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4 Navigations from Ground to Space
Fig. 4.2 A diagram of simple gyroscope structure
according to the different geometric positions of the gyroscope center of gravity, they
are divided into balance gyroscope and gravity gyroscope; according to the different
supporting ways, they are divided into frame gyroscope, liquid floating gyroscope,
gas floating gyroscope, electrostatic gyroscope and flexible gyroscope; according to
the different principles of gyroscope effects, they are divided into rotor gyroscope,
vibratory gyroscope, laser gyroscope, fiber optic gyroscope and atomic gyroscope.
The accelerometer is a device for measuring linear proper acceleration of the
movable object, consisting of sensitive mass, support, potentiometer, spring and
shell (as shown in Fig. 4.3), where the sensitive mass is constrained by the support
to move along only one axis (also known as input axis). The proper acceleration
refers to the acceleration of the movable object in its own instantaneous rest frame,
which is not as same as coordinate acceleration. In the terms of the Newton’s laws of
motion, when the device’s shell is accelerated along the input axis with the movable
object, the sensitive mass with certain inertia tries to keep its original motion state
unchanged, and thus there will be relative motion between the sensitive mass and
the shell, so that the spring will deform. Under the action of the spring force, the
sensitive mass is accelerated to move. As the spring force is balanced with the inertial
force each other, there is no longer relative motion between the sensitive mass and
the shell. At the moment, the deformation of the spring represents the magnitude of
the measured acceleration, and the acceleration is converted into an electrical signal
output by the potentiometer.
In the INS, the spinning axis of the gyroscope rotor, the axis of the inner ring
support and the axis of the outer ring support form a mutually orthogonal coordinate
system; the heading and attitude angles of the movable object are measured with the
4 Navigations from Ground to Space
Fig. 4.2 A diagram of simple gyroscope structure
according to the different geometric positions of the gyroscope center of gravity, they
are divided into balance gyroscope and gravity gyroscope; according to the different
supporting ways, they are divided into frame gyroscope, liquid floating gyroscope,
gas floating gyroscope, electrostatic gyroscope and flexible gyroscope; according to
the different principles of gyroscope effects, they are divided into rotor gyroscope,
vibratory gyroscope, laser gyroscope, fiber optic gyroscope and atomic gyroscope.
The accelerometer is a device for measuring linear proper acceleration of the
movable object, consisting of sensitive mass, support, potentiometer, spring and
shell (as shown in Fig. 4.3), where the sensitive mass is constrained by the support
to move along only one axis (also known as input axis). The proper acceleration
refers to the acceleration of the movable object in its own instantaneous rest frame,
which is not as same as coordinate acceleration. In the terms of the Newton’s laws of
motion, when the device’s shell is accelerated along the input axis with the movable
object, the sensitive mass with certain inertia tries to keep its original motion state
unchanged, and thus there will be relative motion between the sensitive mass and
the shell, so that the spring will deform. Under the action of the spring force, the
sensitive mass is accelerated to move. As the spring force is balanced with the inertial
force each other, there is no longer relative motion between the sensitive mass and
the shell. At the moment, the deformation of the spring represents the magnitude of
the measured acceleration, and the acceleration is converted into an electrical signal
output by the potentiometer.
In the INS, the spinning axis of the gyroscope rotor, the axis of the inner ring
support and the axis of the outer ring support form a mutually orthogonal coordinate
system; the heading and attitude angles of the movable object are measured with the