Showing papers on "Guidance system published in 1991"

Designing a personal guidance system to aid navigation without sight: progress on the GIS component

Abstract: This paper reports on progress towards the development of a personal guidance system for a blind navigator. The system is being developed in light of the unique problems facing the blind traveller, which are discussed first. The system consists of four modules: a locator unit, a detailed spatial database, an algorithm for path selection and a user interface. Suggestions are offered for alternative ways of handling the locator problem using a global positioning system or a database query system. The nature of the geographic information system (GIS) to be used as a host for the database is discussed, followed by brief statement of the criteria for choosing an algorithm for path selection and suggestions on types of user interfaces best suited to the system. A report on a pilot-study GIS is presented. Special problems of database and system design are highlighted.

Robot vision using targets

Abstract: Method and apparatus are disclosed for determining the position and attitude of objects, together with robotic systems employing same, and methods of targeting objects for such purposes. Particularly of interest is the application to continuous conveyors, particularly in the process of automobile manufacture. Also disclosed is the use of naturally occuring object features as targets in a machine vision based robot (or other) guidance system. In one embodiment, a special high speed processor finds at least 3 preselected feature points on an object, which when considered with the data base for the object, allows a rapid 6 degree of freedom solution for the object location relative to the camera and thence connected automation. While primarily envisioned for industrial robots, the invention is useful for all sorts of machines including vehicles, construction machinery and the like--anywhere the target object has a known data base relative to the features in question.

Research on anticipatory route guidance

Abstract: This paper describes the industry-relevant basic research focus of the Michigan IVHS Program in the last two years, with an emphasis on the linkage among the various projects related to anticipatory route guidance. Future direction of this research focus will also be discussed. The critical test for Advanced Traveler Information Systems (ATIS) is whether an individual driver with an appropriately equipped vehicle will get intelligent and safe advice on traffic diversion from his originally chosen route after a congestion-causing incident is detected and verified. Such advice should take into account not only current traffic conditions but also anticipated delay that may occur before the driver reaches his destination. Therefore, the Michigan IVHS research on traffic modeling and route optimization has focused on anticipatory route guidance. The anticipatory guidance system routes the vehicles by minimizing time-dependent link costs incurred by the driver. A novel dynamic programming approach has been used to take advantage of the time-dependent characteristics of the minimal travel-time solution to reduce computation load. The computation of routes is accomplished in the vehicle so that the driver will have complete and private control of not only the objective function, but also the constraints, in the computation for his optimum route. The information to be provided from the infrastructure is a set of anticipated link costs, updated periodically, to reflect current system demand and unexpected traffic incidents. Preliminary analysis has suggested that, to minimize communication load, under certain conditions, all link costs (not just exceptional ones) should be transmitted and appropriate data compression techniques should be used. Since diversion recommendations are generated within the vehicle, no matter where the vehicle happens to be, these recommendations may arise after the driver has passed the location for safe maneuver to divert. Human factors research has been conducted to assess the safe distance before the junction for recommended diversion that should be allowed for safe diversion. This safe distance would depend on the driver characteristics, as well as on the vehicle and road characteristics (including the lane location). The guidance system should be designed so that only safe diversion advice will be given to the driver. Extension of research on anticipatory route guidance includes 1) the projection of link costs through traffic modeling and simulation, 2) inclusion of multiple transportation modes, and 3) coordination with traffic light controls. The research strategy is to generate practical guidelines for ATIS product development, which can be upgraded incrementally as additional research results become available, and as component costs change.

Multiple user class assignment model for route guidance

Abstract: The application of the concept of multiple user class equilibrium assignment to the modeling of route guidance systems is the concern of this paper. In particular, its role in modeling guided and unguided drivers is discussed, as well as its abilty to lead to guidance strategies that are effective even with a large proportion of drivers equipped. A review of previous route guidance model work is given. A multiple user class model of route guidance is then proposed and the properties of such a model are discussed. Finally, a presentation of simulation results obtained from such a model, for two real-life networks and for a number of route guidance scenarios, is given.

