Siheyuan: I eat melons while doing scientific research

Chapter 1426 One in Heaven, One on Earth (4k)

Since we've already started, let's go all the way and do it right the first time.

Completely invisible!
It's really just a matter of the outer shell. If all else fails, just work on the top part and use invisible paint to solve the problems in other areas.

Stealth coatings don't need to be applied as thickly or cover as wide a frequency band as those used on fighter jets and bombers. A coating that effectively targets the C and X bands is sufficient, meaning it doesn't need to be very thick. Given that this aircraft flies low and is relatively small, this method actually yields quite good results.

Gao Zhendong drooled over the kind of faceted shape that would be easily invisible in a military parade decades later, but if he had to consider both options, a perfectly round shape would be better these days, as it has a larger internal volume.

There's no need to be too far ahead of schedule.

The comrades who studied the missiles didn't find anything strange. It's normal to have requirements in terms of shape. To put it simply, this way, they have less to do and their work is simpler.

However, the chief engineer of the committee sensed something different: "Comrade Zhendong, are you planning to make this the same as the plane from a few days ago?"

Because there were missile experts present, he didn't mention stealth technology for the time being. It's similar to how Gao Zhendong, when saying the length was limited by the bomber's bomb bay size, didn't specify which bomber.

The comrades from the Air Force Equipment Bureau were startled. Could this be possible?! They immediately became excited. If this were true, with low altitude and limited stealth, and due to the presence of ground and sea clutter, it would be extremely difficult for the enemy to detect this missile, except for visually spotting it along its flight path! This was much more difficult than watching bombers in the air.

Gao Zhendong nodded: "Yes, that's my idea. Anyway, proper shaping and painting won't have too much impact on the missile, so let's take it into account."

"But isn't the coating quite thick? And it requires certain maintenance." The chief engineer was rather vague, not specifying what kind of coating it was. He still vividly remembered the iron-gray sample he had seen last time. That thickness was acceptable for fighter jets and bombers, but for missiles with a total diameter of only 520mm, the space loss was quite significant.

"Don't worry, the area is not large to begin with, so there aren't many things to consider regarding the coating. I'm confident I can reduce the thickness. As for maintenance... this is a missile, you know. Apart from training missiles and duty missiles, it doesn't really need much maintenance for the coating," Gao Zhendong said with a smile.

Complex coatings, which are even made by layering different proportions of coatings to varying thicknesses, are expensive and require considerable thickness.

However, the chief engineer and the Aircraft Equipment Bureau didn't even mention the cost. If this thing is to be equipped with a nuclear warhead, then cost is not a consideration at all. How much more coating can there be for such a small thing? If it is a conventional warhead, then coating is not even necessary, and cost is even less of an issue.

So their only concern was that the paint would take up space or become ineffective due to lack of maintenance. However, Gao Zhendong's words made the chief engineer chuckle; he'd forgotten about that!
This is a missile. Training missiles don't need any coating, and the maintenance of duty missiles is negligible. In fact, if things go smoothly, it might even be done along with the bomber. As for stockpiled missiles, they don't need any maintenance at all.

To put it more simply, if everything goes smoothly, the coating peeling off is not a problem at all, since this thing is small to begin with.

However, no one said that because it was an extreme case. In reality, given the style of our soldiers, if this thing needs maintenance, the maintenance effect will definitely be excellent.

Even during the period when our weapons were at their worst, which was the transitional period from the late 20th to the early 21st century, although our weapons were inferior, their maintenance was never bad.

The comrades from the Air Force Bureau nodded repeatedly: "Good, this is good! We must send it up!" Even if the conventional strike version can't go up, the nuclear warhead version must go up. If we're going to hammer, we must hammer with the greatest force to make sure we kill it.

"But if this thing really achieves a range of over 800 kilometers, what about guidance?" President Qi, who is in charge of this area, is most worried about this. At this distance, intelligence support is virtually nonexistent, except for satellites in space. However, satellites have too small a monitoring window and too long a reentry time, making it impossible to form a reliable strike capability. And this is a simplified scenario, ignoring the communication issues between the satellite and the missile.

