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Automatic Person Location Technologies and Solutions for Public Safety Users. Peter Hudson Sepura. 28.10.2005. Location Update. Introduction. Market requirements for APLS for Public Safety users The command and control requirements of an APLS solution Review of location technologies
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Automatic Person LocationTechnologies and Solutions for Public Safety Users Peter Hudson Sepura 28.10.2005
Location Update 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
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
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
HELP!.... Which street are you in? Importance of knowing location High Accuracy Low Accuracy
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 GIS or Mapping Application LMU LMU TETRA Radio tower Radio tower Gateway GIS or Mapping Application C&C Server Network Based Solutions Current Accuracy = 200m - 2km Future Accuracy =100m - 500m LMU LMU Radio tower
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 Mapping Server Mapping Application C&C Firewall C & C LAN TETRA Network TETRA gateway Dispatch workstations SDS C & C Servers Radio tower Base station
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
SDS Beacon Receiver GPS Odometer GPS - High accuracy TETRA Network GIS or Mapping Application TETRA Radio tower Radio tower Gateway GIS or Mapping GPS Application Server C&C GPS Station Radio tower Radio tower
Data over network - Size of problem! Typically, position report messages could carry some or all of the following: • Heading • Fix type • Confidence Level • Status • Fix Reason • Terminal ID • 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 • Continuing integration of IC’s 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.
“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
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