Dynamic route guidance and interactive transport management with ALI-SCOUT

Abstract: The operation of the ALI-SCOUT dynamic route guidance system for automotive traffic is explained. Onboard equipment receives routing information from a centrally located traffic guidance computer when passing infrared communications beacons installed at selected traffic signal lights and other strategic locations. The received information consists of a route tree giving the best routes based on current traffic conditions for traveling from the beacon location toward various destination zones. The onboard equipment selects from the route tree according to the destination input by the driver and issues route-guidance instructions along the way by means of a simplified graphic display and synthesized voice. Navigation between beacon locations is accomplished by dead reckoning with map-matching, and travel times for road links along the route are communicated to the beacons to augment the traffic information database of the central traffic guidance computer. >

In-vehicle navigation requirements for monitoring link travel times in a dynamic route guidance system

Abstract: A dynamic route guidance system for automobiles and trucks operating on an arterial highway system was recommended recently to the Illinois Department of Transportation for testing and evaluation. The proposed system is the first among American Intelligent Vehicle Highway System (IVHS) demonstration projects to propose using vehicles equipped with navigation systems to monitor current travel time of the arterial streets comprising the highway network. In evaluating the feasibility of using vehicle probes in a demonstration, it was necessary to determine how many vehicles would need to be equipped to monitor link travel times adequately during peak periods. A traffic analysis assignment was essential as a basis for this determination. Using data from an adjacent study area, it was estimated that 4,000 navigation system-equipped vehicles would be needed for a 200 square mile test area. The analysis which formed the basis of this conclusion is described in this paper.

CARMINAT—An integrated information and guidance system

Abstract: CARMINAT is a European research program conducted under partnership and aimed at integrating a comprehensive information system into motor vehicles. The information may concern the vehicle itself or the traffic situation and other services. It is linked to a navigation and guidance system. Traffic information and services are broadcast by RDS. The route planner takes RDS messages into account to alter the route when necessary. Compatibility with the task of driving is ensured by ergonomic studies and testing. The research phase of Carminat will be followed by large scale pilot programs involving a fleet of vehicles on motorways and in large urban areas.

Vehicle guidance system using beacon transmissions of destination data

Abstract: A vehicle and destination guidance system is proposed wherein a destination can be input by entering the destination and the street in clear language into a vehicle device. The vehicle device is in communication with a beacon device in which, in addition to the various destinations, street names and the associated coordinates are stored. On demand by the vehicle device, the beacon device selects the associated destination coordinates and transmits them to the vehicle device. Additional data can be transmitted in the transmitted telegram which, for example, contain traffic information or street maps. The system is also usable for automatic toll deductions.

Aircraft docking guidance system which takes position reference in anti-collision light of aircraft

Abstract: A plurality of image pickup devices are set on the ground to pick up images of an anti-collision light located on an aircraft to be guided. A position reference producing section produces a signal representing a position reference of the aircraft in accordance with picked-up image signals from the plurality of image pickup devices. A display data producing section produces at least one of direction information and distance information as guidance information to be provided to pilots of the aircraft in accordance with the signal representing the position reference of the aircraft which is supplied from the position reference producing section. A display unit displays at least one of the direction information and distance information from the display data producing section at a position on the ground where the pilots can see and recognize the information.

Self-tuning controller for farm tractor guidance

Abstract: Automatic guidance of farm tractors would improve productivity of many field operations by reducing operator fatigue and improving machine performance. A self-tuning steering controller, which can be used for all noncontact types of positioning systems, was designed for tractor guidance. A simple two degrees-of-freedom model was chosen with which to develop a prediction model used in recursive least-squares parameter estimation. A variable forgetting factor was implemented and its algorithm modified to cope with time-varying nonlinear systems. The self-tuning steering controller based upon minimum variance control was tested and verified with a tractor dynamic simulator. Circular, lane change, and sinusoidal paths were used. A model tractor was also used to verify controller performance for straight-line and sinusoidal paths.

Development of guidance laws for a variable-speed missile

Abstract: The most used guidance law for short-range homing missiles is proportional navigation (PN). In PN, the acceleration command is proportional to the line-of-sight (LOS) angular velocity. Indeed, if a missile and a target move on a collision course with constant speeds, the LOS rate is zero. The speed of a highly maneuverable modem missile varies considerably during flight. The performance of PN is far from being satisfactory in that case.

