Order Missile Research Articles

Integrated Guidance-and-Control Design for Three-Dimensional Interception Based on Deep-Reinforcement Learning

This study applies deep-reinforcement-learning algorithms to integrated guidance and control for three-dimensional, high-maneuverability missile-target interception. Dynamic environment, reward functions concerning multi-factors, agents based on the deep-deterministic-policy-gradient algorithm, and action signals with pitch and yaw fins as control commands were constructed in the research, which control the missile in order to intercept targets. Firstly, the missile-interception system includes dynamics such as the inertia of the missile, the aerodynamic parameters, and fin delays. Secondly, to improve the convergence speed and guidance accuracy, a convergence factor for the angular velocity of the target line of sight and deep dual-filter methods were introduced into the design of the reward function. The method proposed in this paper was then compared with traditional proportional navigation. Next, many simulations were carried out on high-maneuverability targets with different initial conditions by randomization. The numerical-simulation results showed that the proposed guidance strategy has higher guidance accuracy and stronger robustness and generalization capability against the aerodynamic parameters.

Physical Optics Radar Cross Section predictions for an anti-ship cruise missile

The capability of the first strike is crucial in the modern battlefield. An important parameter is the radar signature or Radar Cross Section (RCS) of a weapon system, such as a fighter aircraft, a warship, or a missile, affecting the range at which this weapon system would be detected as a target by an enemy radar. If the attacker is detected too late, there will be minimal time for the defender to react, possibly not sufficient to counter the threat. The RCS of a weapon system is considered generally as classified information. However, it can be measured at a suitable measurement test range, if that weapon system is available. Otherwise, it can be predicted with the help of computational electromagnetics. Concerning the second approach, the following procedure was recently proposed: construction of a three-dimensional model of a target, based on available images and any relevant data, and then computation of the target RCS, with the Physical Optics approximative method. In the present approach, this procedure is applied to an anti-ship cruise missile in order to compute its RCS. Finally, the expected detection range for various naval radars is calculated.

Research on missile overload control technology with prescribed performance

Considering that the present control methods for missile overload don’t take the transient and steady state with prescribed performance into consideration. On the basis of backstepping idea, a controller design method with prescribed performance is proposed for longitudinal channel overload motion model of missile in order to improve the performance of missile control systems. It is proved that the system is stable in the sense of Lyapunov, the tracking error of the system satisfy the prescribed transient and steady performance. The given simulation results demonstrate the effectiveness of the proposed control method.

Active target defense using first order missile models

In this note the active target defense scenario is analyzed. This entails a Target aircraft being pursued by an Attacker missile while a Defender missile is launched by the Target or by a Target-friendly platform to intercept the Attacker missile. The missiles are modeled using first order dynamics and implement Pure Pursuit guidance laws but are subject to turning rate constraints. The Target’s optimal heading is obtained such that the Defender intercepts the Attacker and the terminal Target/Attacker separation is maximized. This work offers more realistic results compared to previous work where simple motion kinematics were used, that is, it was assumed that the missiles are able to turn infinitely fast.

Minimum Variation Guidance Laws for Interceptor Missiles

This paper introduces a new approach to guidance law design using linear quadratic optimal control theory, minimizing throughout the engagement the variation of the control input as well as the integral control effort. The guidance law is derived for arbitrary order missile dynamics and target maneuvers. Explicit results are provided for a first order missile model and a constant target maneuver. It is shown that in the limiting cases the guidance law degenerates to either Contrell's minimum effort law or to a guidance law that enables mitigating saturation. The performance of the guidance law is analyzed theoretically and demonstrated on a few simulation cases.

Integrated Guidance and Control of Missile Using Subspace Stabilization Method

Integrated guidance and control law is developed for high-maneuvering missile in order to minimize the uncertain dynamic couple between guidance loop and control loop. After building up the integrated model of guidance and control through combining guidance equations and autopilot equations, this paper puts forward a type of subspace control law with attack-angle tracking by using subspace stabilization control method. Finally, the simulation results by an example, which designs the integrated controller for a terminal guided missile, are presented to reveal that the integrated system has good dynamic-tracking performance.

Large amplitude oscillations of cruciform tailed missiles. Part 1: Catastrophic yaw fundamental analysis

The amplified resonance called catastrophic yaw can be associated to large amplitude equilibrium points of slightly asymmetric spinning cruciform missiles. The steady-state equations of motion in body fixed system of axes permit the analysis of the equilibrium points that define the long-term behavior of the missile in order to avoid this flight condition. This paper presents the fundamental analysis of a simplified nonlinear model of motion capable of exhibiting this flight condition. The model can be used to derive the conservative design condition that assures the low amplitude of the single equilibrium point.

Comparison of the Notable Acceleration- and Angle-Based Guidance Laws for a Short-Range Air-to-Surface Missile

AbstractIn this study, the velocity pursuit, proportional navigation, and augmented proportional navigation guidance laws whose resulting guidance commands are in the form of lateral acceleration are applied on a short-range air-to-surface missile as well as the body pursuit and linear homing guidance laws which yield angular commands and the attained results are then compared. In the end of the mentioned evaluations in which the final miss distance of the considered missile from the intended target, missile-target engagement time, and maximum lateral acceleration requirement of the missile are chosen as the comparison criteria, it is seen that angle-based guidance laws lead the final miss distance values to become smaller than those with the acceleration-based laws although the maximum lateral acceleration requirements of the angle-based laws are greater. For the missile-target engagement time parameter, almost the same results are obtained for both kinds of the guidance laws. In the scope of the study, an angle control system whose bandwidth reaches to its desired value in an increasing manner within a specified duration is proposed for the lateral motion of the missile in order to lower the lateral acceleration requirement posed by the angle-based guidance laws.

