Automatic Person Location Technologies and Solutions for Public Safety Users

1
Automatic Person Location Technologies and
Solutions for Public Safety Users

• Peter Hudson
• Sepura

28.10.2005
2
Introduction

• Market requirements for APLS for Public Safety
  users
• The command and control requirements of an APLS
  solution
• Review of location technologies
• TETRA services used for location solutions
• Future of APLS enabled products for public safety
  users

3
Market Requirement Drivers APLS

• FCC E911 Mandate in the US
• Call centres
• Terminal or network implemented solutions
• 50 - 100 metre accuracy for at least 67 of cases
• 150 - 300 metre accuracy for at least 95 of
  cases
• EU E112 Mandate in Europe
• Still not implemented !
• No defined accuracy specified !
• Both systems proposing using either TDOA or GPS
  location techniques
• Many emergency services now
  mandating APLS

4
Location Technology - Public Safety

• Know where someone is save LIFE.
• Better allocation of resources, prompt reaction
  to an Emergency save TIME.
• Better Control of the fleet save MONEY
• Improve job satisfaction save CHURN

5
Solution Influencing Factors

• Price
• Accuracy verses coverage
• Ergonomics
• Power consumption
• Timing of solution to reach the market
• Standard solution or proprietary ?
• Can the solution be supported by TETRA ?

6
Command Control Requirements

• Effective management
• Requirements differ from AVLS
• User needs to feel unthreatened by APLS
• Updated positioning details fixed to various
  duties or skills
• Linking of various systems/databases to provide
  officer with advance warning of possible dangers

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Resource management - AVLS
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Resource management - APLS
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Resource management
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Importance of knowing location
High Accuracy
Low Accuracy
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Location Solutions Performance

• Low accuracy, low cost solutions
• Time difference of arrival
• Enhanced observed time difference
• Medium accuracy, medium cost solutions
• Standard GPS
• Assisted GPS
• Low signal strength GPS
• High accuracy, high cost solutions
• Differential GPS
• Combinations of Solutions

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Low accuracy, low cost (terminal) solutions

• Time Difference Of Arrival (TDOA)
• very costly to implement in the network
• accuracy of location is /- 500 metres
• Enhanced Observed Time Difference (EOTD)
• no base station support now claimed
• accuracy of location is 200m - 2km
• Both technologies
• have good indoor/urban canyon penetration, but
  with very poor accuracy - a general show stopping
  issue for network based solutions where location
  accuracy could be critical
• are bandwidth hungry therefore not suitable for
  TETRA

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Network Based Solutions
GIS or
Mapping
Application
LMU
LMU
TETRA
Radio tower
Radio tower
Gateway
GIS or
Mapping
Application
CC
Server
Network Based Solutions
Current Accuracy 200m - 2km
Future Accuracy 100m - 500m
LMU
LMU
Radio tower
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Medium accuracy, medium cost solutions

• Standard GPS
• time to first acquisition (fix) is typically 3
  mins
• gt30 metres accuracy, no indoors or urban canyon
  coverage
• Assisted GPS
• time to first acquisition is typically 30 secs
• gt30 metres accuracy
• Low Signal Strength GPS (high sensitivity)
• time to first acquisition is typically 45 secs
• lt30 metres accuracy
• indoors/urban canyons
• All the above have a location accuracy of lt10
  metres for 95 of cases in open space

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GPS How Does It Work ?

• To enable a location measurement to be made, the
  GPS receiver needs to know were the satellites
  are
• It receives two kinds of data from the
  satellites
• Almanac data
• Ephemeris data
• Once the receiver has obtained this information
  it needs to synchronise time before an accurate
  location measurement can be made.
• By knowing time taken to receive signal from each
  satellite, the receiver can determine exactly how
  far away it is.

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GPS based solutions
Mapping Server
Mapping Application
CC Firewall
C C LAN
TETRA Network
TETRA gateway
Dispatch workstations
SDS
C C Servers
Radio tower
Base station
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High accuracy, high cost solutions

• Differential GPS
• open space accuracy lt10 metres off
• expensive to implement with land based
  differential base stations required and regular
  network broadcasts
• Network bandwidth hungry
• Solution Combinations (GPSBeaconsOdometer)
• accuracy anywhere between 0 - 10 metres
• very expensive beacon network required to
  support this

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GPS - High accuracy
TETRA
Network
GIS or
Mapping
Application
TETRA
Radio tower
Radio tower
Gateway
GIS or
Mapping
GPS
Application
Server
CC
GPS Station
Radio tower
Radio tower
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Data over network - Size of problem!
Typically, position report messages could carry
some or all of the following

• Date
• Time
• Latitude
• Longitude
• Altitude
• Speed

• Heading
• Fix type
• Confidence Level
• Status
• Fix Reason
• Terminal ID

Amount of message traffic generated by APLS
systems is much larger than for AVLS
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TETRA services for APLS

• TETRA services allow use of SDS messaging for
  transmission of GPS data-
• EN 300 392-2 TETRA (Voice plus Data (VD),
  part 2 Air Interface, v2.3.2
• SDS4 and SDS-TL delivers variable length
  messages to 2047 bits(255 bytes)
• GPS location data is provided in the NMEA
  formats, GLL, GSA, GGA etc.
• Typical GLL mesage could contain as much as 48
  bytes of data!
• Location Information Protocol TS 100 392-18-1
  v1.1.1 Jan 2005
• Specifies the effective use of network by using
  compact message formats
• Typical message (compared to GLL) is 11 bytes
  long!

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Future of APLS TETRA Terminals

• Technology Influenced Solutions

• Continuing integration of ICs and components
  enables space saving in handsets and is an
  opportunity to integrate location devices like
  GPS.

• The European Galileo system should be operational
  by 2008 and this is supposed to perform better
  than the existing US DoD GPS system.

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GPS Performance - Trend
Galileo
L1, L2 L5 Frequency ( Galileo?)
Clear Sky Under Foliage Wooden
Building Urban Canyon Single Storey Brick
Building Multi Storey Concrete
building Underground?
High Quality Receiver
Future GPS ?
High Quality Hand Held Receiver
High sensitivity GPS
Other Sensors e.g. Gyroscope, Accelerometers
2002 2003 2004 2005 2006 2007 2008
2010.. 2015 2020 2030
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Benefits of GPS in Public Safety

• Enhances user safety
• Lone worker Emergency Button GPS
• Accurate Location
• Improves resource usage
• Improves response times
• Selection of most appropriate resource
• Reduce wasted resource
• Improves reporting accuracy
• Knowing precisely where an incident took place
• Improves user job satisfaction
• User feels safer and more confident