<s>
LibrePilot	B-Application
is	O
a	O
Free	B-Application
software	I-Application
unmanned	O
aerial	O
vehicle	O
project	O
for	O
model	O
aircraft	O
aimed	O
at	O
supporting	O
both	O
multi-rotor	O
craft	O
as	O
well	O
as	O
fixed-wing	O
aircraft	O
.	O
</s>
<s>
In	O
July	O
2015	O
OpenPilot	O
,	O
was	O
forked	O
to	O
create	O
LibrePilot	B-Application
.	O
</s>
<s>
The	O
OpenPilot	O
software	O
is	O
released	O
under	O
the	O
GPL	B-License
version	O
3	O
license	O
.	O
</s>
<s>
The	O
firmware	O
part	O
of	O
the	O
project	O
is	O
written	O
in	O
C	B-Language
whilst	O
the	O
ground	O
control	O
station	O
is	O
written	O
in	O
C++	B-Language
utilizing	O
Qt	B-Language
.	O
</s>
<s>
The	O
current	O
on-board	O
hardware	O
is	O
based	O
on	O
the	O
STM32	O
microcontroller	B-Architecture
.	O
</s>
<s>
There	O
are	O
two	O
physical	O
boards	O
that	O
are	O
part	O
of	O
the	O
hardware	O
,	O
the	O
first	O
is	O
the	O
main	O
OpenPilot	O
board	O
which	O
contains	O
the	O
core	O
microcontroller	B-Architecture
,	O
SD	B-Device
socket	O
,	O
barometer	O
plus	O
servo	O
connectors	O
and	O
second	O
,	O
the	O
AHRS	B-Device
board	O
which	O
contains	O
the	O
sensor	O
hardware	O
.	O
</s>
<s>
In	O
other	O
words	O
,	O
the	O
hardware	O
consists	O
of	O
two	O
boards	O
:	O
the	O
microcontroller	B-Architecture
board	O
(	O
the	O
core	O
)	O
and	O
the	O
sensors	O
board	O
(	O
the	O
AHRS	B-Device
)	O
.	O
</s>
<s>
The	O
OpenPilot	O
AHRS	B-Device
was	O
a	O
9DOF	O
unit	O
and	O
contains	O
MEMS	B-Architecture
gyroscopes	B-Application
,	O
accelerometers	O
and	O
a	O
3	O
direction	O
magnetometer	O
.	O
</s>
<s>
Combined	O
with	O
the	O
sensors	O
,	O
the	O
OpenPilot	O
AHRS	B-Device
contains	O
its	O
own	O
Cortex	O
M3	O
microcontroller	B-Architecture
which	O
runs	O
a	O
Kálmán	O
filter	O
.	O
</s>
<s>
Filtered	O
orientation	O
data	O
and	O
inertial	O
measurements	O
are	O
presented	O
back	O
to	O
the	O
main	O
OpenPilot	O
board	O
using	O
an	O
SPI	B-Architecture
interface	I-Architecture
.	O
</s>
<s>
The	O
OpenPilot	O
AHRS	B-Device
contained	O
the	O
following	O
components	O
:	O
</s>
