초록 ▼

A fire control system for a boost phase threat missile includes sensors for generating target-missile representative signals, and a multi-hypothesis track filter, which estimates the states of various target hypotheses. The estimated states are typed to generate hypotheses and their likelihoods. The

A fire control system for a boost phase threat missile includes sensors for generating target-missile representative signals, and a multi-hypothesis track filter, which estimates the states of various target hypotheses. The estimated states are typed to generate hypotheses and their likelihoods. The states, hypotheses and likelihoods are applied to a multihypothesis track filter, and the resulting propagated states are applied to an engagement planner, together with the hypotheses and likelihoods. The engagement planner initializes the interceptor(s). Interceptor guidance uses the initialization and the propagated states and typing information to command the interceptor.

대표청구항 ▼

What is claimed is: 1. A method for boost phase fire control, said method comprising the steps of: sensing a target missile to produce target-representative signals representing at least target position; applying said target-representative signals to a multi-hypothesis filter for producing a state

What is claimed is: 1. A method for boost phase fire control, said method comprising the steps of: sensing a target missile to produce target-representative signals representing at least target position; applying said target-representative signals to a multi-hypothesis filter for producing a state vector of the target missile containing at least position and velocity information defining the state of said target missile; using a rocket equation, computing the time derivative of said state vector of the target missile; integrating said time derivative of said state vector to generate estimated target missile position and velocity representing propagated target missile states; and guiding an interceptor to the target missile using the propagated missile states. 2. A method according to claim 1, wherein said step of applying said target-representative signals to a multi-hypothesis filter for producing a state vector of the target containing at least position and velocity information defining the state of said target missile comprises the step of determining the state vector as 3. A method according to claim 1, wherein said step of using the rocket equation, computing the time derivative of said state vector of the target missile includes the step of calculating 4. A method according to claim 1, wherein said step of integrating said time derivative of said state vector to generate estimated target missile position and velocity representing the propagated missile states includes the step of calculating 5. A method for intercepting a boosting target missile, said method comprising the steps of: for each of a plurality of hypotheses of target missile type and stage, generating estimates of at least target missile velocity ({circumflex over (V)}mi), position ({circumflex over (X)}mi), specific mass flow rate ({dot over (M)}), time until burnout of a current target missile stage, and specific impulse (ISP); for each of said plurality of hypotheses, propagating a target hypothesis/stage combination to a time corresponding to the estimated end time of the current stage; deciding if the end of the current stage corresponds to the end of a last stage of the hypothesis; if the end of the current stage corresponds to the end of the last stage of the hypothesis, propagating the states of the hypothesis through burnout of the last stage and ballistically thereafter; and guiding an interceptor to the boosting target missile using the propagated states of the hypothesis. 6. A method according to claim 5, further comprising, after said step of: if the end of the current stage corresponds to the end of the last stage of the hypothesis, propagating the states of the hypothesis through burnout of the last stage and ballistically thereafter, the steps of; if the end of the current stage does not correspond to the end of the last stage of the hypothesis, propagating the states of the hypothesis through burnout of the current stage, and repeating said steps of (a) deciding if the end of the current stage corresponds to the end of the last stage of the hypothesis, (b) if the end of the current stage corresponds to the end of the last stage of the hypothesis, propagating the states of the hypothesis through burnout of the last stage and ballistically thereafter and (c) if the end of the current stage does not correspond to the end of the last stage of the hypothesis, propagating the states of the hypothesis through burnout of the current stage. 7. A method according to claim 5, wherein said step of propagating the target hypothesis/stage combination to a time corresponding to the estimated end time of the current stage is made with the assumptions being made that the target kinematics are expressed by: where {umlaut over (Z)}(t) is the target acceleration vector (Earth-fixed reference frame); {dot over (Z)}(t) is the target velocity vector (Earth-fixed reference frame); Z(t) is the target position vector (Earth-fixed reference frame); μ is the Earth gravitational constant; ω is the Earth angular velocity vector; Isp is the specific impulse of the target rocket motor; gc is the standard gravitational acceleration at Earth's equator; and b(t) is the specific mass flow vector of target rocket motor, and the target state is expressed as a vector containing at least target position, velocity, specific mass flow rate, and acceleration and the derivative of such a vector can be expressed as: and the propagation to the end of the current stage is made by integrating the equation 8. A method according to claim 7, wherein said step of integrating is performed using a numerical integration technique such as a fourth order Runge-Kutta scheme. 