Chapter 746 There is a big problem with triangulation!
"The current situation is that after trials of the triangulation positioning system, the feedback from various services and arms is relatively good, especially from comrades in areas where there are no people, few people, and 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 because the distance is too far, it can at least allow users to grasp their own position while ensuring the power of the positioning base station. In the early stage, During the trial, it also played a practical role in speeding up search and rescue and saving the lives of beacon carriers.”
Chief Lin introduced the current situation to Gao Zhendong.
"Of course, it is not without problems. The biggest problem is caused by the triangulation positioning principle itself. With one more base station, the restrictions on use are much greater. This is the core. In addition, the positioning effect in mountainous areas is poor and multi-path propagation interferes. Seriously, it is also a big problem. Other features, such as limited communication functions, are secondary. After all, the core of this system is positioning. Communication is only an incidental function and can be stripped off at any time.”
Listening to this, Gao Zhendong admires them quite a lot. Their "positioning + communication" architecture and effect are quite similar to our positioning system in the future. It is really impressive that he thought of taking both into account decades ago. Not a simple thing.
Moreover, they grasped matters very accurately and established a primary-secondary relationship in which positioning is the core and communication is the auxiliary. In this way, many things are much easier to handle.
If you want to perfectly balance all situations, the price is very high. When doing scientific research, a very important principle is not to be greedy.
"So our consideration is that in the single base station positioning system, we will not consider communication for the time being. The original triangulation positioning communication is for search and rescue. For single base station positioning, we mainly consider the positioning itself. As for communication, traffic Let other systems or equipment do it.”
Mr. Lin and the others 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 ideas: "Well, your consideration makes sense. Strictly speaking, positioning signals and complex communication data are not suitable for integration. However, simple information is actually not a big problem. . As a secondary goal, simple communication can still be solved. You all have to ask anyway.”
As for ranging, the simplest method is the secondary radar method, query-response, and then calculate the distance based on the time difference. This is the simplest method. Since you have to ask, it is not difficult to mix some simple data into it. Yes, the DME used in civil aviation is a typical example, but DME was officially put into use in 1961. Although Mr. Lin and others did not know much about the complete DME, they only relied on their technical skills and existing technologies to come up with question-and-answer ranging.
"General Engineer Gao, as a result, the positioning terminal will have to deal with more things, and the cost will rise sharply. Not to mention anything else, the Chinese character library alone is a huge cost pressure. There is no need for magnetic cores or anything like that. Having said that, tape capacity is large, but sequential storage is not suitable under such conditions. There is a new device called a disk, which can achieve random reading, but its reliability and size are not suitable if individual soldiers are to be considered. .”
If you want to send data, you must at least have a complete set of commonly used Chinese characters, right? Thousands of commonly used words can be saved for everyone.
Gao Zhendong smiled and said: "I think your survival beacon is very good. It can report its own status and location information."
Mr. Lin was quite proud of this: "Well, yes, but that thing actually doesn't store anything. It just adds a number to indicate the status in the reported data according to the button. There are only two statuses: good and bad. It’s just a species, it’s okay for life-saving purposes, but it’s not enough for use in various situations.”
Gao Zhendong smiled: "You have already found a way to solve the problem, why haven't you said enough?"
These words made Mr. Lin stunned: "Have we found a way to solve the problem? No, I just solved a small problem by opportunism, and the scope of application is very narrow."
Gao Zhendong shook his head: "If you solve more small problems, if you accumulate them together, you can solve the big problem. After all, tactical communication is not a daily routine. You have to talk to neighbors all over the world. Common situations can be covered, basically. That’s enough.”
These words made Mr. Lin deep in thought. After thinking for a while, he slapped his thigh: "General Manager Gao, you mean to compile common situations into a code table and only need to store this code table?"
Gao Zhendong nodded: "Yes, and you don't need to compile this matter. If there are comrades who are doing this, you can go to the Defense Working Committee. They are organizing personnel to compile tactical intelligence and communication protocols. Although they have not yet Completed, but the prototype should be out, For different terminals, a subset of them can be selected for implementation, and the navigation station can analyze and respond to the entire protocol. In this way, the price of the terminal is suppressed, the functions are basically realized, and the navigation station can also respond to all situations. ”
The tactical intelligence communications protocol is still in the process of being implemented. Other comrades may not know about it, but Gao Zhendong does.
