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National Law Enforcement andCorrections Technology Center - West
Location & Trackingof
Offenders Using GPS Based Systems
CTA Conference
Pittsburgh, PA
May 24, 2004
National Law Enforcement andCorrections Technology Center - West
Housekeeping
• Mike Epstein – 310-336-2122– Epstein@law-west.org
• NLECTC• Stop me at any time• Turn cell phones and pagers to stun• Vendors, please
– Don’t market your product– Don’t trash your competition
• Copies of presentation available on request• Fill out your evaluation forms
National Law Enforcement andCorrections Technology Center - West
Presentation Objectives
• Requirements definition• Describe how GPS based location and tracking
devices work• Description of available GPS based location and
tracking devices and services• Effectiveness and limitations of these systems• Systems in use• Post-processing offender tracking data
National Law Enforcement andCorrections Technology Center - West
System Requirements• Track and report the whereabouts of an uncooperative offender
away from his or her home• Notify the designated authorities when
– the offender is in an unauthorized location (Area)– the offender is not where there are supposed to be– the location of an offender is unknown– the tracking device is not working properly– the offender has separated from the tracking device
• Tracking device must– be of reasonable size and weight– operate on portable power for the hours an offender is away from their
house– act as a home detention device– Receive information from the monitoring agency
National Law Enforcement andCorrections Technology Center - West
Derived System Requirements
• Tracking device must– know its location– know if has been tampered with– know the unauthorized locations for the
offender– know the schedule of the offender– be able to communicate
National Law Enforcement andCorrections Technology Center - West
System Design Assumptions
• Use GPS to determine tracking device location• Use commercial communications paths
– Wireless data services between mobile tracking device and monitoring service
– Dial up phone line between tracking device at home and monitoring service
– Internet between monitoring service and responsible agencies
• Use offender worn anklet transmitter for tracking device proximity checks
National Law Enforcement andCorrections Technology Center - West
GPS Tracking Subsystems
OffenderSubsystem
CommunicationsSubsystem
MonitoringSubsystem
CCOSubsystem
In-HouseSubsystem
National Law Enforcement andCorrections Technology Center - West
Offender Subsystem Requirements
• Collect, process, store and communicate geographical location of offender outside their home
• Replace home detention devices
• Tamper proof / resistant / alertable
• Operate for 8 – 12 hours (current battery constraints)
National Law Enforcement andCorrections Technology Center - West
Communications Subsystem Requirements
• Provide reliable communication paths for– location data
• in real time (device to monitor)• after the fact (device at rest to monitor)
– Notifications and alerts• CCO to device• Device to monitor
– Reporting• Monitor to CCO
National Law Enforcement andCorrections Technology Center - West
In-house Subsystem Requirements
• Device charging station
• Device communications station
• (Dedicated) Phone line
• Device at rest proximity monitoring
National Law Enforcement andCorrections Technology Center - West
Monitoring Subsystem Requirements
• Trusted interface with CCO subsystem• Tools for the CCO to
– Enroll and manage offenders– Monitor and manage offender rules
• Hot zones / grace periods / rule status• Rule schedule• Violation notification
– Query offender location• History• Rule violation mapping
– Generate reports– Manage tracking device– Transmit messages to offenders
National Law Enforcement andCorrections Technology Center - West
CCO Subsystem Requirements
• Computer and printer with communication path to the monitoring subsystem (usually internet based)
National Law Enforcement andCorrections Technology Center - West
How GPS Based Location and Tracking Devices Work
National Law Enforcement andCorrections Technology Center - West
GPS – What you need to know• Satellite broadcast system
– 24+ available (6-12 in view)
• Provides Lat, Lon and Alt position and time to a receiver system
• It’s free of charge• 100% of the time accuracies of
70 feet horizontal, 85 feet vertical, 200 nanosecond time errors (20 millionths of a second)
• Receiver can calculate speed• Position data can be enhanced
– WAAS– LAAS or DGPS
Minimums:Lat, Lon – data from three satellitesLat, Lon & Alt – data from four satellites
National Law Enforcement andCorrections Technology Center - West
GPS – WAAS & DGPS/LAAS
• Wide Area Augmentation System (WAAS)– Two FAA launched satellites with North American
coverage in geosynchronous orbits
– Requires upgraded or newer GPS receiver
– Accuracies of 2 meters horizontal and 3 meters vertical
• Differential GPS (DGPS) or Local Area Augmentation System (LAAS)– Specialized applications such as survey work,
accuracies within inches
National Law Enforcement andCorrections Technology Center - West
GPS – Operational Use• Probably won’t work indoors unless receiver is near a window
(receiver can tell you if it is getting good data)• May not work in a car or a bus unless receiver is near a window• If receiver is turned off, reacquisition of the satellite data may take
minutes (0-10 min)• Always on receiver draws a lot of battery power• Most GPS receivers have a sleep mode which restarts quickly
(typically less than 1 min)• Receiver start modes
– Off (Cold)– Sleep (Warm)– On (Hot)
National Law Enforcement andCorrections Technology Center - West
Active Tracking System
Ash St.
