Although Chang Haonan had reduced the length of the message as much as possible, he still wrote about two or three thousand words in the end.

And almost every sentence has to be considered.

After all, many of these details come from the memories of previous lives, and there is definitely no way to write them directly.

In order to improve his convincingness, he had to say that the maximum take-off weight of the An-70 was only three-quarters of that of the Il-76MF, which would be an easier reference in the future.

Fortunately, the core of this proposal, that is, Antonov's lack of money, is easy to explain.

Let's just say it's a guess.

Anyway, everyone can guess.

It's just that Chang Haonan knows very well how short of money they are, so he dares to make such a plan that seems a bit bold.

When this operation was over, he handed over the draft of the telegram to the director of the confidential office, who had been waiting outside, and the whole afternoon had passed, just in time for dinner.

Standing in the cool breeze of early spring in April, the tiredness caused by the afternoon in the confidential room disappeared in an instant.

Chang Haonan remembered that a few hours ago, he decided to go for a good meal.

After hesitating for a moment, I felt that it was a bit unreasonable to eat alone.

After winning many high bonuses (by the standards of this era), and usually eating and drinking without spending his own money, he is now a small tyrant.

In the end, he turned around and prepared to go back and call the comrades from the 14 institutes who came to Yanliang on a business trip, and of course Xu Yang.

As for the name, let's just say that it boosts morale and prepares for the next round of electronic warfare pod tests, anyway, if you count the days, the Jinling side should also ship things over.

But when he pushed open the door of the research room, he found that everyone inside was already beaming, as if he knew in advance that someone was in for a treat tonight.

"Guys, how about going out to dinner together in the evening?"

Although he was a little curious, Chang Haonan, who was in a good mood, decided to talk about the important things first.

Then he received more than a dozen glances with the same doubts and surprises:

"Aren't you going out in the afternoon?"

"yes."

Chang Haonan nodded.

"Then how do you know that Guo Gong has come up with a good idea?"

"Yes, Dr. Xu also thinks his idea is fine."

"And we simulated it on the previous circuit, and it worked."

“……”

Everyone, you say a word to me, Chang Haonan finally understood that this should be an oolong.

"So, what's the idea?"

He took off the scarf around his neck and hung it next to him, walked over to Guo Lin and asked.

Lin Shikuan of the 601 Institute has become a digital design engineer who can take charge of himself under the guidance of him and Yao Mengna, and has solved many problems for the aviation industry under the condition that Chang Haonan is not skilled.

It would be nice if it could be reproduced in the 14th Institute of Electrical Engineering.

"Ahem—"

Hearing Chang Haonan's question, Guo Lin instantly became excited.

It's been so long, and it's finally my turn to play the trick.

He switched to sitting upright in an instant.

It's a pity that no other person has enough eyesight to see the pen and paper handed over to him, so he had to take it from the table next to him, which lowered the B grid of this set of actions a lot.

"I came up with a way to confirm the enemy's location by detecting the radar signal emitted by the enemy."

"Where? The kind that includes distance? ”

Chang Haonan instantly became interested.

Passive tracking of radar radiation sources has been used in anti-aircraft suppression operations (SEAD) since the Vietnam War, but in practice, until the mid-90s, such detection could only tell the location of the target, not determine the distance between friend or foe.

Of course, this is not a problem for general anti-radiation missiles and electronic jamming, because even if I don't know the distance to the target, as long as I always stick in the direction from which the radar wave is coming from, I can always find the source of the signal.

However, with the continuous progress of air defense technology, the signal detectability of the radar itself is constantly decreasing, and even the radar emission source can work while moving at high speed, which leads to the fact that the traditional single-station passive positioning can not continuously and stably track the signal emitted by the radiation source, resulting in a great registration deviation, and the efficiency of the radar to carry out hard killing through the combination of passive detection and anti-radiation missiles has declined sharply in the 90s.

For example, in 1982, the AGM88 Hamm could almost kill indiscriminately, but by 1999, in the face of the weaker resistance of the southern army, the hit rate was reduced to a miserable level.

