Over the last several years ComNavOps has, quite rightly and
wisely, criticized and mocked the Navy’s many absurd, ill-considered,
individual plans and acquisitions. It’s
time, now, to look at the Navy’s overall fleet concept and see how it holds up
to analysis. Of course, given the failure
and poor performance of the many individual elements, it’s probably not too
hard to anticipate the result of this analysis but we’ll go through the
exercise anyway in the hopes that it can offer some guidance about what not to
do.
When I talk about the Navy’s overall plan, I’m referring to
the Navy’s vision of the ideal task force.
Again, we’ve discussed the individual components but let’s bring them
together, now.
HVU (High Value Unit). The ideal task force will have a HVU(s) which
could be a carrier(s), amphibious ships, or vitally important cargo ships
surrounded by escorts.
Escorts. The
escorts are envisioned to be a few (2-3?) Burke class destroyers for AAW and
control of unmanned assets. The Burkes
will be in constant two-way communication with the unmanned assets as well as
the other Burkes and HVUs.
The unmanned assets will consist of:
LUSV (Large Unmanned Surface Vessel). Sailing near the Burkes will be these small
(by ship standards and large relative only to the smaller unmanned vessels),
missile-carrying, unmanned vessels operationally tethered to and controlled by
a Burke. Essentially, these are unmanned,
mini-arsenal ships whose purpose is to supplement the missile magazines of the
Burkes. They have no weapons or sensors,
themselves, and are wholly dependent on the Burkes for control. These vessels will be in constant
communication with the controlling Burkes who will provide them with remote operation
and fire control solutions.
MUSV (Medium Unmanned Surface Vessel). Forming an outer ring around the Burkes will
be these small, sensor vessels operationally tethered to and controlled by a
Burke. Their function is to provide
detection and situational awareness for the task force. They will have no significant weapons or fire
control. Essentially, these are very
large floating sensor barges. These
vessels will be in constant two-way communication with the controlling Burkes,
continuously broadcasting high bandwidth, large volume data streams for
analysis by the computers and analysts on the Burkes as well as receiving
operational remote control.
UAV. Ranging
out beyond the task force ships, these small UAVs will conduct
surveillance. An example would be the MQ-8B/C
Fire Scout. These UAVs will be in
constant communication with the controlling ship for remote operational control
and continuously streaming transmission of sensor data.
USV. Farthest
out from the task force will be these tiny, free roaming, unmanned surface
vessels that will operate way out in front of the task force, detecting and
tracking enemy submarines and providing situational awareness. Sea Hunter and the tiny sailboats we’ve seen
are examples of these assets. These USVs
will be in constant communication with the controlling ship for remote
operational control and will continuously stream sensor data back to the
controlling ship.
P-8/Triton (BAMS – Broad Area Maritime Surveillance). When available, the P-8 Poseidon/Triton
combination, the pairing being referred to as BAMS, will provide overwatch and
far distant surveillance, situational awareness, and, in their spare time,
anti-submarine detection and prosecution.
Discussion
There you have it – the ideal Navy task force. Of course, I’ve ignored a multitude of
problems which would render the individual components ineffective but, setting
that aside, did you notice the one, overriding characteristic of every element
of the task force? That’s right, it’s
the requirement for constant, high bandwidth, streaming communications between
the various elements. We don’t have
Terminator level AI yet so constant control communications are required. None of the unmanned assets have any
significant degree of on-board computer analysis so all data must be streamed
back to the control vessel for analysis, interpretation, and decision making.
What we’ve just described is, in reality, a large task force
sized, floating electromagnetic beacon continuously shouting, “Here I am!”,
while some enemy surveillance technician tasked with finding the American
running dogs smiles and says, “Well, that was easy.”.
Having handed the enemy our exact location, the only remaining
unknown is the exact amount of time it will take for final ship of the task
force to be sunk.
One of the constants of warfare throughout the ages has been
EMCON. This is beyond elementary. You stay silent while, hopefully, tracking
the enemy who is oblivious to your presence.
This allows you to choose the time and conditions of battle, - an enormous
advantage! The ideal task force not only
violates the very concept of EMCON, it is directly the opposite. It is a continuous electromagnetic beacon,
pinpointing your location for the enemy.