Birch St.
Conifer St.
Main S
t.1st Ave.
2nd Ave.
Lincoln A
ve.
White
Ave.
Monitoring Center
AgencyPrograms
GPS Satellite
BaseStation
CommunicationLink
National Law Enforcement andCorrections Technology Center - West
GPS Satellites
Monitoring Station
Elements of an Active Tracking System
WirelessData
Service
Encasement System
GPSReceiver
Microprocessor & Memory
Transmit /
Receiver
Rechargeable Power Supply
Display Screen
Ankle Transmitter
Charging Station
National Law Enforcement andCorrections Technology Center - West
Passive Tracking Device
Ash St.
Birch St.
Conifer St.
Main S
t.1st Ave.
2nd Ave.
Lincoln A
ve.
White
Ave.
Monitoring Center
Officer
GPS Satellite
BaseStation
CommunicationLink
National Law Enforcement andCorrections Technology Center - West
GPS Satellites
Monitoring Station
Elements of a Passive Tracking System
Charging Station
Encasement System
GPSReceiver
Microprocessor & Memory
Rechargeable Power Supply
Display Screen
Ankle Transmitter
National Law Enforcement andCorrections Technology Center - West
Overcoming GPS Tracking Problems
• Newer GPS chipsets
• Newer GPS satellite constellation
• Indoor augmentation technologies– Nanotechnology gyroscope – 802.11? tracking technologies
• Operational and Offender procedures
National Law Enforcement andCorrections Technology Center - West
Description of Available GPS Based Location and Tracking
Devices and Services
National Law Enforcement andCorrections Technology Center - West
Vendors
BI Elmo Tech
iSecureTrac ProTech VerQuis
Active devices Unknown Yes Yes Yes Yes
Passive devices Yes Yes Yes Yes Unknown
Offender “pieces” 2 2 2 2 1
Post processing Unknown Unknown Unknown Yes Yes
Web site www.
bi.
com
www.
elmotech.
com
www.
isecuretrac.
com
www.
ptm.
com
www.
verquis.
com
National Law Enforcement andCorrections Technology Center - West
The Effectiveness and Limitations of These Systems
National Law Enforcement andCorrections Technology Center - West
Pro’s & Con’s of Passive Devices
• Pro’s– Small size – can be belt mounted– No real time communication concerns– Tracking throughout the day– In-home monitoring at night– Lower cost– Less work load for officers, no immediate pager response– Reduced agency liability
• Con’s– After the fact tracking coverage - no immediate
notification in the event of a zone violation
National Law Enforcement andCorrections Technology Center - West
Pro’s & Con’s of Active Devices• Pro’s
– Perceived increased public safety – Immediate response capability– May not require a phone line
• Con’s– High cost - can be $12.50 a day or more– Communication coverage reliance for immediate alerts– More labor intensive - zones & schedule entry– Could require agency response immediately– Greater agency liability – Equipment size and weight (battery power!)
National Law Enforcement andCorrections Technology Center - West
Systems In Use
National Law Enforcement andCorrections Technology Center - West
Florida DOC
• Operating Active Tracking Devices since 2001
• Uses off duty police officers for immediate response to critical violations
• Currently using ProTech Monitoring systems
National Law Enforcement andCorrections Technology Center - West
Colorado DOC
• Largest consumer of Passive Tracking Devices– Operations since early 2003– As many as 240 units in operation– May double this amount next year
• Currently using ProTech Monitoring Systems
National Law Enforcement andCorrections Technology Center - West
WA DOC
• Recently finished a 90 day pilot project at the direction of and with funding from the State Legislature.
