Chapter 538 History: Are you going to kick me again?
Mentioned it a long time ago.
There are more than 1,700 academicians from the two academies in China, covering a wide range of fields.
Therefore, even practitioners in the industry like Xu Yun cannot fully recognize the appearance of each academician.
Like the pick-up scene for the Dark Matter press conference.
Even if Xu Yun and Lu Chaoyang were put together, many academicians would not be able to recognize their identities.
But on the other hand.
These "unrecognizable" academicians are basically relatively young and newly promoted academicians.
For example, in 2023, you will still be in your fifties and sixties.
Xu Yun could still recognize most of the big guys who were over eighty years old and whose professional title was defined as "senior academician".
After all, the reputation of such academicians is basically not low.
If the age is pushed back a little further, it will be reduced to the first few batches of academic members of China.
Then their identity will be more identifiable.
Just like this moment.
Even though some of the big guys looked very young, Xu Yun still recognized their true identities.
For example, the man standing by a tent not far away was flipping through a report or list.
This person has a face with a Chinese character, the corners of his mouth are slightly pursed unconsciously, and his eyes are not big but have a large proportion of black pupils.
He was none other than Academician Sun Junren, who became famous in later generations.
He is a well-known electronic information expert in China. The Radar Engineering Department of PLA College of Communications was established by Academician Sun Junren himself.
There was also a man standing not far from Sun Junren.
This man was probably in his early thirties, with good facial features, a straight nose, and an extremely handsome face, quite a bit like Planck's youthful demeanor.
He was Academician Baozheng, and his reputation in later generations was even greater than that of Academician Sun Junren.
Baozheng is known as the ‘chief referee’ in the Chinese radar industry, the pride of Xidian’s radar department, and the old principal of Xidian.
The Baozheng series of later generations can be said to play a decisive role in the Chinese radar industry. Many radars in China are produced by this series.
Under the situation that the domestic radar profession is "poor and useless".
He has participated in the teaching or tutoring of almost all courses in the radar major, and has dabbled in new knowledge such as information theory and network theory.
Textbooks such as "Radar Indicating Equipment" and "Pulse Technology" were compiled.
The first microwave weather radar in China was also developed by Baozheng.
In addition, he also invented the "impact flashover method" for fault detection of buried power cables, which solved a major problem in the power supply department.
Of course.
Baozheng is still relatively young these days and is far from reaching his future heights.
Therefore, at this time, Baozheng was just standing next to a little old man with a bald forehead, a huge nose, and extremely obvious nasolabial folds, and started to attack.
It's a coincidence.
Xu Yun also happened to know this person.
Because the other party was Mr. Luo Peilin, one of the first academicians of the Chinese Academy of Engineering and the main founder of Xidian’s electronic information engineering profession.
Mr. Luo Peilin also guided the development of my country's first ultra-long-range radar and the first-generation series of computers. He is a truly respected senior.
In addition, Xu Yun also met several outstanding people such as Bi Dexian and Xiao Guozhen.
Some of them are now members of the academic department - later academicians.
Some are still the youth version of Big Brother, waiting for version update or Longchang enlightenment.
In addition, there are some experts that Xu Yun doesn’t know but who seem to be very good. Most of them are great masters whose names Xu Yun has heard of but whose identities he cannot match. After all, there is still a gap of several decades between now and later generations. Some big guys His appearance has changed a lot.
When Xu Yun and others arrived at the watchtower.
Most of these big guys are concentrating on their work.
Some are measuring various data.
Some are calibrating and moving instruments.
Some are wielding hoes to dig out foundations - as mentioned before, watch towers are not actually perfect radar placement points.
In addition, there were many staff coming and going at this time, so the appearance of Lao Guo and others did not attract much attention.
Even if someone noticed the figures of Lao Guo and the others, they only glanced at them and looked away.
Lao Guo didn't greet too many people, and led Qiao Caihong and Xu Yun directly to where Sun Junren was.