To believe that the degree of required communication can
escape notice by the enemy is simply delusional. If anyone has conducted a wargame about this
(I doubt they have or they would have recoiled in horror at the idiocy of the concept),
I’d love to see how they hand-waved away the free detection advantage for the
enemy … and I’m sure their wrists were sore from all the waving!
What about the special case of a carrier as the HVU? Wouldn’t this change things?
Carrier. Of
course, if the HVU is a carrier, this changes things a bit but,
disappointingly, not all that much. A
carrier’s air wing will add another layer to the task force’s defense, which is
good, but it comes at the price of additional communications. The E-2 must communicate with the aircraft it
controls and must transmit its sensor data to the ships of the task force. The individual aircraft must communicate with
the E-2 and the carrier for air traffic control. The carrier must communicate with the
aircraft. And, of course, the Ford class
EMALS is just the world’s largest electromagnetic beacon all by itself!
So, what has this analysis taught us? It has demonstrated that we are violating the
oldest principle of warfare by not concealing our location. We need to be structuring the fleet to
operate with the least amount of communication possible – none, being the ideal
condition.
Every asset we design and procure that requires
communication is a step along the path to defeat. The path to victory is silence (and
firepower!). During the Cold War, we
practiced EMCON operations (we learned how to launch an entire carrier strike
without transmitting!). Unfortunately,
the situation has gotten worse since every new piece of electronics seems to
require even more power and communications.
In combat, you talk, you die. Stop talking!
- We need to reverse this trend.
- We need to restore the requirement that every piece of equipment (I’m looking at you, EMALS) be shielded and EMCON-capable.
- We need to halt the rush down the unmanned path.
- We need to realistically exercise our communications in a combat setting and see how bad the problem is.
- We need to begin designing equipment with minimal communications as a mandatory requirement.
- We need to rethink our command and control concept and eliminate the top down control bias.
- We need start thinking in terms of combat operations rather than technological fixation.
Totally agree, its frightening ! I just have 2 questions. What kind of sensors does the MUSV have ? Is it equivalent to an LSC, frigate or destroyer ? Has there been any study on how to mitigate the electromagnetic signature of EMALS (besides not using them) ?
ReplyDelete"What kind of sensors does the MUSV have ?"
DeleteNo one knows. I've never seen any proposed equipment list and I strongly suspect that the equipment is envisioned to be modular meaning, in the Navy's view, that it could be anything. Of course, this approach has never yet succeeded so of course that's the direction the Navy wants to go.
"study on how to mitigate the electromagnetic signature of EMALS"
Not that I'm aware of and I very strongly suspect that it is not possible since it wasn't designed that way. Trying to retrofit something would be prohibitively expensive, I'm sure, even if technically feasible which I highly doubt.
Good thing that nobody has figured out radio direction finding.
ReplyDeleteIf that technology is ever developed, we're screwed.
Lutefisk
I am tired of pointing out to idiots that crews make submarines work and AI is dumb, very dumb. But no unmanned submersibles are going to be the thing.
ReplyDeleteAnd I am tired of pointing out these things can't be small if they are going to get the job done. And if they aren't small they aren't cheap.
And don't start me on mine warfare.
Couple of quick thoughts about USN fleet concept in general:
ReplyDelete1. Before we can even communicate, will they have the power and bandwidth, what about networks? Can they talk to each other and the ships? Considering all the difficulties we have had in the past with networks and comms, just look at F22 which had a unique comms and then F35s that had a hard time communicating with other fighters, suddenly we going to put all these diverse USV in the water from different manufacturers and different FY lot buys and some miracle, they all going to be able to talk to each other?!? I'm not convinced we can get out of the harbor without some of them losing comms! And since they are unmanned, who's fixing the broken radio? Or getting the network back up? So who stops to fix it? There's no way all these USVs together manage to get the comms up and running all at the same time....let alone how much emission they put up! LOL!
2. These are all relatively small, even the LUSV isn't that big compared to a Burke so how much range/speed do they have? Yeah, seen some impressive range numbers.....at 5 knots per hour! So how does that work with the DDGs and the carrier? Everyone going around at 5 KPH?!? At that speed with all the radio emissions, even if the Chinese are BLIND they will find the TF!!! That's some serious compromise if you have to navigate so slowly around with serious tactical implications....
