental testing.
 
Point Of Contact
Office of Corporate Communication (SEA 00D)
Naval Sea Systems Command
Washington, D.C. 20376
 
Last Update: 24 January 2017