User's Manual

GlobalTrak ™ GT Lite Operation and Maintenance Manual
Over-the-Air Programming
The GT Lite firmware for both the main processor and low power controller are changeable
wirelessly, with full code load capable through GPRS. The method shall includes an
appropriate level of security. GT Lite authenticates OTA Upgrade messages first, then
accesses a password protected repository to download code.
ZigBee Mesh Network
At a configurable interval in hours starting at 0:00 GMT, the ZigBee Mesh Network will wake
to transmit pending Event LM’s to nodes with external communication (as indicated by the
Connectivity Flag). The network will remain awake for a configurable time period to ensure
every node has ample time to enumerate the network and transmit data. Nodes with an
external network will take the data received via ZigBee and pack an LM by appending the last
valid GPS fix. The message will then be placed in the queue for transmission on next
transmission attempt.
DSP: Operations from the M100
ZB: Operations from the ZigBee module
1) DSP: Wake ZigBee module
2) DSP: Send connectivity flag status to ZigBee module
3) ZB: If connectivity flag = True
a) ZB: Wait X seconds for all nodes to wake
b) ZB: Declare node as Coordinator
c) ZB: Enumerate network
d) ZB: If no network is available
i) ZB: Go to sleep
ii) DSP: Return to previous function
e) ZB: If network is available
i) ZB: Listen for ZMT seconds for children to send messages
ii) ZB: If ZigBee messages received
(1) ZB: Pass messages to M100
(2) ZB: Go to sleep
(3) DSP: If GPS mode = Previous valid
(a) DSP: Repack LM with last valid GPS fix
(4) DSP: Place messages in queue with Message Identifier = LZ
(5) DSP: Attempt transmit during next scheduled transmission or transmission of events
(6) DSP: Return to previous function
iii) ZB: If no ZigBee messages received
(1) ZB: Go to sleep
Prepared: R. Straz Date: July 25, 2007 Page 35 of
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