GNSS Module Series
LG69T(AA,AD)_EVB_User_Guide
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4.2.1.
Determination Process of EVB Installation Angle
Before the 6-axis accelerometer sensor is available, the EVB installation angle needs to be determined by
the following steps:
Step 1:
Install the EVB on a vehicle and connect the antenna.
Step 2:
Startup the vehicle and power on the EVB.
Step 3:
Keep the vehicle stationary for at least 20 s on a flat road (the tolerance of the gravity direction is
1°~2°).
Step 4:
Drive the vehicle for 1 minute.
Step 5:
Stop the vehicle and keep it still for at least 5 s. The module saves the calcuated installation angle
to the flash memory through software logic.
4.2.2.
Main Calibration Procedure
The main calibration steps of LG69T (AA) EVB are as following:
Once installation angle is determined, the following steps should be performed to fine tune the calibration
accurately:
Step 1:
Based on
Step 5
above, the yaw rate offset will be automatically initialized with a reliable value.
Then, drive in a straight road (speed > 30 km/h) for at least 5 minutes.
Step 2:
Drive in areas rich of curves (speed > 30 km/h). This process is required to calibrate the yaw rate
gain. It is important to require tight turns (with narrow radius of curvature). Typical scenes that
allow this step to be performed properly are roundabouts, tight turns, and road curves with
direction changed in 90 degress or more. Large turns (e.g. smooth turns on highway, lane
changes, etc.) will not work. Please note that the success of this operation does not depend on
its duration, but the number of vaild turns. In order to have a fine-tuned yaw rate gain, it is
suggested that the firts-boot calibration route should include at least 10 tight turns described
above. During this procedure, the same turn can be repeated for many times.
The most important is that all these operations should be performed under adequate GNSS signal
conditions, which means that the antenna must have maximum sky visibility. Thus, the calibration should
be performed in an open area, i.e. the area away from high-rise buildings, forests, tunnels and any other
element that may cause signal blocking or reflection.
