Automatic Person Location

Technologies and

Solutions for Public Safety Users

Peter HudsonSepura

28.10.2005

Introduction

Location

Update

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

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 cases150 - 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

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

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 ?

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

Resource management - AVLS

Resource management - APLS

Resource management

Importance of knowing location

HighAccuracy

LowAccuracy

HELP!....

Which street are you in?

HELP!....

Which street are you in?

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

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

Network Based Solutions

LMU

Radio tower

Radio tower Radio tower

C&CServer

GIS orMapping

Application

GIS orMapping

Application

TETRAGateway

LMU LMU

LMU

Network Based Solutions

Current Accuracy = 200m - 2km

Future Accuracy =100m - 500m

Medium accuracy, medium cost solutions

Standard GPS time to first acquisition (fix) is typically 3 mins >30 metres accuracy, no indoors or urban canyon coverage

Assisted GPS time to first acquisition is typically 30 secs

>30 metres accuracy

Low Signal Strength GPS (high sensitivity) time to first acquisition is typically 45 secs <30 metres accuracy indoors/urban canyons

All the above have a location accuracy of <10 metres for 95% of cases in open space

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.

GPS based solutions

Radio tower

MappingApplication

TETRANetwork

Mapping Server

C & C Servers

Dispatch workstations

Base station

TETRA gateway

C&C Firewall

C & C LAN

SDS

High accuracy, high cost solutions

Differential GPS open space accuracy <10 metres off expensive to implement with land based differential base stations required and regular network broadcasts Network bandwidth hungry

Solution Combinations (GPS+Beacons+Odometer) accuracy anywhere between 0 - 10 metres very expensive beacon network required to support this

GPS - High accuracy

Radio tower

Radio tower Radio tower

C&CServer

GIS orMapping

Application

GIS orMapping

Application

TETRANetwork

TETRAGateway

GPS

GPS Station

Radio tower

SDS

GPS

Odometer

BeaconReceiver

Data over network - Size of problem!

Heading

Fix type

Confidence Level

Status

Fix Reason

Terminal ID

Typically, position report messages could carry some or all of the following:

Date

Time

Latitude

Longitude

Altitude

Speed

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

TETRA services for APLS

TETRA services allow use of SDS messaging for transmission of GPS data:-

EN 300 392-2: TETRA (Voice plus Data (V+D), 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!

Future of APLS & TETRA Terminals

Technology Influenced Solutions

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

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

Clear Sky

Under Foliage

Wooden Building

Urban Canyon

Single Storey Brick Building

Multi Storey Concrete building

Underground?

2002 2003 2004 2005 2006 2007 2008 2010………………………….. 2015 2020 2030

High sensitivity GPS

L1, L2 + L5 Frequency(+ Galileo?)

Galileo

Future GPS ?

Other Sensors – e.g. Gyroscope, Accelerometers

“GPS” Performance - Trend

High Quality Receiver

High Quality Hand HeldReceiver

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