3. Maintenance. Even assuming the missions are go out, get the job done, come back to port, let's assume 1 week? maybe 2 weeks at sea, there's going to be some things that break, what's the plan with that?!? Do we stop and fix them? Do we move on? Send them back if possible? How much can you fix? Is there a dedicated ship for that? Who decides? Let's say there is some redundancy built in, that just increases the price tag, at some point, they not expendable anymore! That's a lot of money you leaving behind or on the side, let alone capability you were supposedly counting on, right?!? So you can continue the mission if 3 out 5 still work, what happens if another one breaks, now you under the required number, do you continue with the mission even though you just lost so many of them (that USN says they are needed, right?) or do you turn around and go home? How many can we lose for maintenance alone?!? How many more do you need in excess to accomplish the mission? What happens if you lose a few, do we have some in reserve to bring up for the next mission? Now that brings up a whole new problem of production.... doesn't do us any good even if they work and are great as advertised if USN can only buy a few a year and you lose them after a few missions....and then what? Tell the Chinese to give us a few years so we can build a few more?!?
4. Going back to compromises when it comes to capability and range/speed....what happens when you need to get out of there fast?!? Let's say USN is successful with it's mission BUT now Chinese Navy is out for blood and revenge....are we sticking around at 5 KPH so we don't lose all the USVs? Do we recover them? How? Is there a dedicated recovery ship or the DDGs recovers each one assigned to them? How long does that take and what does that do to our force distribution/locations? Do we need new tactics and how we are distributed? Has USN looked at that and worked it out for real? Or we just going to use the same true and tried formations because nothing changes and we shouldn't worry about it? What happens to the DDGs recovering their USV and they come under attack? My guess is any respectable competent captain will ditch the USV and prepare to save his ship...
I somehow doubt that we can use the same tactics, formations and just general way to operate with all these USVs around....shouldn't USN be looking into that?!?
https://www.navalnews.com/naval-news/2025/01/china-suddenly-building-fleet-of-special-barges-suitable-for-taiwan-landings/#:~:text=China's%20roll%2Don%2Froll%2D,for%20military%20use%20when%20needed.
Is it absurd to communicate strictly visually? (Say lasers). Spacing elements at the horizon, and then leap frogging another layer at the horizon beyond quickly creates everything spaced out over hundreds of square miles. Is that a ridiculously small overall footprint? Can that form of communication be easily intercepted?
ReplyDeleteI don't know much about laser communications but I would want to know how they're affected by weather, rain, fog, dust, waves, etc. I know laser guidance is susceptible to weather effects. Supposedly, there are some types of lasers that are less affected by atmospheric effects but I'm not aware of any that are totally unaffected.
Deletehttps://www.cailabs.com/blog/aerospace-and-defense/how-does-atmospheric-turbulence-impact-laser-communication/
DeleteLooked up really quick and found this one company talking about lasers, looks interesting but these lasers and all the components don't look that small, maybe you could install it on some of the bigger USVs but looks kind of big to install on some of the smaller USVs....
This sounds like a juicy target for a swarm of home-on-transmission drone swarm.
ReplyDelete"And, of course, the Ford class EMALS is just the world’s largest electromagnetic beacon all by itself!"
ReplyDeleteChina's type 003 and type 076 also have EMALS. Although different technologies used -
US (Ford Class) - AC power supply/fly wheel energy storage/convert DC to ejector
China (003 and 076) - DC power supply/supercapacitor energy storage
Both US and China use high DC current for final ejection thus have strong EM emission. Apparently, this is not an issue as both have the same problem.
Both having the same problem doesn't make it an non-issue. It just means both have the same weakness.
DeleteThe questions that need to be asked are:
1. Can the system be shielded in a cost-effective manner?
2. If not, are the advantages of the system worth the heightened risk of detection?
ComNavOps has chronicled the significant reliability issues with EMALS on the Ford Class for over a decade now. It would be one thing if the system worked perfectly, but it doesn't even come close. Add in the fact that the system becomes a homing beacon for enemies and it becomes clear: it shouldn't have been installed on the Ford Class.
-Huskers1995
As China uses different technical path of EMALS (DC /super capacitor vs AC/fly wheel) in comparison with US, it is interesting to see how their system works. China seems quite confident as they built 076 even before EMALS on 003 proven work.
DeleteLet's wait and see if the Chinese EMALS works or not. It takes time to see - not if they can eject one aircraft but whether they can operate numerous times with high reliability. If they don't, it is a laugh stock; if they do, then, ... too bad.
I truly do not understand the fascination with EMALS catapults.