This area is located on the shady side of the watchtower. It is about a hundred square meters open and has several sky-blue tents.
There were some supplies and a few tables inside the tent, making it look like a temporary command point.
When he was still seven or eight meters away from the tent, Lao Guo waved his arm towards Sun Junren.
"Hey, Lao Sun! Long time no see!"
Sun Junren was looking at the material distribution list at this time. When he heard someone shouting, he subconsciously raised his head and followed the sound.
After seeing that the visitor was Lao Guo, Sun Junren took a long breath visibly, and his eyes showed a deep joy.
He quickly put the mixing list on the table and walked over quickly:
"Hey, Lao Guo! You've just come out of nowhere. When I arrived at the base, I couldn't see you for a long time. I thought you wanted to default on your debt and run away!"
Say it.
Sun Junren made a fist with his right hand and lightly punched Lao Guo on the shoulder.
Four years ago, Sun Junhe and Lao Guo visited Mao Xiong with the Rabbits' industrial delegation and stayed in Mao Xiong for several months.
Although one of their teams was negotiating the radar business and the other was negotiating nuclear weapons, there seemed to be no overlap.
But what a coincidence.
During their stay at Mao Xiong, they happened to be placed in the same dormitory, a double room, and they could see each other every day when they looked down and up.
As time goes by, you will naturally become familiar with it.
At that time, Mao Xiong's policy towards the delegation was somewhat similar to later generations of overseas student subsidies. Each member of the delegation would receive a ruble subsidy for their daily expenses.
The specific amount was 30 old rubles per person per month - at that time, Mao Xiong had not yet carried out the third post-war currency reform, and 30 rubles was about 7.5 US dollars.
This part of the subsidy is provided by Mao Xiong, so Rabbit, who is in urgent need of foreign exchange, also has a voluntary exchange plan:
Each member of the delegation can exchange the old rubles for Chinese currency, and the purchase price is 1.5 times higher than the normal exchange rate.
Therefore, many members at that time would save their subsidies and exchange them with the country for more money to spend when they return to China.
This chapter is not over yet, please click on the next page to continue reading! After all, the furry bear provides daily meals and accommodation, so you don’t usually have to spend much money.
Of course.
There are also some people who do not choose to redeem.
The idea of these members is basically to buy something from Mao Xiong that is not available in China. After all, the living standards at home and abroad are still very different these days.
Lao Guo is one of them.
But what Lao Guo wants to buy is not a luxury item, but chlorpropamide - Lao Guo's wife Li Pei suffers from severe diabetes.
Chlorpropamide was the first-generation oral hypoglycemic drug invented in 1955. It was very effective after its introduction, but at that time it could only be purchased abroad.
As a result, Lao Guo had saved up three months of subsidies, and before leaving, he found that he was still 20 old rubles short, so he, Sun Junren, and Zhu Guangya each borrowed 10 old rubles to buy medicine.
After returning home.
Lao Guo quickly returned Zhu Guangya's part of the money, but Sun Junren's money was delayed because he couldn't contact anyone, and he couldn't even send a letter.
This is the first time the two have met in more than four years.
Facing Sun Junren who came to "collect debt" aggressively, Lao Guo punched him in the face with a smile:
"How can I run away? Do I, Guo Youlai, look like that kind of person?"
"I haven't had the chance to see you. I've always written this down in my notebook. I can't forget it. I can't forget it."
Say it.
Lao Guo carefully took out a stack of square envelopes from his body and handed it to Sun Junren:
"Well, the money is all here. I knew you were coming today. I prepared it specially."
"Come to think of it, you didn't ask me to ask for the IOU at the beginning. Can I actually not pay you back the money? Haha?"
The speaker has no intention, the listener has intention.
Hearing what Lao Guo said.
Xu Yun's originally relaxed heart suddenly sank slightly.
He remembers it clearly.
