The Navy’s MH-60R Seahawk family helicopter operates from various ships, including the LCS, and performs various roles such as search and targeting, ASW, ASuW, search and rescue, etc.
One of the keys to the usefulness of the MH-60R is the on-board radar. The APS-147 and its successor, the APS-153(V), are multi-mode radars with long/short range search capability, Inverse Synthetic Aperture Radar (ISAR) imaging, and periscope detection modes, among others (1).
The MH-60R radar is derived from the APS-143(V) which is claimed to have a maximum range of 200 nm (3). Of course, maximum range is for a large target on a clear day with calm seas. A more realistic range for smaller targets, such as naval vessels with a degree of stealth, in typical seas with wave clutter will be much, much less.
The APS-147 radar’s design features include wide bandwidth, high average power, fast scan rate (108/minute), frequency agility, scan-to-scan integration over nine scans, and a track-before-detect capability (4).
APS-147 Modes (2)
- Small Target/Periscope Detection
Surveillance Long Range
- Weather Detection and Avoidance
- All Weather Navigation
Search-and-Rescue Short Range
- Enhanced Low Probability of Intercept (LPI) Search
- Target Designation
- Inverse Synthetic Aperture Target Imaging
The APS-153(V) adds Automatic Radar Periscope Detection and Discrimination (ARPDD) capability to the list of modes.
Note that long range search and LPI are two separate and distinct modes. LPI uses less power and produces much shorter detection ranges while long range search is more powerful but increases the probability of intercept to a certainty.
Radar is not the only means of finding targets. The ALQ-210 Electronic Support Measures (ESM) system for provides passive detection, location and identification of emitters and threat warning (1). The system emphasis seems to be on threat warning. I don’t know how effective the system is for targeting or whether it can even generate targeting quality data.
At least among public observers and commentators, if not naval professionals, the helo is seen as the key to distributed lethality and is accorded near-magical capabilities. As we’ve often noted, long range anti-ship missiles are useless without equally long range target detection and identification. The helo is seen by non-professionals as being able to provide that long range search, detection, and targeting capability.
When I distinguish between public observers and naval professionals, the distinction I’m making is that I know what observers believe but I have no idea what naval professionals think about this subject. I have no idea whether the Navy believes that helos are an integral and major component of distributed lethality or not. It may be that the Navy sees no more than an incidental role in the long range search that is necessary to support distributed lethality. Of course, if this is true then I have no idea how the Navy thinks they’ll find targets.
The maximum range of the APS-147/153 is unknown but, for sake of discussion, let’s assume it’s around 200 miles. Again, that’s the maximum range for detection of a large, non-stealthy, non-ECM active target under ideal conditions and using maximum output power – say, a large tanker sailing in good weather. For a smaller, semi-stealthy, active-ECM target such as a modern frigate or destroyer, the detection range is considerably less than the maximum – let’s call it a third to half the max range. That puts our useful detection range at 66-100 miles and against a modern, semi-stealthy, ECM cloaked naval vessel even that may be optimistic.
Of course, even if the helo’s detection range is relatively short, the helo itself can fly out from the host vessel thereby extending the effective detection range. Thus, the effective detection range is the helo’s flight range plus the radar range. The flip side of this is that if the helo is radiating, it’s going to be seen and tracked at longer ranges than it can detect a target at and will be targeted and shot down before it can detect the shooting platform. In other words, if the helo is close enough to detect an enemy vessel, the helo is probably already dead.
This is the key concept and it invalidates the use of a helo as the means of providing long range targeting for the distributed lethality concept. A radiating target (the helo) can be detected at a much greater distance than its own radar can detect the targets it’s looking for. This is not a prescription for survival and it is not a prescription for successful long range targeting. Couple this with the helo’s demonstrated non-survivability in a surface-to-air missile environment and it’s patently obvious that the helo cannot survive long enough to find a target. Could it find a small patrol craft that has no significant SAM capability? Sure, but that’s not really the kind of target distributed lethality is intended to find and destroy, is it? Even then, in enemy waters and airspace, an enemy aircraft will likely be called in to dispose of the helo before it can do much good.
As with so many modern naval assumptions, the concept of distributed lethality depends on the enemy allowing us to freely roam the skies conducting our targeting searches. In a peer war, this is a ridiculous assumption and distributed lethality simply will not work because we have no long range survivable sensor.
I’ve told you why distributed lethality won’t work and why the helo, specifically, can’t be used as the long range sensor. Now, I’ll tell you how the concept could work. The key is a survivable long range sensor. We do have such a sensor available – it’s the small UAV.
If a ship can put out a constant stream of small, cheap UAVs with a combined flight range and sensor range of 200 nm, then we have a chance, at least, of finding a target. Of course, many UAVs, being non-stealthy, will be spotted and destroyed. This is where “cheap” factors in. If the UAVs can be made cheaply enough then they can be considered expendable, almost one-way, assets. So what if some, or many, don’t return? If we have to expend a bunch of UAVs that cost tens (or even hundreds) of thousands of dollars in order to sink an enemy ship that costs hundreds of millions (or billions) of dollars, that’s a great trade.
The key to this cheap, expendable UAV is the sensor’s field of view. It doesn’t matter how many UAVs we throw out if each one’s field of view is so limited that we can’t cover a significant swath of ocean. If the field of view is too limited, the search devolves into dumb luck and that’s no way to win a war. Do we have UAV sized sensors that have a sufficient field of view? I don’t know. Manufacturer’s claims are always ridiculously exaggerated so those are useless in assessing this. This is one of those areas that only the Navy knows for sure. The fact that I’ve seen no attempt to outfit the distributed lethality ships with a multitude of UAVs suggests that the sensor packages are not up to the task but I just don’t know for sure.
So, we now know what won’t work. The helo is not the magic answer. We also know what could work if appropriate sensors were available.
As a parting reminder, distributed lethality is a flawed concept for more reasons that just the long range sensing issue. Simply solving the sensor issue offers a chance of making the concept work but it is still flawed. For example, the enemy is going to be searching for us at the same time we’re searching for them. What happens when a small, lightly armed distributed lethality vessel is found by the enemy before we can find the enemy? The answer is a foregone conclusion: our distributed lethality ship will be sunk. When the Navy idiotically starts talking about using amphibious ships, logistic ships, etc. as distributed lethality vessels, we’re talking about risking high value, but nearly defenseless, assets against the remote possibility of surviving long enough to find a suitable enemy target. It’s not a risk that’s worth taking.
(1)Lockheed Martin MH-60R informational brochure,
(2)Telephonics data sheet
Navy Journal of Underwater Acoustics, “A History of U.S. Navy Airborne and Shipboard Periscope Detection
Radar Design and Development”, January 2014, John G. Shannon, U.S.