Rule-based air combat simulation

An improved version of the Adaptive Maneuvering Logic (AML) program for air-combat maneuvering is discussed. The modifications and improvements incorporated into the AML program are documented

Collision avoidance strategies for unmanned aerial vehicles in formation flight

Collision avoidance strategies for multiple UAVs (Unmanned Aerial Vehicles) based on geometry are investigated in this study. The proposed strategies allow a group of UAVs to avoid obstacles and separate if necessary through a simple algorithm with low computation by expanding the collision-cone approach to formation of UAVs. The geometric approach uses line-of-sight vectors and relative velocity vectors where dynamic constraints are included in the formation. Each UAV can determine which plane and direction are available for collision avoidance. An analysis is performed to define an envelope for collision avoidance, where angular rate limits and obstacle detection range limits are considered. Based on the collision avoidance envelope, each UAV in a formation determines whether the formation can be maintained or not while avoiding obstacles. Numerical simulations are performed to demonstrate the performance of the proposed strategies

YF-17/ADEN system study

The YF-17 aircraft was evaluated as a candidate nonaxisymmetric nozzle flight demonstrator. Configuration design modifications, control system design, flight performance assessment, and program plan and cost we are summarized. Two aircraft configurations were studied. The first was modified as required to install only the augmented deflector exhaust nozzle (ADEN). The second one added a canard installation to take advantage of the full (up to 20 deg) nozzle vectoring capability. Results indicate that: (1) the program is feasible and can be accomplished at reasonable cost and low risk; (2) installation of ADEN increases the aircraft weight by 600 kg (1325 lb); (3) the control system can be modified to accomplish direct lift, pointing capability, variable static margin and deceleration modes of operation; (4) unvectored thrust-minus-drag is similar to the baseline YF-17; and (5) vectoring does not improve maneuvering performance. However, some potential benefits in direct lift, aircraft pointing, handling at low dynamic pressure and takeoff/landing ground roll are available. A 27 month program with 12 months of flight test is envisioned, with the cost estimated to be $15.9 million for the canard equipped aircraft and$13.2 million for the version without canard. The feasiblity of adding a thrust reverser to the YF-17/ADEN was investigated

Operationally Responsive Spacecraft Using Electric Propulsion

A desirable space asset is responsive and flexible to mission requirements, low-cost, and easy to acquire. Highly-efficient electric thrusters have been considered a viable technology to provide these characteristics; however, it has been plagued by limitations and challenges such that operational implementation has been severely limited. The technology is constantly improving, but even with current electric propulsion, a spacecraft is capable of maneuvering consistently and repeatedly in low-Earth orbit to provide a responsive and flexible system. This research develops the necessary algorithm and tools to demonstrate that EP systems can maneuver significantly in a timely fashion to overfly any target within the satellite’s coverage area. An in-depth analysis of a reconnaissance mission reveals the potential the proposed spacecraft holds in today’s competitive, congested, and contested environment. Using Space Mission Analysis and Design concepts along with the developed algorithm, an observation mission is designed for three conventional methods and compared to the proposed responsive system. Analysis strongly supports that such a spacecraft is capable of reliable target overflight at the same cost as non-maneuvering ones, while it is three times as responsive in terms of time-to-overflight by sacrificing one third of its mission life. An electric versus a chemical system can maneuver 5.3 times more. Its responsiveness and mission life are slightly inferior to that of a Walker constellation, but cuts total system cost by almost 70%

Line-of-sight guidance techniques for manned orbital rendezvous

Thesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1963.Vita.Includes bibliographical references (leaves 305-309).by Edwin Eugene Aldrin, Jr.Sc.D

Sensors, measurement fusion and missile trajectory optimisation

When considering advances in “smart” weapons it is clear that air-launched systems have adopted an integrated approach to meet rigorous requirements, whereas air-defence systems have not. The demands on sensors, state observation, missile guidance, and simulation for air-defence is the subject of this research. Historical reviews for each topic, justification of favoured techniques and algorithms are provided, using a nomenclature developed to unify these disciplines. Sensors selected for their enduring impact on future systems are described and simulation models provided. Complex internal systems are reduced to simpler models capable of replicating dominant features, particularly those that adversely effect state observers. Of the state observer architectures considered, a distributed system comprising ground based target and own-missile tracking, data up-link, and on-board missile measurement and track fusion is the natural choice for air-defence. An IMM is used to process radar measurements, combining the estimates from filters with different target dynamics. The remote missile state observer combines up-linked target tracks and missile plots with IMU and seeker data to provide optimal guidance information. The performance of traditional PN and CLOS missile guidance is the basis against which on-line trajectory optimisation is judged. Enhanced guidance laws are presented that demand more from the state observers, stressing the importance of time-to-go and transport delays in strap-down systems employing staring array technology. Algorithms for solving the guidance twopoint boundary value problems created from the missile state observer output using gradient projection in function space are presented. A simulation integrating these aspects was developed whose infrastructure, capable of supporting any dynamical model, is described in the air-defence context. MBDA have extended this work creating the Aircraft and Missile Integration Simulation (AMIS) for integrating different launchers and missiles. The maturity of the AMIS makes it a tool for developing pre-launch algorithms for modern air-launched missiles from modern military aircraft.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Trajectory Control and Optimization for Responsive Spacecraft

The concept of responsive space has been gaining interest, and growing to include systems that can be re-tasked to complete multiple missions within their lifetime. The purpose of this study is to develop an algorithm that produces a maneuver trajectory that will cause a spacecraft to arrive at a particular location within its orbit earlier than expected. The time difference, delta t, is used as a metric to quantify the effects of the maneuver. Two separate algorithms are developed. The first algorithm is an optimal control method and is developed through Optimal Control Theory. The second algorithm is a feedback control method and is developed through Lyapunov Theory. It is shown that the two algorithms produce equivalent results for the maneuvers discussed. In-plane maneuver results are analyzed analytically, and an algebraic expression for delta t is derived. Examples are provided of how the analytic expression can be used for mission planning purposes. The feedback control algorithm is then further developed to demonstrate the simplicity of implementing additional capabilities. Finally, a set of simulations is analyzed to show that in order to maximize the amount of delta t achieved, a spacecraft must be allowed as much lead time as possible, and begin thrusting as early as possible