M.Sc Thesis

M.Sc StudentAharonovich Maayan
SubjectImpact Time Guidance
DepartmentDepartment of Mechanical Engineering
Supervisor PROFESSOR EMERITUS Shaul Gutman
Full Thesis textFull thesis text - English Version


The use of multiple pursuers to strike a target simultaneously, sometimes referred to as a salvo attack, can increase the likelihood of a successful interception. Using such coordination can both overwhelm the defensive capabilities of the target and mitigate the negative side-effects of multiple impacts. In missile guidance, a simultaneous interception can be achieved by timing all of the pursuers to strike at a common impact time through adjustments to the guidance law.

Given the maximal pursuer thrust, the minimal interception time of each pursuer is obtained from the Time-to-go equations. Use of the optimal guidance laws results in a minimal interception time while a decrease in the thrust magnitude can result in an impact at a later time. This demands a propellant capable of real-time adjustments, such as a liquid or future gel propellant. However, most tactical missiles use a solid propellant which has a predetermined thrust profile and is very difficult to regulate in real-time.

In this research, a Vector Guidance (VG) approach to the impact time conflict is presented for both Bounded Control and Linear Quadratic (LQ) Control. The impact time guidance is first formulated for a missile with an adjustable thrust (liquid or gel propellants). However, when the same laws are used with a constant and predetermined thrust (solid propellants), a chattering effect occurs in the guidance direction, which is both difficult to implement and may cause the pursuer to lose reliability. Therefore, the impact time guidance is also formulated for a missile with a constant and predetermined thrust (solid propellant), and the use of standby routes is considered. Lastly, a comparison is made between the Bounded and LQ control.