NCJ Number
187102
Date Published
2000
Length
18 pages
Annotation
This analysis of second-generation systems to provide continuous electronic monitoring of offenders over a wide geographic area explains the current systems and the time- of-arrival methods used in many geolocation techniques.
Abstract
The second-generation systems will enable corrections agencies to monitor and supervise offenders continuously over a wide geographical area with diverse terrain and construction patterns. The major methods used by geolocation vendors include the angle of arrival, the time difference of arrival of signals received at geographically separated antennas, the global positioning system (GPS), server-assisted GPS, the enhanced signal strength method, and location fingerprinting. Two companies introduced GPS-based continuous monitoring systems for criminal offenders in 1997. Jurisdictions in several States use these systems. Another development is the Federal Communications Commission directive to provide enhanced 911 (E911) to cellular phone users. A model for a one-cell second-generation system consists of a service center, interrogator transmitter, locator tags, receivers and their antennas, data lines, and GPS satellites for space-based systems. A simulation model for the tracking system will help clarify architecture, requirements and design issues, and play for potential corrections scenarios before the system is deployed. Figures, tables, and 13 references