0p0 Page 672
Page 672
Tang Hua and Zhou Xuan came from a distance. Tang Hua was carrying an electric guitar, saw Qian Xuesen, and waved to the city gate.
"Tang Hua, you play in a small town in Shanxi. Can the people here stand the sound of the electric guitar?" Qian Xuesen asked while leaning against the wall.
"Of course it's okay, I'm welcome. Look behind me." Tang Hua pointed behind him, and sure enough, a group of Pingyao people followed behind. However, these fans were all elementary school students and middle school students.
"Hello, Director Jiang, hello to you." Tang Hua walked up the tower, "Before the satellite launch, I just waited in Pingyao for a day or two, so I let myself go and entertain myself."
"This is Minister Tang, no, you have to call him Teacher Tang." Jiang Ying said.
"Teacher Tang."
"Hey, that's not good," Tang Hua said, waving his hands. "My songs and classical music don't match up. If you call me a teacher, I may teach you all badly."
Qian Xuesen, Jiang Ying: ...
"Zhou Xuan, you should bring a group of Beijing Film Academy's students over to collect folk songs." Jiang Ying said to Zhou Xuan.
Zhou Xuan: "The students have already gone out, and another place has been arranged for them to gather folk songs."
Tang Hua: "Their junior students were divided into two groups and went to Changchun FAW and Zhengzhou Railway Freight Marshalling Station respectively. There is enough time for them to stay there for three months."
……
"NASA announced the launch plan of the Meridian navigation satellite system two days ago," said Qian Xuesen. "It is the same as ours, and it also uses Doppler frequency shift positioning. The first satellite will be launched in September this year."
Tang Hua: "It seems that they are not simple. They quickly found a solution for satellite navigation and positioning."
Tang Hua knew that the first satellite of the Meridian satellite system, Meridian-1A, was launched in September, and the launch failed. In the first half of 9, Meridian-1960B was successfully launched.Later, it was launched into orbit one after another, and Meridian-1 was successfully launched into the sky, and the navigation satellite network was successfully established. When it was put into use, it happened that the Washington-class ballistic missile nuclear submarine entered service and entered the combat readiness cruise.
In this historical plane, the sextant satellite was launched more than two months earlier than the Meridian-1A, and the Long March-2 on the Chinese side is launched continuously in batches. As long as the first launch is successfully parked in orbit, the next one will be one after another. When the ground is launched according to the program and the satellite network is completed, the sextant will be more ahead than the meridian.
Qian Xuesen: "It's just that in the Meridian satellite system they announced, the total weight of the satellite is only 140 kilograms, and ours is 270 kilograms. What's the difference in weight?"
Tang Hua: "First of all, the power of our satellite radio transmitter should be higher than theirs. In this way, the signal quality at the ground receiving end will be stronger. The user experience of using the satellite navigation system is definitely better than that of the meridian system."
Not only is the signal power high, Tang Hua allowed the sextant satellite's broadcast frequency band to cover part of the meridian system's frequency band.After the two sets of navigation satellite systems are sent to the sky, there will be some conflicts in the frequency bands.China's high-power transmitters will interfere with the working frequency band of the Meridian instrument, but the transmitter of the Meridian instrument will not interfere with the working frequency band of the sextant.
"Secondly, I installed a more complicated anti-piracy system on the satellite of the sextant system, which accounts for a lot of weight." Tang Hua said again.
Qian Xuesen: ...
The radio wave of the navigation satellite is non-directional, and it covers the surface of the earth as soon as it is turned on. Everyone can receive the navigation electromagnetic wave with a radio receiving device.
Now is not the era of free GPS and Beidou-3 flying everywhere. If you want to use satellite navigation services, you have to pay.
Therefore, there must be a user authorization and anti-piracy system, which is composed of satellite radio transmitters and ground client encryption devices.If the user does not pay, there is no authorization. Without authorization, even if you receive the navigation electromagnetic wave with a self-made receiving device, you cannot calculate your own coordinate position.
Not to mention Tang Hua's profiteers, the Ziwuyi navigation system also has similar anti-piracy measures, but it's not as thoughtful as Tang Hua's.
……
After zero o'clock, it was the early morning of June 6.
The launch site is brightly lit. 45 minutes ago, the Long March-2 rocket was refueled, and now it is just waiting for the launch time.
Long March-2 is like an enlarged version of Long March-1, its diameter increased from 1.7 meters to 2.25 meters, its length slightly increased to 28.6 meters, and its weight doubled.
According to Qian Xuesen's theoretical calculation, the Long March-2 can send a load of up to 1.4 tons into a low-earth orbit of 300 kilometers. This carrying capacity is a bit like the Kosmos-3 of the Soviet Union, but it will take two years for the Soviet Union to think of designing a Kosmos-3 of this level. medium/small launch vehicles.
The sextant-1 satellite launched this time is only 270 kilograms. In addition to the safety factor required for the first launch, launching a satellite with an orbital inclination of 89 degrees is originally more difficult than a low-Earth orbit satellite with an ordinary inclination.
"The last 5 minutes are counting down." Qian Xuesen looked at his watch.
