SEPTENTRIO AsteRx SBi, Руководство пользователя

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CHAPTER 3. CONF I GUR I NG THE ASTERX SB I 3
3.2 How to measure and compensate for the
Antenna Lever Arm
The antenna lever-arm is the relative position between the I MU reference point and the GNSS
Antenna Reference Point (ARP). The I MU reference point is clearly marked on the top panel
of the receiver. Refer to the data sheet of your GNSS antenna for the exact location of the
ARP.
I t is important to compensate for the e ff ect of the lever arm, otherwise the receiver may
not be able to calculate an accurate I NS position. The higher the accuracy of the lever-arm
dimensions, the better the accuracy of the I NS solution calculated by the receiver. As shown
in Figure 3-5, lever arm o ff sets can occur in three dimensions.
Figure 3-5: Example of the relative I MU/antenna position in the vehicle ’ s frame
(in blue). I n this example, the lever arm X and Y components are equal to X ’ and Y ’
(positive), while the Z component is Z ’ (negative) + 1.7cm.
Values representing the relative position of the main antenna ARP with respect to the I MU
reference point in the three dimensions of the vehicle reference frame can be provided to the
receiver in the web interface under GNSS/
I NS > External Sensor Setup as shown in Figure 3-6.
Note that in order to correctly reference to the antenna ’ s ARP, it is necessary to compensate
for phase center variations. This can be done in the web interface by going to GNSS/ I NS >
Position and selecting the correct antenna type in the ’ Antenna I nformation ’ fi eld.
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