Hardware-in-the-loop tow missile system simulator

Abstract: A "hardware-in-the-loop" simulator (10) for training people in the use of a missile system to teach target acquisition, missile launch, and missile guidance under simulated battlefield conditions. A battlefield environment (E) including at least one target (T) movable therewithin is created by a simulation module (12). Missile system hardware (H) including the missile acquisition, tracking, and guidance portions is provided. An interface module (20) converts signals produced by the simulating module to an infrared image acceptable by the hardware. The resultant image represents a field-of-view (FOV), including the target, within the battlefield environment. An image module (32) produces a dynamic image representative of the missile's position in the field-of-view. This image is observable by the hardware which utilizes it to determine the position of the missile relative to the target. The hardware also determines if a missile guidance signal is to be sent to the missile to guide it to the target. If so, the interface module is responsive to the guidance signal to simulate, in real-time, the response of the missile to the guidance signal.

Modelling distributed real-time route guidance strategies in a traffic network that exhibits the Braess paradox

Abstract: This paper examines the operational characteristics of a simple traffic network which produces a dynamic form of the Braess paradox when the in-vehicle link data base, that is used to guide vehicles in real-time through the network, is expanded to include a low capacity short cut link which was previously unknown to the drivers The analysis focuses on the ways in which a route guidance system with distributed route selection logic, such as the TravTek system in Orlando, can be made to avoid the inefficiencies associated with the paradox without a priori knowledge of the existence of the paradox and while allowing each vehicle's RGS computer to independently make routing decisions without the explicit knowledge of the concurrent routing decisions of other drivers It is shown that this objective can be achieved by implementing a distributed form of a system optimum routing algorithm coupled with the use of a PROBIT type of error term to reduce some of the instabilities that are intrinsic in the travel time information feedback loop

Simulation evaluation of a low-altitude helicopter flight guidance system adapted for a helmet-mounted display

Abstract: A computer aiding concept for low-altitude helicopter flight has been developed and evaluated in a real-time piloted simulation. The concept included an optimal control trajectory-generation algorithm based upon dynamic programming, and a helmet-mounted display (HMD) presentation of a pathway-in-the-sky, a phantom aircraft, and flight-path vector/predictor guidance symbology. The pilot evaluation was conducted at the NASA-Ames Research Center moving base vertical motion simulator by pilots representing NASA, the US Army, Air Force, and helicopter industry. The pilot manually tracked the trajectory generated by the algorithm utilizing the HMD symbology. The pilots were able to perform the tracking tasks satisfactorily while maintaining a high degree of awareness of the outside world. >

Probability-based decision making for automated highway driving

Abstract: Real-time, rule-based guidance systems for autonomous vehicles on limited-access highways are investigated. The goal of these systems is to plan trajectories that are safe while satisfying the driver's requests based on stochastic information about the vehicle state and the surrounding traffic. A rule-based system is used for high-level planning. Given a stochastic model of the traffic situation driven by current measurements, the probable evolution of traffic and the best trajectory to follow are predicted. Simulation results assess the impact of uncertain knowledge of traffic on the performance of the guidance system, showing that uncertainty can and must be taken into account.

Evidence on drivers' reaction to in-vehicle route guidance advice

Abstract: Presents results of two projects yielding information on drivers' reactions to in-vehicle route guidance advice. The first project involved users of the LISB route guidance system, and the second focused on the DRIVE project CARGOES which provided information on drivers' compliance with advice of different qualities. This paper presents the evidence on driver response from these two sources and highlights some implications that this has for the design, evaluation simulation and marketing of route guidance systems.

Airport pavement marking system for surface movement guidance

Abstract: A surface movement guidance system for airport traffic of a continuous elongated row of one or more indicia extending lengthwise along a route on the airport surface to be traversed by the traffic, which indicia convey information about position on the airport surface.

Video-image-based neural network guidance system with adaptive view-angles for autonomous vehicles

Abstract: This paper describes the guidance function of an autonomous vehicle based on a neural network controller using video images with adaptive view angles for sensory input. The guidance function for an autonomous vehicle provides the low-level control required for maintaining the autonomous vehicle on a prescribed trajectory. Neural networks possess unique properties such as the ability to perform sensor fusion, the ability to learn, and fault tolerant architectures, qualities which are desirable for autonomous vehicle applications. To demonstrate the feasibility of using neural networks in this type of an application, an Intelledex 405 robot fitted with a video camera and vision system was used to model an autonomous vehicle with a limited range of motion. In addition to fixed-angle video images, a set of images using adaptively varied view angles based on speed are used as the input to the neural network controller. It was shown that the neural network was able to control the autonomous vehicle model along a path composed of path segments unlike the exemplars with which it was trained. This system was designed to assess only the guidance system, and it was assumed that other functions employed in autonomous vehicle control systems (mission planning, navigation, and obstacle avoidance) are to be implemented separately and are providing a desired path to the guidance system. The desired path trajectory is presented to the robot in the form of a two-dimensional path, with centerline, that is to be followed. A video camera and associated vision system provides video image data as control feedback to the guidance system. The neural network controller uses Gaussian curves for the output vector to facilitate interpolation and generalization of the output space.

