WESCAM System is a gyrostabilized aerial filming platform.
It appears like a swivelling "ball" attached
to the helicopter with a "window" through
which the camera can film. The television and production
companies, movie industry, police and military forces
are the main users for this kind of equipment.
a gyrostabilized platform ?
who already has operated a camcorder knows that when
you zoom in a subject, the image become unstable due
to the operator's arm and hand instability and shaking.
Imagine now a helicopter that can be considered as a
good vibration generator and from which you have to
zoom in the number of a Tour de France racing cyclist
or the license plate of a moving vehicle on a highway.
Such requirements are impossible to meet without a stabilization
device for the camera. Several camera stabilization
systems have been designed in order to be installed
first category could list all camera mounts such as
those produced by Tyler
for instance. A major disadvantage of those systems
is certainly that the camera itself is exposed to the
elements as beeing installed outside the helicopter
or on a side mount for the best. In the case of this
last installation option, the azimuth range is often
very limited. But, outside installed systems can nevertheless
work as multi-camera in order to shoot 180° or even
360° panoramic movies.
The second category is made of all gyrostabilized "ball"
systems. Canadian Wescam company has forged its name
as a specialist in this kind of systems, but it is not
does a gyrostabilized platform work ?
its name let it think, a gyrostabilized platform is
based on a gyroscopic system. A gyroscope has the property
to hold its revolution plane once turning at high speed
no matter of the external perturbations whether the
revolution plane can freely move around the two other
axles. There are two stabilization systems :
first-one is a support on which the whole camera and
gyroscopic system is suspended by means of a flexible
link. If the support, which is mechanically and directly
connected to the helicopter, vibrates, the camera-gyroscopes
assembly remains stable due to the gyroscopes' physical
second-one is based on an active correction of the vibrations
in phase opposition. The gyroscopic system allows to
evaluate amplitude and frequency of vibrations and that
information is computed in real time by the electronic
of the system that act on the active suspension device.