Showing papers on "Guidance system published in 2003"

Performance Analysis and Architectures for INS-Aided GPS Tracking Loops

Abstract: GPS and inertial sensors have complementary characteristics, which have been exploited in the design of integrated GPS-inertial navigation and guidance systems. Traditionally, most hybrid GPS-inertial systems have been mechanized by combining the information from GPS and an Inertial Navigation System using either loose integration (i.e., integration at the position, velocity and/or attitude level) or tight integration (integration at the pseudorange, Doppler, or carrier phase level). Such integration schemes provide users with limited immunity against momentary GPS outages and also allow detection of certain classes of GPS signal failures. A third scheme of integration can be used, in which the inertial sensors are used to aid the GPS phase frequency and code tracking loops directly. In this paper, this level of coupling is referred to as ultra-tight integration, and it offers potential improvements to GPS performance, such as higher phase-tracking bandwidth, and more resistance to radio frequency interference or multipath noise. In this paper we propose a simple architecture for GPS-inertial systems with ultra-tight integration and present the results of some trade studies and simulations quantifying the performance of such systems. Performances of the ultra-tight GPS-inertial system are evaluated using a simulation tool developed specifically for this study. The metrics used for the evaluation are allowable reduction in the carrier tracking loop-filter bandwidth for improved signal-to-noise ratio, and robustness against carrier-phase cycle-slips. The sensitivity of these metrics to inertial sensor quality and GPS receiver clock noise is discussed and quantified. These studies show that an ultra-tightly coupled system using low cost/performance inertial sensors and a typical temperature-compensated crystal oscillator can function with a carrier tracking loop-filter bandwidth as low as 3Hz. This structure shows a 14dB improvement in phasenoise suppression when compared to a traditional 15Hz loop filter, and comparable carrier-phase tracking bandwidth to that of the inertial sensors (>30Hz).

Active guidance for a finless rocket using neuroevolution

Abstract: Finless rockets are more efficient than finned designs, but are too unstable to fly unassisted. These rockets require an active guidance system to control their orientation during flight and maintain stability. Because rocket dynamics are highly non-linear, developing such a guidance system can be prohibitively costly, especially for relatively small-scale rockets such as sounding rockets. In this paper, we propose a method for evolving a neural network guidance system using the Enforced SubPopulations (ESP) algorithm. Based on a detailed simulation model, a controller is evolved for a finless version of the Interorbital Systems RSX-2 sounding rocket. The resulting performance is compared to that of an unguided standard full-finned version. Our results show that the evolved active guidance controller can greatly increase the final altitude of the rocket, and that ESP can be an effective method for solving real-world, non-linear control tasks.

Control system providing perspective flight guidance

Abstract: A flight guidance system providing perspective flight guidance symbology using positioning and terrain information provides increased pilot situational awareness of the pilot's aircraft. The guidance system uses a positioning system and a detailed mapping system to provide a perspective display for use in an aircraft. A precision pathway flight guidance (PFG) symbology set is thereby displayed on a pilot display. The PFG symbology set includes broken line symbols representing an open tunnel and providing flow field data, a half-bracket symbol to indicate that the aircraft is no longer in the open tunnel represented by the broken line symbols and a quickened flight path vector (QFPV) symbol to provide the pilot with predictive flight path information. A flight director system and tunnel generator component provide for updating the displayed PDFG symbology set based upon current aircraft conditions (e.g., aircraft position) and stored flight path information.

Route guidance systems for improving urban travel and location choices. in: transport and information systems

Abstract: Technological advances in navigation systems for private vehicles have the capability to provide drivers with highway route information on a dashboard-mounted video display screen. These technological advances, together with 2-way radio communication of digital information, automatic measurement of traffic flows, and supercomputer technology, could be combined to provide useful data to drivers concerning expected travel time, route selection, and best departure times. This paper reviews the status of this technology and explores the information and prediction requirements for the computer models needed to implement such a system. Research required to evaluate the potential impact of such a system is also described.

