Airborne multi-frequency multi-angle high resolution passive detector Radio Frequency Interference detection

As a core practical tool in the Earth observation technology system, remote sensing experiments play a key role in promoting the demonstration, implementation of satellite programs, and the application of observations in Earth system science. Addressing the need for multi-frequency and multi-angle high-resolution passive detection of various environmental factors in the polar cryosphere, such as glaciers, snow cover, and frozen soil, a multi-frequency, multi-angle high-resolution passive detector was designed. This detector covers L, P, C, X, K, and Ka bands and supports angles of 20°,30°,and 40°. Ground experiments for soil moisture observation were conducted in Altay Prefecture, Xinjiang, followed by experiments on both soil moisture and snow thickness observation. The instrument is equipped with a radio frequency interference (RFI) detection module, performing kurtosis detection in the L and P bands during the soil moisture experiment, and in the X and K bands during the snow thickness experiment. RFI was detected by analyzing correlations between channels on a C-band synthetic aperture radiometer. Two RFI detection algorithms were experimentally verified based on algorithm theory. By comparing L-band and Cband inversion brightness maps, it was confirmed that RFI is more pronounced at lower frequencies.