Chapter 746 There is a big problem with triangulation!

"The current situation is that after the trial of the triangulation positioning system, the feedback from various military services is relatively good, especially for comrades in unmanned or sparsely populated areas with certain transportation difficulties. The feedback on this system is very good."

"Especially in areas with flat terrain, this system can play a good role. Even if the communication function fails due to the long distance, at least it can allow users to grasp their own position under the premise of ensuring the power of the positioning base station. In the early trial process, it also played a practical role in speeding up the search and rescue and saving the lives of beacon carriers."

Chief Engineer Lin introduced the current situation to Gao Zhendong.

"Of course, there are problems. The biggest problem is the principle of triangulation positioning itself. One more base station will limit its use, which is the core. In addition, poor positioning in mountainous areas and serious multipath interference are also big problems. Other problems such as limited communication functions are secondary. After all, the core of this system is still positioning, and communication is just an additional function that can be removed at any time."

Gao Zhendong listened and admired them very much. The architecture and effect of their "positioning + communication" were quite similar to our positioning system in the future. It was not easy to think of balancing the two decades ago.

Moreover, they have a very accurate grasp of things and have established the primary and secondary relationship of positioning as the core and communication as the auxiliary. This makes many things much easier to handle.

The cost of trying to take all situations into account perfectly is very high. A very important principle in scientific research is not to be greedy.

"So our consideration is to focus on the single-base station positioning system and not consider the communication for the time being. The original triangulation positioning communication is used for search and rescue. For single-base station positioning, we mainly consider the positioning itself, and leave the communication to other systems or equipment."

Mr. Lin and his team were even prepared to give up the communication part directly. As we all know, the more complex a system or a plan is, the greater the possibility of failure or malfunction.

Gao Zhendong half agreed with their idea: "Well, your consideration makes sense. Strictly speaking, it is not appropriate to integrate positioning signals and complex communication data together, but simple information is not a big problem. As a secondary goal, simple communication can still be solved. Anyway, you all want to ask."

As a distance measurement, the simplest means is the secondary radar method, interrogation-response, and then calculating the distance based on the time difference. This is the simplest method. Since it has to be interrogated, it is not difficult to do with some simple data mixed in. The DME used in civil aviation is a typical example. However, DME was officially put into use in 1961. Although General Lin and his team did not know much about the complete DME, they relied on their technical skills and existing technology to come up with question-answer ranging.

"Chief Engineer Gao, in this case, the positioning terminal will have to handle more things, and the cost will increase dramatically. Let's not talk about other things, just the Chinese character library alone is a huge cost pressure. There is no need to talk about magnetic cores. The capacity of the tape is large, but sequential storage is not suitable for this condition. There is a new device called a disk that can achieve random reading, but if the reliability and size are considered for a single soldier, it is not suitable."

If you want to publish data, at least you need to have all the commonly used Chinese characters, right? Thousands of commonly used characters, it would take a lot to save them.

Gao Zhendong smiled and said, "I think your survival beacon is very good. It can report its status and location information."

Mr. Lin was quite pleased with this: "Yes, but that thing doesn't actually store anything. It just adds a number to the data reported by the button to indicate the status. There are only two statuses: good and bad. It's OK for lifesaving, but it's not enough for all kinds of situations."

Gao Zhendong smiled: "Haven't you already found a way to solve the problem? Why do you still say it's not enough?"

Mr. Lin was stunned by this: "Have we found a way to solve the problem? No, I just solved a small problem by taking shortcuts, and the scope of application is very narrow."

Gao Zhendong shook his head: "Solve more small problems, accumulate them together, and you can solve big problems. After all, tactical communication is not like chatting about family matters. You have to talk about everything with your neighbors at the ends of the earth. If it can cover the common situations, it is basically enough."

This made Mr. Lin fall into deep thought. After thinking for a while, he slapped his thigh and said, "Chief Engineer Gao, do you mean to compile common situations into a code table and just store this code table?"

Gao Zhendong nodded: "Yes, and you don't have to compile this. There are comrades doing this. You can go to the Defense Work Committee. They are organizing people to compile tactical intelligence communication protocols. Although it is not yet completed, the prototype should be out. For different terminals, you can select a subset to implement, and the navigation station will implement the analysis and response of the entire protocol. In this way, the terminal price is suppressed, the functions are basically realized, and the navigation station can also handle all situations."

