Military Industry of Great Powers: Build the Strongest Flanker

The so-called Doppler radar measures the wavelength of the echo during signal processing at the receiving end. When the radar wave encounters a moving target, the received radar wave becomes shorter when it approaches, and vice versa. This is Doppler radar. Le effect.

By detecting the difference in wavelength between the received wave and the transmitted wave, as well as the speed of the aircraft itself, the speed and flight attitude of the target can be calculated, stationary targets and moving targets can be distinguished, and the targets can be distinguished from clutter on the ground background.

The principle of phased array radar transmitting radar waves is different from the traditional principle of transmitting radar waves. It uses hundreds of array antennas and uses a computer to control the phase radar beams, superimpose the radar waves, and complete directional scanning, which can achieve a maximum of power.

Zhao Guoqing thought about designing a Doppler radar. He even thought that if Tsinghua University could manufacture a qualified one-micron chip, it would not be impossible to design and manufacture a passive phased array radar.

But doing so will carry a burden. What about the four to five thousand J-5s, J-6s, and J-7s currently in service in the country?

But for the JL-7 radar, which is destined to be eliminated at any time, to adapt to the digital system, Zhao Guoqing is psychologically resistant.

Its biggest flaw is that its detection range is too short, only a dozen kilometers. It has no guidance capability and poor anti-interference ability. It requires manual adjustment of the radar frequency. If you encounter a passive radar wave jammer, it will make you blind in minutes. You just press the button manually. No matter how fast you go, you can catch up with the machine.

As long as people receive a radar wave once, the interference wave sent according to this wavelength will come.

The mature approach is that when the radar encounters an interfering device, it automatically changes frequency and actively jumps in frequency before the passive jammer emits an interfering radar wave.

Of course, there are also more high-end anti-interference measures, which is to add a piece of enemy or friend information to the radar wave. When receiving the radar wave, verify the information first. By constantly changing the identification information, you can carry out anti-interference design on the same band. Of course, this Technology requires the powerful computing power of radar computers, which is difficult to achieve with current technology, let alone other...

"National Day, National Day..."

"Professor Ji, what's wrong?"

"You asked me what's wrong. I see you've been in a daze. What did you think of?"

Zhao Guoqing waved his hands with a wry smile and said: "Looking at these radars, I feel that we can also use short-range air-to-air missiles like the Monster Snake III, and medium-range air-to-air missiles. Not to mention radar guidance, the range of the missiles exceeds that of our radar. The detection range is up!”

"Who says it isn't?"

Zhao Guoqing let out a long sigh and said: "The design of the shock cone air inlet on the nose of the aircraft is destined to not be able to install a large radar. To change this situation, we must move the air inlets to both sides to make room for the nose. Otherwise, our fighter aircraft will It’s difficult to conduct all-weather beyond visual range combat!”

"I didn't expect you to know quite a lot about it. I can't hide the design of fighter planes from you." Ji Hongbo nodded and said, "Let's go and take you to see other workshops!"

Arriving at Workshop 1, Ji Hongbo said: "Workshop 1 is mainly composed of comrades from Institute 607 and Institute 317. Institute 607 is the design unit of the 204 radar. They also have a major project on hand, which is the design of the jl-10PD radar. The 317 Institute is a research unit in the field of semiconductors. It cooperates with the 607 Institute on the miniaturization of the 204 radar. By the way, there is also a 213 factory that works with the 607 Institute to research the jl-10 PD radar. They have independent radar manufacturing. ability!"

607, 317, 213, it was a bit confusing, but the PD radar successfully attracted Zhao Guoqing’s attention.

"Studying Doppler radar?"

In the workshop, a middle-aged man in his forties, wearing work clothes, with short hair and a big beard, looked like he hadn't combed it for a long time. Hearing Zhao Guoqing speak, he suddenly raised his head. Maybe it was because of Zhao Guoqing's age that he was a little agitated. Contempt, his expression changed from curiosity to calmness, and he said something lightly.

"You also know about Doppler radar?"

It was so new. When he saw the drawings, Zhao Guoqing stepped forward to take a look. When he saw the oval-shaped antenna on it, he knew that it was another product that sacrificed performance for the nose shock cone.

"The detection angle should not exceed 30 degrees up and down, and the detection range should not exceed thirty kilometers!"

The man put down the pen and paper in his hand, walked up to Zhao Guoqing, and looked at Zhao Guoqing expressionlessly.

"How did you tell?"

Zhao Guoqing could feel the pressure brought by this person, but this pressure had no impact on him at all. When it comes to technology, technology is the king.

"It's very simple, look at the shape of your antenna design!"

Zhao Guoqing traced the drawing with his hands and folded his hands to draw an included angle. That was the maximum steering angle of the antenna, which was estimated to be only thirty degrees.

The man's expression softened a little, and he said with great interest: "The angle of the antenna is too simple, and it is normal to see, but you have to explain the detection distance, otherwise..."

The man looked at Ji Hongbo who was behind Zhao Guoqing. Ji Hongbo stood behind and said nothing. He continued: "Otherwise, I will have to report it to your leader..."

This threat almost made Zhao Guoqing laugh.

"It's very simple. The one you use in the picture is a CKG-30 magnetron, a continuous wave sector radar wave, the maximum power should be within one kilowatt, 30 kilometers, the radar wave reflection signal power density S1=P1*G1/(4× 3.14×30^2), the antenna receiving gain G2=4×3.14×A2/(B^2), the power P3 received by the radar must be greater than the minimum detectable signal Simin of the radar receiver in order to reliably detect the target. A radar with this shape The resolution of the antenna should not reach xw power!"

The man looked at Ji Hongbo, and Ji Hongbo laughed.

"Lao Gou, his name is Zhao Guoqing. Don't treat him like a young man. His research on radar is also at an expert level!"

"Lao Ji, how many times do you want me to correct you? Don't call me Lao Gou!" The bearded man turned to Zhao Guoqing, stretched out his right hand and said with a smile: "Teacher Zhao, hello, my name is Gou Jin, from Institute 607."

"Hello, Teacher Gou, I am Zhao Guoqing!"

Ji Hongbo said: "The 607 is located in the southwest, and the conditions are very difficult. They developed the 204 radar in a cave and reached a certain international level. It was not easy!"

Zhao Guoqing hurriedly followed up and said: "Learn from the comrades of Institute 607, learn from Teacher Gou!"

Gou Jin waved his hand and said, "Teacher Zhao, stop praising and blushing. To be honest, I have always wanted to ask you in person!"

Being able to guess the approximate performance from the radar's antenna and the parts used, he had no choice but to distrust Zhao Guoqing's understanding of Doppler radar.

In fact, without sufficient in-depth research, these arguments cannot be made.

Zhao Guoqing looked at the specific parameters on the drawings and the annular Doppler transmitting antenna. He was also thinking that there might be a compromise to solve the radar adaptation problem of the shock cone air inlet.

"Ringular phased array UESA technology!"

Yes, it is UESA technology. The phased array antenna is arranged in a loop around the nose of the aircraft, and the receiving antenna is placed in the shock cone barrel...

"Perfect, one hundred kilometers!"