You're an idiot. There are several pieces of the hardware in place. There are several that are already in the field, and there are several that are on track for their trials.
I think the big problem here is that you just do not know the depth to which such a system must be developed.
You have no clue what the term "mission critical" refers to, and you have no clue how long equipment takes to get through an approval process, much less the bog down that the government causes whenever a change needs to be made.
After the experience, I realized that I had been done a favor. I had been exposed to the toxicity of military-funded research toward true innovation. And I experienced this relatively early rather than later in my career. I also had the benefit to speaking to a couple of CEO's from small companies who did receive contracts, and it was just depressing.
If I see someone in military garb approaching me with a contract, I will turn and run as fast as I can.
Do you even know the problems associated with making a gyro stabilized mobile tracking antenna system with a slew rate fast enough to handle the bumps caused in a vehicle?
They are far greater than those associated with doing it in an airframe. THAT is why the mobile units need to stop to facilitate links in some pieces of gear.
Even the manpack has a stationary antenna that gets planted before the link is established.
The handheld is the only thing that is onmi broadcast from that segment of the system. That waveform is easy to integrate into the rest, and those handhelds have been in the field for years, proving the function of that segment of the system.
Using the public system presents a severe security breach in several segment of the implementation that would be required, and it would also be quite susceptible to attack, and jamming.
Well, that's what GAO said about the people running JTRS, that they do not know what they are trying to accomplish, essentially.
Radios, links, SDR's, packets, encryption, multicast, mobility..these things are all technical. It helps to be specific. The more specific, the better. In my talks with with the military, there was an overwhelming attempt to avoid talking about specifics, which is probably why the show cause letter was issued.
Hmm...my guess is that mission critical means that it should not:
Jam
Crash
Overheat
Succumb to multi-path fading
Drop link
...all of which has happend so far.
The bureacracy of the approval process is generally the fault of the parties involved.
You conveniently ALWAYS forget the FACT that they requites for the system were MORE than doubled, and yet the cost has not. So, if anything, the program should be commends for NOT following the standard model where such huge requisite switching horseshit results in a tripling of the cost and an additional ten years.
You have no clue what all has been added to the system or even how the joint forces have evolved since the onset. The entire world has moved forward in electronics, and you are still talking like we are all on '91 era gear.
Essentially, regardless of all the reading you have done or claim to have done on it, what you have missed is that the reasons given for the time and cost extensions are 100% legitimate.
Obama's promised absence of pork spending that fell on it's face, right out of the other side of his mouth, to the tune of far more than that.
You should complain about crap like that, not about programs that are actually part of our defense, and that are actually working.
BICO capacity for R = 1/2 is at about 0.177dB Eb/No, and for R = 1/3 it's about -0.357dB Eb/No. Not a lot of difference there from a capacity perspective.
For uncoded, i.e., raw BER of 1e-1 happens at about -1dB Eb/No (or about
-4dB (equivalent raw Eb/No) at R = 1/2, and -5.77dB (equivalent raw Eb/No) for R = 1/3. The BER curve is pretty flat out there, i.e., it's asymptotic from 1e-1 at -1dB to 5e-1 at -infinity, so for capacity-approaching codes they're all going to be in the ballpark of
1e-1 for the code to work.
Maintaining synchronization down in that mud is a whole 'nuther issue, and satellite transponder bandwidth is expensive enough that it's very rare to see codes lower than R = 1/2. Keeping a practical demod synchronized below about 0dB is not at all trivial.
So I'm skeptical. In a practical system, especially a practical satellite system, I think it'd be very difficult to operate with an input BER of 1e-1.
--
Eric Jacobsen
Minister of Algorithms
Abineau Communications
http://www.abineau.com
Neither is 2Mb/s. And JTRS is struggling to get that.
d
s
Tail wagging the dog.
e
Using antiquated technology. There does exist technology that allows a person to walk and talk at the same time, btw. This is the thesis of my argument.
nt
They need to stop thinking in "waveforms" and start thinking in "networks", which they are starting to do now, and also taking credit for, even though they have wasted 10 years so far. This notion of "waveforms" is what got them into trouble in the first place.