Rule-Based Guidance for Vehicle Highway Driving in the Presence of Uncertainty

Abstract: The principal objective of this research is to study the feasibility of a real-time, rule-based guidance system for an automobile on a limited-access highway. The inputs to the system are parameters describing the traffic situation, road geometry, vehicle state, and a driver selected goal. The output of the system consists of guidance parameters that command control logic governing the throttle, steering angle, and brakes. During our past research, a dynamic expert system accomplished this guidance task under the assumption that all inputs were available deterministically, i.e., without error. This paper investigates the types and effects of uncertainties encountered in a more realistic environment, and it proposes a stochastic methodology to extend the expert system to handle information that is known only in a probabilistic way.

Improved Airbreathing Launch Vehicle Performance with the Use of Rocket Propulsion

Abstract: An efficient performance analysis method is developed to evaluate potential airbreathing/rocket propulsion systems for advanced technology single-stage-to-orbit launch vehicles. Evaluated are tradeoffs between airbreathing, rocket, and concurrent airbreathing/rocket propulsion in maximizing payload delivery to orbit for a given ascent flight trajectory. With the analysis method, several modes of airbreathing/ rocket propulsion are compared to a baseline "airbreather alone" propulsion system in terms of fuel/propella nt required to attain orbital velocity. Concurrent airbreathing/rocket propulsion shows a reduction in fuel/propellant consumption over straight airbreather to rocket propulsion transition. The optimal switch point (staging) is identified for the transition from airbreathing to rocket propulsion.

Anti-tank missile system

Abstract: An anti-tank missile system includes a weapons carrier system with a missile including control means for controlling the missile flight path and a searchhead camera for developing target data during flight of the missile. An elevatable platform is mounted on the weapons carrier system and a sighting device camera is disposed on the elevatable platform for sighting a target. Target data is compiled before a launch of the missile with the aid of the sighting device camera. A fire guidance computer in the weapons carrier system calculates a flight course for the missile. A light waveguide is connected between the missile and the weapons carrier system for transmitting target data developed by the searchhead camera for use by the fire guidance computer and for transmitting guidance signals generated by the fire guidance computer for controlling the control means for guiding the missile during its flight; and wherein the sighting device camera is a high resolution camera and the searchhead camera has at least one of a lower resolution and different spectral range than the sighting device camera.

Benefits of dynamic route guidance systems as part of a future oriented city traffic management system

Abstract: In order to better cope with the future needs of traffic management systems an advanced route guidance and information system called LISB has been introduced and tested in the City of Berlin (West) (1). Infrared transmitters and receivers (beacons) are located at intersections of the main road network transmitting route recommendations to specially equipped vehicles. These vehicles measure their travel times per road section and transmit them via beacons to a central route guidance computer. Based on actual travel times, the central computer calculates the quickest routes in the network. These routes are indicated visually and audibly to the drivers, guiding them to their destinations, taking into account the actual and short-term predicted traffic situation. Within a large-scale field experiment the system's performance, acceptance by the drivers, and benefits for the users as well as for the municipality have been investigated (2). The final results and a way of incorporating individual traffic control systems into traffic management systems will be presented in the following paper.

Combined sensor guidance system

Abstract: A guidance system for a homing missile having an observer filter which utilizes signals representative of range, range rate, acceleration normal to the line-of-sight of the missile, acceleration along the line-of-sight of the missile, and line-of-sight rate of the missile to a target is described. The filter includes means, responsive to a lateral acceleration signal, a measured range rate signal and a range signal for providing an estimated line-of-sight rate signal. The measured line-of-sight rate signal and the estimated line-of-sight rate signal are used to produce a difference output signal. The difference output signal is used to produce an error signal which is applied to the providing means to minimize the difference output signal. The estimated line-of-sight rate signal provides a more accurate estimate of the actual line-of-sight rate of the missile to the target than that which can be obtained with a standard proportional navigation system.

