Implementation and evaluation of coherent synthetic aperture radar processing for level measurements of bulk goods with an FMCW-system

[摘要] In industrial process measurement instrumentation, radarsystems are well established for the measurement of filling levelsof liquids in tanks. Level measurements of bulk goods in silos, onthe other hand, are more challenging because the material is heapedup and its surface has typically a relatively complex shape. In thispaper, the application of synthetic aperture radar (SAR)reconstruction with a frequency modulated continuous wave (FMCW)radar system for level measurements of bulk goods is evaluated. Inthe proposed monostatic setup, echo signals are acquired at discreteantenna positions on top of the silo. Spatially resolved informationabout the surface contour of a bulk good heap is reconstructed bycoherent 'delay and sum' processing. The concept has beenexperimentally evaluated with a 24 to 26 GHz FMCW radarsystem mounted on a linear stepping motor positioning unit.Measurements on a thin metal wire at different range and on a curvedtest-object with a diffusely scattering surface have been performedto analyze the system's point spread function (PSF) and performance.Constant range and azimuth resolutions (−6 dB) of 15 cm and8 cm, respectively, have been obtained up to arange of 6 m, and results of further evaluations show thatthe proposed concept allows more accurate and reliable levelreconstructions of surface profiles compared to the conventionalapproach with measurements at a single antenna position.

[学科分类] 电子、光学、磁材料