Well, jamming is always possible. This is why some missiles are guided by physical wire, and some by laser. The frequency bands are public information. Knowing that, it's pretty easy to create a jammer.
And worrying about data security is like worrying about person's brain being exposed during brain surgery. If the surgeons standing around the table know what they are doing, it is not a problem. If they do not, it is a problem.
The premise of cryptography is that the cranium is always wide open, and everyone in the room is OK with that.
The crypto adversary, by design, is permitted full access to the encrypted data, to take with him, store it on his 1TB hard disk for analysis over a 10-year-period. Whatever. S/he may attack all s/he wants, and nothing bad will happen.
This is the mindset and basis of conception of a cryptographer. It is a fundamental assumption.
Every report that I have ever read about JTRS by oversight committees essentially say that, at least until 2005, it has been a dismal failure, and that the people running it do not know what they are doing [technically that is].
The requirements have not really changed. The only thing that has really changed is that the JTRS people have learned that hype and excitement is not enough to find solutions to hard problems. You actually need to know what you are doing.
e
Military is still using same radios they were using 15 years ago, and will continue to do so for the foreseeable future.
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Oh they work. There is no doubt in my mind that they work.
It is hard for something not to work, when they spend 10x, 100x, 1000x what you normally would to achieve the same result.
And then they jam, crash, explode, not explode, miss, crash, crash again, and crash some more.
Everything from M1-16, which were notorious for jamming in Vietnam:
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To B1-bombers crash:
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... looks very pretty in well-prepared collateral that military puts on. But I have talked to soliders back from Iraq, and they all have horror stories about things not working, especially comm's. And it's not like Windows, where a reboot fixes everything.
The Predator that started this thread has a 33% crash rate:
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Given the amount of money spent by US Military on their "programs", there has to be less expensive ways to get the enemey.
The link above does not say so, but JTRS is hoping to get 2 (that's "two") Mb/s from the bands they have available. I cannot find the table that lists the entire repertoire of bands, but I can tell you, any communications engineer who looks at that table, and hears what they are hoping for, will laugh. I wish someone from IEEE 802.11 committee where on this thread to add some input.
The follow link is classic example of what I am talking about W.R.T. to all hype and no pudding. This guy was acquisitions director. I doubt that he knows what QAM is, yet moving to ultra-exotic quantum mechanics is vaguely under consideration:
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*** But compression and even the new JTRS radios aren=92t going to solve the Army=92s bandwidth problems, Bolton said. =93Whether you ask me to compress, prioritize or go to a different band, those are all Band-Aids. Eventually, you run completely out of bandwidth. Now what? I need that information,=94 he said. One possibility, albeit long-term, may lie in the exotic world of quantum mechanics, where researchers are pondering methods of communication that use no radio transmissions at all, he said.
***
Now normally, this would not be a problem. This is relatively innocent. Thinking ahead is a good idea, and he is just musing out loud. The problem starts when you get 10, 100, 250 of these guys super excited by these buzzwords, and all of a sudden, everyone is an expert on quantum communication. Then you convince a senator, who might have a J.D. in law and is not dumb at all, but doesn't understand difference between a bit and byte, to sign on... and there you have it...a $50 million program on something that, in a room of a 500 people, perhaps only 3 actually know what's going on. And these 3 know better than to be too aggressive about their detractions, because the
497 have already been going around telling their spouses and the rest of the world that they are "key contributors to a technology that will revolutionize the way the military communicates." Now everyone's bacon is on the chopping block, the urge to push at all cost overtakes everyone, even though the truth is what the 3 knew from the beginning: "This whole thing is stupid, and even if it were not, the people actually trying to do it are not qualified to be trying to do it."
This is what JTRS is, only that the overal all, high-level, vague end- result is good and the gap between fantasy and reality is not nearly as great, but still so great that $11 billion has been wasted and the appropriations committees are thorougly frustrated.
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