Regardless of whether the navigator can give accurate figures, the long-distance flight and the circumnavigation of the Age of Discovery at that time were basically the same concept, as long as the ship sailed into the ocean, whether it could dock half by technology and half by luck, there is no accuracy!

If it is a fighter or bomber, it is forgivable to take such a risk, but with the demand for passenger flights, it does not make sense to fly fast if the plane cannot be guaranteed to arrive at its destination safely.

Soon there were two complementary navigation methods, inertial navigation and radio navigation.

Inertial navigation is a very sophisticated device that relies on gyroscopes and accelerometers to calculate the distance and direction traveled. It has the advantage that it does not require external signals such as GPS or radio, nor does it send any signals to the outside world, and it operates entirely on its own.

Theoretically, as long as there is an inertial navigation system on the aircraft, it can be relied on to guide the course, calculate the flight distance, and finally reach the destination.

But...... Inertial navigation, like all mechanical systems, has errors and is constantly accumulating. When flying over short distances, it does not affect the direction and distance too much, but the distance is longer, the error will become larger and larger, and finally, as our ancients said, the difference is thousands of miles.

At this time, radio navigation can appear, in layman's terms, radio navigation is to set up N radio signal transmission stations along the way, with a specific and unique frequency to transmit medium and long wave pulse signals, and later changed to a more stable VHF pulse signal.

There is a special receiver and computing system on the aircraft, after receiving the pulse signals of the three adjacent navigation stations, the relative distance and azimuth can be determined by calculating the signal time difference, which is often called triangulation.

Before the advent of GPS systems, there were several commercial air navigation systems around the world, the common ones being "Omega", "Roland" and the VHF omnidirectional beacons mentioned above.

The first two were developed by the U.S. military and can cover more than 95% of the world's area, and then turned to civilian use, with no charges except for hardware equipment. The last type is established in all countries, but the coverage rate is not high.

With the popularization of GPS receivers, these ground-based radio navigation systems were retired in the late 20th and early 21st centuries, and only partially retained in some countries, but they no longer achieved the effect of global navigation.

Hong Tao had an idea after finding these materials, the current restoration of the GPS satellite network is obviously a fool's dream, that thing is a large set of systems, to have very, very professional knowledge, really not dozens of people can play.

But the "Omega" and "Roland C" systems are much simpler, they are the sum of a bunch of ground transmitters, to put it bluntly, and shortwave radio stations are the same meaning. If these ground navigation stations can be restored, not all of them, they will be able to provide air navigation services in some areas.

Of course, if all navigation stations in any one system could be restored, global flights could theoretically be restored, as long as there were enough pilots.

There are only 8 navigation stations in the world, which are located in North Dakota, Hawaii, Norway, Japan, Libya, the French Reunion Islands, Argentina, and Australia.

"Roland C" is slightly more numerous, with 34 navigation stations, distributed in the United States, Canada, Russia, India, Northern Europe, Greece, Saudi Arabia, and China.

At present, the groups that have joined the survivors' coalition are all over the countries to which the stations belong, except for the French Reunion Islands and Libya, and it is not an extravagant hope to find a way to restore the operation of some of them.

But this idea Hong Tao did not disclose to the alliance committee for the time being, which is pure selfishness. Is it possible to travel long distances with a navigation platform alone? The answer is no, radio navigation not only needs a navigation station, but also has the corresponding receiving equipment, which is installed on the plane.

Both of these radio navigation systems have been abandoned for many years, and are there any aircraft equipped with such old-fashioned navigation equipment? Generally speaking, there should be no main models of major commercial airlines, but it is not excluded that there are some old models or special aircraft, such as private jets and special aircraft.

Why do you think so? Because Hong Tao has seen a news, Trump's Air Force One is an old model of Boeing 747, and in addition to various advanced equipment, the cockpit still retains a radio navigator and navigator.

Lao Mei is definitely not out of money to replace the presidential plane with new equipment, probably for backup considerations. In case the GPS signal is gone, Air Force One cannot be found to be unable to find a base, and then the old system will play a big role.

Since the United States can think so, will other countries' special planes and private jets have the same considerations? Hong Tao thinks it is very possible, so in addition to the Capital Airport and Daxing Airport, Xishan Airport must also be found.

"It's too professional to understand...... But I think it's not unreasonable for Jiao Qiao to say that you are a foreign spy, are these things that ordinary people should know? ”

Zhou Yuan was stunned, but her eyes did not have the worship of the unknown like the little girl, but were full of doubts. In order to prove that he was not blind and suspicious, he also moved Jiao San out.

“…… You just mix it, it's all emphasized with him, it's very promising! Hong Tao really admires Jiao San's ability to gossip, if he needs a propaganda department in the future, he will definitely be the first choice.

"If this is really possible, how long will it take to restore the navigation station?" Fortunately, Jiao San really doesn't have much prestige in terms of intelligence, and Zhou Yuan doesn't want to be compared with him, so he won't mention the matter of spies anymore.

"First of all, it depends on whether the location information of the navigation station can be obtained, and it also depends on whether there is a survivor team nearby. Full recovery is unlikely, and partial recovery should be achieved in a few months. ”

As for the issue of restoring the radio navigation station, Hong Tao has a greater grasp. It sounds unfathomable, but it's actually a radio station, and you can just find a ham and bring it to the generator.

The control of ham in China is relatively strict, but this thing is more popular abroad, and people should not be a problem. The difficulty lies in the location, some places may be far away from the city, and it is difficult to find without accurate coordinates.

"Then why are you in such a hurry for me to help find the plane? Xishan Airport is located outside the Fourth Ring Road, which does not belong to the jurisdiction of the Pingyan Army, and the rescue team is fully capable of going! ”

There are convenient sides to working with smart people, and there are times when there are troubles. They are very understanding and easy to communicate, but they also have a lot of problems. For example, Zhou Yuan, if she doesn't fully understand in her heart, don't think about directing and acting, and the exchange of interests will not be successful.

"I'm not an astronaut...... Well, to be honest, I need time to test it. I also want to go to Changsha, where there are urgently needed researchers. ”

Encountering this kind of special detail, Hong Tao instinctively wanted to make up a story. However, seeing Zhou Yuan's brows furrowed, he realized that it was meaningless to make up nonsense now, so he simply said it. If you want others to cooperate, but you can't fool you, attitude is very important.

"You're going alone?"

"What do you mean?"

"Can I go along? By the way, teach me to fly a plane, the art is not overwhelming. If I really need to run away one day, you won't take me with you, I'll have to fend for myself......"

"You're worried about me, aren't you?" Learn to fly an airplane...... This reason, if Hong Tao can believe it, he will see the ghost.

I don't even know if I can land safely when I fly up by myself, and I still have time to teach her how to drive? This woman must still not fully believe it, and she thinks she knows what the crisis is, and wants to run away alone.

"Take me with you if you want me to feel at ease...... It's not that hard. Sure enough, Zhou Yuan didn't even have an excuse, and directly acquiesced.

"I'm driving a jet, I can't skydive, and there is only one way to die if something happens!" Although there is nothing wrong with bringing Zhou Yuan, Hong Tao instinctively doesn't want others to know too much about himself, especially smart people.

"Cut, are you still afraid of death at this time? Don't forget, I fought zombies alone, and I didn't know if I would survive. Zhou Yuan replied very simply, with a faint smile on her face, as if she was talking about what movie to watch at night.

“…… Find the plane first, otherwise everything is empty talk. "Intimidation doesn't work, let's recruit delays again, anyway, she can't stare at herself every day, and she doesn't want to fly when she wants.