The Design And Implementation Of Container Inspection System

In recent years, the microwave detection theory and technology develop and improve continuously with the development of electronic technology. They have been widely applied in many fields of national economy. Products such as the ocean tide detection systems, traffic tracing cauda prediction systems which have both high practical value and social benefits are developed.This paper is under the actual needs of Shanghai Port, develops a kind of real-time radar system for the height measurement of container stacking. The radar system is a linear frequency modulated continuous wave (LFMCW) radar working at X-band. It has a lot of advantages such as small size, simple structure, low cost. It has been tested in real environment, and achieved good results.This design of the container stacking inspection system consists of the following parts:sending and receiving antennas, microwave radar front-end system, signal acquisition and processing and the results display.To improve isolation of the sending and receiving antennas, dual-mode antennas are used, the two 16 patches array antennas which are of the same structure but are put in different direction in space.Design includes the following steps:adjust the structure and size on the HFSS simulation platform according to the physical size of antenna theory calculations, observe the simulation results, realize high gain, wide bandwidth, and narrow direction-angle microstrip antenna. Considering the requirements of the direction angle, gain and antenna miniaturization, microstrip antenna array which is composed of 2*8 16patches is selected and its connection form mixed series connection and parallel connection fed.Microwave radar front-end system relies on microwave ranging principle, using microstrip antenna design;the system includes VCO, power splitter and mixer. The purchased integrated VCO oscillator chip is used;splitters and mixers are designed on ADS platform and optimize the size, then PCB plate.Signal acquisition and processing and the results display module will use NI USB-6251 data acquisition card and Lab VIEW simulation platform to complete IF signal filtering, FFT transform, numerical calculation and real-time results are displayed on the computer with good intuitive.Finally, integrate the sending and receiving antennas, microwave radar front-end system, signal acquisition and processing and the results display module, the entire system to complete the field measurements with high accuracy and timeliness, good performance, has practical value.