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I forgot to discuss the multiple-target engagement capabilities present is some of the newer jet fighters. If memory serves, the first version appeared in the F-14’s. It’s a data-processing and -book-keeping thing in the avionics software, really.
That’s a really big problem to solve. Which is partly why it has gotten so difficult to successfully debug the avionics software of a new fighter during development and test.
If you are within the autonomous range of your weapons’ seekers, there is no need to paint your target with your aircraft radar beyond the brief moment to get a radar seeker locked, if that, and depending upon the sophistication of the seeker. For IR weapons, there is no need for target painting at all. But you have to be much closer than with radar.
Beyond autonomous range, each weapon’s target must be painted until that weapon closes to autonomous range and then goes autonomous. There is no way around such basic physics! For IR guided stuff, that’s around 1-3 miles, and the same for early radar-guided stuff, with the exception of great big Phoenix with its rather large on-board radar dish.
This got pushed out to and beyond around 10 miles for the radar-guided AIM-120, which is a much more favorable engagement distance. Within that range, the “launch-and-leave” AIM-120 is just as “fire-and-forget” as the IR-guided AIM-9’s. And it’s too long for your target to reach you with an IR-guided weapon (or a radar weapon with the older, shorter autonomous range), because his seekers are quite similar in characteristics to yours, actually.
As long as your avionics need not paint each target until the weapon targeted upon it goes autonomous, there is no reason at all not to book-keep and engage multiple targets at once. Beyond autonomous range, there is a need to paint all the targets engaged for a while, and you only have one radar beam!
Thus there is an inherent intermittency in target painting that is required to engage multiple targets at long ranges, beyond seeker autonomous capability. It is difficult to imagine the software complexity required in order not to cause seeker break-lock in weapon “A”, when the painting beam moves to target “B”. And it is also difficult to imagine the software complexity required inside the missiles themselves to distinguish target “A” from target “B”, as the beam moves from target to target. This opens a really, really big can of worms!
I’m not saying such a thing is impossible. But I am saying not to hold your breath waiting for this! Software complexity and the associated reliability has been, and still is, the weakness in guided missile technology all these decades. In the 1960’s it just barely worked. Now the missiles really do work fairly reliably, as long as the complexity on board the missile is limited. Complexity breeds failure modes!
That being the case, there is no real multi-target engagement capability beyond your chosen weapon’s autonomous range. The newest AIM-120’s may have extended that range some over earlier models. But not a whole lot. Yet every bit helps.
My point is still the same: these are incremental improvements, not total game-changers. The hype that they are game-changers is only marketing lies to sell more development programs to the government. The 12-foot-tall enemy is the accompanying lie about the threat the enemy poses, to help sell more development programs to the government. I’ve played that very game; I know how it works, and how far from the truth it really is.
This is the military-industrial complex that Eisenhower warned us about in his farewell address, in action. It’s a high-dollar business, so participants have boodles of ready cash. They get what they want because they bought the politicians’ jobs for them. So, those politicians work for the corporations, not we who elected them, which is how this perpetuates and grows with time.
It’s a crooked game, and everybody, not just the USA, is infected with this. Or haven’t you noticed the perpetual (money-making) wars everybody (including us) has been waging?
GW
Last edited by GW Johnson (2018-05-16 10:44:21)
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
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GW,
Our missiles have been refined to a point to where a lot of the "hype" is just demonstrated capability. I'm sure someone will point out the AIM-9X's recent failure in Syria to ignore flares ejected from an old Su-22 because the seeker was so finely tweaked to ignore western flares, and apparently eastern flares are "dirty" IR sources, that it didn't reject the eastern flares because they produce a signature that looks like the tailpipe and the target was being chased so that's what the image looked like. Like so many other problems, that was analyzed, the cause determined, and now they're working on a fix for it. The same F-22 that that Super Hornet engaged was subsequently shot down seconds later using AIM-120D. If at first you don't succeed, fire another missile at the target.
