Javad JNSGyro-4T, Operator'S Manual

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3-2 JNSGyro-4T Operator’s Manual www.javad.com
S E T U P A N D M E A S U R I N G
How to Work with JNSGyro-4T
3
How to Work with JNSGyro-4T
Although the attitude system JNSGyro-4T can be used to perform any types of
receiver’s measuring, the attitude mode is its primary purpose. A brief
description of the attitude determination is given below.
Geometry and Coordinate Transformations
The body reference frame is related to the vehicle body. Its axes are called
Nose , Right , and Belly (Figure 3-1).
Figure 3-1. Body reference frame
The inertial reference frame - the local horizon frame - is shown in
Figure 3-2. Its axes are called
North , East , and Down .
Figure 3-2. Local horizon frame
The attitude angles describe orientation of the body frame with respect to
the local horizon and are defined as follows.
Suppose that the two frames are aligned. First, the body frame is rotated in a
positive direction about the
Belly axis by the heading angle
ψ
. Then, the
body frame is rotated in a positive direction about the new Right axis by the
pitch angle
θ
. Finally, the body frame is rotated in a positive direction about