The User Output Frame; Span Translations And Rotations; Figure 17: Vehicle Frame - Novatel SMART7 Installation And Operation Manual

SMART7 with SPAN Operation

4.2.4 The User Output Frame

The user output frame is an arbitrary frame, which can be optionally defined to transfer inertial
output to a more useful position or reference frame.
By default, SPAN position and velocity output is given at the center of navigation of the IMU. To
output position and velocity at a different location, specify a user offset translation using the
SETINSTRANSLATION command.
By default, SPAN attitude output is the rotation from the Local-Level frame to the Vehicle frame.
If attitude output is desired relative to another frame, specify a user offset rotation using the
SETINSROTATION command.

4.3 SPAN Translations and Rotations

A SPAN system combines GNSS and INS into a single system. In a GNSS system, the position is
reported relative to the phase center of the GNSS antenna. In an INS system, the position, velo-
city and attitude data is reported relative to the center of navigation of the IMU. For a SPAN sys-
tem to provide a combined GNSS+INS position, velocity and attitude, it must know where the
GNSS antenna is positioned relative to the IMU.
The orientation of the IMU relative to the forward direction of the vehicle is also needed to con-
vert the velocity and attitude changes sensed by the IMU into the actual motion of the vehicle.
If the SPAN system incorporates other devices, the SPAN system also needs to know the loc-
ation and orientation of these additional devices relative to the IMU.
SMART7 Installation and Operation User Manual 0C

Figure 17: Vehicle Frame

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