The thermonuclear data that Lao Guo and guard Mou Fangdong had to protect at the risk of their lives also contained a small notebook, which recorded many of Lao Guo's to-do matters.
In the middle of the second page of the book, there is a passage:
[January 3, 1958, Moscow, owed Comrade Sun Junren 10 rubles, which is equivalent to the Chinese currency of 4 yuan and 30 cents, and has not yet paid]
According to normal conditions.
Lao Guo would have the opportunity to meet Sun Junren in two months.
However, due to the plane crash, Lao Guo forever lost the opportunity to repay the money with his own hands...
But now it is influenced by Xu Yun.
Sun Junren, who had never come to Factory 221 in history, appeared here today, and Lao Guo finally settled his worries.
Maybe this is the meaning of time travel...
........
Look at the envelope in Lao Guo's hand.
Sun Junren also stopped smiling instantly.
Then he slowly took the envelope, stuffed it into his pocket without looking at it, and sighed:
"Lao Guo, you are serious."
"Hey, repaying debts is a matter of course."
Lao Guo smiled lightly, waved his hand, shook his head and said:
"There's nothing intentional about this. Just don't blame me for delaying it until now."
Upon hearing this, Sun Junren patted Lao Guo on the shoulder and said no more.
It may be difficult for future generations to imagine why two academician-level tycoons did not have the opportunity to meet or even send money for four years... no, including the time Lao Guo sacrificed, it should have been a full 10 years.
But in this day and age, this is actually a very common thing.
Some people remain anonymous and may not see anyone for ten years.
Some people are running around and their whereabouts are uncertain, and their families don't know when they will come back.
There are also some people who are so busy with their work that they forget many things while doing them. When they think about it, they may not have the conditions to do it.
Lao Guo's time is not the longest.
There is a big boss in the base named Wang Ganchang, whose pseudonym is Wang Jing for 28 years.
28 years later, on July 3, he received the mouth organ he bought 28 years ago...
One generation has suffered the hardships of three generations. This sentence is really not self-impressing.
After a while.
Sun Junren took a deep breath and pushed his emotions to the back of his mind.
He turned around and looked at Xu Yun, looking him up and down:
"Lao Guo, this is the seventh-level man who came up with the weather Doppler radar plan... Ahem, Comrade Han Li?"
Lao Guo nodded, turned around at the same time, and introduced Xu Yun:
"Xiao Han, please introduce me. This is an old friend of mine, Comrade Sun Junren, who is currently a seventh-level worker at the Jinling Radar Factory."
Xu Yun glanced at this 'old master' and smiled as if he didn't know anything:
"Hello, Gong Sun, I am Han Li."
Sun Junren took a deep look at Xu Yun.
Don't look at the fact that Liu Bosheng and the chief already know the accuracy of the principle of weather Doppler radar.
But in fact, only professionals like Sun Junren understand how terrifying that principle is.
It can be said like this.
Judging from the information currently available to Sun Junren and others.
The research and development progress of Doppler radar across the sea is at most only 10%-15% of this plan!
This is a very disruptive number.
Even if Xu Yun is only the transmitter of relevant theories rather than the founder, he is still extremely extraordinary.
More importantly...
Sun Junren was by his side when the chief was on the phone with Liu Bosheng, and he knew very well the chief's attitude towards this young man:
Respect, protect.
And if there is a chance, I hope to meet or chat on the phone.
That's the chief...
Speak the truth.
Sun Junren was even a little jealous of Xu Yun.
However, Sun Junren also knew that they had serious business to deal with at this time, so he quickly suppressed this emotion.
I saw him looking around, pointing at the tent and saying to Lao Guo and Xu Yun:
"Lao Guo, Comrade Han Li, it's a little hot outside, let's go to the tent and talk."
Lao Guo and Xu Yun had no objection to this.
