Chapter 405 This thing has to be done!
This is the famous high-tech that Gao Zhendong had in his previous life - the laser gyroscope, which also includes the fiber optic gyroscope.

Brother Zhang’s feeling at this time was probably “a prime number is a number that cannot be divided by other natural numbers except 1 and itself. Okay, now you understand what a prime number is, go and prove the Riemann hypothesis.”

Why not prove the Goldbach conjecture?
Because at least the Goldbach conjecture is understandable and we know it is related to prime numbers; but the Riemann hypothesis is hard to understand and at first glance it seems to have nothing to do with prime numbers.

Mr. Zhang is in this state right now. He hasn't even figured out the connection between these things.

He shook his head, as if trying to get rid of the chaotic thoughts in his head, and then calmed down: "Junior brother, no, no, your span is too big, you have to sort it out carefully for me."

Gao Zhendong was also a little confused. He had to sort things out carefully before he could explain the matter to his senior brother.

He went over it carefully in his head before he began to draw and talk on the paper.

"Brother, first of all, when two coherent light beams meet, interference will occur. The specific manifestation is the change of interference fringes, right? When there is an optical path difference between the two coherent light beams, it will be reflected in the interference fringes."

Mr. Zhang: “Yes, I understand.”

"Then if we use the light from the same light source to split it, transmit it along a closed optical path in the forward and reverse directions, and finally let it enter the same detection device, can we generate interference and produce interference fringes?"

For light to interfere, coherent light is required, that is, the two beams of light must have the same frequency and a fixed phase difference. This determines that light emitted by two different light sources cannot interfere, and must come from the same light source.

This is why students who often do physics experiments, when doing light interference, use a single light source, then a single slit, and then a double slit to see interference fringes.

"Well, that's what happened."

"Then we put this closed light loop and the detection mechanism on the rotating plane we want to detect. When the plane rotates, the optical path of one of the two counter-propagating light beams will become shorter, while the optical path of the other beam will become longer. The optical path difference is positively correlated with the rotation angle. At this time, by detecting the interference fringes, we can know the rotation angle, right?"

"Oh, that seems to be the truth!"

Gao Zhendong smiled: "That's right. This thing is not like a mechanical gyroscope, which requires rotating parts and needs to maintain a large moment of inertia to ensure accuracy. It does not move by itself. And it starts very quickly. As long as the optical path is established, it enters the detection state. Unlike a mechanical gyroscope, there is still a startup process."

The light path is established very quickly, basically it is available as soon as the light is turned on.

Mr. Zhang looked at the picture drawn by Gao Zhendong, his mind spinning wildly, and asked a question: "Then how do I count the interference fringes?"

People who often do physical experiments know that it is a very effective method to convert tiny changes in physical quantities into interference and diffraction of light through some means to amplify them, and to turn changes that are too small to measure into several circles or lines.

"Photosensitive element! This is relatively easy to do with a photosensitive element."

Senior Brother Zhang nodded and raised a new question: "No, this method requires the wavelength range of light to be very narrow, and the light must be very monochromatic. Where can we find such a light source?"

If we just want to increase the light intensity, it can be done relatively easily within a certain range. However, improving the monochromaticity is not something that can be achieved by just great effort.

Gao Zhendong smiled and said, "Brother, not long ago, we invented lasers, which just meet this requirement."

Of course, there are many kinds of lasers, and not every one of them is suitable for this job. The most important point is that the coherence length should be good, that is, how long the transmission distance can maintain a certain degree of coherence.

Senior Brother Zhang patted his head and said, "Right, right, right! This thing is too new, I didn't think of it for a while! Senior Brother Gao, you have done a great job in understanding and tracking cutting-edge technology."

No, in the beginning, it was others who were following me. Of course, I should have surpassed them now. After all, I just took the title of "No. 1 in the world", which was very exciting, but there was no follow-up work.

However, Gao Zhendong couldn't boast directly that he invented the laser, so he had to keep it to himself.

Since he couldn't install it from this direction, he decided to try from another direction.

"Brother Zhang, I have done some preliminary theoretical calculations. This method can detect a very wide range, from 0.001 degrees per hour to 1500 degrees per second, and it responds very quickly. In addition, there are no moving parts such as inertial platforms, servo mechanisms, torquers, angle sensors, etc. There is no need for mass balance, and it is not sensitive to vibration and impact acceleration of the carrier. It has a simple structure and low cost." If we use a term that will be more popular in the future to describe the laser gyroscope, it is that it is an all-solid-state gyroscope. In theory, there can be no moving parts. As long as the state is fixed, there are fewer things to consider.