• Use passive tracking devices to study– availability of technology– geographic and weather related limitations– training requirements– effectiveness for different supervision populations– equipment costs, monitoring fees, staffing levels– ability of offenders to pay– rate of loss and damage to equipment– pilot study limitations
National Law Enforcement andCorrections Technology Center - West
WA DOC (more)
• Pilot study– Used ProTech Monitoring Systems– Fielded 30 – 40 devices spread throughout the
state– Tracked Level III sex offenders– Challenged by homeless population
• Final report sent to the legislature on 1/31/04
National Law Enforcement andCorrections Technology Center - West
WA DOC (more)
• Results– Technology is viable and available
– May increase Officer workload
– Limited success tracking homeless offenders
– Several offenders arrested and sent back to prison based on location data
– Some observed changes to offender behavior
“With clear goals, knowledge of the limitations in the technology, and an understanding of the liability issued involved, utilizing GPS technology to monitor sex offenders is an effective and valuable supervision tool.”
National Law Enforcement andCorrections Technology Center - West
Post-processing Offender Tracking Data
National Law Enforcement andCorrections Technology Center - West
Felons on Probation & Parole Re-offend
• Bureau of Justice Statistics study found 300,000 Bureau of Justice Statistics study found 300,000 inmates studied were inmates studied were convicted of the following new of the following new crimes while on parole or probationcrimes while on parole or probation– Murdered 13,200 people– Raped 11,600 women and 1,600 men– Robbed 39,500 people– Burglarized 39,600 homes– Assaulted 19,200 people– Stole 7,900 motor vehicles
• When investigating crimes, these offenders are prime suspects
National Law Enforcement andCorrections Technology Center - West
Post Processing Data
• Law Enforcement Applications– Compare offender movements with recent area
crimes
• Probation & Parole Applications– Build an automated set of indications and
warnings to flag questionable offender movements
National Law Enforcement andCorrections Technology Center - West
Law Enforcement Application
Offender Tracking Data
Monitoring Facility
Probation / Parole Officer
Law Enforcement
National Law Enforcement andCorrections Technology Center - West
Probation & Parole Application
Offender Tracking Data
Monitoring Facility
Probation / Parole Officer
I & A Filter
National Law Enforcement andCorrections Technology Center - West
Questions ?
National Law Enforcement andCorrections Technology Center - West
Requirements Definition
National Law Enforcement andCorrections Technology Center - West
Requirements Satisfaction
Satisfied Requirements
System Requirements
Reasons for unsatisfied requirements• Cost• Unavailability of technology• Physical laws• Size and weight
National Law Enforcement andCorrections Technology Center - West
System Descriminators
National Law Enforcement andCorrections Technology Center - West
Device Comparisons
• Device notifications
• GPS receiver
• Operating characteristics
• Mechanical characteristics
• Communications
National Law Enforcement andCorrections Technology Center - West
Device Notifications
• Positional data• Hardware violations
– Device tampering / compromised– Battery low– Device attachment tampering / compromised– Device not charging (in house)
• Device status
– Acquiring GPS signal– No GPS signal
National Law Enforcement andCorrections Technology Center - West
Device Notifications (continued)
• Tamper alerts– Case
– Attachment
• System health alerts– Battery low
– Battery not charging (in house)• Monitoring station alerts
– Geographic violations• Device Exclusion / inclusion zones
– No communications from a device
National Law Enforcement andCorrections Technology Center - West
GPS Receiver
• GSP Signal timing– WAAS capable
– Acquisition time• Hot start time
• Warm start time
• Cold start time
• Power drain– Working
– sleeping
National Law Enforcement andCorrections Technology Center - West
Operating Characteristics
• Battery – Life between charges– Charge time– Recharge cycles to replacement
• Device computer capabilities– Power usage– Storage capability
• Attachment system(s)
National Law Enforcement andCorrections Technology Center - West
Mechanical Characteristics
• Weight
• Size
• Antennas– GPS– Comm system
• Environmental capabilities
• Attachment / Tamper system
National Law Enforcement andCorrections Technology Center - West
Communications
• Commercially available services– Wireless data services
• GPRS …. Edge
• 1XRTT …. CDMA 2000
• 2 way pager
• 802.11
– Cell phone– Private radio
Recommended