Then Sun Junren led the three of them to the tent, picked up a small bowl from the table, and handed it to Lao Guo and the others:
"Come, eat some watermelon, we brought it here from the capital."
The mouth of the bowl in Sun Junren's hand is about ten centimeters in diameter, similar to the soup bowls in later generations of noodle shops, and it contains some cut watermelon.
Each piece of watermelon is cut very "delicately" and is about the size of a sugar cube that was used to make coffee in later generations.
Some watermelons also have bamboo sticks stuck in them, so that everyone can eat them.
Seeing this, Lao Guo took the initiative to pick up a watermelon with a bamboo stick stuck in it, put it in his mouth and chewed it a few times. After a while, he spit out two watermelon seeds:
“So sweet!”
"It's delicious, isn't it? We grow it ourselves in our yard."
Sun Junren smiled at him and turned the small bowl to Qiao Caihong and Xu Yun:
"Come on, Comrade Nurse, Comrade Han Li, you two should try it too. It's not easy to eat such fresh watermelon in the West Sea."
Qiao Caihong glanced at Lao Guo, and after receiving his permission, he generously picked up a bamboo stick and handed it to Xu Yun:
"Comrade Han Li, open your mouth."
Xu Yun has basically been 'fed' by Qiao Caihong these days, so he didn't feel embarrassed in this situation and opened his mouth obediently:
"ah......"
Qiao Caihong took advantage of the situation and put the watermelon into Xu Yun's mouth.
The bright red flesh of the melon carries a special fragrance. When you bite into it, the juice fills your teeth and slowly flows down your throat, instantly making your whole body feel refreshed.
Sun Junren put his hands behind his back and waited until Xu Yun took several bites before saying:
"Comrade Han Li, how does it taste?"
Xu Yun licked the corner of his mouth:
“Very sweet and moist.”
"That's good."
Sun Junren glanced at him with a smile and said like an old fox:
"By the way, Comrade Han Li, I almost forgot to say that."
"The quantity of our watermelons is limited and transportation is not easy. Each person can only eat three small pieces of pulp after working for half a day."
"Now that you've eaten...one...three...five...oh, six pieces of watermelon, isn't it time to do something?"
Xu Yun was startled:
"?!"
I#, boss, do you want to do this?
Then Xu Yun glanced at Lao Guo who said "I don't know anything" beside him, and sighed as if he was resigned to his fate:
"Okay, Gong Sun, if there's anything I can do to help you, just tell me."
Sun Junren was waiting for his words. After hearing this, he immediately took out a stack of calculation papers and stacked them in front of Xu Yun like a magic trick:
"Here, these are all."
The corner of Xu Yun's mouth twitched twice more:
"..."
But if you think about it carefully, it's normal.
After all, these days are different from later generations.
Today's radar industry is still in a very primitive stage.
Except for those military industry bosses across the sea who are involved in the development of Doppler radar, most experts basically know nothing about the principles of Doppler radar.
Even though Xu Yun gave a very detailed explanation in the telegram, some steps were still difficult to understand.
"The first is Doppler processing at the echo signal."
After Xu Yun agreed.
Sun Junren quickly picked up a pen and paper and drew a circle on the first question:
"Comrade Han Li, you defined it in the telegram as Range Doppler Map, which means range Doppler processing."
"According to your description, this should be a step that processes distance and speed dimensions, right?"
Xu Yun nodded:
"That's right."
When Sun Junren saw this, he snapped his fingers:
"Then the question is, Comrade Han Li, in this step, can't we just perform Fourier transform on the slow time dimension directly?"
"Why do we first require the time distance image, and then do the Fourier transform on the slow time? Isn't there Doppler information in the phase information in the original matrix?"
When Xu Yun heard this, he couldn't help but raise his eyebrows.
Good guy.
As expected of a top guy in the field of radar, he asked such a core question right from the start.
