Specifications

7.
GPS
Operation
Overview
This
chapter describes how
to configure and
connect
your
TNC
for GPS operation.
Why
do GPS in
the
PK-96?
All
Timewave TNCs
can run
with
Automatic
Packet
Reporting
System
(APR5rv;
software.
The PK-96,
however, has
special firmware which
makes Stand Alone Tracking
and Ultimeter II@ compatibility
pos-
sible. Timewave
also offers
an APRS Adapter
Cable
for the PK-96 which
makes Hardware Singlc Port
Mode
(HSP)
operation
possible.
The PK-96 contains
special GPS features
not
found in
other
packet
Terminal Node
Controllers.
The PK-96
can detect whether
or not a GPS receiver is
connected
with
the GPSAuto command, it then chooses the
appropriate
GPSMode
of operation. If a GPS receiver is detected
upon
power-up,
the PK-96 automatically
sends
a GPS initialization
string.
The
PK-96 can be remotely
polled
by addressing a
packet
to
its
GPOLLCaII,
or by the
polling
features in
APRS.
The
PK-96's GPS commands can be remotely
pro-
grammed
using the GREMprog command which
is very convenient in Stand Alone Tracking
applica-
tions-the
unit never needs
to be taken out of the vehicle to change
GPS settings. GPS
receivers
can be re-
motely
programmed
via
the
PK-96.
The PK-96's internal
time and date can be set from the information
obtained from
the GPS receiver. There
are
provisions
for an extemal input
to cause the sending of
NMEA
strings, such
as
from
a radio control head
button.
The PK-96
can even operate
packet
and GPS at the same
time using the
commercial mode. See the You're in Command
chaper, G section
for
GPS
commands.
What is
APRS?
I nil6s
43 30.AAn
L2 A2.34U
FIGURE 1:APRS computerized
map
plete,
however, there
are tracking features built into APRS which allow
you
to create maps
just
by driving
down the streets of
your
town.
Amateur
operators all over the country are creating
maps which can be
downloaded frorn
on-line systems for use by all. Stations can appear on the maps and each
station may tle
given
a symbol such as a house, car, or
boat.
The real
benefit of using
APRS software is in mobile tracking
applications. Vehicles
and
people
can be tracked and mapped using APRS. APRS also
includes the ability
to send short messages
and bulletins. Using Ultimeter II
weather
information can also be
shown on the
computerized
maps.
Timewave
has included
a copy of
APRS
in
your
PK-96
packaging
so
you
can experi-
ment
with it. Automatic Packet Reporting
System
(APRSrv;
is
a
copyrighted software
program
developed by Bob Bruninga
(WB4APR),
which is
distributed as
shareware for real-time
Packet communica-
tions.
The software keeps lists
of stations
heard and displays
the locations of stations
visually
on a computerized map like
the one
in
Figure l. The maps
can be scaled
from
.5
to 2000 miles.
Few of the maps are com-