  We propose two concepts for the significant improvement of surface current
mapping with bistatic oceanographic High-Frequency Radars. These ameliorations
pertain to the azimuthal processing of radar data with linear or quasi-linear
antenna arrays. The first idea is to take advantage of the remote transmitter
to perform an automatic correction of the complex gains of the receiving
antennas based on the analysis of the signal received in the direct path. This
direct signal can be found at the zero-Doppler and minimal range cell in the
Range-Doppler representation. We term this adjustment as "self-calibration" of
the receiving array, as it can be performed in real-time without any specific
action from the operator. The second idea consists in applying a Direction
Finding technique (instead of traditional Beam Forming) not only to the full
array of antenna but also to subarrays made of a smaller number of sequential
antennas, a method which we refer to as "antenna grouping". The combination of
self-calibration and antenna grouping makes it possible to obtain
high-resolution maps with full coverage, thereby combining the respective
merits of Direction Finding and Beam Forming techniques. In addition the method
is found robust to missing antennas in the array. These techniques are applied
to and illustrated with the multistatic High-Frequency Radar network in Toulon.
