User's Manual

DRAFT TrimTrac 1.5 Technical Manual v0.3ab 46
4. No Reports Generated. The TrimTrac 1.5 is expected to spend a
majority of its time in either the IDLE or DELAY states, during which
the unit will not send any messages until motion causes a transition,
the appropriate RTC-based timeouts have expired, or if an Alert
condition occurs.
Another possible cause would be the motion detector and associated
latches may not be recognizing motion; in which case, the unit may
dwell in IDLE until the IDLE Timeout, T1, expires even though there
may have been motion in the mean time. If missed motion is
suspected, the sensitivity of the motion detector can be manipulated by
adjusting Static Motion Filter Timeout, T7 and the associated Static
Motion Filter Counter, N3, settings and/or by adjusting the Dynamic
Filter Timeout, T21, and Dynamic Motion Filter Counter, N4.
Generally speaking, increasing the ratio between Static Motion Filter
Timeout, T7 and the associated Static Motion Filter Counter, N3, will
increase the motion detector sensitivity in the IDLE state; provided,
however, that Static Motion Filter Timeout, T7, is not set to “0”. If
Static Motion Filter Timeout, T7, is set to “0”, then the Static Motion
Filter Counter, N3, setting is ignored and the motion detector is
undamped.
Additionally, the sensitivity of both motion detector filters can be
adjusted with the Motion Counter Threshold. This parameter
determines how many times during each second motion must be
detected before either the Static Motion Filter Counter, N3, or
Dynamic Motion Filter Counter, N4, are increased by one count.
Unit Does Not Report Stopped Position
In its default configuration, the TrimTrac 1.5 will attempt one additional position
fix after the unit has come to rest. If, however, the unit is in a vehicle that has
come to rest in a covered parking structure or garage, there may be insufficient
GPS signal to compute a final position fix, in which case, the device will log a
Status Message, but a new Position Report may not be available. In application
server-based geo-fence applications, this may be problematic since the server
application may not know whether the device has entered the geo-fence area.
If coming to rest in an obscured GPS signal environment is expected, then
consider setting the GPS Fix Rate to “1=GPS 1Hz”. In so doing, the GPS
receiver will continuously compute new position fixes until the GPS signal is lost.
Then, if the TrimTrac 1.5 comes to rest after losing the GPS signal due to
blockage, the TrimTrac 1.5 will report the very last computed position and set the
Position Age flag to “1=Aged”, as opposed to sending just a new
STATUS_MESSAGE. At least this way, the last reported position could be
where the vehicle entered the parking structure even though it may not have been
able to compute a fix in the parking structure itself.