DeleteIt feels like technology for technology's sake, a non-solution failing to solve a non-problem.
The steam catapults are a proven and reliable way to toss aircraft off of carriers.
And our aircraft carriers are steam driven (nuclear).
And steam doesn't have an electromagnetic signature.
Even if we didn't power our aircraft carriers with nuclear power (and I wouldn't), you still can use steam catapults.
If you drive the screws with electric motors, you can power them by creating the electricity from banks of LM2500 engines (which the navy is highly familiar with).
The hot exhaust from the LM2500s can be directed to boilers that make steam for extra electric power generation.....or steam catapults.
Lutefisk
EMALS does have benefits over steam ejection. The problem is that you need to develop a reliable product. Unfortunately, in recent years, while US fail in several key weapons, China get them developed, for instance, hypersonic weapons, etc.
DeleteAgain, it is too early to say whether Chinese EMALS works or not. It takes time to prove their system working reliably or not.
"China get them developed, for instance, hypersonic weapons"
DeleteHogwash! There is zero evidence that China has either succeeded or failed to develop any particular technology. They are a closed society and do not release any technical assessments other than pure propaganda. Lots of propaganda and an occasional publicized test do not constitute evidence of success.
If you have actual data, please share it. Otherwise, refrain from presenting your opinion as fact.
@Lutefisk there's some benefits to EMALS, in that you can have a gentler acceleration curve, vs steam cats where it's a giant release of steam pressure shooting the plane like a bullet out a gun. This lets you tailor accel profiles for aircraft - some drones and Harriers can't use cats because it'll break thibgs - and improves airframe longevity for the planes that do ride on cats.
DeleteThe issue witth steam is keeping the pressure up as it travels from the boilers to the bow, electricity has somewhat less of an issue in needing to keep pressure up, and you can store it in capacitors, while steam needs to be constanrly on pressure.
It's all an issue about execution.
The chinese have decided to bite the bullet and just figure out EMALS on their own instead of steam cats, because they're starting from.zero in either case.
"improves airframe longevity for the planes that do ride on cats."
DeleteThere is no evidence to support this oft cited claim and simple logic suggests the claim is false. For starters, airframe longevity is determined in large part by cumulative wing stress from g-maneuvers, not launches, as well as the impact of arrested landings. As with so many things, the manufacturer/Navy make highly dubious claims to "sell" what they want. For example, they claimed that the Ford would enable much greater sortie rates and this was proven false by DOT&E as well as being a nonsensical performance parameter since no carrier has ever been sortied limited.
"can't use cats because it'll break things"
This is a ridiculous claim since Harriers were never designed for cats. It's tantamount to criticizing a dog for not being able to fly. If a Harrier were intended to launch from cats it would have been designed not to break just like every other cat-capable aircraft. Further, I'm unaware of any drone that would ever launch from a carrier using a cat that would be broken by the launch. We've launched aircraft all the way from extremely light to extremely heavy. Drones fall somewhere in between.
"store it in capacitors"
Steam is stored in accumulators.
"there's some benefits to EMALS"
There are no performance benefits to EMALS and, as of the last semi-informative report I ever read, there are serious drawbacks due to bounce, among other problems.
There might be operational benefits IF THE SYSTEM WERE PROPERLY DESIGNED which the US EMALS most certainly is not. The requirement to take all four cats down for any one's repair is a major combat damage control flaw as well as the very lengthy requirement to spin up and down.
I would caution you not to blindly accept the manufacturer/Navy claims (about anything!) as they are mostly false as we have repeatedly proven in this blog.
The January congressional review of the Ford program is out- and while exact numbers are still classified, EMALS and AAG are alluded to as having still not met failure per cycle requirements... The weapons elevators have come closer, but the report states they've never tried to perform combat-level amounts of weapons transfers yet, either.
DeleteAnyone surprised?
"January congressional review of the Ford program is out"
DeleteBear in mind that the CRS report was quoting the Jan 2024 DOT&E report which was a summary of the 2023 testing and data. So, that information is well over a year old. Whether anything has significantly changed in the interim is unknown.
If USS Ford's EMALS had acceptably functioned, Pentagon would have announced loudly to the world.
DeleteI assume nothing has changed which raises the question, why are we installing the same system on more Fords?
