Geometric limits, calibration considerations, and error analysis are discussed for an L-band airborne clutter measurement system designed to collect simultaneous bistatic and monostatic clutter measurements in support of the hybrid bistatic radar (HBR) system. The geometric limit is only one of the actual limits to the experimental accuracy. Other important factors include antenna pattern measurement accuracy, aircraft position measurement accuracy, and calibration reference accuracy. The calibration techniques involve the transfer of data from optimal geometries for calibration, to the geometries of interest in this program. A description is given of the implementation of this technique in a clutter measurement system, as well as other calibration equipment, including ground-based navigation beacons, and an active radar calibrator (calibrated target placed in the clutter cell of interest). >