1. A method of performing distortion calibration for an electro-optical sensor, comprising: a) providing a target pattern having a plurality of targets and a reference; b) projecting the target pattern so that the pattern may be shifted in a field-of-view (FOV) measured by the sensor while preserving the relative positions of the targets and the reference; c) moving the target pattern about the sensor's FOV over a plurality of frames; d) passing the projected target pattern through sensor optics whereby the optics' non-linear distortion produces apparent differences in the relative positions of the targets as the target pattern moves; e) observing a position of the reference in said plurality of frames; f) observing positions of the targets in the sensor FOV in said plurality of frames; g) applying a function F representative of the distortion the sensor optics to the observed target and reference positions to provide corrected target and reference positions; h) representing a corrected difference position for a plurality of the targets as the difference between the corrected target position and a corrected reference position; i) fitting coefficients for the function F using the observed target and reference positions over a subset of the targets and frames to minimize the scale-normalized variability of the corrected difference position as the targets move across the FOV; and j) storing the coefficients in a tangible medium with the sensor as calibration terms for the sensor.