TABLE OF CONTENTS A tracking radar is one whose primary function is automatic tracking of targets. It is distinguished from surveillance or track-while-scan radar in that the tracking radar beam responds to the presence of the target and its motion, following it as part of the automatic tracking loop. Range gates and doppler filters may also move with the target, but the ease with which multiple gates and filters are produced by digital technology makes possible tracking in these coordinates on the outputs of the signal processor having fixed gates and filters, in much the same way as is done in angle with surveillance radar. This chapter will be concerned with antennas and angle measurement techniques, range and doppler trackers, errors in the resulting data, and ECM and ECCM techniques for tracking radars.
Before a target is measured or tracked, it must be resolved from its surroundings, detected, and its signal selected as the subject for measurement. Some degree of measurement is implicit in detection, since coarse position data are provided by the identity of the resolution cell or cells that originate the alarm. The measurement process not only indicates the cell containing the target, but also interpolates among adjacent cells to improve the precision of the data. The rms error of the output data may be as small as 0.5% to 1% of the resolution cell width.
The basic interpolation process compares signals in adjacent cells, estimating the target position from the relative amplitudes of...
