PilotAware
British Forum => General Discussion => Topic started by: bnmont on October 30, 2015, 05:35:16 pm
-
I am using the ublox external gps on my PAW unit.
Can I get nmea out to feed my transponder? (adsb Trial)
If so how?
Thanks Brian
-
I am using the ublox external gps on my PAW unit.
Can I get nmea out to feed my transponder? (adsb Trial)
If so how?
Thanks Brian
Hi Brian,
I Provided Ian Fallon with an early release of this feature, and I am pretty happy with the results (Ian please comment). At the moment I am only producing $GPRMC messages, which is the requirement for the TRT-800.
Do you know what messages your transponder wants to receive ?
I am guessing it is probably the same, but we should probably get a straw poll of what transponders need which $GPxxx messages.
If it appears that different transponders need a different mix of messages, I will need to make this configurable, so any input you can provide would be helpful.
I will try and get a release out this weekend with this feature included, how does that sound ?
Thx
Lee
-
I haven't been through the LAA mod (14) process yet so of course I haven't turned it on and tested it, but ... I think we can be quietly confident it works let's put it that way.
See here for the LAA paperwork:
http://www.lightaircraftassociation.co.uk/engineering/StandardForms/LAA-MOD-14%20-%20ADS-B.pdf
-
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.
-
Yes - regarding USB/RS232, there are 2 types RS232 and RS232-TTL
do not get the TTL version the logic levels are inverted and not the correct voltage
one other note, the TRT-800 only takes 4800 baud for NMEA, other types may accept different baud rates.
At present you can select 4800/9600/57600
This should cover the wide majority
Thx
Lee
-
I have a TRT800H so should be good?
Thanks
-
I have a TRT800H so should be good?
Thanks
You have a PM !
-
Hi Lee,
Can you please add the following to suit Becker BXP 6401-2;
EIA-232C or EIA-422 interface with serial asynchronous transmission parameters: 4800, n,8,1 and TX data with NMEA-0183 protocol GGA and VTG sentences.
Many thanks
-
Just put together a Pilot Aware unit and am watching the inbounds to LGW as they overfly my home.Brilliant !
Would also like to connect to my Mode S Transponder when I get the PAW sorted for the aircraft.
Funkwerk TRT800H
from the manual .... NMEA-Format, data format RMC is
expected. 4800 Baud rate
-
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.
-
Yes, Just been looking at that section. On the new updated firmware within the transponder. There is no option to set the SIL=0 and SDA=0 The only option is to set the GPS Certification Level As I understand it, it should be set to D the low level....
I have just had my TT21 firmware updated and it is sitting on me desk until Sunday when it gets put back into the aircraft. I will go through the settings to see whats new.
Trig do the Upgrade for Free, just send it back to them. Posted to them and back in my office in 3 days. Support is excellent.
-
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
-
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.
-
Hi Lee,
Can you please add the following to suit Becker BXP 6401-2;
EIA-232C or EIA-422 interface with serial asynchronous transmission parameters: 4800, n,8,1 and TX data with NMEA-0183 protocol GGA and VTG sentences.
Many thanks
I can do this.
Thx
Lee
-
Just put together a Pilot Aware unit and am watching the inbounds to LGW as they overfly my home.Brilliant !
Would also like to connect to my Mode S Transponder when I get the PAW sorted for the aircraft.
Funkwerk TRT800H
from the manual .... NMEA-Format, data format RMC is
expected. 4800 Baud rate
Supported in version 20151030
Thx
Lee
-
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
-
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
-
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
-
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"
-
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
-
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
-
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.
-
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
-
Hi Pete
Just waiting to hear back from trig regarding required sentences
Currently generating
RMC
GGA
VTG
Thx
Lee
-
Thnx Lee
-
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...
-
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
-
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
-
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 :)
-
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!
-
Screen shot from this afternoon G-CIJO in hangar, other PAW in carpark
-
bnmont - did you connect from PAW the RS232 TX and RX to your TRT800 or just the RS232 TX. I was wondering what the Transponder does with both RS232 Tx & RX connection.
-
My experience is it works fine with TX and RX connected.
-
great - will connect both :o
-
Given the PAW will not be listening for RS232 from the transponder, I strongly suspect it doesn't matter either way.
I guess I wired it that way in case Lee ever decides to log messages coming out of it although I can't imagine why we would need to except curiosity!
-
IanF - I was wondering if its rather the Transponder interrogating the GPS on the TX feed (from trnspndr to PAW)...
I have connected mine up and set trnspndr settings on RS232 to NMEA messages, and then fired up A/C mounted PAWS and then a second PAWS in my car. SD showed both units but info displayed seems like it was PAW to PAW.
How can I check that the ADS-B data is being sent ?? as I could not get Flightradar24 to run properly (poor data network in hangar) and even so would it show with A/C in hangar on the ground?
