High Quality Content by WIKIPEDIA articles! The PJT-531 Battle Field Surveillance Radar- Short Range (BFSR-SR) is a man portable 2D short range Battle Field and Perimeter Surveillance Radar developed by the Indian Defence Research and Development Organization (DRDO). The BFSR has been designed by DRDO`s Bangalore-based laboratory, the Electronics and Radar Development Establishment (LRDE) and is being manufactured by Bharat Electronics Limited (BEL).