Chapter 825 Test, Target Feature Extraction
Of course, using ballistic missiles to counter aircraft carriers is definitely not that simple. It can be solved by developing a target classification algorithm.
First of all, the prerequisite for "target classification" is to detect the target.
But how to enable ballistic missiles to overcome black obstacles and use radar normally during re-entry into the atmosphere is a huge problem...
Reducing the re-entry speed to less than 5 times the speed of sound can be done from The root cause is to avoid the formation of black barriers. However, low-speed ballistic targets are the easiest targets for the air defense system to deal with, which defeats the original purpose of using ballistic missiles to fight ships.
If you wait until you have passed the black barrier area before turning on the radar, the reaction time will be too short and it will not be enough for the missile to adjust its attitude.
Secondly, to find the location of the aircraft carrier battle group in the vast ocean before striking, a complete global ocean monitoring system is needed.
At this moment, China has just launched its first land transmission remote sensing satellite.
The second and third ones are Ziyuan No. 2 01 and 02 that are about to be launched——
This is also the original reason why Chang Haonan rushed out to conduct technical tests before the Spring Festival. .
As for ocean remote sensing satellites...
Sorry, there are not even one yet.
In short, at least in 2000, the development of anti-ship ballistic missiles was still something that could only be thought about -
Most people did not even dare to think about it.
On the contrary, Wang Xiaomo’s idea is more realistic.
In particular, Chang Haonan has previously considered designing an anti-submarine patrol aircraft based on the C808 platform with comfort and range that exceeds or is as good as the P3C.
In the current context where the main tone of the confrontation is to fight without defeat, the importance of this equipment is not less, if not more important than conventional main battle equipment such as tactical aircraft.
Thinking of this, Chang Haonan immediately turned around and looked at Liang Shaoxiu, who was a little distracted from radar-related topics:
"Gong Liang, our Air Police 200 didn't do the hardware right. Low-altitude target shielding, right?”
Since the main function of early warning aircraft when developing is air detection, there are some models that directly limit the longitudinal depression angle of electromagnetic waves on the hardware, in order to use the simplest and crudest way. Solve the interference caused by ground echo.
What's more, a shielding layer will be designed under the antenna to directly block the downward electromagnetic waves at large depression angles.
Chang Haonan definitely did not have this thing when he made the plan, but there is no guarantee that it will be added in the past two years.
“No, we just limited the downward angle in the radar background program”
Liang Shaoxiu replied:
“And because it is still a prototype, this limitation can be passed Special command is released. If you have a new target recognition program, just modify the software part here.”
Since pilots and ground crew are not professional aircraft designers, when the mass-produced aircraft is delivered to them, in order to prevent someone from messing with it, the software programs are locked, leaving only some preset input and output ports. .
However, prototypes or technical verification opportunities have a status similar to "developer mode", allowing engineers to make modifications more conveniently.
“Don’t worry, there is no need to make major changes to the current procedures.”
Chang Haonan turned back and looked at the staff who followed him.
The latter immediately understood and took a password box that he carried with him.
After opening it, there are several hard drives inside.
“I have encapsulated the target feature extraction and analysis functions into a module, which just needs to be inserted behind the existing data processing code.”
Having said that, the operation on the early warning aircraft After all, the computer is not a home computer. Just create an installation file in .msi format and wait for it to be completed automatically.
WindowsXP, which was widely used in military terminals in later generations, was still a trendy gadget that could only be installed on the latest PCs.
It has extremely high hardware requirements and is also unstable.
It’s almost like win11 in 2023.
And it hasn’t been officially released yet.
So, it took Chang Haonan nearly a week to completely complete the program update and necessary ground testing.
It even took longer than it took him to write the program before.
Of course, Liang Shaoxiu and the others are not idle these days.
Instead, he helped coordinate with the navy leaders and borrowed a batch of false targets for training.
It’s not something fancy like a self-propelled bait.
