Edward J. Krakiwsky

Digital map dependent functions of automatic vehicle location systems

A digital map and associated database of a road network are vital for computer-assisted land navigation by automatic vehicle location (AVL) systems. The authors describe the several digital map-dependent functions of these AVL systems. The map-dependent functions detailed are: graphical map representation; initialization of the AVL system; position and location; route determination; route guidance; and auxiliary information provision. Experience in customizing the digital route maps and database obtained by the authors is described.<<ETX>>

Road information systems; impact of geographic information systems technology to automatic vehicle navigation and guidance

A prototype road information system being developed at the University is a special-purpose geographic information system that collects, organizes, and disseminates information related to the street and highway networks of a city or region. The basic structure is the road and street network made up of a series of nodes and links, by which attributes from different applications can be referenced. The structure, if properly designed, can serve many applications such as route determination and guidance, commercial and service information provision, dispatching and monitoring of fleet vehicles, and road inventory and traffic management. The current research effort of the prototype concentrates on data modeling, spatial database management, communications, and real-time applications for the many automatic vehicle location, navigation, and guidance systems presently being developed.<<ETX>>

Design concepts for knowledge-based route guidance systems

Positioning, location, navigation, route guidance, and optimal route determination are defined as the principal tasks performed in automatic vehicle location (AVL) systems. Land-based AVL systems are shown to have two basic configurations: stand-alone and dispatch. The automation of the principal AVL tasks in a real-time environment is described. Automation is achieved through building an AVL system knowledge base of rules and facts. Individual actions are thus automatically controlled and managed in an optimal manner. In this process, the type of AVL system and the underlying application is taken into account. The authors also address coupled systems, in which numeric processes and symbolic processes are combined into one integrated unit.<<ETX>>

Least squares collocation and statistical testing

The authors address the issue of statistical testing in least squares collocation (LSC) in two stages. The first stage concerns the extension and focusing of theLSC equations to the task of statistical testing. The second stage deals with statistical testing titself and is introduced in the second portion of the paper. The paper commences with an overview of the development ofLSC and its relationship to least squares adjustment (LSA). Expressions for the various random variables and their corresponding covariance matrices are derived and in some instances are gleaned from the literature for the following quantities: (i) corrections to the unknown parameters with a priori covariance information; (ii) estimated signal at both the observation and computation points; and (iii) the noise at the observation points. Some of the needed covariance matrices are either obscurely hidden in the literature or not available at all, but, nevertheless are given in the paper. Also given are expressions for the estimated variance factor which forms the basis of various statistical tests. The paper closes with an overview and enumeration of possible statistical tests for detection of outliers in the observations.

Experience with the application of federated filter design to kinematic GPS positioning

The concept and equations for federated filtering are discussed. They have been applied to the treatment of GPS (Global Positioning System) pseudorange and phase data in a decentralized fashion for kinematic single point positioning. It has been found that, by selecting carrier phase as the reference filter and pseudorange as a local filter a judicious selection of the information sharing factor beta /sub j/, which proportions the kinematic system information between the reference phase filter and the local pseudorange filter.<<ETX>>

Fleet management trials in western Canada

THE PURPOSE of this paper is to describe the components of a fleet management system and the preliminary findings of two demonstration projects. Being Canadian based, the paper opens with an overview of the Canadian road-vehicle system. Statistics are given for the road network and the estimated numbers of various types of vehicles. The Canadian Vision 2000 initiative, which is being spear headed by Communications Canada, and consists of approximately 50 communications related companies working in various consortiums, is briefly described. A Western Canadian consortia, consisting of a communications manufacturer, a systems integrator and two carriers, are carrying out various demonstration projects over the next three years. The first project discussed is an assessment of current Canadian digital mapping data for the application of vehicle navigation systems and the second is a test with the Calgary Police Department using Pulsearchs NavTraxTMfleet management system in five vehicles. Some conclusions based on experience to date conclude the paper.

A quality control approach for GPS-based automatic vehicle location and navigation systems

The federated filter, which is a special form of decentralized filters has shown some promising features regarding optimality and other practical aspects. The theory of the federated architecture is discussed. Emphasis is placed on the applications in the field of vehicle navigation using Global Positioning System (GPS). During both theoretical and practical research, it is concluded that federated designs suit optimality needs for systems output and allow the use of existing stand-alone software of individual sensors in an integrated sense without any major modifications. Quality control is feasible, as a malfunction of one of the sensors would be detected and identified before the contamination of the global (combined) output of the system, and hence isolation of errors is feasible in real-time mode.

The diversity among IVHS navigation systems worldwide

More than 100 intelligent vehicle highway system (IVHS) navigation systems are being built worldwide. Japan and the United States are the leaders in developing systems, with the second grouping of countries being Germany, the United Kingdom and Canada. Various positioning technologies such as the Global Positioning System (GPS), the Radio Determination Satellite System RDSS, dead reckoning, signposts, map matching, and terrestrial RF systems are used more in some countries than in others, and these trends are reported. Countries in some regional blocks use certain positioning technologies more prominently than those used in other blocks. Examples of novel systems in the four basic categories (autonomous, fleet management, advisory, and inventory) are given to illustrate the trend toward specific market penetration and thus the diversity among systems. A brief description of future trends is given.

AVLN 2000 automatic vehicle location and navigation system

This prototype system is being tested at the University. The positioning component consists of a GPS Trimble TANS (Trimble Advanced Navigation System) receiver, a pair of Nu-Metrics odometers, and a map-matching module, all integrated by a seven-parameter state vector Kalman filter to yield continuous positioning of the vehicle. An on-board GRiDCase EXP microcomputer is used for real-time computations and display. The system is being field-tested in a route network in the northwest quadrant of the City of Calgary. Enhanced area master files from Statistics Canada are used to produce the road network database.<<ETX>>

AUTOMATIC LAND VEHICLE LOCATION AND NAVIGATION IN THE YEAR 2000

The advancement in tecnhologies of computers, mass storage devices, positioning techniques, and digital communications links have made automation of navigational activities possible. The recent trend has been towards building navigational information systems. Two generations of these information systems are proposed. For the development of each generation a different design methodology and set of techniques are employed. Second generation systems are, however, envisioned to be enhanced versions of first generation systems, but are knowledge-based.