Snake-Hot-Eye-Assisted Multi-Process-Fusion Target Tracking Based on a Roll-Pitch Semi-strapdown Infrared Imaging Seeker

Aiming at intercepting large maneuvering targets precisely, the guidance law of advanced self-seeking missiles requires not only inertial line-of-sight (LOS) angular rate but also target maneuvering acceleration. Moreover, the semi-strapdown stabilization platform has lost the ability to measure the inertial LOS angular rate directly, which needs to be extracted by numerical calculation. The differential operation commonly used in traditional methods can magnify the measurement error of the sensor, resulting in insufficient calculation accuracy of the line-of-sight angular rate. By analyzing the mathematical relationship between the missile–target relative motion and the angle tracking system, a multi-process-fusion integrated filter model of relative motion and angle tracking is presented. To overcome the defect that the infrared seeker cannot directly measure the missile–target distance, following the snake-hot-eye visual mechanism, a visual bionic imaging guidance method of estimating the missile–target relative distance from the infrared images is proposed to improve the observability of the filter model. Finally, target-tracking simulations verify that the estimation accuracy of target acceleration is improved by four times.