viernes, 14 de enero de 2011

Desarme británico: ¿Qué pasa con las Tipo 45?

¿Los destructores tipo 45 son un arma de temer o son un fiasco? 
Por Luis Domobranec

Muchas veces afirmé que los nuevos destructores tipo 45 de la Royal Navy no eran, al menos por ahora, armas de temer. Más allá de los problemas de propulsión que tuvo el HMS Daring en fecha reciente, el sistema de misiles Sea Viper, el principal arma del tipo 45 deja algunas dudas que desearía analizar. Como no soy especialista en el tema radares, quisiera que esto fuera el principio de un debate y no la expresión final de una mera opinión personal.

Enumeremos los componenetes del Sea Viper:
 

PAAMS components 

• PAAMS (S) — British variant with SAMPSON Multi-Function Radar (MFR) 
• PAAMS (E) — French/Italian variant with EMPAR Multi-Function Radar 
• Automatic Command and control system 
• Consoles running Windows 2000 operating system 
• SYLVER vertical missile launcher 
• MBDA Aster missiles 
o Aster 15 - Short range 
o Aster 30 - Medium to long range 
Both variants of the PAAMS operate in conjunction with the BAE Systems Insyte/Thales S1850M Long Range/Early Warning Radar” 

Desde mi punto de vista el talón de Aquiles del sistem es el radar SAMPSON, significativamente adoptado por los británicos, pero no por los franceses e italianos, que como se puede leer optaron por el EMPAR.

Veamos las características del SAMPSON:
 

“Conventional radars, consisting of a rotating transmitter and sensor, have limited power, are vulnerable to enemy jamming and perform only one function - with separate units therefore required for surveillance, tracking and targeting. 
As an active array, SAMPSON uses software to shape and direct its beam allowing several functions to be carried out at once and, through adaptive waveform control, is virtually immune to enemy jamming. Active arrays have both longer range and higher accuracy than conventional radars. 
The SAMPSON uses two planar arrays to provide coverage over only part of the sky; complete coverage is provided by rotating the arrays, essentially similar to the way conventional radar systems operate. This is in contrast to the US AN/SPY-1 system (as used on the Ticonderoga class cruiser and Arleigh Burke class destroyer) or the Dutch/German/Canadian APAR system (as used on the Royal Dutch Navy's De Zeven Provinciën class frigates, the German Navy's Sachsen class frigates, and the Royal Danish Navy's Ivar Huitfeldt class frigates), which use multiple arrays fixed in place to provide continuous coverage of the entire sky. Whilst this may seem to be a disadvantage, the SAMPSON radar rotates at 30 revolutions per minute, meaning no part of the sky lacks coverage for more than one second on average - the precise time varies as the beams can also be swept back and forth electronically. In addition, the use of a smaller number of arrays allows the system to be much lighter, allowing placement of the arrays at the top of a prominent mast rather than on the side of the superstructure as in the US ships. Placing any radar emitter at higher altitude extends the horizon distance, improving performance against low level targets; SAMPSON is at approximately double the height above the waterline than the arrays of its US equivalents. Although precise details of the SAMPSON's performance in this regard are unlikely to enter the public domain, such factors may mitigate the disadvantages of fewer arrays. 
BAE Systems have also claimed that Sampson eliminates the need for several separate systems. They suggest that on the Type 45 destroyer, the Alenia Marconi Systems/Signaal [now Thales Nederland] S 1850M long-range 3D radar that is designed to work in partnership with Sampson "really is superfluous and is not needed to perform the mission of the ship". BAE Systems believes that the reason the large volume search radar has been incorporated in to PAAMS is "more of a historic nature, associated with [the] work sharing issues" that were a huge problem during the trilateral Project Horizon. 

Some tasks are difficult to combine, for example (long range) volume search takes a lot of radar resources, leaving little room for other tasks such as targeting. Combining volume search with other tasks also results either in slow search rates or in low overall quality per task. Driving parameters in radar performance is time-on-target or observation time per beam. This is perhaps a the [sic] key reason why the Royal Navy selected the S1850M Long Range Radar to complement Sampson on the Type 45 destroyers. It is also a reason why NATO in its NATO Anti-Air Warfare System study (NAAWS) defined the preferred AAW system as consisting of a complementary Volume Search Radar and MFR. This - as NATO points out - gives the added advantage that the two systems can use two different radar frequencies; one being a good choice for long range search, the other a good choice for an MFR (which is especially nice as physics makes both tasks difficult to combine).[5] 
The performance of both the SAMPSON radar and the PAAMS' Aster missiles will give the Royal Navy an anti-air warfare capability to replace its long serving Type 42 destroyers. The first Type 45, HMS Daring was launched on February 1 2006. The ship was fitted with SAMPSON and S1850M radars in 2007. She underwent trials before being commissioned in July 2009.” (de Wikipedia) 

Como se puede leer, el radar de barrido electrónico SAMPSON, según su fabricante, puede cumplir las funciones que en otros buques cumplen al menos dos radares, cuando no todo un sistema de radares y controladores de tiro.
Así y todo los británicos agregaron al mismo otro más, “por razones de naturaleza histórica”
 

Los misiles Aster 15 y Aster 30 son guiados por el radar del buque que los lanza, aunque no hay plena coincidencia respecto a eso en las diversas fuentes:

En Wikipedia se dice:
 

“The shipboard radar fulfills roles of sentry, meteo, target discrimination, acquisition and chase. It is capable of simultaneously tracking 300 flying objects, discriminating around 60, and guiding up to 16 missiles.” 