Sun Junren's problem is described in later terms, which can be shortened into another very simple sentence:
Why should the speed dimension FFT be based on the distance dimension FFT instead of directly using the time domain waveform matrix to directly perform the slow time dimension FFT to obtain the speed information?
The FFT refers to the Fast Fourier Transform, but this concept has not yet been proposed at this point in time - because it is an algorithm given to computers.
This sentence can be said to be a very critical difficulty in the principle of Doppler radar. Many people in later generations have fallen into this pit.
Then Xu Yun thought for a while and explained:
"Gong Sun, from a mathematical point of view, the distance-dimensional Fourier transform is performed first for the purpose of velocity calculation."
"Because the velocity is estimated based on the phase difference between adjacent pulses, our radar's own position remains unchanged."
"That is, after the distance-dimensional Fourier transform, the spectrum peak corresponding to the distance of the target does not change."
"That is, what changes is the phase of the frequency point between multiple pulses, and this change is the same as the phase change in the time domain signal."
Say it.
Xu Yun wrote a derivation process on the paper with his hands that could barely move:
If there is a peak amplitude without a target that is much smaller than the peak amplitude with a target:
abs=\sqrt{(A^2 B^2)}\ll abs'
Then there exists: A?A′,B?B′A\ll A', B\ll B'
Therefore, there exists:
Z=A i B,heta=\arctan (B / A)\ll\arctan (B'/ A')
At the same time ds2=?c2dt2 a2(t)dr2=0
It can be obtained that c∫t1t0dta(t)=∫0r1dr
c∫t1 δt1t0 δt0dta(t)=∫0r1dr......
As we all know.
The purpose of doing FFT in the distance dimension is only to find out the relationship between distance and frequency, without any change in the phase of the distance.
Therefore, the speed dimension FFT is based on the distance dimension FFT and only extracts the phase change at the distance position.
If the second speed dimension FFT is not based on the result of the distance dimension FFT, of course the speed of the target can also be obtained.
but......
This speed cannot distinguish whether it is the speed of a single target or the speed of multiple targets.
That is to say, the speed only remains in a straight line, and it cannot distinguish whether there are two targets with the same speed and different distances. This sentence is very important. In a few chapters... ahem, I will test it later.
This chapter is not finished yet, please click on the next page to continue reading the exciting content! Of course.
Later generations of computers would have a clearer answer to this question.
Because computers can use Python to create more intuitive diagrams that are easier to understand.
However, Xu Yun's explanation is quite thorough, at least for industry insiders like Sun Junren.
"So that's it..."
Sun Junren touched his chin, hesitated for a moment, and guessed:
"Since it cannot be converted directly, it means that after the radar is operated, a signal with a frequency of zero but high energy should appear?"
Xu Yun stopped talking:
"?!"
At this moment.
Suddenly there was an urge to turn the table over in my heart.
I#, have a problem!
Nowadays, weather Doppler radar is just a component. Has Sun Junren realized an important situation that will only be discovered eight years after the Doppler radar is put into operation?
Students who have made radar spectra should all know this.
After doing the FFT in the distance dimension and then doing the spectrum of the FFT in the speed dimension, you will find that a very high energy peak will appear at the position where the distance gate number of the zero-velocity channel is equal to 0.
The frequency of this signal is zero, so it is also called the DC component - the so-called DC has only magnitude and no direction.
Sometimes this DC component is relatively small.
Sometimes it will be larger.
When it is large, it can reach the level of 10^5.
When I was little, it was on the order of 10^3.
In principle.
There are many reasons for the DC component to appear.
For example, the isolation between transmitting and receiving is not good enough, it cannot be balanced under noise conditions, etc.
Therefore, these reasons are actually not the point. The real point is...
Before the emergence of Doppler radar, the concept of DC component did not exist in spectrum frequency - because the multi-angle formula has not yet been used in the field of radar to process signals.
more importantly......
If you notice the DC component and try to block it, the rabbits are likely to discover another new world in advance!
That is...
Hysteresis control inverter!
