Tracking Technologies - Technology - Judges Conference Apr 2-3

Tracking TechnologiesCopyright © 2012 National Center for Justice and the Rule of Law – All Rights Reserved

NCJRL Judicial Conference April 2-3, 2012

Technology Framework

TrackingTechnologies

Don MasonAssociate Director

Copyright © 2011 National Center for Justice and the Rule of Law – All Rights Reserved


Digital surveillance devices?


Digital surveillance devices?

Secure Continuous Remote Alcohol Monitor – SCRAM



Location Tracking

• Not one, single technology

• Convergence of several technologies

• Systems for– Tracking inventory, livestock, vehicles, or

humans

– Delivering location-based services to wireless devices


Current Technologies• Cameras (monitoring, surveillance)• “Bumper beepers”• Two-way pagers and cellular telephones• Geographic Information Systems (GIS)• Global Positioning System (GPS)• Vehicle event data recorders (EDR)• Radio Frequency Identification (RFID)• Wireless Local Area Networks (WLAN)• 911 and Enhanced 911 (E-911)


• Cell phones– Networks and how they work

– Cell site location information (CSLI)

• Beepers

• Global Positioning System (GPS)

• Digital Cameras

Our Focus Today



• Smartphones

• GPS

• Digital Cameras

• Beepers

Types of Devices


• Game systems

• MP3 Players

• E-readers

Types of Devices


• Cellular network triangulation

• GPS trilateration

• Geotagging

Processes



Smartphones


Smartphones

• Over 5.7 billion cell phones worldwide– 327 million in US

•103% of population

• 1.6 billion smartphones sold in 2010 alone


Mobile / Cellular phones

• Positions of mobile phones can be tracked, even on the move– Cell phones register their locations with

nearest cellular towers, approx every 7 sec’s

– Nearby antenna towers / base stations pick up signals, roam phone to adjacent towers as appropriate

– Active calls not required (most systems)

– Multilateration based on comparing multiple antenna signal strengths, pattern



Cell Phone Technology

• Has become important public safety tool

• Helps find people in trouble– While GPS helps people find their way out of trouble

– Can locate lost or missing persons (or their phones)

• Even OnStar uses cellular network to communicate with GPS receiver in car

• Accuracy dependent on base station density– More precise in urban areas with more towers


Towers tri-directional


Cellular networks



Cellular networks


Cellular networks


Triangulation

• Comparing signal strengths– Time delays

– Angles of arrival

– Three nearest towers



Triangulation


Cell Site Location Information

• Mobile switching centers may retain the location information in call detail records– At least for a period of time (e.g., 24 hours)

• Authorities can track subscriber’s general movements by following sequence of towers contacted by the phone

• May also obtain last recorded location before signal or power lost


Cell Site Location Information

• Most useful location information comes from initiation or receipt of a call or text

• A call data record (CDR) is kept for billing– Yield historical account of cell phone’s

locations

• Officers may also locate phone in “real time” while a call is in progress



Enhanced 9-1-1

• FCC mandate of 95% of phones

• Locate phone location within 300 meters

• Within 6 minutes


Beepers


• Requires “tailing”– Antenna used to track radio signals

– Up to 5 miles

• Placed on car or package– 1”x2” to 3”x5”

• Does not store information

Beepers



• Use beeps and/or lights to indicate– Direction (but not very well)

– Distance

Beepers


GPS


• Global Positioning System

• Developed by US government for military purposes– Cost unknown, but EU’s competing system

expected to cost around $25 billion

– Still operated by the military

GPS



• Three Components– Satellites

•24 operational, 3 backups

•Any point on earth can “see” at least 6 at all times

•Each knows its distance from the center of the Earth

– Ground Stations•11 around the globe

– Receivers•Calculate their distance from the satellite

GPS


GPS

Satellites


GPS

• 32 Earth-orbiting solar-powered satellites– 24 in operation, plus spares

• Limited life span – about 10 years

• Equipped with up to 4 atomic clocks

• Orbits arranged so at least 4 (ideally 6) satellites “visible” anywhere, any time

• Send high-frequency, low-power radio signals



GPS

Ground Stations


GPS

• Ten ground stations around Earth – Monitor satellite signals and collect accuracy

measurements

• Master control station in Colorado – Determine if adjustments or updates needed

• Four large ground-antenna stations– Send corrective data and commands to

satellites


GPS

Receiver



GPS

• Equipped with quartz clocks constantly reset based on time signal from satellites

• Locate 4 or more (at least 3) satellites

• Calculate distance to each

• Use that information to deduce receiver location– Using “trilateration”

– In three-dimensional space


GPS Devices• Portable

– Portable Navigation Devices•Vehicle•Outdoor

– Mobile phones

• Fixed– Vehicle– Marine– Aviation

• Tracking


Trilateration

• 2-D– Signals from 3 satellites

– Latitude and Longitude

• 3-D– Signals from 4 or more satellites

– More accurate

– Lat/Long plus Elevation/Altitude



2-D Trilateration

• Involves a bunch of difficult calculations

• Instead of learning that, let’s use pictures


2-D Trilateration

Detroit

366 miles


2-D Trilateration

Richmond

Detroit

312 miles



2-D Trilateration

Richmond

Nashville

Detroit

Charleston

388 miles


3-D Trilateration


3-D Trilateration



3-D Trilateration


3-D Trilateration


3-D Trilateration



• Accuracy is limited by:– Earth’s atmosphere

•Weather generally has no effect– But doesn’t work underwater

– Structures, Terrain, Foliage

– Clock errors

– Gravitational effect on satellite orbits

GPS


• Generally, accurate to 15 meters

• Receivers use “Differential GPS” to calculate error– Makes measurement accurate to 10 meters,

but possibly up to 10 centimeters

GPS


• Uses an assistance server to more rapidly or accurately obtain a location– Can be used in lieu of a fully functional GPS

receiver or can be used to enhance the accuracy of a location

• If the GPS receiver has trouble determining a location, A-GPS can make a connection using the cell network to send data

Assisted GPS (A-GPS)



• Many cell phones use A-GPS, cell site triangulation and other technology to determine location

• Other benefits– Uses less battery power

– Less time to get a fix

– Better coverage

– System can be upgraded at network level




Satellites Phone Company’s Receiver

Smartphone

Cell Towers

A-GPSServer


GPS Data

• Data that may be located on the GPS receiver includes:

• Device information

• Owner information

• Waypoints

• Home location

• Points of interest (POI)

• Deleted locations

• Last fix

• Routes/Journeys

• Track logs

• Favorites



Digital Cameras


• Pictures and video, of course– Geotagging

•Especially in smartphones

Digital Cameras


• Adds latitude and longitude coordinates to pictures and video– Stored in metadata; not visible in the image

• Usually derived from GPS– Camera must have a built-in GPS receiver

• Can also be used with text messages, social networking updates, and blog posts

Geotagging



Geotagging


Convergence




Presented by

Don MasonAssociate Director, NCJRL

[email protected]

Tracking Technologies - Technology - Judges Conference Apr 2-3

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