DeleteThere's a story about an operation USN played during the NORPAC82 exercise. The Enterprise battle group ditched its 'Russian trawler' and with total EMCON plus some bad weather 'disappeared'. They kept silent even while doing flight ops.... in strike range of the Kamchatka Peninsula. They did simulated bombing mission going east instead of west and did this for 4 days. When the Russians finally found them they went nuts! Scrambled a bomber task for to 'raid' the Enterprise with missiles. They ended up in the gun sights of F-4s from the USS Midway. There were two carriers out there.
ReplyDeleteCould we do that today? No way.
We could use X-ray wavelength lasers for point-to-point communications between ships and aircraft. They require a lot less power than radios, despite being more cumbersome than solid state IR and UV wavelength lasers. The device itself is physically much larger (a beach ball sized volume vs D-cell battery for a powerful UV or IR laser) than the kinds of lasers used for point-to-point communications or target imaging. However, the frequency is high enough that there is far less beam attenuation due to smoke or atmospheric water vapor, which means bad weather doesn't prevent its use. The static electricity and water vapor that greatly affects radio frequency sensors and communications during storms also has little effect on an X-ray laser. Unless you fly through the beam, you're not going to intercept it. The frequency is exceptionally high, so high data rate burst transmissions are very feasible to do.
ReplyDeleteX-band radar is 8 gigahertz (8*10^9) to 12 gigahertz (12*10^9).
X-ray is 30 petahertz (3*10^16) to 30 exahertz (3*10^19).
Needless to say, the potential bandwidth is enormous. 5 Watts of power would be gross overkill. NASA's Psyche spacecraft uses 4 Watts of power and can transmit at 267Mb/s from 33 million miles away using a near-IR (214-400 terahertz) laser. An X-ray laser would require even less power over the same distances because the beam's focus is even tighter, although the lasing device will be much larger and heavier. NASA has also used these devices for deep space communications between orbiting satellites and lunar landers for sending Ultra-HD video between the moon and Earth. I presume that mounting one on a ship is feasible since they mounted an X-ray laser on the ISS. While this project was developed by NASA, it was paid for by the US Navy, so I know that they're aware of it because they intend to start using X-ray lasers for higher data rate communications between two or more military satellites and Earth.
It would be great to have an all-weather alternative to radios for high data rate communications within the battlegroup. These devices are not terribly expensive or heavy, just much newer than IR / UV laser communications lasers. We're still working on developing gamma ray laser sensing and communications tech, but X-ray frequency lasers are ready for application to naval communications.
kbd512
I've always wondered, how do you maintain point to point comms between two moving points like a ship and an aircraft for two aircraft?
DeleteCNO,
DeleteAt some point, you will require a clear line-of-sight to establish comms between two devices so they can track each other. Afterwards, highly precise computer control software using gyro input and output to steering gear maintains the connection, even when extreme speeds and distances are involved, as is the case with the laser-based deep space communications network. A deep space probe's flight path is far less erratic than a fighter jet, but NASA's Psyche probe is moving at incredible speed (84,000 to 124,000mph, so 2X to 3X faster than the Voyager probes which left our solar system) and distances are measured in millions of miles (as far as 240 million miles), so pointing accuracy requirements are equally extreme. This tech could make radio frequency devices more of an adjunct system, used only when required, perhaps after the shooting starts and EMCON is less important than situational awareness.
kbd512
"flight path is far less erratic than a fighter jet, but NASA's Psyche probe is moving at incredible speed"
DeleteSpeed, along a steady and predictable path is easy to track. A combat maneuvering aircraft or a heeling, pitching, combat maneuvering ship is something else.
I could also envision the initial case where there are no comms as, say, an aircraft heads out to some mission point and a ship also travels unpredictably. Now, how do the two of them "find" each other to initiate a communication without radiating a "here I am" signal for all the world to see?
Has anyone ever tested point-to-point comms under actual combat conditions?
I have heard from many people about the extreme difficulties we have maintaining cell tower to cell tower or microwave tower to microwave tower comm alignment and those are unmoving! I have severe doubts that we can establish and maintain point-to-point comms under combat conditions. I suspect this is one of those cases where the theory sounds easy on paper but the reality is challenging to the point (pardon the pun) of impossibility.
This is similar to establishing a regional combat network on the fly. Easy on paper, impossible in the real world.
Have you heard of any real world, REALISTIC testing?
CNO,
DeleteWe should test a few of these systems:
https://www.ga-asi.com/multi-mission-payloads/lac12-pod
They use conventional lasers, but would serve as a proxy for X-ray lasers.