9. A method according to claim 5, wherein said step of propagating the target hypothesis/stage combination includes the step of, while propagating the hypothesis to the end of the current stage, through subsequent stages, and for a ballistic portion of flight, saving the propagated target state at points sufficiently close in time to completely represent the target trajectory, and making the propagated and saved target states available as the output of the method. 10. A method according to claim 9, wherein said points sufficiently close are one second apart. 11. A method for intercepting a boosting target missile, said method comprising the steps of: generating estimates of at least target missile velocity ({circumflex over (V)}mi), position ({circumflex over (X)}mi), and launch time; for each of a plurality of hypotheses of target missile type and stage, obtaining at least the nominal target missile parameters of staging times, specific mass flow rate ({dot over (M)}), specific thrust (ISP), and angle of attack (AoA); for each of a plurality of hypotheses of target missile type and stage, computing from said estimated target missile velocity ({circumflex over (V)}mi), position ({circumflex over (X)}mi), and launch time, and from said nominal target missile parameters, an estimate of the current stage, and of the time until burnout of the current stage; determining, from said estimates of current stage and time until burnout of current stage the time since ignition of the current stage and then the specific mass flow rate {dot over (M)} at the current time for the target/stage combination; for each of said plurality of hypotheses, propagating the target hypothesis/stage combination to a time corresponding to the estimated end time of the current stage, with the assumption being made that the target kinematics are expressed by: where {umlaut over (Z)}(t) is the target acceleration vector (Earth-fixed reference frame); {dot over (Z)}(t) is the target velocity vector (Earth-fixed reference frame); Z(t) is the target position vector (Earth-fixed reference frame); μ is the Earth gravitational constant; ω is the Earth angular velocity vector; Isp is the specific impulse of the target rocket motor; gc is the standard gravitational acceleration at Earth's equator; and b(t) is the specific mass flow vector of target rocket motor, and the target state is expressed as a vector containing at least target position, velocity, specific mass flow rate, and acceleration and the derivative of such a vector can be expressed as: and the propagation to the end of the current stage is made by integrating the following equation using a numerical integration technique such as a fourth order Runge-Kutta scheme deciding if the end of the current stage corresponds to the end of the last stage of the hypothesis; if the end of the current stage corresponds to the end of the last stage of the hypothesis, propagating the states of the hypothesis through burnout of the last stage and ballistically thereafter; if the end of the current stage does not correspond to the end of the last stage of the hypothesis, propagating the states of the hypothesis through burnout of the current stage, and repeating said steps of (a) deciding if the end of the current stage corresponds to the end of the last stage of the hypothesis, (b) if the end of the current stage corresponds to the end of the last stage of the hypothesis, propagating the states of the hypothesis through burnout of the last stage and ballistically thereafter and (c) if the end of the current stage does not correspond to the end of the last stage of the hypothesis, propagating the states of the hypothesis through burnout of the current stage; and guiding an interceptor to the boosting target missile using the propagated states of the hypothesis. 12. A method according to claim 11, wherein the step of, for each of a plurality of hypotheses of target missile type and stage, computing the time until burnout of the current stage comprises the steps of: subtracting the current time from the estimated launch time; comparing the resulting estimate of time since target launch to the nominal target timeline for the hypothesis to indicate the stage of the hypothesis. 13. A method according to claim 11, wherein said step of propagating the estimated position and velocity of the target missile to the estimated time of the end of the current stage, through subsequent stages, and for a ballistic portion of flight, includes the step of saving the propagated target state at points sufficiently close in time to completely represent the target trajectory. 14. A method according to claim 13, wherein said step of saving the propagated target state at points sufficiently close in time to completely represent the target trajectory includes the step of saving the propagated target state at points about one second apart. 15. A method according to claim 11, wherein said step of propagating the states of the hypothesis through burnout of the last stage and ballistically thereafter comprises the step of propagating the states until a selected time after lift off (TALO).