Showing papers on "Missile published in 1997"

Underwater docking of autonomous undersea vehicles using optical terminal guidance

Abstract: Missions in which an autonomous undersea vehicle docks with an underwater node for the purpose of battery recharging and/or data transfer greatly increase the scope of potential applications possible with UUVs. Robust and accurate vehicle guidance to a small, simple and reliable docking structure is a critical capability which must be developed in order to achieve this end. This paper describes a simple but highly effective underwater vehicle guidance scheme which is based upon an optical quadrant tracker which locks onto a visible light source located at the dock in the same manner as a Sidewinder air-to-air missile tracks its target in air. An optical terminal guidance system based upon this concept was developed by NRaD. Optical guidance and docking was demonstrated using two autonomous underwater vehicles: a SeaGrant Odyssey IIB and the NRaD Flying Plug. The optical docking system was demonstrated to be accurate and robust for vehicle terminal guidance during field operations and provided targeting accuracy on the order of 1 centimeter under real-world conditions, even in turbid bay water. Such a system is projected to provide reliable terminal vehicle guidance to an underwater dock from a maximum acquisition range of approximately 100 meters in typical continental shelf ocean water.

Background adaptive target detection and tracking with multiple observation and processing stages

Abstract: A computationally efficient missile detection and tracking system, operating on data samples from a focal plane assembly (FPA) of an electro-optical sensor which is observing the earth and space, detects missiles, aircraft, resident space objects or other objects in the presence of background clutter, determines missile types and estimates missile position and velocity components in an inertial reference frame. Digitized samples from an array of electro-optical detectors which are viewing the earth and/or space are processed to detect and track missiles, aircraft and resident space objects. Streak detection is used for this purpose, where the target is separated from a background scene by exploiting target motion relative to the background scene. This processing system provides superior performance and simplified implementation as compared to conventional methods. The weight and power of a computer which can implement the processing system is much reduced as compared to conventional implementation.

Tracking an incoming ballistic missile using an extended interval Kalman filter

Abstract: The important tracking problem by radar of an incoming ballistic missile system, which contains uncertainty in modeling and noise in both dynamics and measurements, is studied. The classical extended Kalman filter (EKF) is no longer applicable to such an uncertain system, and so a new extended interval Kalman filter (EIKF) is developed for tracking the missile system. Computer simulation is presented to show the effectiveness of the EIKF algorithm for this uncertain and nonlinear ballistic missile tracking problem.

The airborne laser

Abstract: The Airborne Laser (ABL), a high-flying megawatt laser that pinpoints a ballistic missile lifting off hundreds of kilometers away, is an alternative to terminal defenses. The utility of the ABL in future regional conflicts, and the consequent policy options the United States can exercise, will be highly dependent on its range. The ABL's range in turn is determined by the accuracy with which the primary laser beam can be pointed, the power density it can deliver, and the structural design of the missile being attacked. This paper's examination of these issues, including all the estimates of the ABL's capabilities, are from the author's own analyses. The findings combine information found in the open literature with the basic physics and engineering involved in propagating intense laser beams through the atmosphere.

Multilayer neural networks and adaptive nonlinear control of agile anti-air missiles

Abstract: Research has shown that neural networks can be used to improve upon approximate dynamic inversion for control of uncertain nonlinear systems. In one architecture, the neural network adaptively cancels inversion errors through on-line learning. Such learning is accomplished by a simple weight update rule derived from Lyapunov theory, thus assuring the stability of the closed-loop system. In this paper, the authors review this methodology and extend it to incorporate an important class of neural networks with a single hidden layer. An agile anti-air missile autopilot is subsequently designed using this control scheme. First, a control law based on approximate inversion of the nonlinear dynamics is presented. This control system is augmented by the addition of a multilayer neural network with on-line learning. Finally, numerical results from a nonlinear agile anti-air missile simulation demonstrate the effectiveness of the resulting autopilot.

