rename KP to KB

Author: ufechner7

docs/src/reference_frames.md

@@ -15,21 +15,21 @@ It can have any origin (with respect to the kite), but usually either the center
 - X is defined chord wise, from LE to TE, positive.
 - Z is defined as positive upwards.
 
-### Kite reference frame (KP)
+### Kite reference frame (KB)
 This is a body-fixed reference frame.
 - Y defined spanwise, looking at the kite from the front (so seeing the LE first) the front left is positive.
 - X is defined chord wise, from LE to TE, positive.
 - Z is defined as the cross product of Y and X
 
-The origin of the kite reference frame can be defined by the user by calling the function `init_kp(origin::MVec3)` where the origin must be defined in the `CAD` reference frame.
+The origin of the kite reference frame can be defined by the user by calling the function `init_kb(origin::MVec3)` where the origin must be defined in the `CAD` reference frame.
 
 This reference frame is different from the kite reference frame **K** used in `KiteModels.jl` and `KiteUtils.jl`.
 
 ## The turn rates
-The turn rates $\mathrm{omega} = [\mathrm{omega_x}, \mathrm{omega_y} ,\mathrm{omega_z}]$ are defined in the **KP** reference frame. The unit of the components is $\mathrm{rad}~\mathrm{s^{-1}}$.
+The turn rates $\mathrm{omega} = [\mathrm{omega_x}, \mathrm{omega_y} ,\mathrm{omega_z}]$ are defined in the **KB** reference frame. The unit of the components is $\mathrm{rad}~\mathrm{s^{-1}}$.
 
 ## Input and output
 - when running a simulation, the turnrate of the kite must be provided on each time step
-- the apparent wind speed vector `v_a` is defined in the **KP** reference frame
-- the resulting forces are defined in the **KP** reference frame
-- the **CL**, **CD**, **CS** and the resulting moments and moment coefficients are defined in the **KP** reference frame
+- the apparent wind speed vector `v_a` is defined in the **KB** reference frame
+- the resulting forces are defined in the **KB** reference frame
+- the **CL**, **CD**, **CS** and the resulting moments and moment coefficients are defined in the **KB** reference frame