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Recalling the discussion on planet spacing, the OH-58C was shown to have unequal spacing. In particular, it has an X shape, so that a given planet is closer to one of its immedi-ate neighbors. Because of this, the data extraction locations are dependent on which planet reaches the accelerometer of interest .rst. The sequence order is given in Table 1.
Case Angle Sequence
π 95π
P1 or P3 reach target accelerometer .rst [0 32π
63 63]
π 94π
P2 or P4 reach target accelerometer .rst [0 31π
63 63]
Table 1. Planet Arrival Sequence

Determining the extraction index, Ni j .
For a given initial planet angle, θiP, for planet Pi and ac-celerometer angle, θAj , for accelerometer Aj, the initial car-rier angle separating the two is given by:
θij
= mod(θAj . θiP,2π), (11)
sep

where
 
x . .oor(x/y) · y if y= x
mod(x,y)=(12)
x if y = x

where .oor means to ”round down to the next integer”. This is done to ensure that the counter clockwise angle is used for θij
sep which corresponds to the rotating direction of the carrier. Since the carrier cycle is interpolated to N
ˉequally spaced points, each spacing represents Δθc = 2π
Nˉ.1.

Therefore the closest index point corresponding to when Pi is aligned with Aj is given by:
N. = round(θij Δθc) (13)
ij sep ·

The round function is to ensure the value used is the closest integer value. It is felt that this approximation has a mini-mal effect on the results since it is within a single angular sampling. In addition, all extraction points are based on the same integer value.
Table 2 gives the values for the current setup.
A1  A2  A3  A4  A5 
P1  298.7  313.7  350.7  159.7  170.7 
P2  30.1  45.2  82.2  251.2  262.2 
　
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