We analyzed a time series of 94 GHz radiometer images of a sandbox with buried and unburied, metal and plastic AP and AT dummy mines. The images covered almost a complete 24 hour cycle, with both clear sky and rain conditions occurring. The AP nor the buried mines were visible at any time. The contrast of the visible mines depended mostly on the sky conditions. The plastic mines were (almost) always brighter than the background, the metal mines darker.

The significance of several key multi-frequency, polarimetric back-scatter parameters extracted from calibrated and noise-corrected NASA/JPL DC-8 SAR data are examined. The data were collected during the 1989 MAESTRO-1 campaign over the Flevoland agricultural test site. Calibration uncertainty estimates are used to specify minimum separations between features. Thirteen different backscatter types were identified from the test site data, including eleven different crops, one forest and one water area. Using the parameters with the highest separation for a given class, a hierarchical algorithm was developed to classify the entire image. All three frequencies and all polarizations were used to construct the rules for the classifier. Results indicate that multi-frequency, polarimetric radar backscatter signatures can be useful in classifying several different ground cover types in agricultural areas.

Trihedral triangular corner reflectors are commonly used to calibrate and characterize the quality of SAR images. It is argued and experimentally verified that these do behave as point targets, even when their physical size is larger than the spatial resolution of the SAR. The impact on calibration is discussed. >