The new AESA radars in F-22, F-35, and others include a "receive-only" mode where they detect enemy aircraft through EM emissions from the radars and communications systems aboard enemy aircraft, along with reflections from other radar sources. That problem of painting multiple targets at the same time has been solved by using electronically steered beams from individual elements in the array. The radar is not one big transceiver dish. That's the technology you knew. It's not the technology that the Americans, Europeans, Russians, or Chinese use now.
The F-35 also has a sophisticated 360 degree multi-spectral EO system called DAS. It also has an IRST (FLIR) system and data links to communicate enemy target locations to the weapons it fires. The F-22 needs to be upgraded with the same EO and IRST systems. The F-22's software, all of it, comprises about 1.7 million lines of code, most of that being devoted to the radar. According to LM, the newer F-35's software has over 8 million lines of code and counting and the simulator has over 10 million lines of code. Do the math on which platform is most likely to incorporate more features, thus more capability in a general sense. The sophistication of these platforms and their weaponry is now more software-based than hardware-based. You still need the hardware, obviously, but the software is doing most of the heavy lifting.
In the next decade, the aviator with the best software that filters out things he doesn't need to know about until he/she absolutely needs to know about them is going to prevail, no matter how fancy the rest of the jet is or isn't. Siri is going to say, "Hey buddy, there's a Su-57 at 40km out and that flight of inbound cruise missiles 200km out is far outside of weapons range. Let's take care of the most pressing problem first and then worry about whatever else we can do after there's no one else around who can shoot us down." These new birds are already networked computers with wings and weapons. Most of what matters now is using a computer to defeat your enemies in a timely manner.
Incidentally, there's now serious talk and action towards restarting F-22 production. It's time to give our allies what they say they want. The F-22's stealth characteristics were already being upgraded with component technology taken from the F-35 program, but budget cuts stalled the program and eventually USAF killed the program before the upgrades to all airframes were completed. Contrary to what Rob opined, it's radar signature is lower as a function of the geometry of the airframe design, not any super secret technologies that we don't want to share with our allies. The result has been an even lower signature as a function of more readily maintainable airframe parts and dramatically lower maintenance. Most of the airframe maintenance associated with the B-2A is reapplication of the coatings that provide RCS reduction. It's so much time allocated that it's not even funny, representing more maintenance hours than all other systems combined by a substantial margin.
The new AIM-9's and AIM-120's have lock-on after launch, two-way communications with the launching aircraft, GPS, and home-on-jam capabilities. The new AIM-9X's can be used against both aircraft and ground vehicles with hot engines. Obviously the "dirty flare" problem needs to be fixed. The AIM-120D's should also receive their own miniaturized electronically steered AESA radars as an upgrade to replace the mechanical steered radars presently employed. The narrow "pencil" beams are what increases the range and resolution of the F-22 and F-35 radars without absurd power output levels. Japan has already done this on their AAM-4B missiles based upon AIM-7 missile airframes.
DARPA is working on "Gremlins" drones (networked cruise missiles that gather intelligence, rather than just attacking targets) that feature aerial recovery and refueling. This should enable regular transport aircraft or legacy bombers (B-1 or B-52) to deliver the ISR / strike packages into heavily defended airspace.
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Hi Kbd512:
If I understand you correctly in your post #27, the new radars can paint with more than one beam simultaneously. If that is true, it does help solve the paint-multiple-targets problem rather elegantly.
The only proviso I can think of is to code each beam in some way, so that one and only one of several weapons, sees the beam coded for it.
I don't really see much difference between us, other than I, the much older guy, do not trust the new technology as far as you do. That's less about fact and more about preference. But it is quite the real effect.
I also prefer to navigate with a paper chart looking out the window for confirmation. But, as I said, I'm very old-school about such things.
The item about B2 coating maintenance: there is a reason this airplane is based away from ocean spray and away from desert salt flats. As it turns out, salt gets into the low-RCS materials, and ruins its stealth properties. Permanently. You cannot clean, you must replace. This (and cost plus unsafe tailless landings on carriers) is why there is no Navy A-12 carrier strike bomber.
