Dealing with the Threat of Cruise Missiles

Dennis M Gormley

• Publisher: Routledge
• Year: 2013
• ISBN:
  9781136048081
• Edition: 1
• Topic: History
• Subtopic: Military & Maritime History
• Index: History

How can the core transatlantic Allies make coalitions more effective? One year on from Kosovo, disparities in the capabilities of the coalition partners, as well as uneven levels of prior coordination, persist. To address these problems will require much greater force planning in peacetime.

This stimulating and influential work offers one of the most comprehensive independent assessments to date of the Kosovocampaign, and of the performance of the NATO allies. An important subject area in which there is a great deal of international interest.

Chapter 1

Technological Challenges of Acquiring LACMs

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Growing concern over the proliferation of LACMs is largely driven by the quantum leap in technologies underlying their development. A week before Christmas 2000, an article on the Internet stated that the US intelligence community was concerned that Iraq might have acquired some 4,000 Sony PlayStation 2 video games.¹ This report, of course, became the subject of parody on American television's Jay Leno Show, but it does have its serious side. Each PlayStation 2 contains a 300 MHz, 128-bit processor, plus a graphics package five times more powerful than today's typical graphics workstation. The intelligence community's concern was that a bundled configuration of 12–15 of these units provides enough computer power to control the flight of a UAV. Iraq is believed to have transformed a number of Czech L-29 training aircraft into UAVs capable of delivering a payload of 200kg from a distance of over 600km.²

Facetious or not, the story exemplifies the simple truth that the commercial marketplace has dramatically altered the non-proliferation setting that faces today's security planners. Indeed, even comparatively primitive computer technology, like an Intel 486-class chip, equipped with 16Mb of random-access memory (half of one PlayStation 2's RAM) and a 1Gb hard drive, is sufficient to act as a modern cruise missile's flight-management computer: the hub of its crucial navigational controls.³ Over and above the dramatically increased and miniaturised computing power, it is the widespread availability of cheap guidance, navigation, high-resolution satellite imaging and digital mapping technologies that is most responsible for raising the prospect of cruise-missile proliferation.

Key Enabling Technologies

The first cruise missiles were adapted from drones or manned aircraft and, like today's modern designs, consisted of four major parts: airframe, payload, guidance and propulsion. Guidance and propulsion represent the two major barriers to the spread of LACMs. Early designs used standard liquid-fuelled aircraft engines and autopilots for guidance and control. Later on, command guidance schemes and, more broadly, inertial navigation systems (INS), replaced autopilots, and solid propellants and air-breathing engines (turbojets at first) largely supplanted liquid-propelled engines. But the long flight times of these early cruise missiles meant that INS accumulated operationally unacceptable navigation errors, resulting from inertial drift, wind and thermal up-drafts, and did not permit cruise missiles to fly low, evading terrain obstructions, and thereby avoid enemy radar detection and active defences.

Around 1970 these problems were ameliorated with the development of a new guidance technology known as terrain contour matching (TERCOM).⁴ This uses miniature radar in the missile's nose to sense the terrain over which it is flying and compares it with mapping data stored in the flight-control system. TERCOM thus provides course corrections that permit more accurate delivery of the missile's payload and facilitates very low-level flight to help the missile avoid enemy air defences. An even more sophisticated guidance scheme – digital scene-matching area correlation (DSMAC) – has subsequently further improved cruise-missile accuracy. These developments ushered in a plethora of new types of cruise missiles, notably the US Tomahawk.

So long as TERCOM and DSMAC represented the state of the art, there were three important barriers to proliferation. First, the functionality of these technologies depended on maps derived from highly classified overhead reconnaissance satellites. Second, developing a dedicated mapping infrastructure was prohibitively expensive. Third (and perhaps most important) TERCOM and DSMAC were subject to strong export controls.

