Chapter 737 That's a small problem, the big one is coming

The data is divided into many subsystems and multiple sensors, each with a table, and there are dozens of them in total.

Gao Zhendong was looking through the data while listening to their explanations of each data table.

After looking at it for a while, Gao Zhendong was already very familiar with the meaning of the data tables. He selected a few tables, stood up and walked to the blackboard.

Under the curious gaze of Mr. Li and others, Gao Zhendong drew a coordinate system on the blackboard, which only had the first quadrant.

The horizontal axis of the coordinate system is time, and on the vertical axis, he divided it into several areas, each of which was marked with the name of the data he had selected. Then, using time as an index, he drew curves of the data changing over time, with the time strictly corresponding to each other.

Watching Gao Zhendong's operation, several visiting comrades felt like they had discovered a new world. This method is quite interesting.

This was the first time they saw Gao Zhendong's serious working method when analyzing a problem. After seeing this, they felt that Gao Zhendong was really talking nonsense - extraordinary.

After Gao Zhendong finished drawing, he stared at the comparison chart for a while, then he turned back and selected some data tables from the data pile and added them to the chart.

Finally, he threw away the chalk, dusted his hands, and turned around.

"Comrades, I see some problems. Let's discuss them."

Mr. Li and his colleagues were overjoyed. Professor Gao was indeed reliable and had a keen eye. Just by taking a closer look and analyzing for a while, he came up with an idea.

"Well, okay, thank you Professor Gao, you talk and we listen."

Gao Zhendong did not delay and pointed to a data curve. When everyone saw it, they were shocked. That was the altimeter data. Was there really something wrong with the altimeter?
But Gao Zhendong's words were somewhat beyond their expectations.

"The first problem is with the altimeter."

The first one? It seems there are still many problems?

"This altimeter is used by Zhengxian No. 1, right?" Gao Zhendong said with a smile.

"Yes, it was you who helped us with the altimeter of the Zhengxian No. 1. We thought that the functions and performance of this altimeter met the requirements of the new missile, and it was also very small in size, so we adopted it directly." This is the right approach. If there are ready-made, mature and combat-proven parts, we can just use them directly. There is no need to build a whole new one.

So Gao Zhendong nodded and agreed with this approach: "Yes, this idea is correct. But you have a small problem, the data refresh rate, you should adjust it, the original data refresh rate is too low and not enough."

Qi Gong was a little puzzled: "It turns out that the data refresh rate should be fine. We have converted it and it can still meet the control requirements."

Gao Zhendong shook his head: "It was okay at the beginning, but from this point on, it's not enough."

He pointed his finger to an inflection point in the altimeter data, which was 45 meters. Then it began to descend. When it reached more than 9 meters, there was a sudden rise, and then the data was cut off.

This 9-meter-long data is correlated with a very important point on another line, which is the beginning of a new cycle in the system control loop. It seems that there is indeed a problem with the relationship between the two.

It was enough at the beginning, but not enough here? Qi Gong looked at the turning point Gao Zhendong pointed to, thought for a while, and suddenly slapped his head.

"Hey, look at what a pig brain I have! It's all my fault, it's all my fault this time!" Seeing this, he regretted it deeply. He was so lazy that he shouldn't have been lazy!

The ballistic planning of solid anti-ship missile and Zhengxian No. 1 is different!
The trajectory of the Zhengxian No. 40 missile was maintained above 10 meters throughout the entire process, but the new missile is different. According to the requirements put forward by Gao Zhendong, in order to shorten the enemy's counterattack window, the missile is required to fly over the sea as much as possible, and the terminal trajectory must be reduced to below meters.

The lower the trajectory, the shorter the time left for the control system to control the altitude. The first thing to do is to increase the data refresh rate! Otherwise, there will be no more.

The problem with the altimeter of this missile is that its data refresh rate can meet the requirements for an altitude of 40 meters, but for altitudes below 10 meters, the refresh rate is insufficient, and the time window left for the system to control is very short.

According to the hardware foundation of the radio altimeter, the refresh rate can be made higher. This is why Gao Zhendong mentioned "adjustment". There is no need to redesign it, just adjust a few component parameters.

However, as long as the refresh rate is sufficient, the higher the better. This is a compromise made for reliability these days.

Therefore, after using the altimeter of the Zhengxian No. 10, Engineer Qi did not adjust the data refresh rate. This resulted in problems with the altitude adjustment when the missile's altitude dropped to about meters. In addition, there were waves on the sea, which further worsened the working condition of the altitude control system.

Engineer Li was not a fool. After Gao Zhendong gave the turning point, he immediately found the problem and regretted it deeply. It can be said that the bullet dropping accident this time was caused by his failure to adjust the refresh rate.

