Keywords:
positioning system,personal system,hybrid positioning,accelerometer,gyrometer
Abstract
Recently,many researches are being conducted on the personal or hand-held positioning
technologies using GPS.However,GPS can ’ t work correctly at the location
where the su . cient signal from the GPS satellites can not be received,for
example,in the valley between buildings,underground shopping malls.It is strongly
demanded to develop a complementary positioning system which can work in the
areas where GPS is not available.In this paper,we report the progress of a
personal hybrid positioning system which consists ofa pocket-size accelerometer,
gyrocompass and a wearable PC.Through several basic experiments,it can be
concluded that the positioning system has possibility ofproviding positional information
with high accuracy as a complementary system ofGPS even in the areas
where GPS signal is not available.
1 Introduction
To monitor and control the movement of
goods and people,it is neccesary to obtain
information about one ’ s position on the real
time-basis.Recently,many researches are
being conducted on the personal or hand-
held positioning technologies using GPS.It
is expected that these positioning technologies will be applied to managing and
controlling logistics,securing safety of socially
weak people,and so forth.
However,GPS accuracy and reliability is
limited in the area where the su . cient signal
from the GPS satellites can not be received,
for example,in the valley between buildings,
underground shopping malls.It is necessary
to develop the positioning system which can
complement GPS in ” high density ” urban
areas.
In the case of car navigation,a complementary
positioning system was already developed and reached practicable level.It is
realized by counting number of wheel rotations,sensing steering angles,and
matching positioning trajectory to map.On the
other hand,there is no effective complementary
positioning system for human under the
present circumstances,although the development is strongly demanded.
In this paper,we report the progress of
a personal hybrid positioning system which
consists of a pocket-size accelerometer,gyrocompass and a wearable PC.
2 System
This system consists of a pocket-size
accelerometer,gyrocompass (Japan Aviation Electronics,JIMS-30S )and a wearable
PC(SII,Ruputer Pro ),as illustrated in
Figure 1.
Figure 1:Personal Hybrid Positioning System
Both the pocket-size accelerometer and
gyrocompass are in a cube whose side is
about 3 centimeters,and the cube is fixed to
the lower back of user.Signals from these
sensors are transmitted through the cable
and changed to physical values by the Processor Unit.The Processor Unit is fixed to
the waist of user by waist pouch.The Processor Unit and the wearable PC like a wrist
watch are also connected by the cable and,
the wearable PC is used for computation
and indication of the positional information.
3 Theory
Viewpoint of this paper is in the motion
of walking human ’ s pelvis.
At first,by using this positioning system,
we measured the motion of pelvis when user
walks 6 meters in 10 steps.The time-series
data of rotation angles around each axes
mesured by the gyrometer are illustrated in
Figure 2. The axes are defined in Figure 1.
And,we measured the motion of pelvis when
user walks along a rectangular course.The
time-series data of yaw angle is illustrated
in Figure 3.
Figure 2:The motion of walking human ’ s
pelvis measured by the gyrometer
Figure 3: The time-series data of yaw angle
when user walks along a rectangular course
The experimental data illustrated in Figure 2 and Figure 3 shows that number of
steps is computed by the time-series data of
pitch angle and direction of walking is computed by the time-series data of yaw angle.
