Guidance system

About: Guidance system is a research topic. Over the lifetime, 4282 publications have been published within this topic receiving 45964 citations.

Differential-game-based guidance law using target orientation observations

Abstract: Modern 4th generation air-to-air missiles are quite capable of dealing with today's battlefield needs. Advanced aerodynamics, highly efficient warheads and smart target acquisition systems combine to yield higher missile lethality than ever. However, in order to intercept highly maneuverable targets, such as future unmanned combat air vehicles (UCAV), or to achieve higher tracking precision for missiles equipped with smaller warheads, further improvement in the missile guidance system is still needed. A new concept is presented here for deriving improved differential-game-based guidance laws that make use of information about the target orientation, which is acquired via an imaging seeker. The underlying idea is that of using measurements of the target attitude as a leading indicator of target acceleration. Knowledge of target attitude reduces the reachable set of target acceleration, facilitating the computation of an improved estimate of the zero-effort miss (ZEM) distance. In consequence, missile guidance accuracy is significantly improved. The new concept is applied in a horizontal interception scenario, where it is assumed that the target maneuver direction, constituting a partial attitude information, can be extracted via processing target images, acquired by an imaging sensor. The derivation results in a new guidance law that explicitly exploits the direction of the target acceleration. The performance of the new guidance law is studied via a computer simulation, which demonstrates its superiority over existing state-of-the-art differential-game-based guidance laws. It is demonstrated that a significant decrease in the miss distance can be expected via the use of partial target orientation information.

Modeling and Simulation of an AUV Simulator With Guidance System

Abstract: An intelligent autonomous underwater vehicle (AUV) simulator with path-planning capability was developed. A guidance system of the simulator automatically generates continuous-curvature paths of a cubic B-spline class constrained by the minimum turning radius of the marine vehicle and waypoints. The simulator of the guidance system includes a line-of-sight (LOS) algorithm and a horizontal proportional-derivative (PD) controller, adapting the Euler-Rodriguez quaternion method on the base of 3-D Euler-Lagrange formulation. A web-based interactive simulation system can animate the attitudes and position of the AUV in real time. A 3000-T AUV was used to test the guidance system. Comparisons of linear and cubic path-planning strategies were discussed, including a straight line and a conventional cubic spline method, three parametric methods for planning cubic B-spline paths, and an iterative method for improving and expanding the function of the path generator. Simulation results of the tracking performance tests show that the AUV can precisely approach targets and waypoints using the proposed method. The improvement in the cross-tracking error was approximately 80%, whereas reduction in traveling time was 5%.

Far field approximation for a nozzle exhausting into a vacuum.

Abstract: a perfect update of velocity, position, and attitude occurs prior to the burn from the parking orbit. The system parameters used in the evaluation technique can be estimated using techniques that are relatively unsophisticated but are of sufficient accuracy to accomplish the desired result. These techniques were implemented in computer programs now in use at NASA/ERG. The computer programs were exercised on a Jupiter flyby mission. For this mission and the assumptions made, it can be concluded that the accuracy of the strapdown guidance systems evaluated is adequate to accomplish the guidance and navigation of a Jupiter flyby mission. If the first midcourse correction is made 10 days after launch and the required probability of mission failure attributable to guidance is 0.05, the reliability (mean time to failure) of the pure inertial strapdown guidance systems considered is such that no system examined would succeed if operated continuously from launch to midcourse. If the probability of mission failure attributable to guidance is relaxed to 0.1, the two specified systems still fail if midcourse correction is made 10 days after launch. An optimum system which will succeed is found. Concentrated attention to reduction of system power requirements would yield a significant reduction in the weight attributable to guidance for this specific mission. This might be achieved by development of a lightweight variable thermal impedance for the ISU.