NMEA out to transponder.

[Admin]

I have a Trig TT21 and include below the section from the Installation Manual which details the requirements for GPS input. It looks as though it can accept a number of different protocols but the NATS Non Certified GPS Trial information document states the following requirements for the GPS:

"As a minimum, any GPS that outputs
NMEA 0183 sentences over an RS-232
link."

It looks as though using the NMEA protocol sets the required SIL and SDA values for the trial on many transponders.

Mike

*****Extract from Trigg TT21/TT22 Installation Manual*****
5.6.9 GPS Position Input
The GPS position input is required to support ADS-B functionality. The GPS
position input is an RS232 input to the transponder. The ADS-B features are
optional – no GPS is required for normal Mode S Elementary Surveillance.
The TT21/TT22 GPS input can recognise the following protocols:
    Industry standard “Aviation” protocol
 NMEA 0183 protocol
 Freeflight and Accord NexNav GPS proprietary protocols
 Garmin ADS-B protocol, including ADS-B plus
 Trig ADS-B protocol
 C199 TABS compliant GPS using NMEA protocol
The interface speed can be selected between 4800, 9600, 19200 and 38400
bps.

Hi Mike,

Can you try and find out which NMEA messages it is looking for ?
I am trying to keep the data to a minimum to not overload the transponders

Thx
Lee

[Admin]

Basically you will need an RS232 input into your transponder, ideally 9 pin female connector.
If you don't have this you'll need to do some research and buy or build an appropriate cable based on your transponder. (If you have an EASA aircraft I seriously doubt you can legally do any of this! Permit aircraft can but see the link on the previous post for the mod form - which has to be signed off by your inspector).

Then one of these:

     http://www.ebay.co.uk/itm/271928707196?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

     (be careful to get the right type - thanks Lee for the pointer to this one)

to connect the PAW to it.

Then configure the transponder for NMEA format messages over RS232 (at 4800 baud).
Then configure the PAW USB port setup for the port you plug it into as "Transponder" type (available in forthcoming PAW software) and 4800 baud.

Probably silly questions, but does the  USB - RS232 Dsub cable need the PL2303 chip set as stated in PAW construction manual? Will the drivers need to be loaded into the Pi, or will this be taken care of by Lee in his update?

Thx

Interestingly this item does not use pl2303, it has some kind of clone. Luckily it is recognised by the OS drivers and works correctly 
Thx
Lee

[Admin]

Hi Lee,

Another question for you.

If the PAW is outputting NMEA to the mode S, can it be arranged so that it does this without a tablet being connected via the Wi-Fi interface? The PAW will be obtaining GPS signals from a ublox plugged directly into the Pi. Some others in our group, use Garmin 496's that currently won't interface with PAW. It would be nice if we could still transmit ADSB out under these circumstances.

Thx.

This should be easy to implement, it possibly works like this today to be honest
Thx
Lee

[Richard]

I have a Trig TT21 and include below the section from the Installation Manual which details the requirements for GPS input. It looks as though it can accept a number of different protocols but the NATS Non Certified GPS Trial information document states the following requirements for the GPS:

"As a minimum, any GPS that outputs
NMEA 0183 sentences over an RS-232
link."

It looks as though using the NMEA protocol sets the required SIL and SDA values for the trial on many transponders.

Mike

*****Extract from Trigg TT21/TT22 Installation Manual*****
5.6.9 GPS Position Input
The GPS position input is required to support ADS-B functionality. The GPS
position input is an RS232 input to the transponder. The ADS-B features are
optional – no GPS is required for normal Mode S Elementary Surveillance.
The TT21/TT22 GPS input can recognise the following protocols:
    Industry standard “Aviation” protocol
 NMEA 0183 protocol
 Freeflight and Accord NexNav GPS proprietary protocols
 Garmin ADS-B protocol, including ADS-B plus
 Trig ADS-B protocol
 C199 TABS compliant GPS using NMEA protocol
The interface speed can be selected between 4800, 9600, 19200 and 38400
bps.

