The CAMM vision emerged from studies undertaken by MBDA five years ago to examine future ground-based air-defence (GBAD) requirements for the replacement of the UK's current Rapier and Starstreak short-range air-defence (SHORAD) systems. "It was realised that this would entail reasonably substantial costs but only deliver benefits in one area," says Dr Miller. "So we began to look across domains to assess whether other air-to-air and naval point-defence requirements could be 'collectivised' in a largely common missile."
Out of this came CAMM, a concept for a tri-service air-defence missile and associated weapon system that could replace the ground-based Rapier SHORAD system and the Royal Navy's Seawolf point-defence missile system, and additionally provide technology insertion opportunities for an evolution of the Royal Air Force's Advanced Short-Range Air-to-Air Missile (ASRAAM).
The naval and land-based threat sets, while not identical, have significant overlap. In the naval domain there is a requirement to defeat increasingly stealthy, low-flying anti-ship missiles approaching at both subsonic and supersonic speeds. There is also a need to counter high-performance combat aircraft, helicopters, unmanned aerial vehicles (UAVs) and small surface craft.
On land the threat is characterised by attack helicopters, UAVs, standoff weapons and manned strike and close-support aircraft. A capability to interdict land-based targets of opportunity has also been studied, although it is acknowledged that this should come at no cost to the core air-defence capability.
The solution, as it exists today, is an all-weather, local-area defence missile system that embodies selected new technologies and techniques in the missile round and its launch sequence, while maximising use of, and integration with, legacy components as appropriate. What is more, the missile itself would be common for both shipborne and land-based applications.
"As well as addressing the UK's capability requirements for future land-based and naval anti-air weapons, the MoD was attracted by a common approach that could offer significant benefits in terms of cost of ownership," says Dr Miller.
The MoD committed approximately GBP10 million (USD20 million), through the Joint Sensor and Engagement Networks Integrated Project Team, to seed the CAMM programme under a three-year technology demonstration programme (TDP01) that began in late 2004. MBDA UK has in turn contributed about GBP4 million to this first phase.
The need to drive out cost has underpinned the CAMM engineering approach and system architecture. "We needed to understand the legacy cost drivers in terms of procurement, use and support," says Dr Miller, "and then look hard at how we attack these big cost areas."
These costs are not just associated with the production of the missile in isolation. "We took cognisance of the wider weapon system architecture," explains Dr Miller. "On board a frigate, for instance, that includes the integration of the weapon system with existing radars and combat management system infrastructures. So we identified early on the need for CAMM to be able to integrate with these legacy combat system components.
"Another driver was to avoid having to have regular inspections of the missile. Our aim is to have an all-up-round that has a shelf life of 10 years or more inside its storage and firing canister," says Dr Miller.
The tail-guided missile round itself, a little over 3 m in length and 166 mm in diameter, shows a clear lineage from ASRAAM and incorporates a number of subsystems pulled through with relatively minor changes from that weapon. These include the low-signature solid rocket motor (Roxel); the laser impact/proximity fuze (Thales); and the blast fragmentation warhead (MBDA TDW).
Key technologies
TDP01 has seen focused investment in critical technology areas: notably a low-cost active radar seeker, a dual-band two-way datalink and an open-architecture internal communications bus. In addition, a programme of hardware-in-the-loop (HWIL) integration has been conducted at the CAMM integration facility set up at MBDA's Stevenage site. Dr Miller says these critical 'breakthrough' technologies have now been matured to Technology Readiness Level 5-6.
He identifies the new active radar seeker as key to achieving both the cost and performance targets demanded of CAMM. "Present-generation active radar seekers are very complex electromechanical devices. The CAMM seeker reduces the level of electromechanical complexity - the moving part on the gimbal is very simple.
"Instead, the high-end performance required is achieved through complex algorithms and waveforms. It is essentially a software-driven seeker that has the additional advantage that new software-based functionality can be easily introduced through life."
MBDA's seeker group has in fact been working on this technology for more than a decade and believes it represents a significant leap forward in seeker architecture with applications extending far beyond CAMM. The same is true of the datalink, characterised as a low-cost, dual-band low-probability-of-intercept system, which will provide for two-way communications between the missile and the firing control unit (uplinked messages being sent via a dedicated transmitter group).
