Cruise Missile Characteristics Related To Detection and Engagement Range

The US Navy is committed to an anti-air warfare path of long range intercepts using the Aegis and Standard systems.  The wisdom of this is debatable for a variety of reasons.

Long range intercepts depend on being able to detect the target at long ranges.  You can’t engage what you can’t see!  For targets that obligingly fly at high altitudes, this is a viable approach.  For targets that fly at low altitudes or are less detectable due to small size and/or stealth, this approach is not feasible.  Unfortunately, the trend in anti-ship missile (ASM) technology is towards stealth and sea-skimming altitudes.  Many missiles have options for an initial high altitude cruise phase followed by a sea-skimming attack phase.  The question is how far out from the target does the cruise phase terminate and the sea-skimming attack phase commence?  If the cruise phase terminates and converts to the low altitude attack phase beyond the effective range of defensive missiles then the ASM is, for all practical purposes, a purely sea-skimming missile.  This is what seems to be the typical case today.  Thus, it is quite likely that a defending ship will never see, or at least not have the opportunity to engage, the attacking missile until it enters the radar horizon (20 miles or so).

Another problem with the Navy’s long range intercept path is that it’s very expensive.  For example, the Standard SM-6 costs around $4M each and has a claimed range of 150-300 miles.  Launching volleys of $4M missiles quickly becomes prohibitively expensive.  Of course, the cost of a volley of $4M missiles is, arguably, a bargain if it prevents the destruction of a multi-billion dollar ship!  Still, the price tag of Standard missiles does impact the budget and the number of missiles procured. It’s not just the missiles that are expensive.  The Aegis system that enables the Standard missile costs hundreds of millions of dollars and the developmental costs for the ever-changing software are astronomical.

Before we go any further, let’s take a moment to look at some characteristics of common potential enemy anti-ship missiles as provided by readily available open source information.  Note the attack altitudes and relatively small sizes.  These missiles will be hard to detect and engagement windows will be very short.

C-801

Speed   Mach 0.75

Flight Altitude  <20 m

Attack Altitude  <20 m

Range  40 km

Length  5.8 m

C-802

Speed  Mach 0.9

Flight Altitude  7 m

Attack Altitude  5 m

Range  120 km

Length  6.4 m

Exocet

Speed  Mach 0.92

Flight Altitude  2 m

Range  72-180 km

Length  4.7 m

P-270 Moskit (SS-N-22 Sunburn)

Speed  Mach 3.0

Flight Altitude  20 m

Attack Altitude  <7 m

Range  90-240 km, depending on version and flight profile

Length  9.7 m

P-700 Granit (SS-N-19 Shipwreck)

Speed  Mach >1.6

Flight Altitude  high

Attack Altitude  <25 m

Range  625 km

Length  10.0 m

P-800 Oniks (SS-N-26 Strobile)

Speed  Mach 2.5

Flight Altitude  high

Attack Altitude  10 m

Range  370 miles

Length  8.9 m

Kh-59 MK (AS-13 Kingbolt)

Speed  Mach 0.8

Flight Altitude  7 m

Attack Altitude  ?

Range  285 km

Length  5.7 m

BrahMos

Speed  Mach 3.0

Flight Altitude  high

Attack Altitude  5 m

Range  280 miles

Length  8.4 m

Even if not designed as stealthy airframes, ASMs are small and have an inherently small radar cross section.  A small missile, in sea-skimming mode, down in the wave clutter, will not be readily detected.  First detection is likely to be inside the radar horizon.  Even the presence of an airborne radar plane will not greatly increase the detection range of an incoming sea-skimming missile. 

Also, detection and targeting are two separate issues.  An airborne radar may detect a missile further out but being able to maintain a steady lock sufficient to guide a defensive missile is another matter and likely will not be achievable until the attacking missile has gotten much closer to its target.

What is the overall point of this discussion?  It’s that I suspect that the actual targeting detection range of most ASM’s is going to be very short.  That being the case, one can’t help but ask whether the Navy’s focus on very long range Standard missiles is appropriate.  It would seem that the Evolved Sea Sparrow Missile (RIM-162 ESSM) would be a more likely and useful defensive system.  ESSM range is given as 27 nm which would seem to be an appropriate match to the expected detection range.

In fact, I have doubts that intercepts at ranges of hundreds of miles are even feasible given the cruise characteristics of enemy anti-ship missiles.  What enemy missile or aircraft is going to fly obligingly high, straight, and level for an extended period while we guide a Standard missile to it?  Ballistic anti-ship missiles do fly predictable paths and, for those, long range intercepts are both feasible and desirable – but that’s another topic.

If my conjecture is correct and the vast majority of anti-ship cruise missile engagements are going to occur at radar horizon ranges, shouldn’t the vast majority of our defensive systems also be optimized for those same ranges?  Wouldn’t it be better to emphasize ESSM defenses over Standard missiles?

Further, given engagement ranges of radar horizon and closer, shouldn’t we also greatly beef up our short range engagement capabilities such as RAM, SeaRAM, and CIWS?  Sure, debris from a successful short range intercept may still impact the ship and cause damage but it will be a lot less damage than having an intact, functioning anti-ship cruise missile hit the ship.  Consider that most Burkes have only a single CIWS for close in defense and, for a time, Burkes were built with none.  Burkes do not mount RAM/SeaRAM.  Our short range defenses are lacking, to put it mildly.

We need to do several things to beef up our medium range (out to 30 miles or so) AAW capability.

1. Install multiple RAM/SeaRAM launchers on every ship.
2. Provide at least 3 CIWS for every Burke.
3. Focus on electronic anti-missile defenses (soft kill).
4. Develop radars/sensors optimized for medium/short range use.
5. Develop methods to effectively launch and utilize high density volleys of ESSM and RAM.  This would include the ability to track the incoming target even in the presence of high clutter returns due to near miss defensive missile explosions.  Given the short engagement window, it is vital that we can continuously track and engage rather than have to wait for the radar picture to clear after a near miss.  The traditional engagement sequence of shoot-shoot-look is no longer viable.  The engagement sequence has to be shoot-shoot-shoot-keep shooting!  We also need to be able to track the incoming missile in the presence of many outgoing missiles.

The last point also suggests that Aegis is likely not the optimum AAW radar.  We don’t need bigger and longer range AMDR radars (well, we do for ballistic missile defense but, again, that’s a topic for another post); we need very high definition, very rapid response, enhanced capability medium/short range radars combined with much greater numbers of medium range ESSM and integrated fire control systems.  We need to greatly reduce our emphasis on Aegis/Standard and put far more emphasis on medium range engagement.

We also desperately need to improve our AAW electronic countermeasure (ECM) capability.  The venerable – and never all that effective, according to reports – SLQ-32 needs to be enhanced far beyond even the current SEWIP (Surface Electronic Warfare Improvement Program) block improvements.  We need massively more capable and powerful detection and active jamming/decoy systems (remember our discussion about an electronic warfare version of the Zumwalt?).

In summary, future naval AAW engagements are not going to be the long range intercepts that the Navy has designed for – they’re going to radar horizon, close range, short window, affairs that require an optimized radar fire control system capable of operating a continuous fire defensive system, backed up by extensive short range and ECM capabilities.