A review of guidance laws applicable to unmanned underwater vehicles

Abstract: The main problem in bringing autonomy to any vehicle lies in the design of a suitable guidance law. For truly autonomous operation, the vehicle needs to have a reliable Navigation, Guidance and Control (NGC) system of which the guidance system is the key element that generates suitable trajectories to be followed. In this review paper, various guidance laws found in the literature and their relevance to autonomous underwater vehicles (AUVs) are discussed. Since existing guidance laws for underwater vehicles have emulated from tactical airborne missile systems, a number of approaches for the missile guidance systems are considered. Finally, potential guidance strategies for AUVs are proposed.

Flight guidance system providing perspective flight guidance symbology

Abstract: A flight guidance system providing perspective flight guidance symbology using positioning and terrain information provides increased pilot situational awareness of an aircraft. The guidance system uses a positioning system and a detailed mapping system to provide a perspective display for use in an aircraft. A Perspective Flight Guidance (PFG) symbology set is thereby displayed on a pilot display. The PFG symbology set includes broken line symbols representing an open tunnel and providing flow field data, a half-bracket symbol to indicate that the aircraft is no longer in the open tunnel represented by the broken line symbols and a quickened flight path vector (QFPV) symbol to provide the pilot with predictive flight path information.

Robust motion planning using a maneuver automation with built-in uncertainties

Abstract: In this paper, we extend a recently introduced motion planning framework for autonomous vehicles based on a maneuver automation representation of the vehicle dynamics We bring robustness into the guidance system by accounting for the uncertainties in the motion primitives used by the maneuver automation The uncertainties are taken into account in the offline computation of a guidance function, as well as in a real-time planning policy We illustrate our approach using a high-fidelity simulation model of MIT's autonomous X-Cell miniature helicopter, and present an example that highlights the performance improvement over the original framework We demonstrate that, when uncertainties are present, a nominal planning policy generates suboptimal trajectories in both open- and closed-loop guidance, and that trajectories obtained by applying the robust policy are less sensitive to perturbations in the motion primitives

Steering control of automated vehicles using absolute positioning GPS and magnetic markers

Abstract: Steering control for passenger cars on automated highways is analyzed. The feasibility of an automatic steering system based on absolute positioning global positioning system (GPS) and a magnetic marker guidance system has been evaluated using computer simulations. State estimation and control algorithm issues are examined for such a control system. By use of GPS and a magnetic marker sensor, an accurate and real-time estimation of the vehicle's lateral displacements with respect to the road can be accomplished. A steering control algorithm based on road curvature preview for achieving good road tracking and providing ride comfort is also presented. The proposed estimation and control system are validated by simulation results.

Mode confusion analysis of a flight guidance system using formal methods

Abstract: The paper discusses mode confusion analysis of a flight guidance system using formal methods. The paper describes the use of automated analysis tools, such as model-checkers and theorem provers, to search for potential sources of mode confusion in a representative specification of the mode logic of a Flight Guidance System.

Machine vision–based guidance system for an agricultural small–grain harvester

Abstract: A machine vision guidance system was developed for an agricultural combine harvester. The guidance algorithm separated the uncut crop rows from the surrounding background material, parameterized the crop rows, and calculated a guidance signal. A single monochrome camera mounted on the cab of the combine supplied the crop images. The algorithm was developed for corn and was tested under both laboratory and field conditions. Test results showed that the algorithm was capable of accurately locating crop rows in the image and providing a satisfactory lateral position signal for automated combine guidance. At a speed of 1.3 m/s (3 mph), the system was capable of guiding the combine at the same accuracy level as the GPS recording system available.

Design of optimal midcourse guidance sliding-mode control for missiles with TVC

Abstract: This work discusses a nonlinear midcourse missile controller with thrust vector control (TVC) inputs for the interception of a theater ballistic missile, including autopilot system and guidance system. First, a three degree-of-freedom (DOF) optimal midcourse guidance law is designed to minimize the control effort and the distance between the missile and the target. Then, converting the acceleration command from guidance law into attitude command, a quaternion-based sliding-mode attitude controller is proposed to track the attitude command and to cope with the effects from variations of missile's inertia, aerodynamic force, and wind gusts. The exponential stability of the overall system is thoroughly analyzed via Lyapunov stability theory. Extensive simulations are conducted to validate the effectiveness of the proposed guidance law and the associated TVC.