New Proliferation Vulnerabilities

Guidance Systems

The advent of the Global Positioning System (GPS) has had the most profound effect: it has reduced the primary technical barriers to entering the LACM business.⁵ When conceived by the US military after the Vietnam war, GPS – formally known as Navigation Satellite for Time and Ranging (NAVSTAR) – was intended only for military customers, primarily for the straightforward purpose of helping soldiers, sailors and airmen keep their bearings and avoid enemy detection. The $5bn system (the largest constellation of military satellites yet deployed) consists of 24 primary and four spare vehicles operating in six different polar orbital planes approximately 20,200km high. This positioning ensures that users on the earth can observe at least six satellites at any given time. Signals from three satellites are needed to achieve a precise two-dimensional position, while four satellites are required for a three-dimensional fix; receipt of signals from more than four satellites only increases the accuracy of the fix.⁶

Military uses of GPS abound. The Gulf War offered the US military a showcase for several GPS applications, when over 9,000 hand-held units, most of them commercially acquired, were distributed to US units. While Iraqi units were operating blindly in the featureless desert, US units gained great advantage from navigating accurately. GPS permitted the plotting of safe lanes through minefields and effective registration and aiming of artillery and rocket fire. Since the Gulf War Tomahawk cruise missiles have been upgraded with GPS receivers, obviating dependence on expensive satellite imagery data and lengthy mission-planning cycles. Moreover, as demonstrated in the Kosovo air campaign, the US has transformed unguided free-fall (dumb) bombs into highly lethal ‘smart’ weapons by including a low-cost integrated INS/GPS guidance kit in the Joint Direct Attack Munition (JDAM).⁷

After the Soviet destruction of Korean Air Lines Flight 007 over the Kamchatka Peninsula in 1983, President Reagan decided to make GPS widely and freely available globally, to help to avoid future air disasters. Since then civilian applications of GPS have grown in fits and starts. In 1990, the US Department of Defense instituted a policy of ‘selective availability’, intentionally inserting subtle errors into the GPS code used by civilians. Ways to work around selective availability quickly developed, however. The technique known as Differential GPS (DGPS) uses ground-based radio beacons to correct for errors, often producing navigational fixes better than those provided by the Pentagon's restricted code. Thus, in May 2000, President Clinton ended the selective availability programme, and civilian GPS receivers, once accurate to within 100m, can now operate typically at about 15m.

Russia also has deployed a GPS-equivalent called Global Navigation Satellite System (GLONASS).⁸ The commercial market has created integrated GPS/GLONASS receivers that in tests by Honeywell and Northwest Airlines have shown positional fixes with accuracies consistently under 20m. Using combined GPS/GLONASS receivers to guide cruise missiles minimises degradation in GPS signal quality or accuracy. The low-cost commercial availability of INS with GPS or GLONASS allows developing nations to leap ahead roughly 15 years in navigation development with a single purchase.⁹

Commercial satellite imagery, though less consequential to proliferation than GPS, still is an important enabling technology for LACMs. A new generation of non-military observation satellites has begun to offer imagery products with performance characteristics that greatly exceed the US Landsat and French SPOT satellite systems. Imagery with a spatial resolution of less than 5m is now widely available. And, due to a US presidential decision in March 1994 that broadly reduces export controls on the sale of previously highly classified spy satellite technology and products, over the next few years several commercial satellites will begin to offer imagery with a resolution of 1m. Such commercial satellites will not deliver imagery as quickly as military reconnaissance systems do, but this will not limit their utility for supporting the targeting of LACMs – this can be accomplished in methodical fashion well before missiles are ever employed in combat.¹⁰

GPS and new commercial satellite imagery together can enhance mission planning for cruise missiles. Using an integrated GPS/INS approach to guiding a cruise missile obviates the need to make the detailed digital maps that TERCOM mission planning demands. On the other hand, most countries interested in cruise missiles for land-attack missions will want to improve the weapons' penetration and survivability by flying very low routes to the target, especially during the terminal phase of flight. Sophisticated Western aircraft employ expensive terrain-avoidance radars for this purpose, but these are not needed if accurate terrain elevation data can be programmed into the cruise missile in advance. Commercial products for such mission-planning tasks are now readily available; they consist of high-resolution imagery of the expected route to the target area, DGPS data and geographic information systems (computer hardware and software) that permit integration of GPS data into map products.

