Vectornav VN-100, Руководство пользователя

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80 UM001
6.1.2 Delta Theta and Delta Velocity
Delta Theta and Delta Velocity
Register ID : 80 Async Header: DTV Access : Read
Comment : This register contains the output values of the onboard coning and sculling algorithm.
Size (Bytes): 28
Example Response: $VNRRG,80,+0.665016,-000.119,-000.409,-000.025,+000.011,-000.084,-006.702*6A
Offset Name Format Unit Description
0 DeltaTime float sec Delta time for the integration interval
4 DeltaThetaX float deg Delta rotation vector component in the x-axis.
8 DeltaThetaY float deg Delta rotation vector component in the y-axis.
12 DeltaThetaZ float deg Delta rotation vector component in the z-axis.
16 DeltaVelocityX float m/s Delta velocity vector component in the x-axis.
20 DeltaVelocityY float m/s Delta velocity vector component in the y-axis.
24 DeltaVelocityZ float m/s Delta velocity vector component in the z-axis.
The Delta Theta and Delta Velocity register contains the computed outputs from the onboard coning and
sculling algorithm. The coning and sculling integrations are performed at the IMU sample rate (nominally
at 800Hz) and reset when the register data is output. If polling this register, the values will represent the
delta time, angles, and velocity since the register was last polled. If the Delta Theta/Velocity data is
selected for asynchronous output via the Async Data Output Type register (Register 6, type 30), the
integrals will be reset each time the data is asynchronously output at the configured rate.
The delta time output contains the length of the time interval over which the deltas were calculated. This
can be used to check the interval time or to compute nonlinear “average” rates and accelerations from
the integrated values.
The delta theta is output as a principal rotation vector, defined as the product of the unit vector of the
principal rotation axis and the principal rotation angle in degrees. For small rotations, a typical use case
for delta angles, the principal rotation vector elements may be treated individually as rotations in degrees
about the individual sensor axes (in any Euler rotation sequence) with little error.
The delta velocity output provides the integration of the acceleration in the chosen frame, taking into
account the coupling effects of any simultaneous rotation experienced.
The coning and sculling algorithm can be configured to operate in multiple frames and with a variety of
compensations applied. See the Delta Theta and Delta Velocity Configuration Register in the IMU
subsystem for further details.
You can configure the device to output this register at a fixed rate using the Async Data Output Type
Register in the System subsystem. Once configured the data in this register will be sent out with the
$VNDTV header.