User's Manual

DRAFT TrimTrac 1.5 Technical Manual v0.3ab 60
settings in effect. In TrimTrac 1.5, the GPS receiver and GSM Modem can
operate simultaneously (unlike earlier generations of the TrimTrac locator).
1. When the unit enters the FIX State it enables the GPS hardware and starts
the FIX Timeout, T2 (Very rapid LED blink rate followed by a repeated
Long ON, Long OFF LED blink rate).
2. Upon completion of a successful position fix, the relevant position related
information is extracted and the internal the RTC is updated.
3. After the position fix is achieved, or upon expiration of the FIX Timeout,
T2, the GPS engine can either be turned off or allowed to continue
operating at 1 Hz, depending upon the current configuration. In all cases,
however, the unit transitions to the STATUS state if the TrimTrac 1.5,
even if the device does not have a complete valid almanac. If the unit does
not have a complete, valid almanac after computing the position fix, or if
Almanac Timeout, T6, has expired, the TrimTrac 1.5 will leave the GPS
engine operational for up to fifteen (15) minutes more to collect almanac
(LED Blink: Two Medium Blinks followed by a Long Off). Upon
collection of a complete, valid almanac or expiration of the fifteen (15)
minute almanac collection timer, the unit will power off the GPS engine
unless GPS Fix Rate is set “1=GPS 1Hz” operation; in which case, the
GPS receiver will remain powered and operational.
Alert Processing in the FIX State:
Unless their mode is set “3=Monitor-only”, should either the HPA Status or MPA
Status become set “1=Activated” during the current FIX state, the TrimTrac 1.5
will terminate the current fix attempt and go immediately to the STATUS state.
All other alert conditions shall have no effect on the FIX state.
STATUS State
The TrimTrac 1.5 enters the STATUS State based upon the occurrence of
TriggerType events or, if entering from the FIX state, upon the computation of a
new position fix or expiration of the FIX Timeout, T2.
1.
When the unit enters the STATUS State it retrieves the battery, alert and
operational status information and stores it in the report structure to be
used during the TRANSMIT state.
2.
If entering from the FIX state and the position fix attempt was successful,
the Position Age flag is set “0=Current”.
3.
It then transitions to the TRANSMIT State.
The TrimTrac 1.5 dwells in the STATUS state only long enough to update the
report structure. This process is virtually instantaneous and all alerts shall have
no effect on STATUS state.