Micro Tracker Reference Guide FW 1.7 V1.1
Page 19 of 39
11th october 2018
Restricted distribution
1-
The first position is always a WIFI one whatever the chosen geolocation strategy.
4.6.2
Side operations
The following geolocation policies (
geoloc_method
parameter) are used for periodic-reporting or on-demand
actions.
➢
WIFI only
→
Only WIFI scans are used for position determination
➢
GPS only
→
Only the GPS is used for position determination
➢
LP-GPS only
→
GPS and LP-GPS are used for position determination
➢
WIFI-GPS only
→
WIFI then GPS if WIFI fails in one geolocation cycle
➢
WIFI-LPGPS only
→
WIFI then low power-GPS if WIFI fails in one geolocation cycle
➢
BLE beacon scan only
→
Provide data formatted as a list of MAC address/RSSI(Receive Signal Strengh
Indication) couple that can be used to compute a position
4.6.3
Geolocation technology description
4.6.3.1
GPS
When doing a cold start, the tracker uses systematically a timeout of 5 minutes instead of the configured
one.
To complete a position, the GPS module expects one of the two following conditions to be achieved.
➢
The
GPS_convergence
timeout (time let to the GPS module to have a more precise position)
➢
The
gps_ehpe
value is below the configured value. EHPE (Estimated Horizontal Position Error) is
provided by the GPS module and is expressed in meter.
Once completed the position is reported via LoRa and the GPS module switches to standby state.
Then, it waits
gps_standby_timeout
delay before going to the off state (losing all data and ephemeris)
In the case where
the GPS module didn’t succeed, a GPS timeout message is sent instead of a GPS position
message.
Note
:
1-
If a period smaller than
gps_timeout
is set for
ul_period
the GPS timeout used will be
ul_period
instead of
gps_timeout
GPS state diagram