Place a soldier (player), add a insignia
[this,"111thID"] call BIS_fnc_setUnitInsignia;
Place a vehicle (HEMMT,MRAP).
Best effect is if you place the sun high on the sky, but still on an angle. Otherwise your insignia will always be bright all the time.
Jump in to the vehicle, play as 3rd person. Rotate to the insignia and watch it while you spin, And you will see that the vehicle shadow dosent affect the insignia. It will be bright like it's still in the sun rays, and not obscured.