Missile Guidance Laws For Reentry Strike Based On Pure Proportional Navigation

Guidance laws of reentry strike for missile to intercept stationary or slowly moving target is one of key research points of the missile guidance community.As the air-defense technology develops,the penertration ability of single missile or multiple mutually independent missiles against the air-defense fire network is decreasing.One effective approach to improve the penertration ability of missile is to adopt strike trajectories with impact-angle-constraints.Then,the missile could hit the target at certain flight path angle from certain azimuth.Another effective method is using multiple missiles to hit the target simultaneously and cooperatively.Then,the air-defense system might miss one or several of the whole missile swarm.However,the existing missile guidance laws on reentry strike still suffer from problems such as complex algorithms,too many guidance parameters,robustness limitation,and so on.Based on the commonly used endo-atmospheric interception guidance law,i.e.,pure proportional navigation(PPN),the performance of PPN against the stationary target is thoroughly analyzed.Guidance laws for single missile against the stationary target are thoroughly analyzed in this thesis,and so are the cooperative guidance laws for multiple missiles.Based on the constant-speed assumption of missile,the analytical solutions of PPN against the stationary target is fully explored.For simplicity of theoretical analysis,the constant-speed assumption of missile is commonly adopted for researches when studying endo-atmospheric missile guidance laws.Based on the constant-speed assumption,the analytical solutions of PPN against the stationary target are completely deduced.The solutions of the line-of-sight(LOS)rate,closing speed,commanded acceleration,and missile lead angle are obtained.The relationships among impact angle,LOS angle,missile lead angle,and navigation gain of PPN are also presented.Furthermore,using parcel integration,the time-to-go of missile against stationary target is also given,which is expressed as a series solution.The analytical solutions of PPN obtained could be used as a theoretical support for the following researches on reentry guidance laws for single missile and missile swarm against stationary target.Based on the analytical solutions of PPN,the impact-angle-control(IAC),impact-time-control(ITC),and impact-time-and-angle-control(ITAC)guidance laws of single missile against the stationary target are proposed.Based on the anglar relationship of PPN against stationary target,the PPN-based impact angle control guidance law(PPNIACG)is propsed,which is divided into two phases.In the first phase,the spatial geometric relationship between the missile and target is regulated.When the geometric relationship meets the IAC requirement,the missile enters the second phase and is guided by PPN.Then,the impact angle constraint of missile against the stationary target could be satisfied.Based on the series solution of the missile flight time-to-go of PPN against stationary target,the PPN-based impact time control guidance law(PPNITCG)is proposed,which is also divided into the two phases.In the first phase,the spatial geometric relationship between the missile and target is regulated.When the geometric relationship meets the ITC requirement,the missile enters the second phase and is guided by PPN.Based on PPNIACG and PPNITCG,the PPN-based impact time and angle control guidance law(PPNITACG)is proposed,which could satisfy the IAC and ITC requirements simultaneously.For the above-mentioned three guidance laws,the corresponding three-dimensional(3D)extensions are advanced,based on the traditional decoupling method of missile pitch and yaw planes.Besides,for PPNITCG,based on the 3D relative kinematic equation set established in the LOS rotation coordinate system(LRC),another 3D extension method is proposed,which is to directly construct the dimension-reduced 2D-PPNITCG in the instantaneously rotation plane of LOS(IRPL).Based on the analytical solution of PPN against stationary target,the communication topology of multiple missiles,and the consistency control theory,the cooperative guidance law of multiple missiles with ITC is proposed.For the problem that multiple missiles simultaneously hit the target,considering the communication topology and combining the consistency control theory,the PPN-based impact-time-control cooperative guidance law(PPNITCCG)of multiple missiles against the stationary target is proposed.The flight time-to-goes of multiple missiles are firstly regulated in the first phase to realize the flight time consistency,then the impact angles are regulated in the second phase by adopting reasonable guidance parameters.After that,the 3D extension of PPNITCCG is presented,based on the traditional two-channel decoupling method.The reentry strike guidance laws based on PPN researched in this thesis could be applied to various interception scenarios for missiles to intercept stationary surface targets.The guidance laws for single missile against stationary target are trivial to demonstrate.For validating the effectiveness and robustness of the PPNITCCG proposed in this thesis,a UAV carried air-to-surface missile is adopted for numerical simulation cases.The gravition model and atmosphere model are considered,and the quasi six degree-of-freedom(DOF)cooperative strike simulation model of multiple missiles is constructed,where three missiles cooperate to strike a stationary surface target.The measurement errors are taken into account,and so is the dynamic lag of attitude control system.The blind radius of the missile seeker is also considered.The feasibility and effectiveness of PPNITCCG is demonstrated and compared with that of PPN.