Title: Location
1Location Trackingof Offenders Using GPS Based
Systems
- CTA Conference
- Pittsburgh, PA
- May 24, 2004
2Housekeeping
- Mike Epstein 310-336-2122
- Epstein_at_law-west.org
- NLECTC
- Stop me at any time
- Turn cell phones and pagers to stun
- Vendors, please
- Dont market your product
- Dont trash your competition
- Copies of presentation available on request
- Fill out your evaluation forms
3Presentation 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
4System 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
5Derived 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
6System 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
7GPS Tracking Subsystems
8Offender 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)
9Communications 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
10In-house Subsystem Requirements
- Device charging station
- Device communications station
- (Dedicated) Phone line
- Device at rest proximity monitoring
11Monitoring 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
12CCO Subsystem Requirements
- Computer and printer with communication path to
the monitoring subsystem (usually internet based)
13How GPS Based Location and Tracking Devices Work
14GPS 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 - Its 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
satellites Lat, Lon Alt data from four
satellites
15GPS 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
16GPS Operational Use
- Probably wont 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)
17Active Tracking System
GPS Satellite
AgencyPrograms
CommunicationLink
Monitoring Center
Base Station
18Elements of an Active Tracking System
GPS Satellites
Monitoring Station
Ankle Transmitter
19Passive Tracking Device
GPS Satellite
Officer
Communication
Link
Monitoring
Center
Base
Station
20Elements of a Passive Tracking System
GPS Satellites
Monitoring Station
Ankle Transmitter
21Overcoming GPS Tracking Problems
- Newer GPS chipsets
- Newer GPS satellite constellation
- Indoor augmentation technologies
- Nanotechnology gyroscope
- 802.11? tracking technologies
- Operational and Offender procedures
22Description of Available GPS Based Location and
Tracking Devices and Services
23Vendors
24The Effectiveness and Limitations of These
Systems
25Pros Cons of Passive Devices
- Pros
- 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
- Cons
- After the fact tracking coverage - no immediate
notification in the event of a zone violation
26Pros Cons of Active Devices
- Pros
- Perceived increased public safety
- Immediate response capability
- May not require a phone line
- Cons
- 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!)
27Systems In Use
28Florida DOC
- Operating Active Tracking Devices since 2001
- Uses off duty police officers for immediate
response to critical violations - Currently using ProTech Monitoring systems
29Colorado 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
30WA 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
31WA 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
32WA 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.
33Post-processing Offender Tracking Data
34Felons on Probation Parole Re-offend
- Bureau of Justice Statistics study found 300,000
inmates studied were convicted of the following
new crimes 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
35Post 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
36Law Enforcement Application
Law Enforcement
37Probation Parole Application
Offender Tracking Data
Monitoring Facility
I A Filter
Probation / Parole Officer
38Questions ?
39Requirements Definition
40Requirements Satisfaction
- Reasons for unsatisfied requirements
- Cost
- Unavailability of technology
- Physical laws
- Size and weight
41System Descriminators
42Device Comparisons
- Device notifications
- GPS receiver
- Operating characteristics
- Mechanical characteristics
- Communications
43Device 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
44Device 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
45GPS Receiver
- GSP Signal timing
- WAAS capable
- Acquisition time
- Hot start time
- Warm start time
- Cold start time
- Power drain
- Working
- sleeping
46Operating Characteristics
- Battery
- Life between charges
- Charge time
- Recharge cycles to replacement
- Device computer capabilities
- Power usage
- Storage capability
- Attachment system(s)
47Mechanical Characteristics
- Weight
- Size
- Antennas
- GPS
- Comm system
- Environmental capabilities
- Attachment / Tamper system
48Communications
- Commercially available services
- Wireless data services
- GPRS . Edge
- 1XRTT . CDMA 2000
- 2 way pager
- 802.11
- Cell phone
- Private radio