The terminal guidance problem for a fixed-trim re-entry body is formulated with the objective of synthesizing a closed-loop steering law. A transformation of variables is made that reduces the order of the state system for the guidance problem, and a subsequent linearization with motion along the sight line to the target as a reference produces a further order reduction. The final, reduced-order system, although nonlinear and time-varying, is simple enough to lend itself to synthesis of a class of guidance laws. A generalization of the feedforward device of classical control theory is successfully employed for compensation of roll-autopilot lags. A comparison with existing fixed trim guidance laws is carried out computationally with a simulation model idealizing the navigation and control systems as error-free. The proposed guidance law exhibits superior miss-distance performance in the comparison. / Ph. D.

Optimal intercept trajectories for a boost-sustain-coast medium-range air-to-air missile are synthesized using optimal control theory. Optimality in time/range/energy at intercept of a target is the main objective. Attainable sets and their boundaries are obtained and used to generate optimal intercept points in a three-dimensional scenario. A three-phase closed-loop guidance scheme is used to generate an efficient guidance law against a maneuvering target. In the present study, target maneuvers are restricted to the horizontal plane. An initial boost-phase with near-optimal guidance in the presence of active control constraints and thrust switches is simulated. Target maneuvers are neglected during this phase. A new method of gain evaluation is detailed. A midcourse guidance scheme with neighboring guidance, transversal comparisons, and chasing center-of-attainability of target to augment performance is studied. Modifications in terminal guidance using proportional navigation, such as chasing the center-of-attainability of target, altitude shaping, and drag-resolution schemes are used to attempt better performance at intercept. A composite guidance strategy using a combination of neighboring guidance and proportional navigation for the midcourse guidance is introduced. The excellent performance of this guidance strategy and the improvement in storage requirements for on-board use make it a very special scheme. / Ph. D.

The field of guided projectile research has continually grown over the past several decades. Guided projectiles, typically encompassing bullets, mortars, and artillery shells, incorporate some sort of guidance and control mechanism to generate trajectory alterations. This serves to increase accuracy and decrease collateral damage. Control mechanisms for smart weapons must be able to withstand extreme acceleration loads at launch while remain simple for cost and reliability reasons. One type of control mechanism utilizes controllable internal translating masses (ITM's) that oscillate within the projectile to generate control forces. Several techniques for using internal translating masses for smart weapon flight control purposes are explored here. Specifically, the use of ITM's as direct control mechanisms, as a means to increase control authority, and as a means to protect the smart weapons sensor suite are examined. It is first shown that oscillating a mass orthogonal to the projectile axis of symmetry generates reasonable control force in statically-stable rounds. Trade studies examine the impact of mass size, mass offset from the center of gravity, and reductions in static stability on control authority. Then, the topic of static margin control through mass center modification is explored. This is accomplished by translating a mass in flight along the projectile axis of symmetry. Results show that this system allows for greater control authority and reduced throw-off error at launch. Another study, aimed at examining shock reduction potential at launch rather than static margin alteration, also considers ITM movement along the projectile centerline. In these studies, the ITM is comprised of sensitive electronic sensors, and is configured as a first-order damper during launch. Trade study results show that although the mechanism cannot substantially reduce the magnitude of launch loads, it is successful at dampening harmful structural vibrations typically experienced after muzzle exit. Finally, an active control system is developed for the ITM control mechanism using sliding mode methodology. Example cases and Monte Carlo simulations incorporating model uncertainties and sensor errors show that ITM control of projectiles can substantially reduce dispersion error. Furthermore, the novel sliding mode control law is shown to be highly robust to feedback disturbances. In a final study, combined ITM-canard control of projectiles is explored, concluding that ITM mechanisms can serve as a useful supplement in increasing the efficiency of currently-deployed control mechanisms.

No description available.

International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / The Guided Weapons Evaluation Facility (GWEF) at Eglin Air Force Base is the Air Force’s premiere munitions hardware-in-the-loop (HITL) simulation facility. HITL simulation testing is a ground based tool used to evaluate the performance of a weapon system at a fraction of the cost of free flight testing. The weapon system is stimulated in a laboratory setting with the electromagnetic environment and physical motion it would experience in an operational setting. The system’s responses to that environment are measured to provide various measures of performance including target tracking ability and miss distance. Electrical interfaces are required in order to control the weapon’s guidance system and to receive and inject signals from the HITL simulation computer system to the weapon under test. These interfaces are usually developed using external control circuits and copper cabling to the guidance unit. The GWEF had a requirement to develop a missile interface with no external copper wires or antennas to support a unique test configuration. The requirement led to the development of a Fiber Optic Telemetry (FOTM) package which would be contained completely within the missile body cavity. The constraints on the FOTM design were considerable. Lack of a suitable commercial off-the-shelf fiber optic telemetry package led to the eventual in house design and fabrication of the FOTM. This paper describes the requirements, design constraints and results achieved in the FOTM design. Although not classical telemetry it does share similarities with conventional telemetry units used for open air weapons testing including size constraints, data rates and thermal considerations.

