en Research Paper Research Paper <font face="TTE1DF74D0t00" size="2"><p align="left">In this paper, after defining pure proportional navigation guidance in the 3-</p><p align="left">dimensional state from a new point of view, range estimation for passive homing missiles is</p><p align="left">explained. Modeling has been performed by using line of sight coordinates with a particular</p><p align="left">definition. To obtain convergent estimates of those state variables involved particularly in</p><p align="left">range channel and unavailable from IR trackers, nonlinear filters such as sequential U-D</p><p align="left">extended Kalman filter and Unscented Kalman filter in modified spherical coordinate</p><p align="left">combined with a modified proportional navigation guidance law are proposed. Simulation</p><p align="left">results indicate that the proposed tracking filters in conjunction with the dual guidance law</p><p align="left">are able to provide the convergence of the range estimate for both maneuvering and nonmaneuvering</p><p align="left">targets.</p></font> IR Homing Missile,Pure Proportional Navigation Guidance,Range, 115 126 http://ijeee.iust.ac.ir/browse.php?a_code=A-10-3-65&slc_lang=en&sid=1 A. Moharampour محرم پور 18003194753284600210 18003194753284600210 Yes J. Poshtan پشتان 18003194753284600211 18003194753284600211 No A. Khaki-Sedigh خاکی صدیق 18003194753284600212 18003194753284600212 No