This study investigates the effects of incorporating Doppler velocity measurements directly into track association and maintenance parts for single and multiple target tracking unit in a multi function phased array radar (MFPAR). Since Doppler velocity is the major discriminant of clutter from a desired target, the measurement set has been expanded from range, azimuth and elevation angles to include Doppler velocity measurements.We have developed data association and maintenance part of a well known tracking method, Interacting Multiple Model Probabilistic Data Association Filter (IMMPDAF), with the Doppler velocity measurements and demonstrated the performance improvement through simulations in terms of track update interval, track maintenance rate, RMS position estimation error, probability of detection and processing time. Since Doppler velocity measurements are employed in track maintenance, non-linear filters are used in the scheme leading to the use of Extended Kalman Filter (EKF) based PDAF. Comprehensive simulations have revealed that using Doppler velocity measurements along with 3D position measurements in heavy clutter conditions lead to an increase in track maintenance rate, track update interval; a decrease in position estimation error, processing time and no considerable effect on the probability of detection. This result is very significant for the efficient use of the limited resources of a multi function phased array radar.