En DEAGEL.com leemos: 

“Until mid-course the guidance of an ASTER missile is based on the Inertial Navigation System (INS) updated through an uplink, in the terminal phase the guidance is provided by an active Radiofrequency seeker. The final stage of the ASTER missile is a "dart" equipped with the seeker, a sustainer motor, a proximity fuze and a blast fragmentation warhead. “ 

Sea como fuere vayamos a los hechos. A continuación se enumera un listado de pruebas exitosas de los Aster: 

Combat performance 

As of April 2008, the Aster has never been used in actual combat. 
During trials, between 1993 and 1994, all flight sequences, altitudes and ranges, were validated. This was also the period during which the launch sequence of Aster 30 was validated. 
In May 1996, trials of the Aster 15 active electromagnetical final guidance system against live targets began. All six attempts were successful: 
• 8 April 1997: interception of a C22 target simulating a subsonic antiship missile, flying at 10 metres, at a distance of 7 kilometres. 
• 23 May 1997: Direct impact on an Exocet anti-ship missile of the first generation, at 9 kilometres, to protect a distant ship (7 kilometres). 
• 13 November 1997: interception of a C22 target in very low flight in a strong countermeasures environment. In this test, the Aster was not armed with its military warhead so that the distance between the Aster and the target could be recorded. The C22 was recovered bearing two strong cuts due to the fins of the Aster missile. 
• 30 December 1997: Interception of a live C22 target by an Aster 30 at a distance of 30 kilometres, an altitude of 11,000 metres, and a speed of 900 km/h. The Aster climbed up to 15,000 metres before falling on the target at a speed of 2880 km/h. The closest distance between the Aster and the C22 was four metres. 
• 29 June 2001 : Interception of a Arabel missile in low altitude, in less than five seconds. 
• In 2001 : Interception by the Aster 15 of a target simulating an aircraft flying at Mach-1 at an altitude of 100 metres. 
• In 2002-2003 : Trial of Aster 15 from Sylver A43 launcher with EMPAR and SAAM-it system onboard Italian experimental ship Carabiniere F 581 
• In 2004-2005 : Trial of Aster 30 from Sylver A50 launcher with EMPAR and PAAMS(E) system onboard Italian experimental ship Carabiniere F 581 
• On 3 April 2008, the Republic of Singapore Navy frigate RSS Intrepid shot down an aerial drone off the French port of Toulon during an exercise. 

Sólo en los tres últimos ensayos se dice qué radar se utilizó: el EMPAR en el caso de los italianos, y si bien no se menciona cual es el radar de la RSS Intrepid, el mismo es el Thales Herakles.

Sabemos sin embargo que los británicos hicieron sus propias pruebas. Los resultados de las mismas fueron los siguientes:
 

Testing 
During its first major warfare sea exercise aboard HMS Daring the ship's Combat Management System crashed while under simulated air attack due to a power failure. The ship lost use of its combat management system, i.e. PAAMS. The ship's crew reverted to use of binoculars to spot incoming airborne threats until the CMS had been restarted.[4] 
In 2009 two test firings of PAAMS in the British (Sea Viper) configuration from the Longbow trials barge failed due to "failures in the terminal phase of the engagement." It is believed that "production weaknesses" of Aster 30 missiles were to blame.[5] The first live firing by a Type 45 destroyer is planned for late 2010.[5] 
On 29 September 2010 the Type 45 destroyer HMS Dauntless successfully identified, tracked and engaged a target drone with the Sea Viper system while at sea. Previously to that the longbow barge had also successfully fired a salvo of Aster 30 missiles at another target drone moving at high speed.[6] 

En la primera prueba - fallida – se dice que el buque perdió el uso de su sistema de gestión de combate, es decir, del PAAMS, sin especificar cuál de sus componenetes.
Se dice sin embargo que la tripulación recurrió al uso de binoculares…

En la segunda prueba se dice que la falla se dio en la fase final de “enganche” del blanco, debido a una “debilidad de producción” (sic) en el misil Aster 30.
Curiosamente no encontre datos de tales fallas en pruebas hechas por otros países.

En la última – y única – prueba exitosa un misil Aster 30 impactó en un dron que se movía a “velocidad elevada”. El Sea Viper nunca fue probado contra un blanco moviéndose a velocidad supersónica.

Para finalizar cito un fragmento de una nota ya publicada en este capítulo dedicado a la Royal Navy:
 

Post de FDRA 

“The UK Public Accounts Committee went so far to describe the missile-system, named "Sea Viper" in British service, as "disgraceful" in 2009 ... and that was before the most recent test failure. However the flaws in the Aster missiles are now reportedly rectified and successful firings have since taken place. The UK Ministry of Defence expects to declare its first Sea Viper system operational next year: until then, the Type 45 destroyers will continue to be almost unarmed, able to employ only basic guns and cannon.*” 

Traduzco el primer renglón: “El Comité de Cuentas Públicas del Reino Unido llegó a decir que el uso del sistema de misiles Sea Viper por parte del Reino Unido era un escándalo.” 

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