| Title |
Altitude-Hypothesis-Based Multiple-Model Vertical-Plane Homing Filter for Bearing-Only Homing Missiles |
| DOI |
https://doi.org/10.5370/KIEE.2026.75.7.1579 |
| Keywords |
Bearing-only Homing Missile; Vertical-Plane Terminal Homing Filter; Interacting Multiple Model Filter; Low-altitude Surface Target |
| Abstract |
This paper proposes an IMM-based vertical-plane homing filter for bearing-only homing missiles engaging low-altitude surface targets with uncertain altitude. In a conventional augmented extended Kalman filter (A-EKF), target altitude is estimated with X-axis position from a single line-of-sight (LOS) angle measurement. This coupling makes the Fisher information matrix ill-conditioned under low LOS-rate conditions, degrading estimation accuracy and possibly causing divergence. The proposed filter partitions target altitude uncertainty into a finite set of hypotheses and employs altitude-conditioned subfilters. Treating altitude as a known parameter in each subfilter removes the X-axis position-altitude coupling and improves X-axis state observability. The IMM mode probabilities are interpreted as Bayesian posterior probabilities for altitude estimation. Monte Carlo simulations show improved LOS-rate estimation accuracy and reduced miss distance over conventional methods. |