A Dynamic Modelling Framework of Real-Time Guidance Systems in General Urban Traffic Networks

Abstract: There is considerable interest around the world in developing and implementing realtime driver information and/or guidance systems to reduce congestion in the urban traffic networks. However most of these attempts have proceed without much insight into the significant influence of many of the key elements and phenomena involved in a traffic system under information that could determine the effectiveness of alternative designs of such systems. These include: the context, extent and form of the information provided to the drivers, the response and compliance of the drivers to the information, the system-wide implications of particle equipping of the vehicle population, frequency of information update, etc. In this paper a simulation-based framework that incorporates these elements is presented along with illustrative results on its application to realistically sized networks. The traffic simulation is performed using macroscopic local speed-flow relations in discretized segments, while individual drivers' route choice decisions are modelled at the network nodes. The network path processing is based on k-shortest path tree-building that allows the drivers to select among several competing route. Efficient data structures are utilized for storing the network and the k-shortest paths are found using efficient binary heap-sorting procedures. The program can simulate networks with only a fraction of the drivers receiving information. The driver route switching behavior is based on candidate mechanisms of choosing to stay on a route unless an alternative route becomes sufficiently attractive. In addition, the model can also be used to evaluate the effectiveness of guidance instructions provided by a central controller. Simulations are carried out for different behavioral model parameters as well as for different fractions of drivers with information, the results of which are provided with a discussion of substantive conclusions and key insights. The simulations are carried out on a supercomputer, and the advantages of vector processing are also discussed.

Aerospace plane guidance using time-scale decomposition - A geometric approach

Abstract: A method is proposed for developing the necessary guidance logic to steer single-stage vehicles into orbit. The minimum-fuel ascent problem is first considered to analyze the effects of dynamic pressure, acceleration, and heating constraints on guidance systems to thereby develop the guidance logic. The optimal solution consists of behavior with two time scales, and the control law is used to develop near-optimal guidance. The solution uses the slow manifold to delineate the control for minimum-fuel reduced-order trajectory and a separate control for tracking the optimal reduced-order trajectory. A family of fast manifolds is then employed to resolve the tracking problem via the feedback linearization methodology from nonlinear geometric control theory. The two-time-scale decomposition is found to produce a near-optimal ascent by tracking the applicable state-constraint boundary, as well as to simplify the control-design task.

Optical guidance system for an automated guidance vehicle

Abstract: of the Disclosure: An optical guidance system for an automated guided vehicle comprises an optical guideline network including a main guideline and milestones adapted to be installed above the path of the vehicle, a two dimensions optical sensor mounted on the vehicle for scanning the optical guideline and associated milesontes and producing a video image of the optical guideline and associated milestones, and an image processing system also mounted on the vehicle and responsive to the optical sensor for generating lateral and orientation offset signals from the localization of the optical guideline on the video image.

Effectiveness of in-vehicle navigation systems in alleviating non recurring congestion

Abstract: The effectiveness of in-vehicle navigation systems in alleviating nonrecurrent congestions is examined. Computer simulation modeling is used to assess the effectiveness of four different types of navigation systems consisting of static map, dynamic map, route guidance and advanced route guidance systems. The study is conducted for the Irvine network, Orange County, California. The results of the study shows that the performance of descriptive in-vehicle navigation systems (static map and dynamic map) is dependent on the initial network flow conditions and could lead to severe worsening of traffic condition. The prescriptive systems (route guidance and advanced route guidance) could substantially improve the traffic situation; the performance of these systems is dependent on the level of market penetration, i.e. the fraction of drivers equipped with the navigation system. The appropriate level for the Irvine network is shown to be 30% or more.

Development of advanced dynamic navigation system

Abstract: The Dynamic Navigation System is an information-providing type navigation and route guidance system. Fundamentally the system is suited for phased implementation. Some measures, however, must be taken in advance to enhance it to the advanced phase. For these measures, information providing data formats, travel time collection methods and small-delay system architecture have been studied. As a result, the flexible data composition for information provision, the on-board travel time measurement for efficient and accurate data collection and the autonomous communication network concept called 'HYPO NET' have been proposed.