Nonlinear performance of a PI controlled missile: an explanation

Abstract: Considers the practical interest of an approach to nonlinear system analysis. Based on the incremental norm, this approach proposes performance and robustness analysis criteria. Using computationally efficient tests involving linear matrix inequality optimization, these criteria enable us to guarantee the performance and the robustness of a realistic PI controlled nonlinear missile.

High-Performance Supersonic Missile Inlet Design Using Automated Optimization

Abstract: A multilevel design strategy for supersonic missile inlet design is developed. The multilevel design strategy combines an efe cient simple physical model analysis tool and a sophisticated computational e uid dynamics (CFD) Navier ‐ Stokes analysis tool. The efe cient simple analysis tool is incorporated into the optimization loop, and the sophisticated CFD analysis tool is used to verify, select, and e lter the e nal design. The genetic algorithms and multistart gradient line search optimizers are used to search the nonsmooth design space. A geometry model for the supersonic missile inlet is developed. A supersonic missile inlet that starts at Mach 2.6 and cruises at Mach 4 was designed. Signie cant improvement of the inlet total pressure recovery has been obtained. Detailed e owe eld analysis is also presented.

Nonlinear missile autopilot design using time-scale separation

Abstract: Time-Scale separation helps improve the robustness of feedback linearized autopilots by simplifying the feedback linearization maps, and by permitting the design of low-order controllers. This paper presents the development of three distinct timescale separation schemes for the design of feedback linearized missile autopilots. A six degrees-of-freedom missile model is used in this work. The performance of these autopilots are compared with the design that does not use time-scale separation. Simulation results illustrating controller tracking performance and robustness are presented.

Plant Inversion Control of Tail-Controlled Missiles

Abstract: In this paper, a nonlinear tracking control technique developed for the control of nonlinear nonmini- mum systems has been applied to the autopilot design of a missile system. To avoid the instability problem associated with unstable zero dynamics, pseudo-inversion is applied with output-redefinition method to the autopilot system of a tail-controlled skid-to-turn(STT) missile. The robustness problems of the output-redefinition methods against uncer- tain aerodynamic coefficients of the missile are briefly inves- tigated and an auxiliary robust control loop using classical proportional-integral error feedback controller is suggested and verified through numerical simulation.

Hybrid neural adaptive control for bank-to-turn missiles

Abstract: A novel hybrid neural adaptive bank-to-turn (BTT) lateral autopilot is described for a short-range command-to-line-of-sight (CLOS) surface-to-air missile. This employs a multiinput-multioutput Gaussian radial basis function (RBF) network in parallel with a constant parameter, independently regulated lateral autopilot, to adaptively compensate for roll-induced cross-coupling time-varying aerodynamic derivatives and control surface constraints, in order to achieve consistent tracking performance over the flight envelope. The hybrid neural autopilot is evaluated in three dimensional (six-degree of freedom) simulation studies against realistic pitch acceleration and roll rate profiles generated from a typical CLOS guidance scenario, and its performance compared with a carefully designed gain scheduled autopilot. The results are found to be encouraging and clearly demonstrate the potential advantages of the neurocontrol scheme.

Future challenges to ballistic missile defense

Abstract: The United States is in the midst of an ambitious effort to build and deploy a wide range of ballistic missile defense systems. Proponents of the systems argue that they will be effective against a host of current and postulated threats from ballistic missiles. In reality, success or failure will depend not only on the technology used in defenses, but also on the tactics and technologies used in missile attacks. Resourceful and determined attackers seek to stress a defense beyond its limits. They can do this by altering their weapons' characteristics with tactics or devices known as countermeasures, such as maneuvers, decoys, and infrared and radar stealth, which hinder or prevent the defense from identifying or hitting their incoming missiles. The ability of a defense to adapt to and deal with countermeasures is the ultimate test of its combat worthiness.