General Atomics has used them for communicating between pairs of airborne aircraft and ships, so at the very least it works in principle. It wouldn't hurt to evaluate how well the system might work under combat conditions. Some concepts require more testing, and this is one of them.
kbd512
What's the effective range?
DeleteHow is initial connection established when the location of the other platform is "somewhere about 500 miles in that general direction"?
CNO,
DeleteEffective range is determined by operating altitude, atmospheric conditions, and the type of laser being used. The higher the altitude, the greater the effective range. The laser power required to transmit from a medium altitude orbit to an Earth terminal is trivial, measured in single digit Watts. X-ray lasers are not significantly affected by atmospheric conditions, and the source tech for the kind of X-ray laser I'm talking about is the kind of IR laser we're actually using in all the present lasercomm systems. The IR laser strikes a high pressure gas and stimulates X-ray emissions. The total emitted power is much lower than it is for IR lasers, but the data rate can be much higher.
The Psyche probe's laser is only 4W, sufficient to transmit back to an Earth orbiting lasercomm relay satellite from 240 million miles away, at 6.25Mbps. At 33 million miles, the data rate was 267Mbps. NASA / US Navy TBIRD lasercomm relay satellite's data rate was 12kg, 3kg for the electronics and laser package, 200Gbps throughput rate, from a 530km orbit above Earth, and I believe it used 3W of laser power and up to 100W in total, nearly all of it to run its power-hungry DSP electronics. TBIRD was operated for 2 years before end of mission.
LightMatter's new photonics chip provides 800Gbps throughput and consumes 3W of power to do that, about 10% of the power of NVIDIA's best GPU chip for DSP / AI / graphics, so I would estimate 5W of total input power for an airborne relay's electronics and laser payload. This is sufficient to relay 53 Ultra-HD video feeds at 60 frames per second, from various other airborne sensors.
If we use airborne relay drones that fly / orbit in a grid pattern or formation, then we can point our lasers up and use mission clocks to determine roughly where to point our lasers, then use a low power transmit pattern to locate and “lock-on” to the airborne relay terminal. These would be soaring drones, miniature semi-autonomous motor-gliders, mostly using thermals and wind currents to remain aloft. We’d run the motor only to reposition them or for station keeping. NASA, Airbus, BAE, AeroVironment, Lockheed-Martin, Facebook, Google, and many other tech companies have already accumulated extensive experience operating these kinds of drones. Development work is ongoing, from the early 1980s to the present day, as a lower cost alternative to satellites. Many of these aircraft now use thin film photovoltaics, batteries, and electric motors, so they won’t consume JP5, although an onboard fuel cell would greatly enhance their deployment speed, at the cost of not remaining aloft for more than a week or so, due to the added weight.
We can use large constellations of small satellites, soaring drones, or both, and perhaps mount sensors on the drones so they might find something worth transmitting back.
kbd512
I am still completely missing the mechanism of 'locking on' from point to point. Assuming one knows the general whereabouts of a target comm point (a big assumption that I fear we're hand waving away), broadcasting a wide area signal of some sort to enable lock on seems to invite the enemy, presumably also in the general area, to receive the area broadcast and localize it back to the sender.
DeleteI envision this as being analogous to shining a flashlight in the general direction of someone far away. Yes, they'll see the signal and can then 'lock on' and reply with a flashlight back to me but every other person in the target's area will also see my initial light. Yes, I know that a laser is much narrower than a flashlight beam but if it's too narrow, the intended target will never 'see' it. If it's wide enough to allow for the uncertainty of initial location, then anyone can see it.
I'm sorry but I just don't see how an aircraft on an unpredictable path (that's what combat is!) can be 'locked' into a comm signal.
A satellite following an absolutely known path, sure, I get that but an aircraft in combat? Not seeing it.
What am I missing?
CNO,
DeleteCoherent light sources still diverge from the point of transmission, similar to radio frequency signals, but they’re highly directional in nature. Total divergence (the area and volume covered by the beam) is much lower than for RF emissions from an omnidirectional radio antenna, so total emitted power can be much lower, but over 100km the divergence is significant. You don't need to have the laser pointed back at the receiving terminal with absolute precision to still send and receive data, even though pointing accuracy absolutely will affect error-free data transfer rate, little different than a digital signal sent over a highly directional RF antenna such as a satellite dish.