Multi-sensor guidance system for extreme force launch shock applications

Abstract: A projectile navigation system operable within an extremely high G-shock loading environment during the launch phase may include a set of Kalman filters configured to repeatedly calculate a navigational solution by solving a set of non-linear equations of motions of the projectile utilizing a current parameter vector, position, velocity, and attitude of the projectile. The system may include a suite of solid state sensors to calibrate the Kalman filter equations. If desired, the system may also include a satellite based positioning-determining (SBPD) attitude determination system configured to update the state of the host projectile by making real time attitude measurements of the projectile, and a parameter estimator configured to estimate and update a parameter vector of the host projectile. An external guidance and control processor may be used to generate guidance and control signals, enabling real time navigation of the host projectile.

Method and system for guiding an aircraft along a preferred flight path having a random origin

Abstract: An aircraft FMS/guidance system which provides for automated and immediate calculation of a preferred flight path and full heading, pitch-and-roll guidance along that path for paths of random origins, such as during late-occurring missed approaches and circling-to-land maneuvers.

V-GPS - image-based control for 3D guidance systems

Abstract: We present our approach for pose verification with monocular cameras in 3-dimensional space based on the image-based control paradigm. We describe the extensions to our previous control system for mobile navigation that allow us to estimate the complete set of those parameters in space. The major contribution of this approach is a sensor-independent formulation that allows a flexible configuration with a variety of sensor systems including standard cameras, omnidirectional cameras and laser systems. Our second contribution is a way to re-initialize the tracked landmarks during a multi-segment navigation in applications with significant derivations from the pre-taught trajectory as it is the case for handheld systems and flying robots. The presented system can be used as a guidance system for visitors. The localization is based on known landmarks that are in our case natural landmarks in the environment. These landmarks correspond to the satellites of a GPS system. We call it V-GPS (vision-based GPS) because of this similarity in the concept. A camera carried by a person allows to navigate along pre-specified paths through environments, like galleries, hospitals, parks, and other public places.

Missile defense system with dynamic trajectory adjustment

Abstract: A missile defense system includes a tracking station for monitoring the course and/or trajectory of an incoming missile. The incoming missile course and/or trajectory information is communicated to an intercept missile, whose course and/or trajectory are calculated based on the information of the incoming missile received from the tracking system and the intercept missile location received from, for example, a GPS system. The tracking system monitors the flight of the incoming missile to determine any changes to its course and/or trajectory, and communicates these changes to the intercept missile. The intercept missile adjusts its course and/or trajectory based on the updated information received from the tracking station to provide accurate and reliable intercept of the incoming missile.

The research on the key technologies for improving efficiency of parking guidance system

Abstract: An important part of today's traffic is parking and most especially in the congested urban areas. This often leads to additional traffic. As part of ITS deployment in China, parking guidance system is drawing attention for alleviating congestion. Considering the existing traffic management measures, the schematic of integrating advanced parking guidance and information system into urban traffic flow guidance system is put forward in the first part of this paper. The rest of this paper deals with the key technologies for improving the efficiency of parking guidance system such as information, routing, toll collection by using dedicated short range communications, communication technology in the mobile environment, prediction method of available parking spaces, etc. The last section provides some suggestions that future study needs.

Flight Guidance System Requirements Specification

Abstract: This report describes a requirements specification written in the RSML-e language for the mode logic of a Flight Guidance System of a typical regional jet aircraft. This model was created as one of the first steps in a five-year project sponsored by the NASA Langley Research Center, Rockwell Collins Inc., and the Critical Systems Research Group of the University of Minnesota to develop new methods and tools to improve the safety of avionics designs. This model will be used to demonstrate the application of a variety of methods and techniques, including safety analysis of system and subsystem requirements, verification of key properties using theorem provers and model checkers, identification of potential sources mode confusion in system designs, partitioning of applications based on the criticality of system hazards, and autogeneration of avionics quality code. While this model is representative of the mode logic of a typical regional jet aircraft, it does not describe an actual or planned product. Several aspects of a full Flight Guidance System, such as recovery from failed sensors, have been omitted, and no claims are made regarding the accuracy or completeness of this specification.