System and method for simultaneously guiding multiple missiles

Abstract: A system and method that covertly provides in-flight target update data to a large number of missiles. The system and method covertly guides the missiles using a transponder located on a satellite that relays encoded target update data to receivers located on each of the missiles. The target update data is derived from intelligence data acquired by a remote sensing device. The target update data is typically transmitted to the missile launch site where it is encoded and transmitted to the transponder on the satellite. The encoding is preferably accomplished using direct sequence spread spectrum/code division multiple access (CDMA) encoding produced using unique seeds that are supplied to pseudo random code generators that uniquely encode the data to be transmitted to each missile. The receivers on each of the missiles have pseudo random code generators that are loaded with the unique seeds. The present system and method enable rapid response to fast-changing battlefield environments, particularly where mobile or relocatable targets are involved.

Computational Analysis and Validation for Lateral Jet Controlled Missiles

Abstract: Comparison of three-dimensional, viscous, turbulent Navier–Stokes simulation for generic missile bodies with wind-tunnel tests have been performed with and without lateral jet thrusters for  ow Mach number range of 2–5 and angles of attack of 0–20 deg. Computationalresults show good overall engineering predictive capability for the surface pressure, normal force coefŽ cient, and jet interaction effects. Further analysisof the computationalresults shows that the favorable upstream pressure zone (lambda zone) created by the lateral jet, unfavorable pressure loss behind the jet caused by its blockage effect, and the jet wraparound effect are the three principal competing physical mechanisms that inhibit or enhance the jet ampliŽ cation factor. Canted jet studies to enhance the Ž rst of these effects show substantial increase in favorable pressure; however, it does not recover axial component of the thrust vector. Qualitative computations for multijets and hot/binary gas thruster jets have been presented to demonstrate the overall computational capability for missile design applications.

The grand plans [ballistic missile defense]

Abstract: The United States plans to use a layered approach to protect its forces and allies against short-range ballistic missiles, which have ranges less than 3500 km. Area defenses such as the land-based Theater High Altitude Area Defense (Thaad) and the sea-based upper-tier defenses will cover broad areas. Patriot PAC-2 and PAC-3 and the sea-based lower-tier defenses will be a backup for targets missed by the upper tier and protect high-value targets such as airfields, ports, headquarters, and population centers. The Airborne Laser will aim to destroy missiles during the boost phase, when their rocket motors are burning and before they can deploy warheads, decoys, or submunitions. A theater battle management system will coordinate the system's many components.

Missile autopilot design via functional inversion and time-scaled transformation

Abstract: This paper presents a new approach to acceleration control of STT (Skid-To-Turn) missiles. In the design and stability analysis of our autopilot, we assume perfect roll-stabilization but consider fully all other nonlinearities of the missile dynamics including the coupling effect due to bank angle. Our autopilot controller consists of a partial-linearizing controller and a dynamic compensator. The partial-linearizing controller along with a time scaled transformation can convert the nonlinear missile dynamics to the so-called normalized system which is completely independent of Mach number and almost independent of air density. The dynamic compensator is designed based on this normalized system. This normalized system greatly simplifies the design process of an autopilot controller regardless of flight conditions. Our autopilot controller can provide fast and exact set-point tracking performance but without the slow-varying conditions on angle of attack and side-slip angle required often in the prior works.

A guidance system for air-to-air missiles

Abstract: A method and system for providing navigational data required to guide an air-to-air missile to a target. The missile is equipped either with an infrared seeking sensor or a radar system. The trajectory of the target is predicted on the basis of a series of location measurements. A flight path of the missile is predicted such that the missile will intercept the target. Based on the predicted missile flight path, signals corresponding to the required rotational angle of the missile's sensor or radar antenna are generated and supplied to the sensor or radar's rotation control unit to cause the missile to move along the predicted flight path.

Parametrically varying flight control system design with full block scalings

Abstract: A systematic procedure for synthesizing a parametrically varying controller for nonlinear systems is presented and applied to a high performance flight control system of a tail-fin controlled missile. The strongly nonlinear and parameter dependent system has to be stabilized and must exhibit high performance over a large operating range.

A new approach to nonlinear autopilot design for bank-to-turn missiles

Abstract: Presents an autopilot controller for bank-to-turn (BTT) missiles. In the design and stability analysis of the proposed autopilot controller, all the nonlinearities of the missile dynamics including the coupling effect due to bank and roll angles as well as the asymmetry of missile body are fully considered. It is shown that through a kind of partial linearization along with singular perturbation techniques we can transform the missile dynamics, which are of nonminimum phase, into an approximately I/O feedback-linearizable system. Thereby, the I/O dynamic characteristics of pitch, yaw and roll channels can be made linear, decoupled, and completely independent of flight conditions such as missile velocity and air density.

History of Ramjet and Scramjet Propulsion Development for U.S. Navy Missiles

Abstract: history of high-speed airbreathing propulsion ramjet engines and their respective vehicle and weapon systems developed under the support of the U.S. Navy is presented. These include surface- and air-launched subsonic combustion ramjets, supersonic combustion ramjets (scramjets), and mixed-cycle ramjet/scramjet/rocket engines intended primarily for missile applications for flight speeds from Mach 2 to Mach 8.

Gps-aided navigation system requirements for smart munitions and guided missiles

Abstract: The Global Positioning System (GPS) is finding increasing use as an effective means of improving accuracy of Inertial Navigation Systems (INS) carried on board guided projectile and missile systems. Two warfare areas that have provided strong motivation for using integrated GPS/INS are Naval Surface Fire Support (NSFS) and Tactical Ballistic Missile Defense (TBMD). This paper presents an overview of various techniques for the integration of the GPS and the INS in a guided weapon system. Then the development of a multi-purpose GPS/INS simulation and analysis tool is described. The model was developed with the flexibility to support a variety of possible technology demonstration and full scale development programs involving GPS-aided guided weapons. The simulation includes detailed models of the GPS satellites and receiver, jamming environment, navigation Kalman filter, inertial navigation system with strapdown inertial measurement unit, six degree-of-freedom airframe and guidance and control components. To illustrate navigation capability, the performance of a GPS-aided smart munition is analyzed in detail. A review of some emerging technology trends and potential future applications for GPS/INS is also provided.

Missile launcher apparatus

Abstract: A missile launcher for use on a surface vessel includes an array of vertical sleeves each being of a size to receive a missile carrying container. The sleeves are maintained in a linear array by means of a series of frames and the lower, or breech, ends of the sleeves are collectively connected to a plenum into which water is injected during a hot launch of a missile. A selected one of the sleeves does not carry a missile but rather, functions as an exhaust or gas take up for the exhaust gases of the other missiles.

An engagement model to optimize defense against a multiple attack assuming perfect kill assessment

Abstract: We present an air-defense engagement model to counter an attack by multiple antiship missiles, assuming perfect kill assessment. In this model, the probability of shooting down all incoming missiles is maximized. A generating function is employed to produce an algorithm which is used to evaluate the outcomes.

Geographically limited missile

Abstract: This invention is directed to a self-destruct device (10) for an airborne projectile (8, 38). This device includes a navigational system (14) which allows the projectile to determine its own position, and a memory (24) for storing a plurality of positions, some of them are designated as acceptable positions (40) for this projectile, and others as unacceptable (44, 46, 48,). An electronic control unit (12) searches for a location in the memory which corresponds to the position of the projectile as given by the navigational system to determine if this position is acceptable or unacceptable, in which case it initiates a self-destruct signal (26) which causes the projectile to self-destruct.

Fly over homing guidance for fire and forget missile systems

Abstract: The fly over homing guidance system for terminal homing missile guidance is fire and forget missile guidance method wherein on board target sensing tracks the target and guides the missile to the target, but instead of being guided to a direct impact as is conventionally done, the missile is guided toward a precise distance over the top of the target, intentionally avoiding impact. A second sensor on the missile detects the leading edge of the target, such as the turret of a tank. The warhead is then fired down onto the top of the target as the missile is guided or directed over it. Further, the shot line of the warhead is substantially perpendicular to the top of the target, maximizing lethality. This allows the use of the same angle of attack and warhead for all modes of target engagement and thus maintains high lethality for every firing scenario.

