FASTRAK MANUAL
Rev. G
D-2
JUNE 2012
Figure D-1 Position and Orientation Measurements System Block Diagram
, each loop of the transmitter antenna is in turn excited
with a driving signal identical in frequency and phase. Each excitation produces a single axis
transmitter dipole. The transmitter excitation is a pattern of three states. Exciting the transmitter
results in an output at the receiver of a set of three linearly independent vectors. The three output
(receiver) vectors contain sufficient information to determine the position and orientation of the
receiver relative to the transmitter. Essentially nine measurements are available to solve for the
six unknowns of x,y,z for position and azimuth (yaw), elevation (pitch), and roll for orientation.
DEFINITIONS
For resolution and accuracy considerations, the electromagnetic instruments are treated as
“black boxes” thereby focusing on the performance of the instruments and negating the process
of solution from the definitions.
A key element for determining resolution and accuracy from a “black box” point of view
is the system’s signal-to-noise (S/N) ratio. First, consider the black box system shown in
. The Magnetic Linkage is the magnetic field or B field which is a vector quantity derived
from the vector sum of the radial and tangential field components for a magnetic dipole. It
contains both the magnetic moment vector
m
and the inverse cube of the range factors given by
the quantity
r
K/
3
.