Tang Hua: "You can turn on the walkie-talkie and stay connected with the control center."
……
"It's about to launch." Qian Xuesen, who was next to the walkie-talkie, told the people waiting for the launch upstairs at the Pingyao City Gate.
In the dark night, the tail of the rocket on the launch pad in the distance shone with dazzling light. As the rocket rose slowly, the brightness of the flame at the tail became higher and higher.The audience above the city gate couldn't help cheering.
"Don't worry, don't worry, let's celebrate after the rocket flies into the sky!" Qian Xuesen shouted to the students of Yangyin.
The rocket climbed normally.At the moment of take-off, the upward acceleration of the Long March-2 is 0.35 G. Since the engine burns hundreds of kilograms of fuel every second, the upward acceleration of the rocket is getting higher and higher. After 1 minute, the Long March-2 disappeared from people's sight.
Then came a long few minutes of waiting.
"The telemetry signals of Taizhou and Jiguanshan are normal, and the satellite should be in orbit!"
Yao Tongbin's voice on the walkie-talkie.
Qian Xuesen: "Now we can celebrate. China's third artificial satellite, the first test satellite of the sextant satellite navigation system, has been successfully launched into space!"
……
Around the summer solstice in 1959, the satellite system's supporting computing center and four ground tracking-injection stations were ready.In addition to the large computer used to calculate satellite trajectories, the computing center also has an atomic clock.
On the grasslands of Inner Mongolia, the Communications Department of the General Staff ran to the depths of the grasslands to stand by with satellite navigation ground equipment.The Beihai Fleet, the cruiser Chongqing of the Chinese Navy installed the first set of marine sextant navigation system, and went to sea ahead of schedule, sailing between the Yellow Sea and the East China Sea.
In Vladivostok, the Sverdlov-class cruiser of the Soviet Pacific Fleet also installed a prototype of the navigation system, preparing to try to receive the signal after the first satellite was debugged.In Murmansk, the Soviet K-3 "Komsomolskaya" nuclear submarine just returned from a training voyage. The naval base shipped a large box to the submarine, and then added some strange wires to the submarine's periscope telescopic antenna.
As for the two pre-sale users who purchased the sextant satellite navigation system at the Canton Fair, they have not yet received the big boxes. During the navigable period of the longitude line, open the receiver to locate.
By the way, in addition to positioning, it also comes with a timing function, which is accurate to the millisecond level.
The first to report the successful launch of the satellite was the radio station on the morning of June 6, and the newspapers would not publish the report until June 22.For the introduction of the sextant system, let’s start with a three-dimensional shape of the earth. Five polar-orbiting satellites draw outlines outside the earth. With these five lines added to the earth, it looks like a peeled but not broken orange. .
In order to explain the orbit of the satellite, the reporter who wrote the article spent a long time explaining what is a polar orbiting satellite and a sun-synchronous orbit with the most simple metaphor.
Then skip the technical details and tell readers directly that the satellite navigation system allows people to know their position anywhere without looking at the compass, identifying landmarks or looking at the stars, as long as they can receive signals from satellites.
In this way, scientific expedition teams in the field, field troops in large-scale movements, and ships sailing at sea will no longer get lost.
Not only will you not get lost, but the positioning accuracy of the sextant satellite navigation system exceeds any previous navigation method.When the ground end is completely stationary, the positioning accuracy can reach 100 meters.When moving at low speed on the ground, such as on a moving ship, the positioning accuracy is 200 to 400 meters.
Due to the limitation of Doppler frequency shift positioning, the ground terminal can hardly locate accurately when moving at high speed, so the sextant system cannot be used for aircraft and cruise missiles.
However, the newspaper reports still concealed some information-in fact, the sextant satellite navigation system still has high-frequency military codes, which are not open to commercial users, and only supply military platforms in China and the Soviet Union.The static positioning accuracy of the high-frequency military code is 25 meters, and it is still 80-150 meters when moving at low speed.The frequency band used by the high-frequency military code also "crushes" the military high-precision frequency band of the meridian navigation system.
Chapter 225, India with both sides
如同1957年12月的航天发射，6月22日这天，美国在太平洋的巴布亚新几内亚、堪培拉监听站也轻松探测到了六分仪-1号卫星从自己头顶呼啸而过。
The first Chinese space launch to be detected was a listening station in Okinawa, where radar and radio direction-finding systems both mapped the trajectory of the Long March-2 rocket.The obvious fact is that the rocket launched by China this time should be larger than the previous two, because the radar emission signal is much stronger, and the position of the second-stage rocket that fell in the East China Sea is also different from last time.
When the satellite flew to the listening station in Papua New Guinea, the United States had already analyzed the flight trajectory of the Chinese satellite: the orbit had an inclination of 89 degrees, an orbit height of 1080 kilometers, and a super-circular orbit with almost no eccentricity.This is really a polar orbiting satellite!
Taiyuan Space Launch/Test and Control Center.
The Americans are busy studying Chinese satellites, and the Taiyuan Center and the four ground tracking-injection stations are also busy measuring and controlling their own satellites.