Digital Beamformation Technology in Scan Radar and Its Essentiality for Achieving Predefined Surveillance under Air-borne Operations

Aims: To develop a precise Digital Beam Forming control at the receiver of a Digital RADAR under clutter condition.

Place and Duration of Study: Electronics & Communication Engineering Department, Sikkim Manipal Institute of Technology, Sikkim, India, between March 2012 and May 2012.

Methodology: Under a slow motion clutter environment, the target dimension is being varied i.e., appearing different targets with descending order RCS, the receiver performance is tested in terms of detectability of the target. Then at each case it has been observed how the target peak is gradually reduced w.r.t the decreasing RCS of the target. But, after employing the precise Digital Beam Formation at the receiver towards the lowest RCS target, it has been observed that by what extent, the target peak is improved in order to get a sustainable target to clutter ratio.

Results: In Case-1, Digital Beamformation is done in an arbitrary direction & the Signal-to-Clutter Ratio (SCR) is noticed for larger as well the smaller dimension target. In Case-2, the Tx and Rx Beamformation is done towards larger dimension target. Keeping the dimension of the larger target constant, the dimension of the smaller target is gradually decreased and the decreasing SCR is noticed at the output of the receiver beamformer. At a certain decreasing value of smaller target RCS, the target gets hidden in clutter and not being detected. Under Case-3, the receiver Beamformation direction has been switched towards the smaller target so as to successfully retrieve the smaller target from clutter.

Conclusion: By the precise Digital Beam Forming control at the receiver, the Signal-to-Clutter Ratio (SCR) of the smaller target as discussed in Case 3, is improved by a great extent. Due to the limitation of the system dynamic range the smaller RCS target can’t be distinguished from clutter, but at this condition, if the precise Digital Beam Forming (DBF) towards an optimum direction can be formed, it may help at a great extent to find the smaller RCS target being distinguished from the clutter. The simulation results in this paper prove the fact with vivid depictions and clarifications.