Design of Lfmcw Radar Level Measurement System Based on Sopc

Abstract

Aiming at the special conditions that it is very difficult to measure precisely and continuously by the traditional level measurement. This paper designed the linear frequency modulation continuous wave radar level measurement system base on SOPC. The paper introduced the overall design of the system, and elaborated on the function of hardware and software implementation of SOPC system . T Keywords-Level measurement, SOPC, Linear Frequency Modulated Continuous Wave Rada I. INTRODUCTION In the smelting and chemical production processes we often encounter in a large number of solid and liquid materials. Level is a very important process parameter. Through the accurate measurement of the material level, the operator can take response measures on the production based on changes of material level. In the complex modern technology production process, especially in the dicky measurement conditions such as the mixing tank, high temperature, large steam, corrosive medium, easy scarring, and the operator is far away from the scene, the real-time accurate measurement of the material level is particularly important for the optimal control and the safety of the production process. It can become the key to automatic production of the enterprises(1). Linear frequency modulation continuous wave (LFMW) radar measures the distance through modulating the continuous wave emitted and using the frequency and the phase of the echo information.It is a more advanced level measurement method because of the prominent advantages such as high accuracy, free from environmental restrictions. The current study just emerged in the field of level measurement at home and abroad, it will has a broad application prospects(2). II. OVERALL SYSTEM DESIGN The radar level measurement system includes two parts:data acquisition and SOPC system . Data acquisition is using the antenna of radar to transmit and receive the echoe of the material level. It exports mixing frequency signal through the integrate front part of radar. After pretreating it forms digital signal through A / D converter. And it controls the linearity of VCO by using the correction of the sawtooth wave voltage signal exported through the A / D converter. SOPC system includes 3 parts: FPGA, memory, and the external interface. FPGA is built on the FPGA chip, and the core is the Nios processor . The design uses the chip EP1C12Q240C8 of series Cyclone. In FPGA, the A / D and D / A conversion and control modules are achieved by writing VHDL program; DSP module is designed by DSP Builder in Matlab; the remaining parts are designed in the SOPC Builder(3). According to the functions and the determined programs of system, the overall structure of system is shown in figure 1: