Showing papers on "Missile published in 2005"

Optimal Guidance Laws with Terminal Impact Angle Constraint

Abstract: Optimal guidance laws providing the specified impact angle as well as zero terminal miss distance are generalized for arbitrary missile dynamics. The optimal guidance command is represented by a linear combination of the ramp and the step responses of the missile’s lateral acceleration. Optimal guidance laws in the form of the state feedback for the lag-free and the first-order lag system are derived, and their characteristics are investigated. Practical timeto-go calculation methods, which are important for the implementation of the optimal guidance laws, are proposed to consider the path curvature. Nonlinear and adjoint simulations are performed to investigate the performance of the proposed laws.

A Two-Sided Optimization for Theater Ballistic Missile Defense

Abstract: We describe JOINT DEFENDER, a new two-sided optimization model for planning the pre-positioning of defensive missile interceptors to counter an attack threat. In our basic model, a defender pre-positions ballistic missile defense platforms to minimize the worst-case damage an attacker can achieve; we assume that the attacker will be aware of defensive pre-positioning decisions, and that both sides have complete information as to target values, attacking-missile launch sites, weapon system capabilities, etc. Other model variants investigate the value of secrecy by restricting the attacker's and/or defender's access to information. For a realistic scenario, we can evaluate a completely transparent exchange in a few minutes on a laptop computer, and can plan near-optimal secret defenses in seconds. JOINT DEFENDER's mathematical foundation and its computational efficiency complement current missile-defense planning tools that use heuristics or supercomputing. The model can also provide unique insight into the value of secrecy and deception to either side. We demonstrate with two hypothetical North Korean scenarios.

Unified approach to missile guidance laws: a 3D extension

Abstract: Since the proportional navigation guidance law was first introduced, many of the researchers had proposed different methodologies to investigate the corresponding performances of all the existing guidance laws. Even though a unified approach was proposed a few years ago, other authors found that under the proposed framework, all the existing guidance laws, namely ideal proportional navigation (IPN), true proportional navigation (TPN), and pure proportional navigation (PPN), were indeed special cases of the mentioned general guidance law. However, the results were restricted to two-dimensional space. In this paper, the author not only extends the results to three-dimensional space, but also to general IPN (GIPN), general TPN (GTPN), and PPN. Unlike conventional researchers, a modified polar coordinate (MPC) is adopted. It is shown that with the property of this MPC, for the line of sight (LOS) based guidance laws (GIPN and GTPN) the number of differential equations required to fully describe the relative dynamics can be reduced from six to three, however, for the missile's velocity-based guidance law, i.e., PPN, five differential equations are required. All the terms of differential equations involve only products and additions of variables. For all the mentioned guidance laws in this paper, only two transformed variables are required to describe the capture region, while the third variable is required to provide the condition of finite turn rate.

The Silicon Oscillating Accelerometer: A High-Performance MEMS Accelerometer for Precision Navigation and Strategic Guidance Applications

Abstract: "The intercontinental ballistic missile (ICBM) and submarine-launched strategic missiles developed over the past 50 years have employed successive generations of increasingly accurate inertial guidance systems. The comparatively short time of guided flight and high acceleration levels characteristic of the ballistic missile application place a premium on accelerometer performance to achieve desired weapon system accuracy. Currently, the U.S. strategic missile arsenal relies on variants of the pendulous integrating gyro accelerometer (PIGA) to meet the high-performance, radiation-hard requirements of the weapon system. Likewise, precision navigation systems, such as the currently deployed SSBN Ship Inertial Navigation Systems (SINS), employ highly specialized and complex electromechanical instruments that, like the PIGA, present a system life-cycle cost and maintenance challenge. The PIGA and the Electromagnetic Accelerometer (EMA) demonstrate unsurpassed performance, however, their life-cycle cost has motivated a search for a highperformance, solid-state, strategic accelerometer. The Draper Laboratory is currently in the process of developing the Silicon Oscillating Accelerometer (SOA), a MEMS-based sensor that has demonstrated in laboratory testing the part-per-million (ppm)/µg scalefactor and bias performance stability required of precision guidance navigation applications. The ICBM and SSBN applications have significantly different environmental, acceleration dynamic range, and resolution requirements that are best satisfied by optimizing the SOA geometry for each application. The design flexibility and wafer-scale fabrication methods of the silicon MEMS process enable manufacturing both instrument designs with essentially zero incremental cost associated with the additional instrument assembly line. That is, the SOAs developed for the ICBM guidance and SSBN navigation applications share a common sensor package, electronics architecture, main housing and instrument assembly process. This paper will give an overview of the Draper SOA and compare and contrast performance data taken to date on both versions of the SOA."

Aerodynamic Predictions, Comparisons, and Validations Using Missile DATCOM (97) and Aeroprediction 98 (AP98)

Abstract: The U.S. Air Force Missile DATCOM (97 version) and the Naval Surface Warfare Center Dahlgren Division Aeroprediction 98 (AP98) are two widely used aerodynamic prediction codes. These codes predict aerodynamic forces, moments, and stability derivatives as a function of angle of attack and Mach number for a wide range of axisymmetric and nonaxisymmetric missile configurations. This study evaluates the accuracy of each code compared to experimental wind-tunnel data for a variety of missile configurations and flight conditions. The missile configurations in this study include axisymmetric body alone, body wing tail, and body tail. The aerodynamic forces under investigation were normal force, pitching moment, axial force, and center-of-pressure location. For the configurations detailed in this paper, these case studies show normal force prediction for both codes to have minimal error. Both AP98 and Missile DATCOM were effective in predicting pitching-moment coefficients, though at times limiting factors were necessary. Finally, both AP98 and DATCOM predict reasonable axial-force coefficients for most cases, though AP98 proved more accurate for the body-wing-tail and body-tail configurations evaluated in this study.

Effect of Atmospheric Transmission and Radiance on Aircraft Infrared Signatures

Abstract: This paper elaborates the role of atmosphere in determining infrared signatures of aircraft as perceived by a ground-based infrared detector, similar to the case of an infrared guided heat-seeking surface-to-air missile. The main objectives are to assess the effect of atmosphere on aircraft infrared signature and to evaluate infrared bands in which a conventional fighter-class aircraft is most susceptible to infrared guided missiles. Such an analysis is of paramount importance for aircraft infrared signature management and aircraft mission planning. First, the lock-on range is derived as a function of aircraft, missile seeker, and atmospheric parameters. Thus, the role of atmospheric radiance and transmittance in determining aircraft signature level as perceived by the missile infrared seeker is brought out. The role of various atmospheric constituents in dictating infrared characteristics of the atmosphere is also discussed. The Berger’s model is used for computing atmospheric/sky radiance and the Lowtran-7 model to compute atmospheric transmissivity. The infrared bands in which the aircraft signature is prominent are identified, and the variation of aircraft signature level and lock-on range with respect to a typical surface-to-air missile within these bands are analyzed and discussed for a representative case.

Directed infrared countermeasures (DIRCM) system and method

Abstract: An agile, high-power, reliable DIRCM system that is easily extended to address sophisticated UV or UV-visible capable multi-band threats includes a missile warner having missile warning receivers (MWRs), one or two-color suitably in the mid-IR range, that detect likely missile launch and pass the threat coordinates to a pointer-tracker having a Roll/Nod gimbal on which the IR laser transmitter is mounted. The pointer-tracker slews the gimbal to initiate tracking based on the threat coordinates and then uses its detector to continue to track and verify the threat. If the threat is verified, the pointer-tracker engages the laser to fire and jam the missile's IR seeker. By slewing the gimbal based on unverified threat coordinates to initiate tracking the system is highly agile and can respond to short and near simultaneous MANPADS shots.

The Cuban Missile Crisis

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Portable air defense ground based launch detection system

Abstract: A ground based launch detection system consisting of a sensor grid of electro-optical sensors for detecting the launch of a threat missile which targets commercial aircraft in proximity to a commercial airport or airfield. The electro-optical sensors are configured in a wireless network which broadcast threat lines to neighboring sensors with overlapping field of views. When a threat missile is verified, threat data is sent to a centrally located processing facility which determines which aircraft in the vicinity are targets and send a dispense countermeasure signal to the aircraft.

FLIR-to-missile boresight correlation and non-uniformity compensation of the missile seeker

Abstract: The present invention provides for simple and streamlined boresight correlation of FLIR-to-missile video. Boresight correlation (42) is performed with un-NUCed missile video (40), which allows boresight correlation and NUC (46) to be performed simultaneously thereby reducing the time required to acquire a target and fire the missile. The current approach uses the motion of the missile seeker for NUCing to produce spatial gradient filtering in the missile image by differencing images as the seeker moves. This compensates DC non-uniformities in the image. A FLIR image (44) is processed with a matching displace and subtract spatial filter constructed based on the tracked scene motion. The FLIR image is resampled to match the missile image resolution, and the two images are preprocessed and correlated using conventional methods. Improved NUC (46) is provided by cross-referencing multiple measurements of each area of the scene as viewed by different pixels in the imager. This approach is based on the simple yet novel premise that every pixel in the array that looks at the same thing should see the same thing. As a result, the NUC terms adapt to non-uniformities in the imager and not the scene.

Differential Geometric Guidance Based on the Involute of the Target's Trajectory

Abstract: This paper presents a novel approach to missile guidance using the differential geometry of curves and not relying on the line of sight information. The target’s trajectory is treated as a smooth curve of known curvature and the new algorithm is based on the involute of the target’s curve. The missile’s trajectory uses the concept of virtual target to generate the correct involute trace. It is shown that the missile is either on the trace immediately or may be able to reach it through an alignment procedure. In general, following the trace requires a three-dimensional maneuver in which the missile flies above the target’s tangent plane. The projection of the three-dimensional trajectory onto the tangent plane coincides with the involute trace, but is traversed in the time-to-go, thus resulting in the intercept. Two air-to-air scenarios of point masses are considered for a maneuvering target of the F-16 fighter class: 1) a two-dimensional engagement with target executing a constant g turn; 2) a three-dimensional engagement with target executing a barrel-roll maneuver. Perfect target information is assumed in simulations. In the first case, intercepts occur both for the involute law and proportional-navigation (PN) guidance; PN based intercepts occur quicker, but the involute-based trajectories are more difficult to evade and always result in a side impact. In the second case, PN fails to intercept the target, while the involute law is successful.

Hypersonic airbreathing propulsion

Abstract: Hypersonic airbreathing propulsion technology is rapidly maturing to enable flight vehicles with transformational capabilities. APL has a rich history of leading-edge accomplishments in this arena. Laboratory-invented technology is being transitioned to a missile flight demonstration, and APL is contributing to a variety of hypersonic technologies and vehicle system concepts being developed by the DoD. Building from a substantial knowledge base on the operation of these emerging propulsion systems, this article discusses science and technology issues that will enable future performance improvements and expanded operational envelopes for these systems. Critical technology challenges include improving our understanding of the stressing aerothermal environment, achieving the necessary component and integrated engine performance, dealing with the engine system dynamics to achieve robust operation, developing proper scaling laws to enable transition from ground test to flight systems, and developing advanced lightweight, high-temperature materials and cooling techniques to handle the engine environment. We also briefly address the potential warfighting payoff of systems that use high-speed missiles.

Decades of improvements in re-entry ballistic vehicle tracking

Abstract: This paper deals with a missile defense challenge, which has been studied extensively for decades and still remains a topic of active research, the tracking of a ballistic vehicle in its re-entry phase. With Anti-Ballistic Missile or Anti-Tactical-Ballistic Missile goals, most of missile defenses need to track re-entry vehicles with a view to locating them precisely and allowing low altitude interception. The re-entry vehicle leaves a quiet exoatmospheric phase and a quasi-Keplerian motion to an endo-atmospheric phase with large aerodynamic loads and a sudden deceleration. The motion is then obviously nonlinear and furthermore both the extent and the evolution of the drag are difficult to predict. Since the sixties, while more and more efficient sensors, such as sophisticated phased-array radars, were developed, the associated data processing techniques have been improved, taking advantage of computer performance increases. Although re-entry vehicle tracking is undoubtedly a non-linear filtering problem, it was firstly solved by rustic linear filters with fixed weight and an assumed drag table. Then, Kalman filters were exploited. Uncoupled and polynomial for a while, they are now fully coupled and really non-linear. They are called Extended Kalman filters, are based on the linearization about the estimated state and are the current efficient and classic solution to non-linear filtering. Moreover, they perform drag estimation which may be useful to the identification capabilities of the missile defense. In the future, even more sophisticated techniques, such as the promising and fashionable particle filtering, are likely to be developed in re-entry vehicle tracking.

Path Following of Optimal Trajectories Using Preview Control

Abstract: This paper investigates the use of optimal preview control for tracking trajectories for air-to-surface missiles. A trajectory is generated off-line by solving a trajectory optimization problem, which incorporates the mission constraints and a model of the missile dynamics. A controller is then designed using optimal preview control to track the reference trajectory on-line and preserve the mission constraints. The control design process involves linearizing and discretizing the missile model and designing an outer guidance loop. By exploiting the structure of the problem, the preview gain sequence can be easily computed via the closed-loop transition matrix and the preview length can be tuned in accordance with the tracking requirements. The preview controller is used up to the radar acquisition range when a seeker is used to detect the target and a closed-loop guidance law is activated. A closed-loop guidance trajectory is presented using this approach and the results are discussed.

Missile identification and tracking system and method

Abstract: Sensors determine the kinematic measurements of a boosting missile, and the information is applied to a plurality of pairs or sets of filters, one of which is matched to the characteristics of a particular target type, and the other of which is general, and not matched to a particular target, for producing from each filter of the set missile position, velocity, acceleration, and specific mass flow rate states, and covariances of those states. From the filtered information, the estimates are made of at least missile mass flow rate, thrust, velocity at stage burnout, and remaining burn time. The likelihood is computed that the states and covariances from the filter sets represent the same target. The largest likelihood is selected as representing the target. In one mode, the estimated parameters are weighted and summed for a composite likelihood.

Capture Conditions in a Pursuit-Evasion Game between Players with Biproper Dynamics1

Abstract: Capture conditions in a planar pursuit-evasion game between a guided missile and its aerial target, each having either forward control or tail control, are derived analytically. The adversaries closed-loop maneuver dynamics are represented by first-order biproper transfer functions. A distinction is made between open and closed capture zones in the reduced-order game space. It is shown that locating the control surface forward, instead of aft, provides considerable advantages with regard to the existence and size of different capture zones. A new game space decomposition with two singular regions is also presented and the conditions for its existence are given.

Experimental Study on Behavior of RC Panels Covered with Steel Plates Subjected to Missile Impact

Abstract: This paper describes an experimental study on the behavior of concrete panels with steel plate subjected to missile impact. Two tests were carried out, divided in accordance with the types of projectile, non-deformable and deformable. In all, 40 specimens of 750mm square were prepared. The panel specimen was suspended vertically by two steel wire ropes to allow free movement after projectile impact, and was subjected to a projectile. As a result, it is confirmed that a RC panel with steel plate on its back side has higher impact resistance performance than a RC panel and that thickness of concrete panel, thickness of steel plate and the impact velocity of the projectile have a great effect on the failure modes of steel concrete panels. Moreover, based on the experimental results, the quantitative evaluation method for impact resistance performance of RC panels covered with steel plates is examined. The formula for perforation velocity of a half steel concrete panel, proposed in accordance with the bulging height, is effective to evaluate the impact resistance performance of RC panels with steel plates.

Commercial airliner missile protection using formation drone aircraft

Abstract: A commercial airliner ( 100 ) controls and is flown in formation with a drone aircraft ( 200 ) that includes missile detection and diversion equipment ( 215 ) capable of protecting the airliner from a man portable missile ( 130 ).

Self powdered missile turbojet

Abstract: A turbojet engine includes a core engine, an afterburner, and a converging-diverging exhaust nozzle in serial flow communication. An integral starter-generator is disposed inside the core engine and is joined to the rotor for equal speed rotation therewith. An electrical controller coordinates operation of the engine for subsonic, transonic, and supersonic operation of the engine in a missile self-powered by the starter-generator.

Effects of High Order Sliding Mode Guidance and Observers On Hit-to-Kill Interceptions

Abstract: Maneuvering targets present challenges to missile design in the areas of sensor, tracker, flight control, lethality systems, missile systems integration, and in the design of guidance, navigation, and control algorithms in particular. Classical Proportional Navigation (PN) and Augmented PN (APN) work against a wide range of targets including some maneuvering targets. However for robustness these algorithms require the interceptor to have a maneuver advantage over the target of at least 3:1. The effects of smooth second order sliding mode guidance laws, and second order sliding mode observers/differentiators on hit-to-kill interceptions are studied in this paper. It also explores the effects of using sliding mode guidance with Kalman filtering, sliding mode guidance with sliding mode observers/differentiators, and classical PN with sliding mode observers/differentiators. Sliding mode observers/differentiators dramatically reduce the complexity of target state estimation. The algorithms presented here have been verified using the high fidelity Phoenix six-degree-of-freedom (6-DOF) developed at Radiance Technologies.

Reachability guidance: a novel concept to improve mid-course guidance

Abstract: Reachability guidance is a new concept developed from a combination of robot and missile guidance using shortest path techniques. It has been developed to improve mid-course guidance in medium range tactical, missile to missile, engagements. This paper considers the limitations of a range of missile guidance genres in solving challenging missile to missile engagements and identifies that the ability of the missile to reach the target is a common area of uncertainty. Using the SAM versus supersonic sea-skimming ASM problem as an illustrative example, a novel technique which employs the earliest intercept line (EIL) to facilitate reachability ('R') guidance is introduced.

Direct Intercept Guidance using Differential Geometry Concepts

Abstract: This paper examines the application of differential geometry to the engagement of both nonmanoeuvring and manoeuvring targets. The kinematics of the engagement for both manoeuvring and nonmanoeuvring target are developed and expressed in differential geometric terms. Two-dimensional geometry is then used to determine the intercept conditions for a straight line target and a constant manoeuvre target. The intercept conditions for both targets are developed for the case when the interceptor missile guides onto a straight line interception. These two cases are shown to have a common set of core conditions such that it enables a unified guidance law to be developed. The guidance law is shown to be globally stable using Lyapunov theory, so that guidance capture is assured for any initial condition. The analysis and guidance law design does not rely on local linearisation and can be shown to produce guidance trajectories that mirror proportional navigation for the straight line interception of a nonmanoeuvring target for which proportional navigation was originally developed. The paper finishes with simulation in two dimensions, illustrating the convergence and solution properties of the approach.

High Angle of Attack Aerodynamic Predictions Using Missile Datcom

Abstract: The USAF Missile Datcom is an industry standard tool used for predicting the aerodynamics of conventional missile configurations. Typical aerodynamic models are constructed from wind tunnel data and used to simulate the flight profile and behavior of a missile. However, certain configurations require data beyond the usual 20 degrees angle of attack obtained in the wind tunnel. Comparisons have been made with existing subsonic high angle of attack wind tunnel data in order to assess Datcom’s capabilities in predicting the aerodynamics of a configuration to angles of attack in excess of 20 degrees. Results presented herein indicate that Missile Datcom can reasonably predict the aerodynamics of standard body, fin, and body-fin configurations to angles of attack up to 90 degrees.

Autopilot for Missiles Steered by Aerodynamic Lift and Divert Thrusters using Nonlinear Dynamic Sliding Manifolds

Abstract: A new approach to the design of a kinetic-kill longitudinal autopilot steering the missile trajectory by the combination of aerodynamic lift and divert-thrusters (dual-thrusters control) and with its attitude oriented by attitude-thrusters is presented. The proposed approach may increase the total divert acceleration capability by up to 100%, improving the “end-game” intercept accuracy, when such capability is required. The pitch plane autopilot design is based on second order sliding mode control using nonlinear dynamic sliding manifold technique. A robust, high accuracy tracking of the missile normal acceleration guidance command is achieved in presence of considerable model uncertainties created by the interactions between the airflow and the thrusters jets. Results of the computer simulation demonstrate excellent, robust, high accuracy tracking performance of the proposed design.

Handheld gas propelled missile launcher

Abstract: A handheld gas propelled missile launcher which deploys projectiles of varying payloads through the muzzle, and a ballistic module for changing payloads expeditiously.

System and method for transitioning from a missile warning system to a fine tracking system in a directional infrared countermeasures system

Abstract: A method for transitioning a target from a missile warning system to a fine tracking system in a directional countermeasures system includes capturing at least one image within a field of view of the missile warning system. The method further includes identifying a threat from the captured image or images and identifying features surrounding the threat. These features are registered with the threat and image within a field of view of the fine tracking system is captured. The registered features are used to identify a location of a threat within this captured image.

'Earliest Intercept Line Guidance': a novel concept for improving mid-course guidance in Area Air Defence

Abstract: This is the second in what will be a series of papers on Earliest Intercept Line (EIL) Guidance. This paper expands on an initial paper which set out the concept of ’Reachability Guidance’ as a method of improving Surface to Air missile (SAM) performance against an anti-ship missile (ASM). This paper reprises the concept and further develops the necessary non-linear trajectory shaping-techniques using an approach based on Dubins’ shortest paths. The concept has been developed to overcome limitations in common missile guidance genres; the most common problem is increased miss-distance due to lateral acceleration saturation generated by unpredictable target missile manoeuvre. The paper employs a 2D constant speed, SAM versus a highly manoeuvrable supersonic sea-skimming ASM problem to illustrate the concept. The paper goes on to show that the EIL can be employed to improve reachability by improving mid-course guidance and preventing unnecessary lateral acceleration saturation.