Root-mean-square miss distance of proportional navigation missile against sinusoidal target

The performance of a proportional navigation homing missile against a target performing a sinusoidal weave maneuver is evaluated. The missile's effectiveness is measured in terms of the root-mean-square miss distance over a set of engagements in which the initial phase of the target weave is uniformly distributed. Closed form solutions for the root-mean-square miss are derived for the case where the missile guidance system is modeled by a first-order lag and the lateral acceleration is unlimited. The analysis is then extended to include the effects of acceleration saturation and higher order missile dynamics. Comparisons are made between a first-order and a fifth-order guidance system, and the root-mean-square miss is determined numerically as a function of the interceptor's effective navigation gain, time constant and acceleration limit, and the target's weave amplitude and frequency. UTURE homing interceptor missiles will face new and unique challenges as the sophistication of the threat spectrum in- creases. Engagements against air targets can occur at both very low and very high altitudes, with the threats accidentally or intentionally performing weaving or spiraling maneuvers during their midcourse and terminal phases.14 The lateral displacement, acceleration ca- pability, and weave frequency of the target maneuver can greatly enhance the threat's ability to survive a counterattack. To counter this, the defensive missile must have sufficient lateral acceleration, guidance system time constant, and terminal homing time to achieve a high probability of intercept. Whereas the per- formance of the interceptor will be influenced by many scenario- dependent factors,58 a major consideration will be the fundamental response of the proportional navigation (PN) guidance system to the postulated target weave motion.9'10 In the general case, the target dynamics may involve arbitrary periodic motion in three dimensions. A useful starting point for analysis, however, is the response of the PN homing system to a single plane sinusoidal maneuver of constant amplitude and fre- quency. The phase angle of target weave, which is associated with initial conditions at the start of the missile's terminal guidance, can be treated as a random variable, uniformly distributed between 0 and 2n over a set of engagements. The missile's dynamics are approxi- mated by a simple first-order transfer function, and unlimited lateral acceleration capability is assumed. The miss distance can then be parameterized in terms of the effective PN navigation gain N, the missile time constant T, and the amplitude AT and frequency co of the target weave. This paper focuses on root-mean-square (rms) miss distance as a recommended measure of effectiveness in analyzing missile perfor- mance against weaving targets. This measure allows uncertainties in target phase characteristics to be accounted for in the terminal per- formance results. The weaving target problem was first addressed by Chadwick, 9 who determined analytical expressions for the rms miss distance of the single lag PN missile for values of N =2 and 3. Zarchan 10 employed adjoint theory and transfer function tech- niques to determine formulas for the peak miss distance against a weaving target for values of N between 3 and 6. The present paper derives general closed-form expressions for the rms miss distance against a sinusoidal target. New results are obtained for arbitrary

Laser Radiation-Gasdynamic Coupling in the SF,-Air Laminar Boundary Layer

PRACTICAL problems arise where the shielding of aerodynamic surfaces from high-power laser beams is of importance. For example, a highly absorbing gas can be injected into the boundary layer of an airplane or missile in order to protect its surface materials from the incoming laser radiation. Initial work demonstrated that SF6 is a very strong absorber u of CO2 laser radiation. Therefore, this work deals solely with the radiative gasdynamic interaction associated with CO2 laser radiation absorption in a SF6-air laminar compressible boundary layer. However, the implicit finite difference technique employed is applicable to any arbitrary laser wavelength provided an absorption coefficient for the associated absorbing gas is known as a function of pressure and temperature. Contents This work extends earlier flat plate results3 to include the stagnation point and downstream region of an axisymmetric body. The explicit numerical scheme used in the flat plate results required initial guesses for the unknown derivatives at the wall (standard shooting point technique) to be correct to within six or seven significant figures before the solution would begin to converge. Therefore, this explicit scheme was replaced with a more efficient implicit numerical scheme4 which does not have these stability difficulties. The boundary-layer equations (laminar, nonlinear, partial differential equations) are solved with mass injection rate of SF6 and incoming CO2 laser radiation. A self-similar solution is employed at the stagnation point to obtain an initial profile as input to the implicit finite difference solution for the nonsimilar region downstream of the stagnation point. The laser beam is of uniform intensity and parallel to the flow direction. As the laser beam is attenuated, the temperature in the boundary layer increases which in turn affects the absorption coefficient of the gas. Therefore, the radiative transport equation is fully coupled to the fluid mechanic boundary-layer equations. In the present analysis, the gas absorbs but does not emit. The radiation that reaches the wall is totally absorbed by the wall and not reflected back into the boundary layer. The translational, rotational, and vibrational energies of the absorbing gas are in thermal equilibrium. Profile variations across the boundary layer are considered in velocity, tern