I was forbidden from eating Doritos in public while working on items for that airplane. The security types were afraid it would give away the shape of the airplane. I swear, all of us were forbidden from eating Doritos in public!
You use these vulnerable materials if you push for the ultimate stealth. But you can get much of the same stealth benefit from ordinary fiberglass, and not be vulnerable to salt contamination. It was a fiberglass Windecker Eagle that started the entire stealth airplane journey. They used a transponder to unsettle Cuban air defenses with one of those airplanes. The Cubans never knew they were there until they turned on the transponder.
Even simple shape goes a long way: the flying wing B-49 of 1947 was very hard to see on the kilohertz radar of the times, and would still be rather low signature today. That was an aluminum airplane. Just no propellers to make that wild oscillating prop cross section. The engines were buried well enough to reduce that kind of spinning-blade return from the compressor faces.
There's even a semi-stealth version of the F-16. It has a modified inlet lip shape, and a canopy that reflects radar to kill the cockpit cavity return. I know how to build a towed ribbon decoy with more radar cross section than that version of the F-16. The other models require massive chaff deployments to protect them.
The modern stealth only applies at modern battlefield radar frequencies. If you look at the old kilohertz band search track radars, all these stealthy airplanes (except the B-49 and that oddball F-16) look like battleships because their cross sections are so large at low frequency. That right there proves how important simple shape is.
I know you can't get a precise location on a target at kilohertz frequencies, and I know nobody wants to use equipment like that anymore because it's so big, unwieldy, and power-consumptive. But it does see right through modern stealth, and you can vector an interceptor within visual range that way. If the interceptor can spot the target visually, he can shoot it down. With guns, if that's all that will work. I doubt any sort of drone or UAV could do that for many, many years yet.
GW
Last edited by GW Johnson (2018-05-17 13:26:43)
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
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GW,
That's exactly how the individual pencil beams from the newest AESA radars work. Individual weapons receive guidance information from the launching aircraft's radar, not by receiving radar reflections from the aircraft's radar, but by the radar beam itself encoding the locations of multiple moving targets. The new transceivers like the F-35's APG-81 and the F-22's APG-77v1 (based upon APG-81) have dozens of electronically steered (nothing physically moves, apart from electrons) array elements that can target multiple points miles away from each other. The radars in the latest versions of the F-15E, F-16 (various models), and F/A-18E/F/G are all based upon the same technology. Some have more array elements, more output wattage, and/or more sophisticated software than others. At the end of the day, the software and computer are deciding what's important and what's not.
These AESA radars can be put in any aircraft that can supply enough electrical power and our enemies are starting to use the same technology as they phase out their older PESA radars. The Russians used a vacuum tube based PESA in their MiG-31 long before we had any PESA or AESA radar in an operational fighter. The Zaslon ("Barrier") PESA in the MiG-31 had a stupid amount of power behind it and could injure people on the ground or in other aircraft. The first airborne PESA the US had was in the B-1 bomber. IIRC, we skipped over PESA and went straight from mechanical systems to AESA in tactical fighters. The mechanical dish like the one the AIM-120 uses is archaic.
The F-35's sensor fusion means multiple sensors can be slaved via the input from another sensor like the radar. The IRST system can be slaved to the APG-81 or vice versa. The DAS is also the missile warning system. Think of DAS as a combined high resolution EO / FLIR system looking in all directions at all times. When a F-35 pilot looks between his or her legs, they don’t see their junk, they see color images from below the aircraft. My Cadillac Escalade also uses this technology to see 360 degrees around the car and the radar transceivers automatically brake the car if I get too close to an object near the vehicle. Think of the IRST as a FLIR with even higher resolution and substantially greater zoom range that can be radar slaved to find targets for missiles that the radar can then guide to the targets by transmitting guidance information to the missile's onboard computer via the datalink. The radar is also part of the EW suite and a far more powerful and sophisticated jammer than most turbine-powered pod-based systems like those aboard EA-6B / EA-18G.