"That's not a big problem. With strapdown inertial navigation, a little less accuracy is fine." The Air Force Equipment Bureau and the National Defense Industry Commission were quite open-minded. The main thing was to ensure nuclear strike capability, and for nuclear strikes, a little less accuracy was no big deal.

Inertial navigation is the only option that comes to mind right now. With a diameter of 520mm, it's perfectly fine to install a laser gyroscope. The accuracy of laser gyroscopes is also quite high, so even if the missile's flight environment is more complex, it can still guarantee a certain level of accuracy. The only problem is that it's a bit expensive; laser gyroscopes are pricey. While strapdown inertial navigation can save the inertial platform, it still requires three gyroscopes.

Gao Zhendong laughed: "We can use a lower-precision strapdown inertial navigation system. As for how to ensure accuracy, we can change the guidance method. Or, we can retain the high-precision strapdown inertial navigation system, but when conditions are right, we can use another guidance method to further improve accuracy." Accuracy and price are directly linked.

"Change the guidance method? What method? Starlight? That stuff can't hold that, can it? And this is flying at low altitude, so it's greatly affected by clouds," said the chief engineer.

Upon hearing his words, Gao Zhendong suddenly laughed even harder. Mainly, he felt the situation was somewhat coincidental; the guidance method he wanted to use was completely different from starlight guidance, in a purely physical sense.

"No, the guidance method I'm considering is completely different from starlight guidance. The principles are similar to some extent, but they are worlds apart."

This left the comrades confused. The chief engineer frowned and said, "If it's too low-class, it's better not to use it..."

In his view, the effect is that the light in the sky is starlight, while the other effect is on the ground, so it's better not to use it. It might even interfere with the accuracy of the strapdown inertial navigation system.

He didn't consider navigation and positioning systems, mainly because current tactical navigation and positioning systems simply can't reach that distance, and they rely on response positioning. If used on a high-speed missile, the missile might have already flown hundreds of meters away before the response signal even returns.

Even without considering these factors, the positioning error of the tactical navigation and positioning system is sufficient for command and other uses. If it is to be used for precision strikes, it is roughly equivalent to strapdown inertial navigation, both being at the hundred-meter level.

Gao Zhendong shook his head, and amidst the bewildered looks of his comrades, said, "That's not what I meant. What I meant was that this guidance method is the opposite of starlight; it relies on the ground..."

Huh? So this is what it's like underground!

The comrades then realized why he was laughing so hard; it was quite a coincidence.

"Relying on the ground? Do you mean you want to rely on typical ground landmarks for guidance? But typical landmarks aren't everywhere, and they're difficult for missiles to identify, plus there's no one on the loop." At a distance of 800 kilometers, it's impossible for a person to be on the loop. Relying on the missile itself to identify typical landmarks is too difficult.

Gao Zhendong shook his head: "That's somewhat interesting, but it doesn't rely on landmarks, it relies on terrain! I want to use terrain-matching guidance to solve the problem!" Terrain-matching guidance was an early Tomahawk missile, aside from its anti-ship variant, used to solve high-precision targeting issues, and it's been very effective. It's also one of the few solutions for precision strikes by long-range cruise missiles under current technological conditions.

The comrades had never heard of this term before, and Gao Zhendong knew that it would be difficult to explain without an explanation, so he stood up and started drawing on the blackboard in the office, explaining what terrain matching guidance was all about.

Fortunately, the comrades present had a top-notch understanding of guidance technology and quickly grasped Gao Zhendong's meaning.

"I understand now. This is how you use the changes in terrain elevation to guide the missile." The chief engineer's face was full of excitement, the kind of pure delight one feels when encountering a new technology, the pure curiosity and enthusiasm of a technician.

"This method is brilliant! Using the terrain's undulations to guide missiles is remarkably similar to starlight guidance, except one is in the sky and the other is on the ground." The comrades found Gao Zhendong's description incredibly ingenious, but even more ingenious was the navigation concept itself.