Route guidance system based on visual activity of the driver

Abstract: A route guidance system is disclosed that enables a vehicle driver to confidently decide the branch road to be taken without hesitation even at a complicated intersection or the like. The present invention provides a vehicle route guidance system 1 for guiding a vehicle along a route to a destination. The vehicle route guidance system 1 includes destination setting means 14, 24 for setting a destination, visual activity discriminating means 38, 40 for discriminating whether a driver's visual activity is right in light of route guidance to the set destination, and affirmation/vision guidance means for affirming the driver's visual activity when it is right and giving route guidance by visually guiding the driver when it is wrong. A route guidance method and a route guidance program are also disclosed.

Development of U.S. Air Force Intercontinental Ballistic Missile Weapon Systems

Abstract: The history of the development of U.S. Air Force intercontinental ballistic missiles is briefly discussed. Emphasis is placed on the technical challenges and the achievements made by the intercontinental ballistic missileteam over the past 56 years. The discussion covers all important subsystems in the construction of an intercontinental ballistic missile, that is, rocket propulsion, missile basing, guidance/control, and reentry systems. One of the most remarkable accomplishments of the program is its actual service life, which has far exceeded the original design requirements and goals. The intercontinental ballistic missile program has been one of the most successful programs in the history of the Department of Defense. Besides achieving its nuclear deterrence mission and helping the United States win the Cold War, the intercontinental ballistic missile program also made pivotal contributions in the early stages of the space race with the former Soviet Union. Technologies developed by the intercontinental ballistic missile program have also contributed to nonmilitary and scientific application. Notable examples are miniaturized, high-speed computer chips, composite materials, and high-temperature thermal protection systems.

Empirical virtual sliding target guidance law design: an aerodynamic approach

Abstract: We present a novel empirical virtual sliding target (VST) guidance law for the midcourse phase of a long range surface-to-air missile that uses the simplicity of the conventional proportional navigation (PN) guidance law while exploiting the aerodynamic characteristics of a missile's flight through the atmosphere to enable the missile to achieve superior performance than that achieved by conventional PN guidance laws. The missile trajectory emulates the trajectory of an optimal control based guidance law formulated on a realistic aerodynamic model of the missile-target engagement. The trajectory of the missile is controlled by controlling the speed of a virtual target that slides towards a predicted intercept point during the midcourse phase. Several sliding schemes, both linear and nonlinear, are proposed and the effect of the variation of the sliding parameters, which control the sliding speed of the virtual target, on the missile performance, are examined through extensive simulations that take into account the atmospheric characteristics as well as limitations on the missile in terms of the energy available and lateral acceleration limits. Launch envelopes for these sliding schemes for approaching and receding targets are also obtained. These results amply demonstrate the superiority of the proposed guidance law over the conventional PN law.

Magnetic anomaly guidance system for mine countermeasures using autonomous underwater vehicles

Abstract: This paper describes a magnetic anomaly guidance system that, with support from the Office of Naval Research, is being developed for fully autonomous detection, localization and classification of ferrous mines in Very Shallow Water/Surf Zone (VSW/SZ) environments. The magnetic guidance system's hardware configurations and magnetic target signature processing methods specifically have been developed for autonomous guidance of small, maneuverable sensing platforms, such as Underwater Bottom Vehicles, (UBVs), to magnetic targets. The prototype magnetic anomaly guidance is a three-axis magnetometer-gradiometer comprised by an array of triaxial fluxgate magnetometers and triaxial accelerometers. This design allows development of magnetic gradient tensor contraction scalars that provide the basis for a unique method for magnetic guidance of UBVs to underwater and buried mines. The triaxial accelerometer array can be used for mitigation of the target-detection-range-reducing effects of large changes in sensor platform orientation. Field test results indicate that a simple magnetic guidance algorithm based on comparison of the magnitudes of contractions of gradient tensor subsets measured by "primary guidance axes" of the sensor array will provide a robust and practical method for fully autonomous guidance of highmobility UBVs to magnetic targets. Target detection range can be enhanced by using rotationally invariant tensor contractions for robust proximity sensing and "pseudo-robust" scalar total field quantities for "homing in on" magnetic targets. Sensor system stability and DLC performance also would be improved by the use of better, temperature-compensated magnetometers. The results indicate that the magnetic anomaly guidance system and its method for target localization are particularly appropriate for homing in on magnetic targets from high-mobility sensing platforms such as small UBVs or Navy Divers.