Indeed, assuming that an adversary could collect highly accurate DGPS positional data on major reference features en route to prospective targets (which requires physical access to these ‘way points’), a TERCOM-like guidance system for intermediate and terminal guidance – all without depending on GPS or GLONASS updates – appears feasible. DGPS positional data, collected in peacetime, would be added to digitised satellite imagery to create a pre-programmed strip map used in conjunction with a radar altimeter to guide the cruise missile to its intended target.¹¹ It is important to keep in mind that the biggest difficulty in developing the TERCOM guidance technique has much less to do with the technological sophistication of TERCOM itself than with the mapping infrastructure it needs. This extensive and costly infra-structure stemmed from the US need to plan for a wide variety of world-wide contingencies, including thousands of different targets. By comparison, a regional power's requirements would more likely be confined to a much smaller target set for cruise-missile strikes.

Propulsion Systems

Whereas all the key enabling technologies for cruise-missile guidance and control are now readily available, those for advanced propulsion systems are not. It remains difficult for regional powers to manufacture or acquire gas-turbine engines required for LACMs with ranges above 300km.¹² China, for example, has produced the WP-11 turbojet engine for its HY-4 ASCM, but has had to rely on Russian technical support to produce advanced turbofan designs.¹³ Such countries as India, Israel, South Africa and Taiwan are currently developing small turbojet engines that produce high thrust levels at the expense of fuel efficiency, and these could conceivably support cruise missiles capable of ranges up to 1,000km. For the foreseeable future, though, the manufacture of highly advanced turbofan designs is likely to remain limited to the US and Russia.

That does not mean, however, that advanced turbofan engines cannot be acquired for cruise-missile applications in relatively small lots. The Williams turbofan engine that powers the US Tomahawk cruise missile is export-restricted. But Williams also produces the FJ-44 and the newer FJ-44-2, civil versions of its military counterpart, for use in such commercial aircraft as the Cessna Citation and others. These versions produce a thrust that places them just outside the control of the MTCR.¹⁴ Eventually, therefore, perhaps as many as 200 used Williams turbofan engines could become available for purchase in the surplus market. Although such advanced engine designs will not be available in large numbers, prospective proliferators could use other unrestricted turbojet engines produced by Britain, France, China, Russia, Japan, Canada and several other countries. In fact, the most widely proliferated turbojet engine is likely to be the one that propels various versions of the US-exported Harpoon anti-ship missile, which has already been transferred to 23 nations in Europe (including NATO allies), the Middle East (including Iran), the Far East and South America.

Finally, some countries might convert non-weaponised UAVs into LACMs. Such vehicles do not require anything like an advanced gas-turbine engine to achieve one-way ranges of over 1,000km. In fact they are far more likely to be powered by simple and cheap propeller-driven engines than by more modern gas-turbine engines.

Basic Prerequisites for Cruise-missile Development

Knowledge and skills as well as technology are required to manufacture cruise missiles indigenously from scratch, or to convert existing ASCMs or non-weaponised UAVs into LACMs. Also required is systems engineering capability. Arguably, what separates the industrial from the developing world is the capacity to integrate technology components into complex systems. If a nation seeks to acquire a small number of inaccurate, unreliable missiles, it can do so in a relatively straightforward and perfunctory fashion. Thus, the 1998 Commission to Assess the Ballistic Missile Threat to the United States (known as the Rumsfeld Commission, after its chairman, the current US Secretary of Defense, Donald Rumsfeld) concluded that countries like North Korea and Iran could compress the development of long-range ballistic missiles into a much shorter time than it took either the US or Soviet Union to accomplish.¹⁵ But producing significant quantities of highly effective cruise missiles calls not only for access to commercially available components but also for indigenous or foreign-provided systems-engineering talent.

Aeronautical engineering skills would be needed to make the fundamental calculations ...

Table of contents

• Cover
• Title Page
• Copyright Page
• Table of Contents
• Glossary
• Introduction
• Chapter 1 Technological Challenges of Acquiring LACMs
• Chapter 2 Alternative Ways to Acquire LACMs
• Chapter 3 Motivations and Constraints Affecting the Pace and Scope of Proliferation
• Chapter 4 Defending Against Cruise Missiles
• Chapter 5 Strengthening Non-proliferation Policy
• Conclusion Prospects for Cruise-Missile Proliferation
• Appendix Selected Cruise-missile Systems and Programmes
• Notes