The laser gyroscope is not without flaws, but those flaws are like boiling soup poured on snow, disappearing without a trace compared to its huge advantages.

Senior Brother Zhang was so happy that he almost burst into tears: "Yes, yes, yes, all the problems you mentioned can be easily solved because of its structure! This is it, this is it. Moreover, the wavelength and optical path of light are not affected by temperature, and the drift and stability are very good! This thing must be developed!"

Gao Zhendong still gave his senior brother a shot of prevention: "But there is a problem, senior brother, this thing, even if you start now, it is still difficult. I don't think you will be able to use it in a short time."

Aside from the principle and design, the biggest trouble with ring lasers is processing, as each optical device involved has very high precision requirements.

Mr. Zhang didn't care: "Haha, it's okay, it's okay, this thing, even if it takes ten or twenty years, it's worth it."

That’s not the case, Gao Zhendong thought.

"That's all I can think of for now, but the specific implementation is not something I'm good at. This is not my major. Brother Zhang, you may need to find a relevant research institute to do it."

At this point, Gao Zhendong thought of something that needed to be made clear first: "In addition, interference fringes are only one of the measurement principles, including some of the structural examples I mentioned. In fact, the core purpose is to obtain the rotation by measuring the optical path difference of coherent light emitted by the same light source. When you talk about this principle to specific researchers, you must explain this to them clearly, so as not to limit the thinking of specific researchers and make them focus all on interference measurement. Maybe there is a better way."

Mr. Zhang wrote it down truthfully. Look, how humble the junior brother was. He did not think that he was the best in the world just because he was the first to come up with the idea. Instead, he pointed out objectively that there might be a better way.

Brother Zhang was very satisfied with today's gains. He saw that only by going to the birthplace of technology could the problem be better solved. He was sure that even if the Anti-Ship Missile Research Institute knew his difficulties, they would not be able to come up with a solution, not even a solution that was only theoretical and could not be put into practice like the one proposed by his junior brother.

Senior Brother Zhang stayed with Gao Zhendong for a long time in a hurry. After having a delicious meal with Gao Zhendong, he returned to the Defense Working Committee to report the situation. Given the nature of their work, his reporting object was directly to the leader of the Defense Working Committee.

After hearing what Mr. Zhang had learned from Gao Zhendong, the leaders of the Defense Work Committee were very happy. They had never heard of this thing before.

Then I thought, how many of the things in Gao Zhendong's place have I heard of before?
"What are you going to do next?" He was happy. Although he knew that this technology might take a considerable amount of time to be put into use, its broad prospects made him decide immediately that he had to do it!

Defense, aviation, aerospace, the scope of this thing's use is too wide. Apart from other things, according to the performance range described by Gao Zhendong, once this thing is installed on aircraft, ships and other vehicles, most of the problems of these vehicles' self-positioning can be solved.

When there is no GPS, it does not mean that the vehicle does not know its own position. Mechanical gyroscopes, radio navigation, starlight navigation and other technologies are all in use. However, these technologies are affected by various environmental conditions.

Mechanical gyroscopes are greatly affected by manufacturing and the motion state of the carrier, and are expensive. The ones that are affordable are not very accurate, and the ones that are accurate are not worthy of use. Well, according to the direction and speed of the vehicle's movement, determining its own position on the nautical chart or navigation chart is a kind of artificial inertial navigation.

Radio navigation requires the deployment of navigation stations. In the days when radio technology was not very developed, its effectiveness was greatly affected by geographical factors.

As for starlight, guess why it is used more often on long-range missiles or ships? For vehicles below the stratosphere, this thing depends on the weather. For ships, anyway, the positioning response speed is not required to be high, so it is not impossible to use it.

By the way, using a theodolite to position according to the sun or celestial bodies is strictly speaking also a form of star navigation.

Therefore, around the S2 period, we often see this plane getting lost or that ship getting lost in various battle examples.

For example, those who have seen the famous Gallic comedy film "The Great Escape" will surely remember the beginning of the film, when the crew flew out of the clouds and looked at the towering iconic iron tower, and the captain said to the navigator in a joking voice: "Galais!!"

Hearing the leader's question, Senior Brother Zhang wisely did not take over the work. This was not his professional direction. He was only responsible for: "Leader, can you organize relevant units to study this thing?"

　Two chapters completed today.

　　Tomorrow morning, I will resume updating two chapters at 6am.

　　
　
(End of this chapter)