What he regretted most was that there was no problem with the hardware in terms of capabilities, whether it was the radio altimeter or the control computer. From the root, one was ready and the other could be calculated. The problem was that he did not adjust the parameters in time. When Qi Gong thought about the money that was wasted, he felt distressed. The money spent on an experiment was not just the missile itself.

Not to mention the serious failure caused by this simple problem, which may even bring major interference to the development of solid anti-ship missiles.

Seeing how distressed he was, Gao Zhendong hurried to comfort him.

"Not really, Engineer Qi. Even if you adjusted the data refresh rate of the radio altimeter in time, this telemetry missile would still most likely fall, or the test would still fail. You don't have to be so sad. The result will be the same."

Hearing Gao Zhendong's words, everyone, including Mr. Li, felt as if they were hit on the head with a club, and their heads were buzzing.

Professor Gao, if you don’t know how to comfort others, you don’t have to comfort them.

Why does your consolation sound even more fucking sad?

Qi Gong looked at Gao Zhendong with a helpless look. So the big one was still behind?

"Professor Gao, do you mean that this bullet has more serious problems?"

Gao Zhendong had an expression that said "big things are coming": "Yes, that's right, the biggest problem with this missile is not the radio altimeter, but the radar unlocking problem you mentioned. This is the big problem."

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"Ah? Could it be that the radar was unlocked because the missile was abnormally maneuvering due to a malfunction of the radio altimeter?"

Gao Zhendong shook his head: "That's really not the case. Look here."

Gao Zhendong pointed to the time point when the radar was unlocked, and then swiped his hand downwards. Everyone could see that it was obvious that the time point when the radar was unlocked was much earlier than the abnormal maneuver of the missile, and it occurred when the missile dropped below 20 meters.

Professor Gao's method is really good. It can show the chronological order of the failures at a glance, which greatly facilitates accident analysis.

The comparison of the chronological order of events is very important. In the analysis of aircraft accidents, this comparative data is basically the focus.

While Mr. Li and his colleagues felt that they had "learned something", they then thought about how they had learned it from their own failed experiments and suddenly felt that they had lost out.

Engineer Qi knew a lot about radar, otherwise he wouldn't have designed a guidance system. So when Gao Zhendong pointed out the time correspondence, he had already thought of a lot of things based on the cause of the radio altimeter's failure.

"Professor Gao, what you mean is that as the altitude dropped further, the sea surface clutter caused the radar's performance to deteriorate, eventually leading to the loss of lock?"

The lower the altitude, the more seriously the radar will be affected by clutter. This is basically a foregone conclusion, especially when the sea is windy and rough.

The working principle and the entire system of radar are far more complicated than those of radio altimeter. Complexity is not a good thing here, so radar will have problems earlier than radio altimeter. After all, there is no problem with the radio altimeter itself, the problem is that the refresh rate is too low.

Originally, the radar of this solid anti-ship missile was Qi Gong's masterpiece. He thought of many ways and finally used the small caliber of the solid anti-ship missile to achieve a radar performance that was basically the same as that of the Zhengxian No. 1. He was quite proud of this.

But now it seems that this problem has not been completely solved, or even not solved at all. It can be locked at a height of 40 meters, but it cannot be locked at the end. What is the difference between this and not being solved?
Gao Zhendong nodded: "Yes, I guess so. So even if there is no problem with the radio altimeter, the problem with the radar will eventually lead to the loss of the target or even the loss of the missile."

This made Qi Gong a little frustrated. This was indeed the biggest problem. The radio altimeter was a minor problem. This was a difficult and complicated disease. He had put a lot of effort into it, but he didn't expect that he still couldn't solve it.

"We have thought of many ways to solve this problem. The diameter and energy supply of this missile are much worse than those of the Zhengxian No. 1."

Gao Zhendong roughly understood what he meant and thought of many ways, but it was still the same... In fact, it's not that there is no progress. After all, achieving the same performance as the Zhengxian No. 1 with a smaller volume, caliber and weight is already a big improvement.

He thought about it and felt that maybe he could provide them with some directional solutions. After all, he and radar were inextricably linked.

"Engineer Qi, if you don't mind, could you show me the design data of the missile-borne radar?"

Qi Gong and Su Weihua were overjoyed when they heard this. They said, "Why didn't you tell me earlier that you also knew this?"

They didn't bring this thing with them, but they remembered the general plan and design in their heads. Moreover, Gao Zhendong usually provides solutions in principle, so it doesn't matter if there are no detailed contents at the moment.

(End of this chapter)