TrimTrac ProE Locator, Technical Manual

Page: 109 / 233

TrimTrac ProE Locator Technical Manual v2.0e 91
FIX State
The FIX State is the state where the GPS engine is running trying to get a fix.
While in this state the GPS hardware is always turned on and the GSM radio
hardware may or may not be turned off depending upon the current configuration
settings in effect. In TrimTrac ProE, 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 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 ProE 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 ProE
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 ProE 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.