Instead, it is a simple method to install different styles of models or corner reflectors on the buoys.
Used to cost-effectively simulate targets of various sizes from sampans to destroyers in non-live fire training.
Belonging to the early years, the army had to endure the period when there was no solution.
The advantage is that it can be deployed with a transport boat or tugboat, and it can be recycled without damage after use.
But later I found that the effect was actually pretty good.
However, because it is a buoy, it cannot be deployed in places such as the high seas and oceans. It can only play a role in relatively shallow locations.
……
The last day before New Year’s Eve.
"Mr. Chang, comrades from the North Sea Fleet sent back a message saying that they have set up all the 35 preset false targets. In addition, the three warships 107, 110, and 519 that are training in the nearby waters will also cooperate with us. Compare the real ship target with the signal characteristics of the corner reflector."
Liang Shaoxiu hung up the phone and said to Chang Haonan not far away.
The latter was at the floor-to-ceiling window of the tower at this time, watching Air Police 200 drive from the apron onto the taxiway:
"Notify No. 20001, prepare to take off."
< br>If it makes sense, then Chang Haonan, as the deputy chief designer, Liang Shaoxiu should be regarded as his leader in the Air Police 200 project.
However, the content of this test actually has nothing to do with the early warning aircraft itself, and the two parties are closer to cooperation.
The reason why it is carried out within the framework of Air Police 200 is simply for convenience.
Moreover, Liang Shaoxiu has actually been learning from Chang Haonan since the time he solved the problem of ice on the wings of the Y-8 platform at the end of 1996.
Like Lin Shikuan from Institute 601 back then, he was considered a half-disciple brought out by Chang Haonan.
So, there was this strange scene in front of us where the chief commander reported the situation to the deputy chief commander, and then the deputy chief commander issued instructions to the chief commander.
A few minutes later, Air Police 200 rose into the sky from the end of the runway, dragging four lines of faint black smoke, and gradually disappeared from everyone's sight.
"Mr. Chang, Comrade Shaoxiu has complained to me many times before, saying that the performance of the turboprop 6 is still a bit lagging behind..." Wang Xiaomo looked at the black wake that had not completely dispersed in mid-air and said, Chang Haonan next to him said:
“I heard that when your aviation power group was established last year, you mentioned a development plan for a turboprop engine?”
Obviously , this is implying...or indicating that we want a turboprop engine with better performance.
In other words, a flying platform with better performance.
If it was Liang Shaoxiu who said this, it would be difficult to determine the balance between suggestions and dissatisfaction.
But Wang Xiaomo has nothing to do with the aviation system, so he has no worries in this regard.
“Indeed.”
Chang Haonan nodded:
"But the design power of that machine is only 1600kw. It is planned to be used for 10-ton helicopters or 20-ton turboprops like the Y-7, which is not the same level."
"As for the 4000kw-class turboprop? …I’m not talking about those that are fictitious. They are indeed not a high priority at the moment.”
“We actually have R&D capabilities here, but the number of technical personnel is still too small to take care of both. There are not too many models, so we can only get the most urgent ones first..."
"..."
When the Air Police 200 landed back, it was almost three hours later. .
According to Chang Haonan's test requirements, the aircraft must conduct four rounds of searches for targets from different angles, that is, two zigzag routes that are generally perpendicular to each other.
For the Air Police 200, which has a somewhat limited range, this is even the longest flight since the first flight of the prototype...
After the ground crew rushed over to conduct inspections on the aircraft While performing maintenance, the engineer on board had also taken down the recorded radar data and handed it to Chang Haonan.
It is naturally impossible to use supercomputing here in Xingcheng Base.
Fortunately, if you just want to check the results or simply adjust parameters, you can use an ordinary computer.
But if the algorithm needs to be improved in the future, then we have to go back to the capital and do it again.
“We marked targets 1-39 in the order we completed the search for the first time.”
