Non‐uniform sampling and super‐resolution method to increase the accuracy of tank gauging radar

Abstract

Different methods are proposed for fluid level measurement in storage tanks. Majority of these methods have some in-contact elements or are based on mechanical waves which are vulnerable to changes due to temperature change, pressure change or ageing. Electromagnetic based (i.e. radar) level measurement is a contactless method and it is less vulnerable to such changes. However, a wide band or ultra-wide band radar signal should be transmitted in order to achieve the required accuracy. Usually, linear frequency modulation or step frequency waveforms are used for this goal and matched filter (MF) processing or fast Fourier transform (FFT) are used to find the true level of the liquid inside the tank. In this study, the authors have shown that, those super-resolution methods used for array signal processing and direction finding can be also used in tank gauging problem. Through the simulations and also practical laboratory test, it is shown that, if the frequency steps are selected non-uniformly, the super-resolution methods produce more accurate result compared with MF or FFT processing.