This paper is studied on the aspects of the intelligent electronic warfare in any action involving the use of EM spectrum to control the spectrum attack of an enemy or impede enemy assaults via the spectrum. The purpose of EW is to deny the opponent the advantage of and ensure friendly unimpeded access to the EM spectrum The principal EW activities have been developed over time to exploit the opportunities and vulnerabilities that are inherent in the physics of EM energy and now it is taking its new dimensions in the era of applying AI techniques and algorithms to make system intelligent .The EW is subdivided into EA, EP and EWS .The study of this paper is mainly focused on EWS measures to counter the electronic attack by the enemy to recognize the threat, targeting, planning and conduct of future operation. Basically these measures are taken out by the designed systems and trained operator to make electronic intercepts (ELINT) and then classify based known Signal Intelligence, to detect the return information to identify the unique characteristics of specific radar by the signals by the human operator can be susceptible to different natural, environmental and conscience of the present human operator. In this context estimation of the radar Antenna Scan Period (ASP) and recognition of the Antenna Scan Type (AST) is important measure in analysing level of threat from the radar.