GPS-MicrophoneGPS-MicrophoneGPS ProcessingGPS Processing Standard NMEA 2.0 Standard NMEA 2.0

GGA and RMC GGA and RMC sentencessentences

Utilizes SIRF3 based Utilizes SIRF3 based receiverreceiver

Typical accuracy Typical accuracy within 5 meterswithin 5 meters

Data Modem Interface Data Modem Interface FFSK/MSK data FFSK/MSK data

communication over communication over existing voice channel existing voice channel

2400 bits-per-second 2400 bits-per-second data ratedata rate

FEC, CRC, Interleaving FEC, CRC, Interleaving and data scrambling and data scrambling usedused

Messages include 8 Messages include 8 character unit ID character unit ID

GPS-MicrophoneGPS-Microphone

Poll-Based Position Poll-Based Position Reporting Reporting

GPS-Mic always GPS-Mic always responds to responds to location query location query requests from the requests from the BasestationBasestation

GPS-MicrophoneGPS-Microphone

Automatic Position Automatic Position Reporting ModesReporting Modes

1.1. Push-To-Talk (PTT) Push-To-Talk (PTT) switch activatedswitch activated Position report Position report

sent either on sent either on every PTT or a every PTT or a time-throttled time-throttled basisbasis

GPS-MicrophoneGPS-MicrophoneAutomatic Position Automatic Position

Reporting ModesReporting Modes

2.2. Fixed-Time BasedFixed-Time Based Periodic reporting Periodic reporting

of positionof position Time interval Time interval

value : 1 – 255value : 1 – 255 Time interval Time interval

units: seconds, units: seconds, minutes, hours, minutes, hours, or daysor days

GPS-MicrophoneGPS-MicrophoneAutomatic Position Reporting Automatic Position Reporting

ModesModes

3.3. Fixed-Distance Based Fixed-Distance Based Position reported if Position reported if

location change exceeds location change exceeds set distance thresholdset distance threshold

Distance Threshold : 100 Distance Threshold : 100 meters – 64 Kmmeters – 64 Km

Operational modes: Operational modes: absolute (e.g. geo-fence) absolute (e.g. geo-fence) or relative (between or relative (between successive location reads)successive location reads)

Uses separate periodic Uses separate periodic time check which may be time check which may be set by user set by user

GPS-MicrophoneGPS-MicrophonePanic Position Reporting ModePanic Position Reporting Mode

Special “man down” button on Special “man down” button on unit initiates periodic panic unit initiates periodic panic message with position reportmessage with position report

Manual activation/deactivation Manual activation/deactivation button press period is button press period is programmableprogrammable

Rate of reporting to Rate of reporting to Basestation is programmableBasestation is programmable

Basestation can acknowledge Basestation can acknowledge and deactivate through over-and deactivate through over-the-air commandthe-air command

GPS-MicrophoneGPS-MicrophoneOn-Board Memory FeaturesOn-Board Memory Features

Unit can store up to 1500 position reports in non-volatile Unit can store up to 1500 position reports in non-volatile memorymemory

Programmable location storage modes:Programmable location storage modes: Conditional and Temporary Conditional and Temporary

Only used to prevent data loss if currently unable Only used to prevent data loss if currently unable to reportto report

Copy or AuditCopy or AuditLocations are both stored on-board and reported Locations are both stored on-board and reported

over the airover the air Deferred Over-The-AirDeferred Over-The-Air

Locations are stored on-board but not reported Locations are stored on-board but not reported over the air, unless directed to through Base over the air, unless directed to through Base station command.station command.

GPS-MicrophoneGPS-MicrophoneUnit and Basestation Messaging FeaturesUnit and Basestation Messaging Features

High-reliability communication protocol using High-reliability communication protocol using handshakes and retrieshandshakes and retries

Supports Base station broadcast messages to all unitsSupports Base station broadcast messages to all units Efficient time-slot management scheme for unit Efficient time-slot management scheme for unit

responses to reduce probability of collisions and responses to reduce probability of collisions and need for extraneous data messagingneed for extraneous data messaging

Supports Base station multi-cast messages to up to 15 Supports Base station multi-cast messages to up to 15 separate GPS-Mic groups separate GPS-Mic groups Units may be assigned to groups at time of Unit ID Units may be assigned to groups at time of Unit ID

designation and provisioningdesignation and provisioning Can reduce data messaging and simplify equipment Can reduce data messaging and simplify equipment

managementmanagement