Bi-directional remote controller and data broadcasting guidance system and method using the same

Abstract: Disclosed is a data broadcasting guidance system and method which guides a user and enhances the availability of the data broadcasting. The data broadcasting guidance system includes means for extracting guidance information while a data broadcasting is displayed; means for requesting a guidance on the data broadcasting; and means for notifying the extracted guidance information in response to the request from the requesting means. Accordingly, the guidance information to navigate the data broadcasting is supplied and the remote controller is controlled more exactly and faster so that the user's attention is drawn to the data broadcasting and the broadcast gets popular.

Parking guidance system for front wheel steering vehicles using trajectory generation

Abstract: This paper first addresses the issues related to the parking trajectory generation problem of front wheel steering vehicles. Then, taking both the implicit vehicle dynamic control restricts and explicit obstacle avoidance requirements into consideration, the mapping and inverse mapping relationship between the sequence of the control action and the result parking trajectory is carefully analyzed and approximately modeled using wavelet transformation and RBF neural networks. Finally, a guidance system is constructed to help the driver to complete the parking process.

Bottom-Following for Remotely Operated Vehicles: Algorithms and Experiments

Abstract: This paper addresses the problem of designing high precision bottom followers for remotely operated vehicles In the framework of hierarchical control architectures able to uncouple the robot's kinematics (guidance) and dynamics (velocity control), the task of bottom-following is accomplished by suitable guidance task functions, which enable the system to handle unmodeled, ie, not measured or estimated, kinematics interactions between the robot and the operating environment In order to increase the bottom followers' reliability, the paper discusses possible techniques for modeling and handling the environmental and measurement uncertainty in the estimate of the local interactions between the vehicle and the operating environment, ie, altitude and bottom slope In particular, according to at-sea operational experience, the problem of managing dropouts due to erroneous tracking of multi-path echoes by the ROV altimeter(s) is addressed Results of a large set of pool trials carried out with the Romeo ROV are reported and discussed

Back illumination method for counter measuring ir guided missiles

Abstract: Commercial aircraft are protected from attack by infrared seeking guided missiles through the utilization of a ground-based directed infrared countermeasure system in which the deployment of an IR guided missile is detected off-aircraft and more particularly on the ground. An infrared laser beam is projected towards the detected missile such that the projected laser infrared radiation impinges upon the missile from the rear. The off-axis infrared radiation illuminates the IR transmissive dome at the head of the missile where it is internally reflected back towards the IR detector carried by the missile through the total internal reflection characteristics of the dome. The domes of these missiles are typically made of a high index of refraction IR transmissive materials such that the material is prone to total internal reflection. The infrared laser generated radiation is a modulated so as to interfere with the guidance system of the missile causing it to execute a turn and plunge to the ground. In one embodiment, the long wavelength infrared laser is a 100-W laser with a beam width of 100 microradians, thus to provide a zone of protection of about three miles.

Control and navigation system for a motor vehicle, is able to be used to automate or semi-automate control of the vehicle according to input driver preferences, e.g. for optimizing fuel use or so that a journey takes a set time

Abstract: Control and navigation system for a motor vehicle that can be connected to a traffic guidance system and has means for control and regulation of the vehicle-driving behavior, whereby control and regulation is automatic or semi-automatic. In contrast to existing systems, where a navigation system generates instructions or advice for a driver to follow, the inventive system operates automatically or semi- automatically, so that after a driver has input chosen parameters the system acts accordingly. E.g. a driver may want to optimize fuel use in which case the route chosen will be the shortest, while vehicle behavior will be controlled to maximize fuel usage.