That's right.
The opportunity for the emergence of hysteresis control inverters is the DC component of Doppler radar.
It would take another seven years before the concept of DC component was discovered in the frequency spectrum, then DC isolation would be considered across the sea, and two years later the hysteresis control inverter would be invented.
You may not be familiar with this stuff, but one of its key applications is certainly familiar to everyone:
It is a vital application of stepper lithography machine exposure pool and microprocessor.
The reason why Philips was able to overcome the technological blockade back then was to invent step-scanning lithography technology.
One of the important breakthroughs is the development of hysteresis control inverter.
And that was already in the late 1990s...
True.
The span from DC component to hysteresis control inverter is very long, and the span from hysteresis control inverter to lithography machine is even further apart.
In a sense.
This is as difficult as going from the sentence "The 21st century is the century of biology" to a novel of 3 million words. There are too many coincidences in the whole process.
But the problem is....
In this copy, there is Xu Yun, a tentacle monster with 30,000 updates per day!
As long as he gives a little guidance, this is a process that can evolve smoothly.
After all, due to the existence of the 404 master, Xu Yun was unable to change certain general trends.
But this kind of kicking the butt of history can still be tried.
For example...
Let the rabbits have the ability to produce 1 micron chips in the 1980s?
hiss.......
This picture is so beautiful.
Xu Yun then wiped the non-existent saliva from the corner of his mouth and brought his mind back to reality.
Although the picture is beautiful, the more critical thing now is to deal with the assembly of the weather Doppler radar.
So he coughed lightly, raised his eyelids and looked at Sun Junren, and explained:
"Yes, Gong Sun, according to theoretical derivation, Doppler radar should indeed appear such a special signal."
"And according to the speculations of other seniors of Fengling Yueying Club, if it is not a periodic signal, then the process of taking the limit should be omitted when expressing it with a mathematical formula, and the integral limit can take any period."
"Of course, these are just theoretical calculations. It may be possible that the signal will not appear at all by then."
Hear this.
Sun Junren nodded slightly.
This period is currently at the peak of the development of physical phenomena, and mathematical theories are often questioned because they cannot explain phenomena. Therefore, the situation mentioned by Xu Yun is entirely possible.
Moreover, Sun Junren is not yet aware of the possible impact of the DC component. At most, he just feels that this is a relatively special situation.
So it's very fast.
Sun Junren turned his attention to the second question and pointed to Baozheng beside him:
"Then let's talk about the next question, Comrade Han Li. This is a question raised by my assistant Comrade Bao Zheng."
Then Sun Junren turned over a page of manuscript paper and said aloud:
"Comrade Han Li, according to the theory you proposed, the weather Doppler radar uses the clutter suppression idea in filtering. The process is indeed very subtle."
"But according to Comrade Baozheng's calculation results, this suppression process seems to be a bit weak. At least a Doppler filter with zero notch is definitely unable to suppress rain clutter and ground clutter."
"For example, within the range of 2-5 pulses we should be able to handle it normally."
"But if the input to the filter is 8-10 pulses, it's almost impossible to shape them as you say."
"So if weather Doppler radar wants to take on a larger range of data collection tasks, then this problem must be solved."
Hear this.
Xu Yun couldn't help but glance at Bao Zheng, who was standing next to Sun Junren.
Good guy.
This boss really didn't disappoint him.
The two questions raised by him and Sun Junren are basically the two most critical theoretical issues outside the implementation process of early meteorological Doppler radar.
And it is different from the DC component.
This problem of Baozheng is not a minor problem, but will directly affect the efficiency of the weather Doppler radar.
Another thing is...
Sun Junren's prediction of the DC component was not part of Xu Yun's plan, it was an accident that even Xu Yun did not expect.
But the filtering problem raised by Academician Baozheng was deliberately created by Xu Yun, a fisherman...
Mentioned earlier.