Hi Mike,

Can you try and find out which NMEA messages it is looking for ?
I am trying to keep the data to a minimum to not overload the transponders

Thx
Lee

Lee,
  I've just been looking for the info required there is nothing in the Trig Manuals but I did find this from a Q&A Sheet

"Q: Can the Trig transponders receive NMEA GPS data from any GPS receiver?
A: Yes, you can connect any NMEA GPS position source to a Trig transponder, and with the correct configuration the
transponder will broadcast ADS-B position squitters. However there are limitations with the NMEA data. The NMEA
messages do not include Receiver Autonomous Integrity Monitoring (RAIM) information, which means that the position
transmitted by the Trig transponder will be indentified as "low quality" on most traffic information systems. Please note
that this type of NMEA GPS/transponder configuration will not meet forthcoming FAA ADS-B requirements, but in the end
it will be rather beneficial for use in flight tracking and traffic avoidance."

http://www.sea-aviation-parts.com/documents/SEA_TRIG_FAQ.pdf

It may be no use.... But it says "Any NMEA will provide"

[Admin]

Lee,
  I've just been looking for the info required there is nothing in the Trig Manuals but I did find this from a Q&A Sheet

"Q: Can the Trig transponders receive NMEA GPS data from any GPS receiver?
A: Yes, you can connect any NMEA GPS position source to a Trig transponder, and with the correct configuration the
transponder will broadcast ADS-B position squitters. However there are limitations with the NMEA data. The NMEA
messages do not include Receiver Autonomous Integrity Monitoring (RAIM) information, which means that the position
transmitted by the Trig transponder will be indentified as "low quality" on most traffic information systems. Please note
that this type of NMEA GPS/transponder configuration will not meet forthcoming FAA ADS-B requirements, but in the end
it will be rather beneficial for use in flight tracking and traffic avoidance."

http://www.sea-aviation-parts.com/documents/SEA_TRIG_FAQ.pdf

It may be no use.... But it says "Any NMEA will provide"

Hi Richard

What I really need to know are the 'minimum required', some are interchangeable and overlapping, eg GPGGA/GPRMC
I have contacted Trig directly, hopefully they will provide the required information

Thx
Lee

[Mike P]

Sorry Lee, I have been out all day and only just seen your question. I am afraid that I have to agree with Richard re lack of any info in the manual so can't help. Hopefully Trig will provide you with the answer.
Mike

[AlanB]

I have a trig tt21 connected to a GPS, AVMap EKP V and have the following selected going to the Autopilot and Transponder

APA
APB
RMB
RMC

The manual describes

RMC Time, Latitude, Longitude, Speed Over Ground, Course Over Ground and date.

Which is what I suspect the trig needs.

[Pete]

Hi Lee.

How about a TRIG TT31

From the Installation Manual

The GPS position input is an RS232 input to the transponder.
" The TT31 GPS input can recognise either the industry standard "Aviation" format or the NMEA 0183 format, the interface speed can be selected between 4800, 9600 and 19200 bps"

Hopefully the PA can accommodate the above requirement?.

Regards
Pete

[Admin]

Hi Pete

Just waiting to hear back from trig regarding required sentences
Currently generating

RMC
GGA
VTG

Thx
Lee

[Pete]

Thnx Lee

[Richard]

I have a trig tt21 connected to a GPS, AVMap EKP V and have the following selected going to the Autopilot and Transponder

APA
APB
RMB
RMC

The manual describes

RMC Time, Latitude, Longitude, Speed Over Ground, Course Over Ground and date.

Which is what I suspect the trig needs.

The GPS supplying to my Trig TT21 is supplied by an Evermore 320 producing GGA, GLL, GSA, GSV, RMC, and VTG

The Dynon D100 Uses ....."To use the GPS-related features on your EFIS and/or EMS,
your GPS must output either “aviation format” or the
following NMEA sentences in its serial stream: $GPRMC,
$GPRMB, $GPGGA, and one of $GPBOD or $GPAPB."

This is also runing my Dynon D100..$GPRMC....  all works OK So can it be found by elimination? Its looking like you are correct and RMC would be good to go...

[Admin]

Hi Richard,

GPRMB, provides a navigation sentence, I think we can omit that, I cannot see how a GPS source can provide this anyway.

GPBOD, Bearing - origin to destination, again this should not be required for positional information.

GPAPB, Autopilot format B.

The above do not seem related to a GPS source, but hopefully Trig can comment.

Thx
Lee

[Admin]

Many thanks to james Forbes at Trig.
So it appears that the Trig transponders only require GPRMC sentences, therefore these should work with the existing set of transponder output sentences supported by PAW

Thx
Lee

[bnmont]

Went to the airfield this afternoon, connected PAW to my TRT800 transponder.
Working well on the ground, SD on second PAW in carpark displaying plane reg as soon as transponder put out of standby mode.
Check flights,inspection etc to be done!

Thanks 

[Admin]

Went to the airfield this afternoon, connected PAW to my TRT800 transponder.
Working well on the ground, SD on second PAW in carpark displaying plane reg as soon as transponder put out of standby mode.
Check flights,inspection etc to be done!

Thanks 

thats great news!