The tactical intelligence communications protocol is still in the implementation process. Other comrades may not know about it, but Gao Zhendong knows it.

When General Lin heard this, a stone in his heart was put down: "If that's the case, it's great, we can enjoy the work results of other comrades, hahaha. But to handle such complex functions, ordinary circuits are not up to the task, not even digital circuits. But using C6108 for this is a bit too expensive, and the volume will also increase to a certain extent, right?" If C6108 is used, C6110 will be used, and the total amount is not cheap. At the same time, the weight is still one or two kilograms, three or five kilograms, and using C6108 here will more or less have some performance overflow, which is a pity!
Gao Zhendong smiled and said, "You don't have to worry about this. Just use C6108 to design a prototype first. When the time comes, I'll have something else for you to use, hehe."

The MCU is being designed by the guys sent by the Defense Work Committee. Success is almost inevitable because Gao Zhendong has paved the way for them. The price and size of this thing are much more gentle than C6108.

Mr. Lin and his team were completely relieved. The person in front of them was famous in the public for his computer skills! Before they came to find Gao Zhendong, they had no idea that he would also be good at other technical fields. When they first got the unit and the name of the person, they even thought that the Defense Work Committee had made a mistake.

So when it comes to computers, if he says there is something new, then there must be something new, and we just have to wait to use it.

At this point, Mr. Lin suddenly remembered that he had been talking about communications for a long time and had not yet discussed positioning.

Seeing him talking about this, Gao Zhendong thought for a moment: "Positioning actually mainly involves two issues - distance measurement and angle measurement. This is the same whether it is triangulation positioning or single base station positioning. It's just that the angle measurement of triangulation positioning is implicit in the measurement of the lengths of the two sides of the triangle. Unlike triangulation positioning which uses a rectangular coordinate system, if single base station positioning is required, the polar coordinate system must be used, which is more convenient."

The plane rectangular coordinate system has two parameters, the horizontal coordinate and the vertical coordinate. For triangulation positioning, two base stations are placed, one at the origin and the other on the horizontal or vertical axis, which is very convenient for calculation.

The polar coordinate system also has two parameters, distance and azimuth (angle). For single base station positioning, it is convenient to place the base station at the origin of the polar coordinates!

Mr. Lin thought about Gao Zhendong's words, drew a polar coordinate system on the blackboard, and nodded: "Well, that makes sense. In this way, we can break down a big problem into two small problems: distance measurement and angle measurement."

Gao Zhendong smiled and said, "Yes, so let's talk about distance measurement first."

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Mr. Lin was a little puzzled: "We have basically solved the problem of distance measurement in triangulation positioning, so this is easy to say."

"I just want to see the details and see what the current ranging terminal capacity is."

"Terminal capacity? It's unlimited. We can produce as many front-end devices as we want."

Gao Zhendong shook his head: "What I mean is, how many front-end devices can initiate positioning at the same time?"

Mr. Lin was silent for a moment. He thought hard for a long time before he uttered a sentence: "If multiple devices initiate the positioning at the same time, only one device can be positioned at the same time, and..."

"And other terminals may receive incorrect positioning data, right?" This sentence is the real problem. Everyone is doing things on the same frequency, so there is crosstalk.

"Yes..." Mr. Lin was silent for a while. He originally thought that triangulation positioning had been very successful based on the existing technology. However, after Chief Engineer Gao asked this question, he found that it seemed that the current success was based on the fact that there were very few users in the trial period, and it was mainly used for personnel positioning and search and rescue. In this case, the number of positioning requests was extremely small.

If it is really used in combat, when multiple terminals frequently initiate positioning requests, it would be fine if it cannot be positioned. The biggest problem is positioning error, which would be a big problem!
"Chief Engineer Gao, this problem is very serious. There is a problem with our work." Chief Engineer Lin did not evade the question. He said that once the problem is discovered, it should be solved. There is still time.

"Yes, there are big problems with the planning and use of your receiving and transmitting frequency band. In addition to the above, there are some other problems. However, since we need to solve them, these problems no longer exist. I will not go into details one by one. Let's consider how to solve this problem."

Mr. Lin quit when he heard this. How can that be? I want to hear it! If I don’t find all my problems and figure out the reasons, what will I do if I make the same mistake again in another job next time?
(End of this chapter)