06 Smoothing and Filtering – VBOX IISX

Velocity

VBOX IISX units have three smoothing settings, or Dynamic Modes, for velocity: High Dynamics, Normal and Low Dynamics. High dynamics has the least amount of smoothing and must be used for high-dynamic tests where Time or Distance measurements are critical, such as brake stop and acceleration tests.

Acceleration Channels

The smoothing routine is set by selecting a value from 0 – 5.0 ( in steps of 0.1). This value corresponds to the size in time (seconds) of a moving window smoothing routine.

For example, if you select 0.3, a smoothing window of 0.3 seconds (6 samples @20 Hz) will be applied to the data.

Kalman Filter

This facility provides filtering separately to the Velocity and Position channels (longitude, latitude and height). Note that with any live filter routine, you will experience more latency when using higher levels of filtering, hence the Kalman Filter velocity settings should be set to zero for brake stops and acceleration runs.

It is often better to record unfiltered data than to use the software filter routines available in the VBOX Setup Software. This will have much less impact on latency.

You cannot adjust the level of filtering; the Kalman filter can only be enabled or disabled.

Note: Once the filter is turned on for the VBOX IISX, it remains on until you turn it off manually or you perform a GPS Coldstart. It will even remain on when you disconnect the VBOX IISX from its power supply.