Principle and application of radar imaging
Series of lectures on innovation and Entrepreneurship of electronic information in Nanjing University
On the evening of April 17, 2020, this series of lectures on electronic information innovation and Entrepreneurship of Nanjing University invited Associate Professor Bai yechao, who introduced the "principle and application of radar imaging". The lecture attracted more than 60 people from freshmen to seniors. Although it is only an online lecture, the positive interaction between teachers and students still once played up a strong atmosphere of academic exchange.
01
Lecture content
Mr. Bai first briefly introduced the history of radar development. In 1864, Maxwell put forward the electromagnetic theory and got the theoretical support for the first time. In 1925, Hopkins University first observed the short wave narrow pulse echo reflected from the ionosphere. In 1940, MIT established the radiation laboratory and started the formal research on Radar Technology. Today, radar includes transmitter, transceiver switch, antenna control, receiver and display modules. So that the radar can measure the target distance, azimuth, altitude, trajectory and so on. The radar equation is the hot topic that Mr. Bai will talk about next. That is to say, when the radar transmits at a certain power and encounters the return of the target, the relationship between the transmitting power and the receiving power.
In addition to the traditional radar, Mr. Bai also introduced the knowledge of phased array radar, as well as the new technology of phased array radar: reducing volume, reducing cost and improving reliability; digital beam integration technology; all digital transceiver components, etc. In terms of radar imaging technology, Mr. Bai extended the concepts of inverse synthetic aperture radar imaging and turntable imaging on the basis of previous research. Such technologies are widely used in many fields, including terrain mapping and geological research, agriculture and forestry, marine research and monitoring, battlefield investigation, precise guidance, target resolution, target identification, space mapping, urban construction survey, field detection Disaster reduction and prevention.
02
How do you feel
He Dongchen
2019 undergraduate Department of Electronics
As a freshman, we have gained a lot. We have realized the corresponding role of radar imaging in the military and civil fields. At the same time, we also have a corresponding interest in the subject of radar imaging. We also have a corresponding understanding of UAV technology combining machine learning and radio communication.
Wang Jingyi
2019 undergraduate Department of Electronics
Through this lecture, I learned a little about the principle of radar imaging technology and its important position in military. If scholars continue to study this technology, the future application will be more and more flexible, more and more powerful, providing greater security for national defense!
He Dongchen summed up that in a word, from this lecture, we not only know the more cutting-edge scientific knowledge, but also know more about the application of our major in the future, what are the more important needs of the country in the field of radar imaging, and what research we can do in the future, so as to achieve both personal value and personal value The purpose of making corresponding contributions to the country.
03
Interview the teacher
At 10 a.m. on the 9th, the academic department interviewed Mr. Bai online through QQ group telephone.
When asked if Mr. Bai is the first time to give an online lecture, what's the difference with the school lecture.
"It's really the first online lecture," Mr. Bai said. "There are many differences between online lectures and school lectures. The main reason is that students can't get feedback from them, can't grasp their understanding and interest, can't control the depth and focus of the lecture."
Then we asked which major is more close to this lecture. Mr. Bai said that radar imaging is in favor of big electronics and communication engineering. Interested students can learn more about these two majors.
Questions about 4D imaging radar
At present, the research on 4D radar imaging technology is being carried out in the field of cutting-edge science and technology. What's the difference between 4D radar and traditional 3D laser radar?
4D radar is very related to the two-dimensional array imaging in the lecture. Compared with 3D lidar, 4D radar imaging uses long wave band, low frequency, and strong ability to penetrate rain and fog. It can be used in the night by using active irradiation, and has a long working distance, which can detect objects in a far distance.
As we all know, the fourth dimension refers to time. What role does it play in 4D radar imaging?
In radar, the target velocity can be obtained by transmitting multi pulse in a period of time and processing the echo phase of the target. The fourth dimension is to obtain speed through time processing, and speed is very important in automatic driving and intelligent transportation.
Do you think there are any bottlenecks in radar imaging technology at this stage in China? If there are students from Nantah who will develop in this field in the future, what are your expectations for them?
The combination of 4D imaging technology and artificial intelligence technology to mine more visual semantic information is now a research hotspot. The country has also set up a major project in this area, which is also a very promising and applied direction in automatic driving. These aspects require a high level of mathematics. If the students are interested, they should learn mathematics well, or enter the laboratory to participate in research earlier.
What are you waiting for to summarize your interest? Mr. Bai welcomes you, who are full of passion, to work together to further study the radar.
The main research directions of Professor Bai's research group include UAV formation communication, radar communication integration, machine learning, etc.
Interested students can contact Mr. Bai directly~
Picture and text interview with academic department
Typesetting: Ren Shenghao, media department