Minor mode on the IWRL6432 requires users to set an argument for the maximum velocity that the IWRL6432 can detect minor mode points with. Points detected in minor mode with a velocity greater than this threshold are ignored. This threshold is called the minor motion velocity inclusion threshold.
If the minor motion velocity inclusion threshold is set too low, the no points will appear on the visualizer, so it is critical to get this value high enough if using minor mode.
This is meant to ensure that minor mode points only detect slow moving objects with small changes in phase. If a fast-moving object appeared in a scene with a radar running minor motion, the radar running minor motion would see huge difference in phase across the minor motion chirps, likely violating the Nyquist criteria, resulting in an incomprehensible signal.
To effectively set a minor mode velocity inclusion threshold, users should calculate the relationship between real speed, speed calculated by the radar and the doppler bin these correspond to.
The radar calculates speed in both major and minor motion as
calculated velocity = lambda*deltaPhi/(4 * pi * Tburst)
However, the real speed of an object in minor mode, assuming 1 chirp/frame, is
real velocity = lambda*deltaPhi/(4 * pi * Tframe).
See the fundamentals app note for derivations of these formulas.
So, if a user wants to observe objects moving at a velocity v0, they should set the argument in the CLI to be v0 * Tburst / Tframe to account for this difference in calculation.
The most effective way to use this CLI argument though is to calculate the minimum doppler bin that a point in minor mode can be placed into. This is calculated as the doppler step, which is
doppler step = c / (Tburst* 2 * fc).
Simply set the inclusion threshold slightly higher than this value, and points should appear in minor mode.