The radar operator responsible for following up on the test flight is a Navy Lieutenant Colonel , named Su Changyun, was sitting behind Chang Haonan and Wang Xiaomo at this time, introducing the details of the flight just now:
"It was supposed to be 35 false targets plus 3 ships, a total of 38, but we were on target An illegal fishing boat was found in the sea, so another one came out."
"Then this fishing boat ended up..."
Although this matter had nothing to do with the test, Chang Haonan still couldn't restrain his curiosity.
“We contacted the 110th Dalian Ship through the North Sea Fleet Command, and finally caught them and found out that they were a group of people stowaway.”
“Okay... that’s pretty good. ."
Wang Xiaomo next to him showed a helpless smile:
"Being able to become the first combat result under the command of an early warning aircraft in the history of our country is considered to be recorded in history to a certain extent. …”
"And it also provides us with the typical signal characteristics of a fishing boat."
Chang Haonan added next to him:
"In the future, we can add it to the white list of anti-ship weapons, or at least The aiming coefficient is arranged at the end to avoid accidental shooting..."
Other people here naturally don't know the story of Xiongfeng 3 fishing boats, so they can only assume that he is preparing for a rainy day.
After a brief interlude, everyone returned their attention to the radar data.
There are two sets of data in total, one is original and the other is processed by the recognition algorithm.
In addition to being used for comparison, the difference between the two sets of data itself can also be used as a basis for judging the nature of the target -
Since the radar display is not specifically set, So the result output to the above is a dot.
But in the background running log, the difference can be clearly seen.
The most intuitive thing is that the latter has richer, or clearer, data levels than the former.
"Two targets 1 and 2, four directions, each with two sets of data. The first set was directly hidden in the sea clutter and was not seen. The second set was seen but very faint. It should be a simulated periscope... ”
“The RCS from 3 to 16 is quite large, but it was exposed in the second set of data. It is completely different from the signal characteristics of the three targets 36, 37, and 38... ... Considering the difference in quantity, the first dozen should be different large corner reflectors, and the last three should be the three real warships..."
"17 and 18, four directions There is almost no difference in the detected signal characteristics. It should be a small corner reflector, used to simulate speedboats or patrol boats..."
"..."
Every time Chang Haonan finished speaking, , Su Changyun compared it with the "standard answer" sent by the fleet.
In the end, except for the misjudgment of "reef" and "small boat", everything else was correct.
As far as the first test is concerned, the results are already quite good -
After all, the radar and the computer will not know what the human definition of the target is, it is only responsible for finding the difference.
As for the inductive analysis of signals with different characteristics, it needs to be calibrated slowly later.
For example, the targets with characteristics A are large and medium-sized surface ships, the targets with characteristics B are ordinary bulk carriers, and the targets with characteristics C are container ships...
In fact, this was the fundamental purpose of Chang Haonan coming over for testing.
Although the conditions of early warning aircraft cannot be directly transferred to remote sensing satellites, the methods of feature extraction and selection of calibration anchor points are the same.
“Although it is not perfect yet, the potential is indeed great.”
After seeing all the results, Wang Xiaomo came to a conclusion almost immediately:
“Especially In terms of decoy identification, it is almost accurate at a glance, but unfortunately the amount of storage and calculation required is too large, so it is not suitable to be placed on a fighter radar.”
"That's not necessarily true."
Chang Haonan was already adjusting parameters and calibration methods, but after hearing the other party's words, he still stopped what he was doing:
"The main function of fighter radar is The function is still air search, the background is cleaner and the target features are more monotonous. I can write a simplified version for use with 1473 and 1493 series radars..."
"! >Wang Xiaomo just said it casually, but he didn't expect Chang Haonan to actually come up with a feasible plan.
He stood up and said:
"Then I'll contact the 14th institute. It just so happens that these types of radars, oh, and 346, haven't been finalized yet. We can take this opportunity to work together... ”
(End of this chapter)