SEPTENTRIO AsteRx SBi, Руководство пользователя

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CHAPTER 3. CONF I GUR I NG THE ASTERX SB I 3
Figure 3-6: Setting the lever arm o ff sets.
The External Setup page in the receiver web interface provides a visualization tool that allows
users to get an idea of the relative positioning of the ARP and PO
I in the vehicle reference
frame with given lever-arm settings.
Accurately determining the lever-arm can be di
ffi cult. I deally, both the I MU and the antenna
are installed in known locations so that existing 3D models can be used to determine the
lever-arm o
ff sets in the X, Y and Z dimensions. I f the locations of either the antenna or the
I MU are not known, point clouds obtained from 3D laser scanning or similar techniques
could be used to build a reference frame that allows for the lever-arm to be accurately
measured. For temporary setups or test purposes where the accuracy of the
I NS solution
is not of paramount importance, it may be su ffi cient to measure the lever arm manually,
e.g. using a tape ruler. However, this should never be the method of choice for permanent
installations.
3.3 How to compensate for deviations in the
antenna orientation
The attitude of a vehicle can be determined from the orientation of the baseline between
two antennas attached to the vehicle. By default, the receiver determines the attitude angles
assuming that the baseline between the antenna ARP is parallel to the longitudinal axis of
the vehicle. Attitude biases appear when this is not the case. The user can provide the value
of the attitude o
ff set angles in the web interface under GNSS/ I NS > I NS/Attitude > Advanced
as shown in Figure 3-7. Providing this information will let the receiver compensate for the
o
ff sets before calculating the attitude by subtracting them from the attitude angles.
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