This circumstance also gave birth to third-generation electronic warfare aircraft, represented by the EA18G.

Now Guo Lin said that he could solve this problem, which really shocked Chang Haonan.

"Uh...... Not really. ”

Guo Lin scratched his head a little embarrassed:

"But it can sort radar signals in a complex electromagnetic environment and effectively identify the most threatening one, at least much stronger than our existing methods, which can only obtain target signals intermittently."

"Oh......"

This answer made Chang Haonan's thirst for knowledge just now drop slightly.

But it's okay, at least it's an improvement:

"Tell me about it."

"In this way, a few years ago, someone proposed a transformation algorithm based on harmonic suppression of the autocorrelation function, which can transform the TOA of the pulse signal from the time domain to the PRI domain, and effectively suppress the harmonics of the real PRI of the pulse signal, that is, if we assume that the TOA of each pulse is an ideal unit impact function δ......"

"Wait a minute, wait a minute."

Chang Haonan directly stopped Guo Lin's introduction:

"I know the PRI, we can go straight to the next paragraph."

"Uh...... Good. ”

Guo Lin next to him also realized that he was a little carried away, and even tried to introduce this basic knowledge to the other party, so he quickly gathered his thoughts and continued:

"In short, the error of the pulse phase factor of the PRI algorithm will increase as the pulse TOA of the jitter PRI signal increases, and the accumulated pulses of the jitter signal will be dispersed into different PRI boxes."

"So I thought that the algorithm could be improved in two ways, one was to introduce the concept of a variable time starting point to avoid errors caused by the phase factor, and the other was to use overlapping PRI boxes for anti-shake processing...... Anyway, this is what I designed the process to look like. ”

He was obviously prepared, and directly took out a beautifully drawn flow chart from below and handed it to Chang Haonan.

The latter had forgotten about the thought of going to dinner on the way, and picked up the piece of paper and looked down to think.

After watching motionless for more than ten minutes, Chang Haonan finally raised his head again and looked at Guo Lin next to him:

"It's a very perfect idea, and it's quite okay for a person to think of this level."

"I'm not alone, other comrades have also helped me correct some things these days, but fortunately, from the test results, the repetition frequency of the three groups of signals can be identified at the same time through an improved PRI transform calculation, and there is no false PRI peak, and the processing ability of strong jitter signals has been greatly improved."

Guo Lin was a little embarrassed to stroke his hair.

He deliberately did not consult Xu Yang and Chang Haonan before this afternoon, just to see if he could get this idea through with his own level.

"Good idea."

"However, it is probably not enough to identify the target signal alone, or to use electronic jamming for soft killing, in operations facing the new century."

"I have a relatively straightforward personality, I like to cut grass and eradicate roots, and it is always a hidden danger not to blow up the radar on the opposite side."

Chang Haonan put down the paper in his hand:

"But then again, you inspired me."

"On the basis of being able to effectively sort radar signals in complex environments, there is no need for us to focus on anti-radiation operations...... It should be possible to use some means to allow the aircraft to use passive radar to directly have the ability to detect and track targets, I mean, even if there is no target with the radar turned on, of course, if the target with the radar turned on, it is better. ”

"Ahh

Guo Lin's expression became a little stiff.

Chang Haonan also noticed that the other party seemed to be a little hit:

"However, your algorithm still has academic value, if it is sent, it may be a little difficult for professional journals of control, but there is still hope for journals that intersect aerospace and control disciplines, such as IEEE Transactions on Aerospace and Electronic Systems."

"This is out...... Is it really okay? ”

As an employee of 14 institutes, this sensitivity is still there.

"No problem, the PRI algorithm itself is not a new thing, and it is a fairly basic research, rather than pinching it in your own hands, it is better to send it out to more people to see."

"The key to getting into the specific model is the part I just had in mind."

“……”

This time, Guo Lin was hit even harder.

(End of chapter)