We present a methodology for tracking the centroid of small
extended objects using measurements from a forward looking infrared
imaging sensor. The statistical characterization of the centroid of a frame
as a noisy linear measurement of the centroid of the target is obtained.
The offset measurement noise is shown to be autocorrelated. State variable
models and the corresponding filters for tracking the target centroid
with these measurements are presented. Their performances are compared,
and it is verified with simulations that the filter that models the
autocorrelated measurement noise provides the best performance.