On a New Six Degree of Freedom Modelling Method for Homing Missiles and its Application for Design/Analysis

  • R. N. Bhattacherjee Defence Research & Development Laboratory, Hyderabad
  • A. Saha Defence Research & Development Laboratory, Hyderabad
Keywords: Proportional navigation, Yaw LOS rates, Newtonian equivalent model (NEM), Seeker servosystem, Homing missiles


Development of an accurate six-degree-of-freedom (6-DOF) simulation model for homing missiles incorporating seeker servosystem detailed modelling is reported. A new modelling concept for seeker servosystem simulation, the Newtonian equivalent model (NEM) has been evolved, where body motion coupling is modelled through forces and moments transformed to the seeker. The NEM-based modelling of seeker head and its integration in 6-DOF has been discussed. In the presence of body coupling, the simulation model for seeker tracking or pointing error, gimbal angles and inertial line of sight (LOS) rates as measured by the seeker mounted rate gyros have been obtained through the new modelling method. A novel method of obtaining optimum pitch and yaw LOS rates for proportional navigation (PN) guidance mechanisation is formulated based on synthesised sight line rates measured in the seeker inner gimbal axis. This new method has been validated through simulation studies using the 6-DOF model developed and by comparing the results with those obtained by the conventional method of generating LOS rates for PN guidance. Other important applications of the 6-DOF model discussed are guidance and control design validation/tuning seeker feedforward compensation design tuning of switchover point from open-loop to closed-loop PN guidance. Importance of the detailed 6-DOF simulation model as the ultimate performance evaluation tool for the weapon system in terms of both terminal performance and adequacy of seeker field of view, gimbal angle freedom, etc. has been brought out.

Author Biographies

R. N. Bhattacherjee, Defence Research & Development Laboratory, Hyderabad
Shri R.N.  Bhattacherrjee obtained his BE (Electrical Engineering) from Jadavpur University.Calcutta inl1970 and MTech (Guidance and Control) from Indian Institute of Technology. Madras. in 1976. He joined DRDO in 1977. as Scientist. at DRDL. The areas of his research include guided missile systems. covering, system design. specifications. guidance and control algorithms. modelling. simlnulation and performance evaluation. Presently, he is working on design. modelling and simulation for a third generation antitank missile.
A. Saha, Defence Research & Development Laboratory, Hyderabad
Shri A Saha obtained his BTech (Electrical Engineering) from  University, Kera)a, in 1988 arld ME (Control & Guidance) from Jadavpur University, Calcutta, in 1992. He joined DRDO as Scientist at the Defence Research & Development Laboratory (DRDL), Hyderabad, in 1992. Presently. he is working on design. moclling and I.!igital simulation of control and guidance systemfor a third generatlon antitank missile. He is a life member of the Astronautical Society of India.
How to Cite
Bhattacherjee, R., & Saha, A. (2013). On a New Six Degree of Freedom Modelling Method for Homing Missiles and its Application for Design/Analysis. Defence Science Journal, 47(3), 327-341. https://doi.org/10.14429/dsj.47.4015
Armaments & Explosives