"Using strapdown inertial navigation to solve orientation problems on plains and at sea, and also improving accuracy by combining terrain matching during flight!" The terrain matching results can continuously recalibrate the strapdown inertial navigation system, eliminating accumulated errors, which can greatly improve the final accuracy of the strapdown inertial navigation.

"If we consider it this way, we don't really need very high accuracy in strapdown inertial navigation. At least we don't need such expensive gyroscopes. A cheap gyroscope plus a Doppler terrain matching radar can solve the problem well." Doppler terrain matching radar is not considered expensive for us anymore, not to mention that we don't need the radar to have a long detection range here. As long as the accuracy is about right, it will be fine.

"Interesting, very interesting! This coordination is excellent. Comrade Zhendong, you've solved a major problem for us!" The comrades from the Air Force Equipment Bureau looked at the extremely abstract "little airplane" and several curves representing the terrain undulations on the blackboard and praised it highly.

Although it looks abstract, the effect is anything but abstract; it's very real.

At this moment, Su Weihua raised his hand.

The chief engineer, knowing his relationship with Gao Zhendong, chuckled and said, "Go ahead!"

"But where do we get the map? Doesn't this require a 3D elevation map?"

His words seemed to choke everyone, and the joyful discussion came to an abrupt halt!

According to Gao Zhendong, this type of topographic map divides the ground into individual cells and stores the terrain based on a characteristic elevation of each cell, such as the average elevation. This is essentially like adding a mosaic effect to a high-resolution 3D topographic map, effectively reducing storage requirements while preserving terrain features.

But no matter how much you reduce storage requirements, there's one thing you can't avoid—where do the maps come from? They still have to be 3D elevation maps.

Domestically, it's relatively easy to solve; most areas have them. But what about those outside the known areas? We can't expect to fight a war on our own soil, can we? That would be too much. A significant portion of these are designed for nuclear strikes. Even for conventional strikes, we can't fight on our own territory.

This leads to the biggest problem: what to do with the map?
This requires a three-dimensional topographic map; satellites taking pictures in the sky are of no use at all.

Are we supposed to send people out to survey each place one by one? That's a bit of a pipe dream.

In most places, the conditions simply aren't available. If everyone could create high-precision topographic maps, it would mean the land was already their own, so what's the point of fighting?

I'll give you the map if you take it first—I can only take it if you give me the map first.

A deadlock is a valid condition.

Just as everyone was speechless, Gao Zhendong's voice rang out.

"Don't worry, by the time this missile is finished, we'll probably already have the ability to acquire maps." It will take time to develop this thing, but one of its supporting technologies has already been activated.

"Huh? When did we become capable of this?" Not to mention others, even the chief engineer of the committee, who was in charge of the overall situation in this regard, was very surprised.

When did this happen? How come I don't know?
Gao Zhendong laughed: "Have you forgotten about SAR radar? One branch of SAR radar can scan and obtain three-dimensional terrain maps tens or even hundreds of kilometers away without contact, through clouds and fog. I've calculated it, and the accuracy is sufficient."

To be honest, these words left everyone, including General Manager Qi and Su Weihua, completely bewildered. What? There are more experts? Just how much technology are they hiding that we don't know about?
At this point, they began to have extreme doubts about their own expertise.

Before coming here: I know everything about missiles!

After arriving here: What is a missile? What is this? And what is this yet again?
The speed was so fast, it was like Gao Zhendong watching a military parade in his past life. Before watching, he was a well-educated military enthusiast, but after watching, he was a complete military illiterate.

They weren't even shocked, mainly because they had no idea what it was.

However, the other two groups understood, after all, this matter had not been initiated for very long, and it left a deep impression.

Thinking about it carefully, I do have that recollection. Gao Zhendong did mention this when he started up the SAR radar!
It's all interconnected! No wonder he only brought this out now.

"Ah, yes, yes, that's right!" I never expected that such a big problem that could have gripped everyone's necks would be solved so easily, or rather, it could be said that we were prepared for it all along.

Although the results are not yet in, at least the approach is correct, which is already quite remarkable.

(End of this chapter)