A correlation-based method for precise radar distance measurements in dispersive waveguides

This contribution deals with guided radar distance measurements in the field of industrial tank level control. The aim is to achieve a submillimeter gauging accuracy even when conducting the measurement within a highly dispersive environment of large and thus overmoded cylindrical waveguides. Normally multimode propagation causes a decrease in measurement precision. Therefore, the effects of intermodal dispersion are fundamentally reviewed and based on these results, a correlation-based signal processing method is presented. The method is able to exploit the otherwise parasitic dispersion effects to enhance the measurement precision even in constellation with a simple waveguide transition or antenna, respectively. Measurement results in a frequency range of 8.5 to 10.5 GHz are provided for two different kinds of waveguide transitions proving the capability of the method.