Generalized analysis of biased proportional navigation guidance with fractional power error feedback

This study presents a comprehensive analysis of biased proportional navigation guidance laws with variable gain in the bias command that achieve stationary target interception with a desired impact angle under the restriction of permissible look angle. More specifically, this study investigates the bias shaping approach, which takes the bias gain function given by a product of factors in range and look angle. The linear feedback and fractional power feedback of impact-angle error are considered for command structures. For each command form, this study examines the conditions that should be satisfied by the gain functions to guarantee mission accomplishment without violation of the constraints. The analysis particularly focuses on estimating the set of feasible initial or final conditions that ensure compliance with the constraints along the trajectory. Numerical simulation is performed for a range of initial and final flight-path angles to verify the analytical results. The findings of this study provide a general foundation for the design of a nonswitching guidance law for impact-angle control with limited look angle through shaping of gain profiles

Analysis of guidance laws with non-monotonic line-of-sight rate convergence

This study presents analyses of guidance laws that involve non-monotonic convergence in heading error from a new perspective based on an advanced stability concept. Pure proportional navigation with range-varying navigation gain is considered, and the gain condition to guarantee asymptotic convergence to the collision course is investigated while allowing the heading error to exhibit patterns that involve intermediate diversion. The extended stability criterion considered in this study allows local increase of the function in some finite intervals, which is less conservative than the standard stability theorem. The existing guidance laws involving intentional modulation of the heading error as well as the design of the navigation gain are discussed with respect to the new stability criterion

Inverse optimality of pure proportional navigation guidance for stationary targets

The main contribution of this study is the optimality analysis of the PPNG performed in full generality. The new theoretical findings can explain the result of the former analysis in which the PPNG is derived as the minimum effort solution [5] and also describe a comprehensive design framework including the observability-enhanced guidance laws developed for the dual homing guidance problem. Furthermore, this study provides several examples illustrating how the PPNG with various navigation gain functions can be understood as optimal control solutions

Stochastic Real-time Optimal Control: A Pseudospectral Approach for Bearing-Only Trajectory Optimization

A method is presented to couple and solve the optimal control and the optimal estimation problems simultaneously, allowing systems with bearing-only sensors to maneuver to obtain observability for relative navigation without unnecessarily detracting from a primary mission. A fundamentally new approach to trajectory optimization and the dual control problem is developed, constraining polynomial approximations of the Fisher Information Matrix to provide an information gradient and allow prescription of the level of future estimation certainty required for mission accomplishment. Disturbances, modeling deficiencies, and corrupted measurements are addressed with recursive updating of the target estimate with an Unscented Kalman Filter and the optimal path with Radau pseudospectral collocation methods and sequential quadratic programming. The basic real-time optimal control (RTOC) structure is investigated, specifically addressing limitations of current techniques in this area that lose error integration. The resulting guidance method can be applied to any bearing-only system, such as submarines using passive sonar, anti-radiation missiles, or small UAVs seeking to land on power lines for energy harvesting. Methods and tools required for implementation are developed, including variable calculation timing and tip-tail blending for potential discontinuities. Validation is accomplished with simulation and flight test, autonomously landing a quadrotor helicopter on a wire

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

Aeronautical engineering: A continuing bibliography with indexes (supplement 319)

This report lists 349 reports, articles and other documents recently announced in the NASA STI Database. The coverage includes documents on the engineering and theoretical aspects of design, construction, evaluation, testing, operation, and performance of aircraft (including aircraft engines) and associated components, equipment, and systems. It also includes research and development in aerodynamics, aeronautics, and ground support equipment for aeronautical vehicles

Aeronautical engineering: A continuing bibliography with indexes (supplement 272)

This bibliography lists 719 reports, articles, and other documents introduced into the NASA scientific and technical information system in November, 1991. Subject coverage includes: design, construction and testing of aircraft and aircraft engines; aircraft components, equipment, and systems; ground support systems; and theoretical and applied aspects of aerodynamics and general fluid dynamics

Aeronautical engineering, a continuing bibliography with indexes

This bibliography lists 823 reports, articles, and other documents introduced into the NASA scientific and technical information system in November 1984

Aeronautical engineering: A continuing bibliography with indexes, supplement 190

This bibliography lists 510 reports, articles and other documents introduced into the NASA scientific and technical information system in July 1985

Aeronautical Engineering: A continuing bibliography

This bibliography lists 347 reports, articles and other documents introduced into the scientific and technical information system. Documents on the engineering and theoretical aspects of design, construction, evaluation, testing, operation, and performance of aircraft (including aircraft engines) and associated compounds, equipment, and systems are included. Research and development in aerodynamics, aeronautics and ground support equipment for aeronautical vehicles are also included