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NCJ Number: 90348 Add to Shopping cart Find in a Library
Title: Operational Model for Predicting Time Between Losses of a Vehicle in a Computer-Tracked Vehicle Location System
Author(s): R C Larson
Corporate Author: Public Systems Evaluation, Inc
United States of America
Date Published: Unknown
Page Count: 61
Sponsoring Agency: National Institute of Justice/
Rockville, MD 20849
NCJRS Photocopy Services
Rockville, MD 20849-6000
Public Systems Evaluation, Inc
Cambridge, MA 02139
US Dept of Justice

US Dept of Justice NIJ Pub
Washington, DC 20531
Grant Number: 75-NI-99-0014
Sale Source: National Institute of Justice/
NCJRS paper reproduction
Box 6000, Dept F
Rockville, MD 20849
United States of America

NCJRS Photocopy Services
Box 6000
Rockville, MD 20849-6000
United States of America
Document: PDF
Language: English
Country: United States of America
Annotation: Several simplified mathematical models are developed to analyze the factors to the probability of the loss of a vehicle in a computer-tracked vehicle location system.
Abstract: Until recently system error has usually been measured in feet or meters and stated in terms of average errors or percentages of position estimations which are within a certain distance of the true position. Systems such as FLAIR pose new problems, however, in analyzing, modeling, and interpreting system errors. These systems use an in-car odometer and compass to provide a crude form of inertial guidance. The somewhat noisy information from these instruments is transmitted at one-second intervals in the FLAIR system to a central receiver. The computer may correct the estimated location back to the most likely position whenever the estimated position is infeasible. Sources of error include random error, systematic error which creates a bias in the odometer readings, the street patterns of the city in question, the number of binary digits used to transmit information on vehicular heading and distance, and the sampling interval. Open loop tracking and system subvertability also have a bearing on system performance. Diagrams and tables are included. (Author summary modified)
Index Term(s): Automated vehicle monitors; Mathematical modeling; Vehicle location monitors
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