The two rate gyros are mounted on the inner gimbal to measure the rotation angle rate of the inner gimbal relative to the inertial space. The measured value is equal to the true LOS angle rate and can be used to guide the missile.

Any movement of the platform in inertial space will be sensed by the inertial devices.

Cahill which reported an effect that is consistent with the absolute motion of the earth through

inertial space. Our conclusions are:

A rigorous analysis of the use of

inertial space references for navigation purposes completed by the Instrumentation Laboratory in February 1947, pointed to the gyroscope, rather than the accelerometer as the key sensor.

It is the ideal inertial coordinate frame; at the starting time for the initial alignment, i frame coincides with e frame and is fixed in the inertial space.

At the starting time for the initial alignment, [i.sub.b0] frame coincides with b frame and is fixed in the inertial space.

Like SR, GR still requires the existence of a quasi-Newtonian

inertial space to account for the "absolute" nature of inertia and rotation.

F represents the skew symmetric matrix of forces, [epsilon] represents the misalignment error state vector, [SIGMA] represents the skew symmetric matrix of the Earth rotation rate relative to

inertial space, N represents the tensor of the gravitational gradients and R represents the rotation matrix.

The stable member is held fixed in

inertial space at an attitude initialized by the fire control system during a pre-launch sequence.

The freely falling mirror was isolated by being in

inertial space; the long-period isolator served to also locate the reference mirror in

inertial space.

In space missions, what really matters is the relative dynamics of spacecraft with respect to the reference body, rather than the absolute dynamics of spacecraft in the

inertial space. The 6-DOF relative dynamics of spacecraft, which will be written in a similar form with the absolute dynamics, can be obtained based on the results in Sections 2.1 and 2.2.

The position of the body-axes reference frame of the platform O XYZ in the

inertial space relative to the initial reference frame O [X.sub.A] [Y.sub.A] [Z.sub.A] is defined by means of the sequence of rotations on angles [psi], [??], [gamma] as it is shown in Figure 1.