When Mr. Lin heard this, a stone fell in his heart: "If that's the case, that would be great. We can enjoy the results of other comrades' work, hahaha. But to handle such complex functions, ordinary circuits can There is no limit, even digital circuits cannot do it, but C6108 is used in This is a bit too expensive, and the volume will increase to a certain extent, right? "If you use C6108, you will also need to use C6110. The sum of 7,788 is not cheap. At the same time, the weight is still a pound or two. It’s heavy, and the C6108 is used here, and the performance is somewhat overflowing, which is distressing!
Gao Zhendong smiled and said: "You don't have to think about this. You can just use C6108 to design the principle prototype first. When the time comes, there will be something else for you to use, hahaha."
The single-chip microcomputer is being designed by the young men sent by the National Defense Work Committee. Success is almost inevitable because Gao Zhendong has paved the way for them. The price and volume and weight of this thing are much gentler than the C6108.
Mr. Lin and the others were completely relieved. The person in front of them was really famous among the public for his role as a computer! Before they came to Gao Zhendong, they had no idea that he knew other technical fields. Even when they first got the name of the company and the person, they thought that the working committee had made a mistake.
So when it comes to computers, if he says there is something new, then it must be there, just wait and use it.
At this point, Mr. Lin just remembered and talked for a long time, focusing on communication, but not on positioning.
Seeing him talking about this matter, Gao Zhendong thought for a moment: "Positioning is actually mainly about two issues - ranging and angle measurement. Whether it is triangulation positioning or single base station positioning, it is actually the same. It's just that The angle measurement of triangulation positioning is implicit in the measurement of the length of the two sides of the triangle. Unlike triangulation positioning that uses a plane rectangular coordinate system, if you want to position a single base station, you have to switch to a polar coordinate system, which is more convenient. .”
The plane rectangular coordinate system has two parameters, the abscissa and the ordinate. There are two base stations for triangulation. One is placed at the origin, and the other is placed on the horizontal or vertical axis, which is very convenient for calculation.
The polar coordinate system also has two parameters, distance and orientation (angle). For single base station positioning, it is convenient to place the base station toward the origin of the polar coordinates!
Mr. Lin thought about Gao Zhendong's words in his head, drew a polar coordinate system on the blackboard, and nodded: "Well, that makes sense. In this way, a big problem can be broken down into two small problems. Measure distance and angle.”
Gao Zhendong smiled and said: "Yes, so let's talk about ranging first."
Mr. Lin was a little puzzled: "We have basically solved the distance measurement in triangulation. This is easy to say."
"I just want to see the details, how big the capacity of current ranging terminals is."
"Terminal capacity? It's unlimited. You can produce as many front-end devices as you want."
Gao Zhendong shook his head: "What I mean is, how many front-end devices can initiate positioning at the same time?"
Mr. Lin fell silent for a moment, and thought hard for a long time before saying something: "If multiple devices are initiated at the same time, only one device can be positioned at the same time, and..."
"And other terminals may receive wrong positioning data, right?" This sentence is the real problem. Everyone is doing things on the same frequency, so they are connected.
"Yes..." Mr. Lin was a little silent. He originally thought that triangulation positioning relied on existing technology and was very successful. However, after Chief Engineer Gao asked, he discovered that the current success seems to be based on the extremely small number of users during the trial period. Basically, and mainly used for personnel positioning and search and rescue. In this case, the number of positioning requests is very small.
If it really needs to be used in combat, if multiple terminals frequently initiate positioning requests, forget about not being able to determine the position. The biggest problem is positioning errors, which will cause big problems!
"General Engineer Gao, this problem is very serious. There is a problem in our work." Mr. Lin did not run away. He just found the problem and solved it. It was still too late.
"Yes, there are big problems in the planning and use of your transceiver frequency band. In addition to the above, there are some other problems. But since they need to be solved, these problems will no longer exist. I will not cover them one by one. As you said, let’s consider how to solve this problem.”
Mr. Lin gave up after hearing this. How can that be done? I want to hear it! If you don’t find all your problems and figure out the reasons, what should you do if you do it again in another job next time?
(End of chapter)