外文翻譯---汽車防撞雷達(dá)系統(tǒng)（英文）

1、Car Collision-Prevention Radar System Ni Guoqi Liu Changman Guan Yongjun Wang Mansheng Department of Fire Control & Command, Guilin Air Force Academy Modulator Abstract: In these years, there is a high rate of c

2、ar chain- collision accidents on the highways, especially on the expressways. Yet, until recently no good solution to this problem has been worked out. In this paper, an attempt to solve the problem completely is present

3、ed, that is, the car-carried range finding radar, which can automatically control the driving speed and keep a given space between the cars. 4 Oscillation Source Key words: car, collision-prevention, radar 1. Introd

4、uction It is over 100 years since the car came into being in Germany in 1886. Since then, the development of car industry has brought radical changes to the human life all over the world .In recent years, with the develo

5、pment of the national economy in china, the road traffic has been growing rapidly and the construction of expressways is in its prime, which has played an important role in the rapid development of our national economy.

6、 But, for some reasons like low cadroad rate, low graded roads, mixed pedestrian/car traffic and poor management. Traffic accidents have been happening at a high rate[']. For example, on the expressway from Shanghai

7、 to Nanjing, there is more than one car chain collision accident each year. The accidents resulted in great loss of lives and property, then what is the way to prevent all this? The authors of this article believe that,

8、in addition to attaching more importance to traffic safety, stricter traffic laws and better management. We should set up an advanced car carried collision-prevention radar system to automatically limit the car speed and

9、 reduce traffic accidents. 2. General Plan and Basic Principles 2.1 Block Diagram of General Structure The general plan is designed according to the above design principles, as shown in the following diagram. Speed Reg

10、ulator Indication I I - Figure 1: General structure of car collision-prevention radar We adopt the design of the traditional gun-control radar, that is, one antenna is shared for both transmission and reception, and a

11、 mono-pulse system is employed. In this way, the cost is lowered and signal processing is simplified. The ranging accuracy of this type of radar is less than 5 meters. The antenna for transmission and reception is set at

12、 the front of the car to transmit electromagnetic waves forward. An electromagnetic reflection plate is set at the back of the car in front so as to reflect the wave coming from the car behind. The car behind receives si

13、gnal from the car in front, which is amplified, detected and collated, in order to work out the space between the two cars. The space signal is sent both system 0-7803-h677-8/01/$10.000200 I IEEE. 872 Through the rece

14、ption and transmission transformation switch, the reflected magnetic wave signal enters the receiver channel and gets the intermediate frequency after frequency mixing in the mixer and then the intermediate frequency s

15、ignal is sent into the rectifier to detector out the video signal after being bipolarity amplification. The superheterodyne receiver used in this system works smoothly with a higher sensibility and a modest cost. In this

16、 system, we adopt the no-cooling millimeter wave heterodyne receiver in which the beam lead GaAs semi-conductor devices are adopted. It is very suit for the receiver which frequency range is between 30 to 100 gigahertz.

17、At present the wave-guide component frequency over 100 gigahertz and its technology have found a wide application. So, many different transmitting vectors and technology also have found its application with the developme

18、nt of millimeter wave integrated circuit. Many multifunction components have been adopted on suspension-banded line and micro-banded line and fin-line and notched line and wave-guide. Their frequency is between 35 and 10

19、0 gigahertz. The millimeter wave receiver can be made as the same as the structure of ordinary microwave receiver. General speaking, the millimeter wave receiver use the higher intermediate frequency, but the millimeter

20、wave receiver on the low frequency (30 gigaherz) is adopted as the same as technology of the micro wave receiver. Such as integrated circuit receiver, gas discharge tube reception and transmission switch, receiver protec

21、tion device, wave filter, amplitude limited circulator, isolator and PIN switch and so on[5J. 2.3.2. DiPital P r o c e a Now, the radar signal digital processing is becoming very popular. It becomes the reality for us

22、to generate the digital signal and to be filtered, with the development of analog/digital converter and integrated circuit technology and the appearance of the fast Fourier Calculation. The digital processing has shown i

23、ts advantages in its stability and repeatability and flexibility. In theory, no restriction is put on wave pattern and wave filter function. With the appearance of the digital computer, we can effectively deal with the c

24、ontinuous radar’s signal according to the sampled theorem. The frequency spectrum is calculated based on the sampled-signal group. 2.3.3, Digtal Pulse Comp ression The digital system provide us with a large capability

25、to do processing in effective time. The handled data can be stored in the memory after analogy to digital conversion processing and continue to carry out the processing in no-real time rate (faster or slower). Why the

26、pulse compression technology is adopted? It is mainly because of its great improved test ability and less interference. It will become serious problem for radar to interference one another in a very dense active electro

27、magnetic environment. So the pulse compression radar can be designed to reduce it interference by using different modulation codes and different matched wave filter. 2.3.4 D i e i t w h e d F i l t a i g The ideal

28、method of digital matched filtering is to adopt the weighted method of calculating tapped delay line. But it is replaced recently by the fast Fourior transform for its peripheral convolution. The wide dynamic state range

29、 and the high speed matched filter processing devices have come into being with the development of the assembly line faster Fourier transform technology and the development of the floating point equipment. A new matched

30、filter processing method called step transform use the Sub aperture processing and reduce the faster Fourier transform scale, its hardware is not more than the half of the faster Fourier convolution processing. 2.4 Indic

31、ator In this system, the radar indicator is just kind of accessory equipment. Which provide drivers the distance between two cars, and display the speed. We adopt the more popular plasma indicator, which can complete the

32、 classical program with the microprocessor and precompiled program. This plasma indicator can generate the dot line and special symbols, such as small circles and blocks. The plasma indicator has lots of advantages: