Study On The Algorithm Of The DSP-based FMCW Radar Material Level Measuring Instrument

Material level measuring instrument is an important and indispensable industrialinstrument in industrial control field. FMCW (Linear Frequency Modulation ContinuousWave) radar material level measuring instrument has main advantages as follows: highprecision, low radiant power, anti-interference ability, installation and maintenanceconveniently, etc. Therefore the sustainable growth of the market share has been made inrecent years by FMCW radar material level measuring instrument, which indicates a highvalue to research and apply.Based on consulted large numbers of literature both home and abroad. The systemcomponents and ranging principles of FMCW radar material level measuring instrument wereanalyzed. The radar beat signal processing was studied, which contains removed thefrequency flyback signal, windowed FFT and improved spectral analysis algorithms.According to the windowed FFT spectrum, the spectrum analysis has been researched in thispaper. Firstly, the commonly used spectrum analysis methods were introduced which namedChirp-Z transform and spectrum maximum estimation method. Secondly, based on theanalysis of their advantages and disadvantages, the hybrid algorithm was proposed whichcombines the respective advantages of those two methods. The veracity and validity of thisnew algorithm has been validated by Matlab emulation. So the frequency of beat signal can befound out quickly and accurately.Finally, the experimental prototype has been designed by project team. After explain thechip selection and the overall circuit, the detailed description of the AD sampling, FFToperation and hybrid algorithms are implemented. And then, the integration testing resultsshow that the experimental prototype can complete the ranging function with the precision as7cm.The mainly reasons which effects the ranging accuracy can be attributed as follows:FMCW radar module quality, electromagnetic interference and AD sampling quality.Therefore, this system needed for a further research and improvement, so that it can work intothe practical application.