Major capability lift for Anzac class

The Navy's Anzac-class frigate upgrade presents the Navy with an interesting choice - much will depend on its assessment of the risks and returns inherent in the competing solutions.
It may be that the lengthy delays that have smitten the ASMD program - aside from frustrating those itching to get on with the job - may have also been a major blessing in disguise. Thanks to advances in radar technologies that have occurred in the interim, the Anzac class may well benefit from new capabilities that were not under initial consideration.

And the procrastination has been nothing short of extraordinary. The ASMD upgrade was deferred pending the findings of the 2003 Defence Capability Review and its revised budget went unapproved until the end of 2003 when the Government announced funding approval. However further delay ensued and it wasn't until April 2005 that a Project Alliance Agreement was negotiated and executed with the ANZAC Ship Alliance under a $260 million contract to implement the Phase 2A high priority aspects of the upgrade.

These high priority aspects include an infra-red search & track system for improved detection of low level aircraft and incoming missiles, an upgrade to the ships's 9LV Mk 3E combat management system to match the functionality of the new equipment and increase its data processing capability, and an upgrade to the SPS-49 surface search radar to improve its small target detection capability.

We now understand that since funds became available contract negotiations with the supplier of the selected IR&ST system began almost immediately and it is anticipated that by the time this article is published Defence Minister Hill will have announced which system was selected. As we have indicated previously there were only two serious contenders, Sagem's Vampir and Thales' Sirius systems and it is widely anticipated that the Vampir will be installed in the Anzac class. The upgrade of the 9LV combat management system to the Mk 3E level has been developed locally by Saab Systems Australia.

Since the decision to acquire a second conventional fire control radar, providing the all-important second channel of fire, now had to be considered against a phased array solution, this requirement, together with the Very Short Range Air Defence (VSRAD) capability were set aside for further consideration under Phase 2B. This phase also included the possibility of equipping some or all of the Anzac ships not only with the phased array illuminator (CEA-MOUNT) but also with the CEA-FAR active phased array 3D surveillance radar, dependant on the results of trials and risk mitigation studies carried out under Phase 2A.

Phase 2B phased array radar opportunities
It is now common knowledge that under Phase 2B, two options are being prepared for government consideration. Presumably, in view of the successful outcome of the trials and studies, the first is to equip all eight Anzac ships with the CEA-FAR active phased array surveillance radar and a modified CEA-MOUNT fire control illuminator.

The other option is to install a second conventional fire control radar together with the VSRAD system - MBDA's Mistral 2 in its naval TETRAL form is a certainty - to provide an additional layer of air defence in view of the limited channels of fire available, compared to the multiple channels offered by the CEA-MOUNT (thus discounting the possibility of 'leakers' getting through). TETRAL can also be cued by the IRST where conditions and circumstances require.

Despite this project's extensive delays, which have necessitated cost revalidation by equipment suppliers, risk mitigation studies undertaken during 2004 have allowed the project to proceed within current approved funds ($516 million) and maintain the planned delivery date of 2008. However if the phased array radar option is chosen--which we understand is the Anzac Alliance's preference-initial operating capability will slip to 2009. Neither option will exceed the Phase 2 budget.

Should a non-phased array radar option be approved the upgrade will be implemented ship-by-ship. If the PAR option is approved, then the upgrade will be implemented ship-by-ship in stages of increasing capability. The final ships will receive the full capability and the earlier ships will be progressively upgraded during scheduled maintenance availabilities.

The S-band CEA-FAR radar design is based upon a modular tile and panel active array concept. The active array comprises a number of static faces usually six, to provide 360-degree surveillance. Each array face is made up of a number of panels and by increasing their number the performance of the radar is increased.

For the maritime trial aboard HMAS Arunta, four faces were fitted, two on each side forward of the mast. Normally six faces are preferred but the four used were more than sufficient for the trial. The number of signal processors used with CEA-FAR can be configured from one shared by all faces to one for each face. This allows the scan time to be significantly improved by the parallel operation of the faces for most modes.

The most significant advantage of the six faces is the low degradation of the beam pattern and gain as the beam scan angle approaches the edge of the face coverage. For an ESSM equipped Anzac frigate expected to operate in a complex air threat environment, a CEA-FAR radar would consist of six faces of eight panels and multiple signal processors.

>From a practical viewpoint the array could also be split into forward and aft sections to provide all round unimpeded visibility. This also reduces the potential for battle damage or system failure to knock out the entire radar. If half of the six-face CEA-FAR antenna is lost the other three continue working. This division of capability into forward and aft zones--the two-island concept--is a feature of the B+V MEKO D-200 frigate and the MEKO X 8,000 tonne future surface combatant concept designs.

The CEA-FAR configuration for the Anzac ship might well comprise six faces located at the top of the main mast in place of the present Target Indication Radar, and underneath these, multiple CEA-MOUNT illuminator faces, mounted to provide 360-degree surveillance.

Technical features of the CEA-FAR radar, which set it apart from conventional radar technology, include:

* no external cooling for the array faces

* no waveguides in the entire system

* array faces need not be collocated and can be distributed around the ship

* the ability to automatically detect and classify air targets

The X-Band CEA-MOUNT is an active phased array missile illuminator based on the technology concepts of the CEA-FAR radar applied to a transmit-only array. It has been designed as a slaved illuminator to meet the guidance needs of the semi-active homing ESSM and SM-2 family of missiles. It is able to engage multiple simultaneous targets and provide uplink with flexible beam management over a broad azimuth and elevation sector from each face.

The CEA-MOUNT system proposed for the Anzac class is a medium range version matched to the Evolved Sea Sparrow Missile (ESSM). Key operational advantages are that the Illuminator face provides multiple missile channels of fire and far higher availability and redundancy than current missile fire control systems. However, CEA-MOUNT is also designed for SM-2 compatibility, supporting all guidance modes.

Endorsement of the active PAR option for the Anzac class will endow the ships with surveillance and search and track capabilities beyond anything anticipated when the class was first introduced. It will also provide a welcome boost to the indigenous systems' exportability, particularly for the range of frigates now joining the ESSM club.

Interestingly, the Anzac fleet will boast more advanced active phased array radar systems than the new air warfare destroyers, whose venerable Aegis combat system includes a passive SPY-1 radar system. RF expert Fred Haddock points out that SPY-1 uses a below decks TWT-based RF source and the RF energy is
He says active systems generate RF at the antenna in a multitude of solid state transmit/receive elements under computer control, the number of elements being a function of the performance requirements of the radar. This method of generating RF power is much more efficient and the radar is much more immune to battle damage than one having a complex waveguide configuration.

Perhaps we shall see SPY-1 eventually replaced by an S-band radar with family links to the Australia-United States AUSPAR development.

By Tom Muir, Canberra