This month´s cover ...

Illustrations are from Recursive Estimation of Radar Biases Using Electronic Chargs by Andres R. Guesalaga, Department of Electrical Engineering, Catholic University of Chile, 4860 Vicuna Mackenna, Casilla 306-22, Santiago, Chile. Complete work describing the application of the extended Kalman filter (EKF) to the estimation of range and bearing biases in marine radars by performing a map-matching between the data from hydrographic charts and the radar images may be found in IEEE Transactions on Aerospace and Electronic Systems, 40, 2 (April 2004), 725-734.