nmea - talkers - listeners and lessons learned.
 

On Jul 19, 10:38*am, Josh Assing wrote:
The SR161 can be used to consolidate incoming NMEA positional data from a
GPS with the AIS NMEA data into a combined high-speed data stream on a
single serial port.

In that scenario there is no need for any multiplexer.

but how does it talk to other non-high speed nmea devices then?

Basically you can take any inbound NMEA data stream or combined
datastreams at 4800 and the SR161 will combine that data with the AIS
data and output the combine original and AIS data streams on a single
outbound port. It is only for inbound data. You can't have two way
communication to the original NMEA devices - just an inbound feed to
the AIS receiver from the NMEA data stream.

nmea - talkers - listeners and lessons learned.
 

On Jul 20, 8:59*am, Doug Miller wrote:
...
GPS does affect AIS perfofrmance but of course you'll need a GPS for
your nav package in order to calculate collision information (e.g.
distance from you, closest point of approach and time to closest point
of approach).

Thanks for that. Just to be clear, I have GPSes on my system and the
computer that will run my AIS software already has GPS positioning
data. What I think you are saying is that I should route one of the
GPSes through the SR161 when I install it to make the 161 work
better. Is that right?

Cheers,

-- Tom.

nmea - talkers - listeners and lessons learned.
 

On Sun, 20 Jul 2008 09:02:35 -0700 (PDT), Doug Miller
wrote:

On Jul 19, 10:38*am, Josh Assing wrote:
The SR161 can be used to consolidate incoming NMEA positional data from a
GPS with the AIS NMEA data into a combined high-speed data stream on a
single serial port.

In that scenario there is no need for any multiplexer.

but how does it talk to other non-high speed nmea devices then?

Basically you can take any inbound NMEA data stream or combined
datastreams at 4800 and the SR161 will combine that data with the AIS
data and output the combine original and AIS data streams on a single
outbound port. It is only for inbound data. You can't have two way
communication to the original NMEA devices - just an inbound feed to
the AIS receiver from the NMEA data stream.


I found that neither of my navigation programs (Ozi Explorer and Tiki
Navigator) could handle the combined NMEA/AIS signal from the SR161 -
or more correctly, they couldn't be set to accept both NMEA and AIS on
the same serial port. I understand that some other nav programs will
accept the combined data.


--
Peter Bennett, VE7CEI
peterbb4 (at) interchange.ubc.ca
GPS and NMEA info: http://vancouver-webpages.com/peter
Vancouver Power Squadron: http://vancouver.powersquadron.ca

nmea - talkers - listeners and lessons learned.
 

On Jul 20, 5:03*pm, Peter Bennett wrote:
On Sun, 20 Jul 2008 09:02:35 -0700 (PDT), Doug Miller



wrote:
On Jul 19, 10:38*am, Josh Assing wrote:
The SR161 can be used to consolidate incomingNMEApositional data from a
GPS with the AISNMEAdata into a combined high-speed data stream on a
single serial port.

In that scenario there is no need for any multiplexer.

but how does it talk to other non-high speednmeadevices then?

Basically you can take any inboundNMEAdata stream or combined
datastreams at 4800 and the SR161 will combine that data with the AIS
data and output the combine original and AIS data streams on a single
outbound port. It is only for inbound data. You can't have two way
communication to the originalNMEAdevices - just an inbound feed to
the AIS receiver from theNMEAdata stream.

I found that neither of my navigation programs (Ozi Explorer and Tiki
Navigator) could handle the combinedNMEA/AIS signal from the SR161 -
or more correctly, they couldn't be set to accept bothNMEAand AIS on
the same serial port. *I understand that some other nav programs will
accept the combined data.

--
Peter Bennett, VE7CEI *
peterbb4 (at) interchange.ubc.ca *
GPS andNMEAinfo:http://vancouver-webpages.com/peter
Vancouver Power Squadron:http://vancouver.powersquadron.ca

One solution I have recommended to folks with this issue that works
quite well is to use something like GPSGate (http://www.gpsgate.com/
index.php?id=13) to take the input from a real serial port and
duplicate it onto two virtual serial ports. Then connect each of the
virtual serial ports to your nav software. For example, I believe you
need to do this with MaxSea.
Also would be a good idea to give feedback to the nav program authors
that they should support multiple data streams on one port since this
issue will also come up if you use a multiplexer to consolidate NMEA
data streams.

Doug Miller