There's no such thing as an aircraft that can deflect RF emissions across all wavelengths, but the resolution achievable with longer wavelengths is insufficient to put a warhead within lethal distance of a fighter because lower wavelengths only know that a target is there, somewhere, in a block of airspace. Such radars will definitely know a target is "out there", but within a block of airspace measured in cubic miles, so knowing approximately where something is happens to be useless for precisely guiding a weapon to within terminal distance of said target.
You can't launch a missile at five cubic miles of air and hope its onboard seeker fixes the location of the target while the missile is on its way. This has been attempted, as has using multiple longer wavelength systems to achieve a more precise target fix. The problem is that abrupt changes in target direction or speed make this very difficult to do. Radar A finds a stealth aircraft and then Radars B and C attempt to triangulate its position using different geographical vantage points. Unfortunately, that information has to be continuously communicated amongst the radars while the target is flying around at just under the speed of sound. It's not impossible, but it requires multiple radars in geographically dispersed locations. The target stealth aircraft then has to fly between three or more of those radars, more radars being better, to achieve a more precise fix. The radar sets then have to maintain that target fix while they find the rest of the stealth aircraft. You've seen how huge the antennas are for these low frequency radars, so heavy vehicles or fixed emplacements are required. Take one or more of those radars out with a comparatively low cost cruise missile and the game is over. You need higher wavelength radars to prevent that from happening. The newest Russian and Chinese missiles combine RF, IR, and even laser sensors to try to fix the target so that if one engagement method is denied to the missile, the other(s) can take over. This gets really expensive, really quick.
The aforementioned is why our stealth and jamming tech focuses on wavelengths useful for precisely guiding weapons to targets and for determining if the missile is within terminal distance to detonate its warhead. It's designed in such a way that you have to get within visual range of the aircraft to launch a missile against it that will actually guide all the way to the target. You're relegated to a modern version of WWII style air combat wherein both RF and IR guided missiles only work at ridiculously short ranges or with certain target aspects, like flying directly at the stealth aircraft from the side and matching any target direction and speed changes. Even so, he who shoots first will probably win because modern weapons really are that lethal. In that sense, you're right about still needing guns. I can envision scenarios where visual engagements with guns and IR guided missiles are all that will work in a practical sense when longer range RF guided weapons never find their targets.
The onboard fuel and heat exchangers dramatically reduce the airframe and engine IR signatures by cooling the skin of the aircraft, tailpipe excepted, and the tailpipe itself is designed to diffuse the hot exhaust products. There are pictures of this technology on the web in action that show the IR signature of the AV-8B and F-35B in a hover while coming aboard a ship. Stealth against both RF and IR guided missiles is the name of the game. Lasers will become more important in good weather. That'd be why Russia and China are trying to steal, replicate, or defeat the stealth using sensor fusion.
Hopefully I didn't ramble too much, but that seems to be where this is headed. It's also getting obscenely expensive for everyone involved. When can we stop inventing new ways to murder each other? What's so fascinating about it? Doesn't death come soon enough anyway? Wouldn't walking around on another planet with a guy you just met from Russia or China be a lot more interesting story to tell your kids?
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It's also getting obscenely expensive for everyone involved. When can we stop inventing new ways to murder each other? What's so fascinating about it? Doesn't death come soon enough anyway? Wouldn't walking around on another planet with a guy you just met from Russia or China be a lot more interesting story to tell your kids?
And that's the point. Arms manufacturers want to ensure the government continues to pay hundreds of billions of dollars per year to buy their stuff. After the Soviet Union broke up, the US didn't have a big bad guy any more. President Bill Clinton actually reduced military spending and balanced the budget. Still spending more than the next several countries combined; more than the combined total of all non-allies with a military budget greater than $2 billion. But arms manufacturers didn't like that, so let's pick a fight with Russia. And China. And meddle in the Middle East. Hasn't that worked out well?
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Rob,
I've long argued for closing overseas military bases. That's at least $150B in tax payer money our government doesn't need to spend. The military shouldn't build any permanent bases overseas. The US maintains an offensive fighting force that should destroy whatever it's tasked with destroying and then that force should immediately return to the US. Any problem that can't be solved through destruction requires a different solution, namely diplomacy and commerce.
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