Abstract:
This research investigates the necessary components to design cooperative
guidance strategies for area air defense applications, as a part of a project supported
by UK MoD and French DGA MCM-ITP (Materials and Components for
Missile - Innovation and Technology Partnership) programme. The main considerations
in developing the cooperative guidance scheme are the uncertainty
of the target manoeuvre and the zone defence concept. For the interception of
unpredictable targets before they reach any asset in the defended area, Earliest
Intercept Geometry (EIG) and Intercept Geometry (IG) are introduced; EIG is analytically
obtained and IG is numerically computed in consideration of physical
constraints of the missile and target. Then, two mid course guidance laws are
proposed using the geometries, termed the Earliest Intercept Geometry Guidance
Law (EIGGL) and Intercept Geometry Guidance Law (IGGL). Since the EIG or IG
represents a capture zone of the missile, the defended assets can be protected if
the guidance law guarantees no overlapping between the geometry (EIG or IG)
and the defended area. In many-on-many engagement scenarios, it is clear that
the performance of the guidance scheme depends on the target allocation policy,
thus an optimal target allocation algorithm is designed using the EIG and IG to
maximize the reachability and safety margin. Multiple co-existing hypotheses
about future target trajectory in the mid course and homing phase result in an
initial angular di erence between actual flight path and the flight path demanded
by the homing guidance law at handover, termed the heading error. Even if
a hypothesis of future target trajectory is common to mid course and homing
guidance laws, heading error can be caused by errors in uplink data because of
radar/launcher misalignment, tracker lag, radar measurement error etc. Since this
error might result in an abrupt change of the missile acceleration, it is undesirable.
In order to resolve this problem, an optimal homing guidance law is developed by
introducing a second order polynomial function into the cost function of the guidance
problem. The performance of the optimal guidance law heavily depends on
the accuracy of the time-to-go estimates. Because the optimal guidance laws are
used in the calculation of the IG and the terminal homing guidance, a time-togo
estimation algorithm is also proposed. The performance of each algorithm is
demonstrated using simple numerical examples. Furthermore, the overall performance
of the cooperative guidance algorithm is verified using scenarios in naval
and ground context and a Simulink Common Model (CM). For the algorithm test
and development, these scenarios and CM have been shared between partners
and have evolved during the project. Future work within this research area is
discussed further in the last chapter of this thesis, along with other applications
for the cooperative guidance scheme
ii