Approved for public release; distribution is unlimited / Boost phase interception of ballistic missiles is envisioned as the primary response of the layered defense architecture implemented in the ballistic missile defense system. A limited time frame in which to take action and the necessity to implement hit-to-kill technology in the kill vehicle counterbalances the many advantages of boost phase interception. Direct hit missile technology is constrained by the requirement to minimize miss distance to a negligible amount between the kill vehicle and optimum aimpoint on the target. This thesis examines kill vehicle effectiveness, which is tantamount to miss distance, as a function of both the kill vehicle maximum acceleration capability and the guidance system time constant necessary to destroy a target. The kill vehicle guidance system is modeled in MATLAB as a fifth-order binomial series with proportional navigation. The simulation examines the effect of an accelerating target attributed to powered flight and aimpoint displacement caused by a shift in tracking point from the target plume to the payload when resolution occurs. The kill vehicle minimum requirements as indi-cated by the simulation include a lateral acceleration capability of four times the target acceleration and a guidance system time constant that is less than one-tenth the estimated flight time. / Lieutenant, Canadian Navy

Approved for public release; distribution is unlimited / Thermo mechanical modeling and simulation of a satellite and intercontinental ballistic missile assumes importance due to the increased interest in assessing the potential of such attacks. Effective and innovative methods are sought in assessing the structural integrity of such structural components. In this study, we present modeling and simulation aspects of two generic models loaded by high energy laser beam. We present an application of MSC software in modeling thermo-mechanical behavior, both steady state and transient behavior of satellite and missile structures. Thermal energies used for simulation correspond to high energy laser flux available at low earth orbits as reported in literature. A brief review of the concepts involved is outlined. The analysis is performed under several scenarios that include thermal failures due to steady state as well as transient thermal exposures. The thermal exposure times and locations are varied to assess typical failure modes of the structure. Analysis is done in order to define suitable material thicknesses that will make a satellite or a ballistic missile hardened enough to withstand these specific amounts of energy. Other parameters of interest pertaining to this study are the pulse width, and resulting transient phenomena affecting the behavior. Temperature gradients as well as resulting thermal stresses and thermal deformations are reported in this study. / Outstanding Thesis

In this thesis, a multiple hypotheses tracking (MHT) algorithm is developed to successfully track multiple ballistic missiles within the boost phase. The success of previous work on the MHT algorithm and its application in other scientific fields enables this study to realize an efficient form of the algorithm and examine its feasibility in tracking multiple crossing ballistic missiles even though various accelerations due to staging are present. A framework is developed for the MHT, which includes a linear assignment problem approach used to search the measurement-to-contact association matrix for the set of exact N-best feasible hypotheses. To test the new MHT, an event in which multiple ballistic missiles have been launched and threaten the North American continent is considered. To aid in the interception and destruction of the threat far from their intended targets, the research focuses on the boost-phase portion of the missile flight. The near-simultaneous attacks are detected by a network of radar sensors positioned near the missile launch sites. Each sensor provides position reports or track files for the MHT routine to process. To quantify the performance of the algorithm, data from the National Air and Space Intelligence Center's IMPULSE ICBM model is used and demonstrates the feasibility of this approach. This is especially significant to the U.S. Missile Defense Agency since the IMPULSE model represents the cognizant analyst's accurate representation of the ballistic threats in a realistic environment. The results show that this new algorithm works exceptionally well in a realistic environment where complex interactions of missile staging, non-linear thrust profiles and sensor noise can significantly degrade the track algorithm performance especially in multiple target scenarios.

The protection of aircraft against shoulder fired heat seeking missiles is of growing concern in the aviation community. This thesis presents a simple method for shielding the infrared signature of a jet engine from heat seeking missiles. The research efforts investigated two approaches to shield the thermal signature of the Noel Penny Type 401 turbojet at the Texas A&M University Propulsion Lab Test Cell. First, liquid nitrogen was injected through a manifold at a flow rate equivalent to the flow rate of exhaust gases, producing a small temperature reduction in the exhaust but no infrared shielding. Second, water was injected at a flow rate of 13% of the flow of exhaust gases, producing a greater temperature reduction and some shielding. Water was then injected through a manifold at a flow rate of 118% of the flow rate of exhaust gases, producing a substantial reduction in temperature and complete shielding of the infrared signature. Additionally, numerical simulations were performed using FLUENT to support these experiments. Results are presented in the form of thermocouple data and thermal images from the experiments, and in the form of temperature contours and streamtraces from the simulations.

Uppgiften är att utarbeta ett förslag på inriktning vid val av ett framtida markbaserat precisionsbekämpningssystem för den nya Försvarsmakten. Uppsatsen tar avstamp utifrån RMA, även kallad ”den nya krigföringen”, som antas vara den vision som gäller när det nya försvaret skall formas. Inledningsvis studeras de trender och pågående projekt som föreligger. Dessa får sedan lägga grunden för ett antal spelkort som bedöms utifrån de förväntade krav som kommer att ställas i framtiden. Kraven är framtagna med hjälp av studerade scenarier, rapporter samt intervjuer. Systemverkan kommer att vara en avgörande parameter. För att erhålla avsedd systemverkan är det viktigt med god precision, verkan i alla måltyper, lång räckvidd och mobilitet på systemen. Balansen mellan precision, räckvidd och verkan är betydelsefull. Balans råder då dessa parametrar har tillräckligt utrymme i stridsdelen. Det system som bäst svara mot de ställda kraven är en robot med fiberoptisk länk. Följande fördelar ses med systemet; god precision, lång räckvidd, god verkan, hög störresistens samt förmågan att verifiera och gradera verkan. Att endast förlita sig på eldrörsartilleri som precisionsbekämpningssystem är inte tillräckligt med de nya krav som ställs. Försvarsmakten bör välja ett markrobotsystem som framtida precisionsbekämpningssystem. Genom detta val erhålls ett system som i första hand löser precisionsbekämpning, vilket medför att ingen hänsyn behöver tas till den ständigt pågående växelverkan mellan understöd, bekämpning och precisionsbekämpning. På detta sätt blir ”bekämpningsfamiljen” mer komplett. / Avdelning: ALB - Slutet Mag 3 C-upps.Hylla: Upps. ChP 99-01