The laser beam from TBIRD is 12mm in diameter at the emitter, has a 150 microradian beam divergence, so it will expand to just under 177m^2 (15.012m^2 in diameter) at 100km. If the beam's transmit power was 5W, then it arrives at the receiving terminal with 0.00002825W/mm^2 of power.
The real difference is that whereas RF emissions still have significant spillage when emitted from highly directional antennas (frequently called “side lobes” when referring to radar emissions), which does make detection much easier and able to occur from locations not directly in front of the source emitter, accomplishing that same feat with optical electronic warfare equipment is much more difficult. It’s not impossible, but probability of detection is greatly reduced.
Anybody with a radio antenna and sensitive receiver can easily listen for RF broadcasts and detect that a transmission took place. To accomplish that same feat with optical gear requires that your equipment is actually struck by photons from the sending laser. If you’re not in the beam path, your ability to merely detect that a transmission took place is dramatically reduced. A burst transmission from a laser device will also be exceptionally brief because its data transfer rate is so high relative to any kind of RF data transmission.
Let's say our airborne relay is operating at a pre-determined altitude of 10,000m and is orbiting inside a block of airspace 1km wide. We should change this after every mission and randomize the locations of the terminals. Since that altitude and block of airspace represents a fixed volume at a known “grid square” in my lasercomm computer’s map of nearby terminals, I don't need to transmit to numerous different directions and distances to "hunt for" the nearest data terminal. My transmitting laser doesn't know exactly where the relay is, it only knows it's at 10,000m on this particular day, 100,000m away from my present position, and the relay's making a 1,000m diameter orbit over such and such grid square. I would need to transmit into a maximum of 209 separate “baskets of airspace” in order to locate my relay to establish communications by “covering” each possible location with laser radiation. Statistically speaking, I’m going to find the terminal after transmitting through half of that volume of airspace. The entire process of finding the terminal and delivering the data would be done and over with inside of a second. I don’t need to spend multiple minutes transmitting my data.
Since every kind of system for sharing data will involve a series of compromises and trade-offs, if not lasercomm, what alternative information sharing technology did you have in mind?
kbd512
"say our airborne relay is operating at a pre-determined altitude of 10,000m and is orbiting inside a block of airspace 1km wide."
DeleteWhat happens when our airborne relay is forced to relocate due to enemy action? How does the other node find it?
I find it extremely hard to believe that we can predict a receiving target's location within a 177m2 area in a combat situation. That's an incredibly precise location for a free-wheeling combat aircraft. Consider: we send a recon aircraft out some 500 miles to have a look around. The aircraft will be maneuvering to avoid enemy search radars, threat aircraft, bad weather, etc. Do you really think we can predict to within 177m2 where that aircraft is at any time?
"If you’re not in the beam path, your ability to merely detect that a transmission took place is dramatically reduced."
Wouldn't this work both ways? If our target receiver is not within our predicted 177m2 area, wouldn't he have essentially zero chance of detecting the signal?
"what alternative information sharing technology did you have in mind?"
I'm not a comms expert so I don't have any answer. My fear is that there is no good answer, only a variety of bad answers. This is why we desperately need to try this under realistic combat conditions and, to the best of my knowledge, we have never done so.
Please recognize that I'm not disagreeing with anything, just trying to understand what seems like a nearly insurmountable problem!
DeleteSeems like the highly variable communicator (airplane in this instance) has to initiate the communication because it knows the position of the other communicator that isn't maneuvering so much.
DeleteMaybe I shouldn't have suggested "lasers" initially.
EMCOM is related to sea control, temporary sea control as it usually is. Why? Some emitters are not avoidable. Namely, sound. If marine mammals are surfing on your bow wake a tuna boat will find you from far away. A peer competitor will find you from far, far away.
ReplyDeleteEMCON is still important but only in creating that temporary sea control. Understanding how this works is vital to winning and surviving.
"If marine mammals are surfing on your bow wake a tuna boat will find you from far away."
Delete?????
Think of dolphins playing in the surf at the beach, only they are playing on the wave the fast moving ship is creating. The ship is loud. It is detectable. High end tuna boats can use the same technique to move on a bearing towards a splashing school. While on that bearing they launch a drone to visually fix the tuna. Easy Peasy. The Soviet bombers would find us. It's just a matter of time. EMCON is useful. It's not magic.
Delete