<s>
gpsd	B-Language
is	O
a	O
computer	O
software	O
program	O
that	O
collects	O
data	O
from	O
a	O
Global	O
Positioning	O
System	O
(	O
GPS	O
)	O
receiver	O
and	O
provides	O
the	O
data	O
via	O
an	O
Internet	B-Protocol
Protocol	I-Protocol
(	O
IP	O
)	O
network	O
to	O
potentially	O
multiple	O
client	O
applications	O
in	O
a	O
server-client	B-Operating_System
application	O
architecture	O
.	O
</s>
<s>
Gpsd	B-Language
may	O
be	O
run	O
as	O
a	O
daemon	B-Operating_System
to	O
operate	O
transparently	O
as	O
a	O
background	O
task	O
of	O
the	O
server	O
.	O
</s>
<s>
The	O
network	O
interface	B-Application
provides	O
a	O
standardized	O
data	O
format	O
for	O
multiple	O
concurrent	O
client	O
applications	O
,	O
such	O
as	O
Kismet	B-Protocol
or	O
GPS	B-Application
navigation	I-Application
software	I-Application
.	O
</s>
<s>
Gpsd	B-Language
is	O
commonly	O
used	O
on	O
Unix-like	B-Operating_System
operating	I-Operating_System
systems	I-Operating_System
.	O
</s>
<s>
It	O
is	O
distributed	O
as	O
free	B-Application
software	I-Application
under	O
the	O
3-clause	O
BSD	B-Operating_System
license	I-Operating_System
.	O
</s>
<s>
gpsd	B-Language
provides	O
a	O
TCP/IP	B-Protocol
service	O
by	O
binding	O
to	O
port	O
2947	O
by	O
default	O
.	O
</s>
<s>
These	O
commands	O
use	O
a	O
JSON-based	O
syntax	O
and	O
provide	O
JSON	B-General_Concept
responses	O
.	O
</s>
<s>
The	O
application	O
supports	O
many	O
types	O
of	O
GPS	O
receivers	O
with	O
connections	O
via	O
serial	B-Protocol
ports	I-Protocol
,	O
USB	B-Protocol
,	O
and	O
Bluetooth	B-Protocol
.	O
</s>
<s>
Starting	O
in	O
2009	O
,	O
gpsd	B-Language
also	O
supports	O
AIS	O
receivers	O
.	O
</s>
<s>
gpsd	B-Language
supports	O
interfacing	O
with	O
the	O
Network	B-Protocol
Time	I-Protocol
Protocol	I-Protocol
(	O
NTP	O
)	O
server	O
ntpd	B-Protocol
via	O
shared	B-Operating_System
memory	I-Operating_System
to	O
enable	O
setting	O
the	O
host	O
platform	O
's	O
time	O
via	O
the	O
GPS	O
clock	O
.	O
</s>
<s>
gpsd	B-Language
was	O
originally	O
written	O
by	O
Remco	O
Treffkorn	O
with	O
Derrick	O
Brashear	O
,	O
then	O
maintained	O
by	O
Russell	O
Nelson	O
.	O
</s>