The other 'breakthrough' technology refined and matured through TDP01 is an open system architecture that enables the various electronic subsystems within the missile to interface and communicate via a standard bus. Known as PrOTeUS (Programmable Open Technology for Upgradable Systems), this is another generic technology that has been the subject of joint MoD and MBDA research for some time, but its maturation has dovetailed neatly with the CAMM programme.
"PrOTeUS essentially gives the missile designer far more freedom than before by using a standard commercial bus to exchange message traffic between the electronics units," Dr Miller says. "It means we can build up the prototype missile in the lab using available COTS [commercial off-the-shelf] technology, and then use exactly the same technology in the real missile rather than have to totally redesign the architecture as before.
"Currently we have baselined on IEEE 1394 Firewire technology," he adds, "but the approach is inherently adaptable to enable change as bus technology evolves."
Another innovative concept embodied in CAMM is that of 'soft vertical launch' (SVL), whereby the missile is ejected 'cold' from its launch canister prior to main motor ignition. The base of the launch canister, containing a gas charge and piston, is effectively a low-pressure gun barrel that ejects the missile upwards to an altitude of 80-100 ft. As it ascends, the missile orientates itself by means of firing small tail-mounted thrusters mounted just aft of the fin surfaces, to steer the round through its turnover manoeuvre before the main motor is fired to begin powered flight.
SVL is seen to offer a multiplicity of benefits: safety is improved because there is no efflux to manage; there is no risk of a hang-fire; the shipboard footprint is much reduced; and there is a significant performance benefit from having all of the rocket motor's energy expended efficiently in the direction of intended travel.
A series of hardware demonstration trials, performed by MBDA in 2002 under an earlier TDP jointly funded with the MoD, have proved the underpinning technology. These culminated in a proof-of-principle test conducted using ASRAAM-based missile hardware (using a cut-down motor to meet range safety limitations) and a representative box canister.
"CAMM canisters could be quad-packed to fit in an existing Sylver or Mk 41 vertical-launch cell," says Dr Miller. "Alternatively we can offer the option of fitting the SVL launch canister in small standalone clusters or patterns that best suit the deck area and topside characteristics of the host ship.
"As for land-based applications, we have already conceptualised a mobile configuration based on a 4-tonne flatbed truck. This would have 12 rounds [in two sets of six] stowed flat for transport and then erected for launch."
One area where the CAMM weapon system seeks to maximise the re-use of existing technology is in its command-and-control segment. "As far as possible we will re-use threat evaluation and engagement control functionality previously developed by MBDA for the UK variant of the Principal Anti-Air Missile System [PAAMS]," says Dr Miller, "modifying or 're-tuning' the PAAMS algorithms as necessary to match the CAMM missile performance envelope."
TDP02 plan
TDP01 achievements included seeker radio-frequency (RF) chamber and outdoor trials, outdoor testing of the datalink and laboratory proving of the PrOTeUS open architecture. These hardware demonstration and proving activities culminated in a programme of HWIL testing at the CAMM integration facility. Here, critical subsystems - the inertial measurement unit, electronics processing unit, control fin actuator, seeker and datalink communications - were progressively integrated on the bench and 'flown' in both naval and ground-based air defence 'environments' within a high-fidelity synthetic environment.
The MoD is now committing almost GBP15 million to a second phase of technology demonstrations (TDP02), intended to further mature and validate critical CAMM technologies. This programme, extending through to early 2011, will include captive airborne seeker trials (due to commence aboard an Andover testbed aircraft at the end of 2008), the manufacture of flightworthy subsystems, a mid-course guidance firing and further soft-launch trials.
"We have reached a very high state of maturity in the pre-demonstration and manufacture phase, performed successful early HWIL trials and pulled through customer-funded research efforts," points out Dr Miller, adding: "Many of the technologies embodied are ones that the MoD had picked out some years ago, showing the relevance of this long-term research. What we are now doing is leaving the research phase and transitioning into what I would call system definition as a precursor to full-scale engineering development.
He adds: "The CAMM vision for a single common missile for both the naval and land customer remains intact. Indeed, our evidence suggests that a single missile/single warstock is entirely feasible."