Mechanism for thrust vector control using multiple nozzles and only two yoke plates

Abstract: In a missile thrust vector control (TVC) system, two yoke plates are used which surround a pair of pivotably-mounted rocket nozzles. The rocket nozzles pass through corresponding elongated slots disposed on each yoke plate, the elongate slots engaging said rocket nozzles and operating to actuate the movement of the rocket nozzles in accordance with command signals issued by the missile autopilot. The actuator yoke plates are mounted for movement in orthogonal directions, and for rotation in unison. The orthogonal movement of the yoke plates effects corresponding movement of the rocket nozzles in the yaw and pitch directions. Simultaneous rotation of the yoke plates produces a relative twisting of the pivotably-mounted rocket nozzles causing thrust angles to deviate from the missile central axis in opposite directions but equal degree, thereby imparting a roll moment to the missile. In this fashion, any combination of movements of the missile during flight is made possible.

Robustness of a Variable Structure Control System for Maneuverable Flight Vehicles

Abstract: One of the key issues related to design of supermaneuverable missiles is precise control during rapid maneuvers. An autopilot synthesis for a marginally stable air-to-air missile with the inclusion of on/off reaction jets to supplement pitch control provided by the elevators is presented. The proposed control method is an extension of variable structure control theory to include simultaneous use of continuous and discontinuous actuators. Stability and robustness issues are addressed, and autopilot synthesis is then carried out. A blending of aerodynamic and propulsive controls is also introduced, based on linear programming that optimizes continuous and discontinuous control, into a single input at low angles of attack. Results from digital simulation of a controlled 180-deg maneuver of a hypothetical next-generation air-to-air missile model show that the proposed method provides stable and robust control over a wide range of e ight conditions.

Boost engine cutoff estimation in Doppler measurement system

Abstract: An estimate of the time of the boost engine cut-off of a missile is provided by irradiating the missile after it is launched with continuous wave signals. The reflected continuous wave signals are detected and an inflection in the Doppler measurements of the reflected continuous wave signals provide an initial estimate of the boost engine cut-off time. A Kalman filter is used to provide initial estimates of the position and velocity of the missile at the boost engine cut-off time and a square root information filter responding to the Doppler measurement residuals after boost engine cut-off reduces the error in the initial estimate of the boost engine cut-off time to a minimum.

System for guiding a missile in alignment onto a target

Abstract: The present invention relates to a system for guiding a missile in alignment onto a moving target. In particular, the guidance computer of the system has a first unit for estimating the state of the missile and the movements of a target on the basis of the measurement of the position of the missile with respect to a datum axis, obtained by angular deviation measuring means, and by using a model of the dynamic behavior of the missile as well as kinematic model of the target. Additionally, the guidance computer has a second unit linked to the first unit for deriving tracking orders and datum values for slaving the missile, and a third unit linked to the first and second units for deriving the control order applied to the missile and the first unit.

Stochastic Analysis of the Interception of Maneuvering Antisurface Missiles

Abstract: The interception of a maneuvering antisurface missile, as in ballistic missile defense and ship defense scenarios, is formulated as an imperfect information, zero-sum, pursuit-evasion game with a state constraint imposed on the evader. Assuming that the perfect information version ofthegamedoes not yield a successful result forthedefense, the solution of this game is in mixed strategies. The blind antisurface missile is programmed to perform a random maneuver sequence. The guidance law of the interceptor missile includes a bias, which partially compensates for the inability to achieve a satisfactory deterministic outcome and yields a nonzero probability of success. Moreover, the defense system must launch the interceptor missile at a randomly selected initial range from the incoming antisurface missile based on the solution of a game of timing. A new methodology is presented to assess the probability of successful interception as a function of the parameters of the scenario.