Chapter 1090 20 minutes of "quasi live broadcast"


Chapter 1090: 20 Minutes of "Quasi Live Broadcast"

Shen Junrong's hand holding the teacup suddenly stopped in mid-air.

It wasn't until he was burned by the warmth that he hurriedly retracted his hand and put the cup in front of Chang Haonan:

"So fast?"

He brought a He asked with a shocked expression:

"But, the launch plan..."

You know, it's only mid-September.

The launch on October 15th can only be regarded as a tentative date.

After all, no one dares to guarantee that the weather conditions will be suitable for launch a month in advance.

If there are any temporary adjustments, all the relay plans will be drastically changed.

It would be fine if it were just a paper modification, but due to the limited effective coverage of the small micro, it would also involve issues such as antenna pointing and even satellite attitude correction.

“Of course it is calculated based on the existing launch time.”

Chang Haonan smiled and picked up the cup:

“But according to our plan, the Qingluan satellite group We will wait until 8 hours before launch to start the attitude adjustment... So it doesn't matter if the plan changes, it will not affect the operation of the satellite itself."

This answer made Shen Junrong immediately startled, and then he didn't even care. He touched his burned fingers, quickly opened the briefcase on the coffee table, took out the folder that was visible at a glance, and started flipping through it quickly.

The entire plan is of course very long.

But the core content is actually less than five pages.

So, in just ten minutes, Shen Junrong saw the end.

As the pages turned, the expression on his face changed from shock to solemnity, and then to a bit of confusion.

After thinking for a while, he went back and read these pages again.

However, the confusion on his face did not lighten at all.

This revolving lantern of expression changes naturally did not escape Chang Haonan's eyes, so he put down his tea cup and asked with concern:

"Mr. Shen, is there anything wrong with my plan... ?"

Shen Junrong raised his head:

"No...no, there is..."

After some rather confusing expressions, he finally organized his words:

"It's not that you have a problem, it's that I have a question to ask you..."

At first glance Chang Haonan almost didn't laugh at this sentence pattern. It took a lot of effort to finally hold it in, and switched back to a serious expression:

"You said."

Shen Junrong immediately turned over the plan. One page:

"The satellite attitude adjustment part... Is it a little difficult to determine the new attitude of all four satellites in such a short period of time?"

As an experienced engineering expert, the question he raised was directly aimed at Key:

"Of course I am not questioning your calculations. If this is the Dongfanghong 4 platform, there is indeed no problem, but yours is a small satellite, and the attitude sensor of the lightweight platform is affected by its size and size. Due to functional limitations, the performance is difficult to compare with traditional aerospace-grade components. It generally requires multiple rounds of calibration to ensure sufficient pointing accuracy..."

Obviously, although the Qingluan satellite group itself is not subordinate to Manned space project, but during this period, Shen Junrong was also interested in the former.

At least, we even know the parameters of the sensors used on the satellite.

However, using a lightweight and low-cost attitude sensor configuration of magnetometer + sun sensor + gyroscope to efficiently determine satellite attitude was originally one of the key projects of Qingluan system testing -

Aerospace-grade components are indeed accurate And reliable, but the manufacturing method of precious metal packaging determines its high cost. It is simply impossible to reduce it to a level that can be applied on a large scale.

Besides, the output cannot keep up.

Therefore, Chang Haonan immediately explained:

"If the attitude is determined directly based on the measurement value of the attitude sensor through a deterministic algorithm, it is indeed difficult to overcome the impact of measurement errors on the accuracy of attitude determination."

"However, the Gauss-Newton algorithm can be used first. Preliminary solution..."

While speaking, he suddenly looked around, as if he was looking for something.

Shen Junrong quickly gestured to Zhang Weiyong who was waiting next to him.

The latter quickly handed over pen and paper.