The filter design solution Xu Yun gave before was a relatively simple 2-pulse MTI canceller, which was relatively cheap to produce.
There is a very special thing about this thing, that is, it is very narrow in the Doppler space.
It is so narrow that it can only accommodate two pulses at a time. If the pulse is thick, it can only be one, and any more will cause it to expand.
As for ways to fix it...
Think of this.
Xu Yun couldn't help but show a trace of embarrassment on his face, shook his head and said:
"Gong Sun, to tell you the truth, it may be very difficult to solve this problem. It cannot be solved by your small factory."
Sun Junren raised his head and glanced at him, with a true expression on his face:
"Indeed, but it doesn't matter. Comrade Han Li, just say whatever you want."
"Even if it can't solve the problem, it can at least help Xiaobao and I solve our puzzles, don't you think?"
Baozheng on the side also nodded innocently.
Xu Yun:
"..."
These big guys seem to be surprisingly thick-skinned...
But this is fine.
Since you are so thick-skinned, don't blame me for pretending to be stupid.
Anyway, Biao's acting skills have been tested by three copies of Mavericks, Lao Su and Xiaomai, and he has never been afraid of anyone.
So Xu Yun quickly showed an expression of approval:
"In that case, Gong Sun, let me just talk about it casually."
"The method of implementing a strong filter bank is actually very simple to put it bluntly. It is to use the discrete Fourier transform."
"That is to use a Doppler filter bank and a combination of 2 PRFs to establish a blur function to solve this problem."
“Fuzzy function and PRF?”
Sun Junren blinked, quickly picked up his pen and calculated:
"Oh, you mean to introduce multiple beams, right? Then use a matrix to construct a response function, and perform efficient frequency domain calculations on the augmented area..."
"Well...this is a very innovative idea..."
"L selects the smallest positive integer raised to the power of m that is greater than 2N?1, that is, L=2ceil(log?2(2N?1)), and then constructs a y sequence of L points y=gL(Wn2/2⊙x
)..."
"Where W=exp?(?j2πaN), n=[?N/2,...,N/2?1], ⊙ represents the dot multiplication operation..."
The results are written and written.
Sun Junren suddenly paused and his breathing stopped for a moment.
A few seconds later.
Sun Junren calmly folded the calculation paper and put it aside, raised his head and said to Xu Yun with a 'casual' smile:
"I see... But Comrade Han Li, this calculation process should be more difficult, right? It seems like the amount of calculation is huge?"
Xu Yun still nodded with a cute look on his face:
"Yes, this step requires digital processing using computer software, so I said it cannot be done by your small factory."
Say it.
Xu Yun quickly pretended to cough slightly to cover up the corners of his mouth that were about to rise higher than the Dragon King.
no doubt.
Sun Junren's action just now was definitely a sign of taking the bait!
After all, the idea proposed by Xu Yun is not difficult in theory, but no one has ever thought of it.
That is...
The Chirp-z transformation is performed through the fuzzy function to convert the Doppler distance into a convolution form.
And here we are.
Sun Junren will find that the data he calculated has been converted into variants of the other two parameters:
Ground speed and deflection angle.
These two parameters are necessary data for fighter jet radar!
The two rabbits started researching this aspect ten years ago, but there is still no actual output data!
Of course.
Fighter radar is not Xu Yun's ultimate goal.
After all, the early warning technology of fighter radars in later generations is very complex. The gap between domestic fighter radars and those across the sea is actually not that big.
Some people think it's more than that.
Some people think there is still a gap.
But no matter which point of view one holds, no one thinks that this gap exists in the concept of "generation".
Oh, except for the military propaganda where the aircraft carrier can be photographed as a small fishing boat...
Therefore, Xu Yun's real target is not the radar.
But...
What you need to develop radar.
That is -
Domestic industrial software!
........
Note:
The 10,000-word update on the fifth day, the double monthly pass will end soon, please give me a monthly pass!!!