"Like this...convert the 6-dimensional observations of the magnetometer and solar sensor into optimal quaternions, thereby reducing the observational degree of freedom from 9 dimensions to 7 dimensions, and then use the optimal quaternions to combine the gyro data as Observed quantities, using the attitude quaternion and the angular velocity in the inertial frame as state quantities for UKF filtering, can minimize the impact of measurement errors and improve the accuracy of attitude calculation..."

Chang Haonan's side Description, one side outlines the calculation method of the filtering state equation and Kalman gain matrix.

Of course, the specific results cannot be calculated by the human brain.

Zhang Weiyong has been conducting state simulations on Shuguang-3 since the second half of last year, and it was not until shortly before the launch of the satellite that all parameters were finally determined.

After finishing writing, Chang Haonan put the pen aside calmly:

"Although the accuracy is still impossible to match that of large platforms, medium-orbit satellites are not particularly sensitive to attitude, and even if four sets of backups are included, the cost of the entire attitude positioning system is less than 10% of the traditional solution. , enough for large-scale application in the future..."

"Four sets of backups?"

Shen Junrong has not seen the complete design plan of Qingluan satellite.

Chang Haonan smiled and nodded:

“There is no way. Due to cost and construction period considerations, the space-borne computer does not need to be aerospace-grade products. If we don’t prepare a few sets of backups, , how is it possible to achieve the reliability required by satellites? ”

His ultimate goal obviously cannot be just four satellites -

With China's infrastructure level, the value of constellations like OneWeb or Starlink that directly target civilian ground terminals is indeed questionable.

But even as a communication bridge between other satellite networks, the number of terminals connected to medium and low orbit communication satellites cannot be underestimated.

Shen Junrong had already guessed this, but after hearing this, he realized that he seemed to have greatly underestimated the ambition of the young man in front of him.

He stared blankly at the paper filled with formulas in his hand for a while, then sighed softly:

"When you proposed to the Science and Technology Commission to establish the Equipment Industry Department, I felt that you had a long-term vision and would not stop at trivial matters..."

"The result seems to be still the same now. It's a bit underestimated..."

Shen Junrong's last year as deputy director of the Science and Technology Commission coincided with the time when Chang Haonan first entered Ding Gaoheng's field of vision.

The first and only time the two met before was at an enlarged team meeting to discuss whether the Equipment Industry Department should be established.

At that time, the latter could only be regarded as a young technician who had a certain influence on decision-making.

But in just a few years, it has grown into a towering tree-like existence...

After the short emo, Shen Junrong quickly returned to the topic:

"Since technically The feasibility has been determined, and the next step is the specific plan."

At this point, he was suddenly silent for a while when he should have relaxed.

Then he stood up and walked to the office window with his hands behind his back:

"The news center has prepared the script and a full set of broadcast plans, but it has not yet been finalized whether the entire mission will be included in the live broadcast plan."

"The current hesitation of superiors is that since the China Star 7 Communication After the failure of the satellite launch, due to safety considerations, the space launch mission will no longer be broadcast live in principle... But the nature of the mission this time is different after all, and there is excellent content to maintain the indoor picture for a long time. If it is adopted If all the scenes are broadcast, the publicity effect will be greatly reduced..."

Hearing this, Chang Haonan suddenly became energetic:

"The live broadcast does not necessarily need to be at the launch site, it is okay. It is carried out at the receiving terminal of the Qingluan constellation. Anyway, the focus is on the continuous images in the cabin... In addition, the relay communication maintenance time is about 30-40 minutes, but it still needs to be trimmed from beginning to end to deal with some sensitive content that is inconvenient to display. , so the best way is to delay the quasi-live broadcast by 8-10 minutes, so as to leave an estimated 20 minutes of content.”

“I have already seen the image and voice system in the Shenzhou 5 spacecraft. Indicators, with the performance of the Qingluan constellation, can completely ensure the smooth flow of data transmission throughout the entire process. In addition, Comrade Guo Lin also mentioned the weather problem in Beijing to me, so we will keep a preliminary plan in Haojing, but we need to send two people accordingly. Team just in case..."

(End of this chapter)

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