-
Disconnect the ARF board in one or both of the units.
-
The TRT800 can be put into test mode IIRC it will or should display a P top left showing that it is getting a position fix from a gps, I think the P will only show when unit is out of standby mode.
Its in the manual somewhere.
-
Set the a/c PAW to another hex code, not the correct one for the a/c.
Assuming you have the transponder set up with the correct hex code and registration you'll see your reg on the 2nd unit or worst case the real a/c hex code from the transponder. If you see the temporary "wrong" hex code - that is over the P3i interface (ARF).
Really it's much simpler to run FlightRadar24 and see yourself on there with it NOT showing as "T-MLAT" (the vanilla Mode S system) instead showing something like "F-EGTK2"
-
How can I check that the ADS-B data is being sent ?? as I could not get Flightradar24 to run properly (poor data network in hangar) and even so would it show with A/C in hangar on the ground?
Bryan, you need my new CAA/NATS/FASVIG Verification mode :-)
Well until you get a copy of that, why not turn on the ADSB logging, it will be pretty noisy
but you just need to look for your ICAO code coming through as an ADSB message.
If you want a copy of the CAA/NATS/FASVIG Verification mode, send me a PM, I can do that for you
Thx
Lee
-
Set the a/c PAW to another hex code, not the correct one for the a/c.
Yep, thats clever!
If you want to check the values of
SIL,SDA, NACp, etc you will need the Verification mode, or fly into correct airspace and see if the settings are correct
Thx
Lee
-
Well until you get a copy of that, why not turn on the ADSB logging, it will be pretty noisy
but you just need to look for your ICAO code coming through as an ADSB message.
Doh! Yes, that is the other thing I did - forgot to mention that. Good point!
-
Bryan, you need my new CAA/NATS/FASVIG Verification mode :-)
Will that be in a later version of PAW software, Lee? I think it would be extremely useful, especially for those of us that are outside the NATS trial area.
-
Bryan, you need my new CAA/NATS/FASVIG Verification mode :-)
Will that be in a later version of PAW software, Lee? I think it would be extremely useful, especially for those of us that are outside the NATS trial area.
The exact intention of this, is for those outside the trial area.
The code is in an engineering build right now, and will flow into the release procedure
Thx
Lee
-
Great job Lee, thanks. I'm happy to wait unless it's going to be months before it gets into the release version. I still have to procure the new ES transponder (and attack piggy bank for same). It's a winter project.
-
The NATS ADS-B Trial is sort of over. NATS will be publishing their final report in a week or so. I saw a preview presentation from NATS yesterday at the CAA Conspicuity Working Group which was very positive.
( I also briefed the CWG on PAW - I took along all the hardware bits and pieces to show to them.)
My hope is that the PAW ADS-B Verification Mode can replace Test Flight/email exchange with NATS that is part of the LAA MOD 7 and MOD 14 approval procedure. I suggested the idea of what I called the PAW ADS-B Message Analyser to Lee ( http://forum.pilotaware.com/index.php/topic,213.0.html (http://forum.pilotaware.com/index.php/topic,213.0.html) ) as a permanent solution is needed because NATS R&D will not wish to be a permanent part of the LAA MOD procedure. Also, NATS cannot help where pilots are not able to fly into the NATS ADS-B ground receiver coverage area, which currently does not cover the entire UK ( http://fasvig.org/nats-uk-ads-b-3000ft-coverage-area (http://fasvig.org/nats-uk-ads-b-3000ft-coverage-area) ).
I have proposed to the LAA the idea of using this new PAW capability as the ADS-B verification element in their ADS-B Out MOD procedures. If it is accepted by the LAA I would also like to get the BMAA and BGA onboard for their members that use Mode S ES transponders.
Steve
-
Hi Steve,
You read my mind. It would be great if the verification process could be part of the LAA (in my case) system - perhaps a squiggle from the inspector to say that he's seen the appropriate settings via PAW or some such.
I assume, notwithstanding that the NATS trial is "sort of over" the intention is that we can all continue to use our non-certified but validated systems.
Good luck with your negotiations and thanks for all you are doing on our behalf.
-
The LAA MOD 14 procedure was originally created to support the NATS Southern England ADS-B trial.
However, LAA MOD 14 and also MOD 7 plus Technical Leaflet TL3.03 have now all been updated for permanent installations of ADS-B Out via Mode S ES transponders with an uncertified GPS position source.
-
I got this today so working OK with trt800 transponder
-
Thanks for posting Brian
For everybody elses benefit, this was an early eng build Brian was trying out, in the 20151114 release this appears on the web interface under traffic
Thx
Lee
-
FYI,
http://fasvig.org/trig-transponder-support-for-uncertified-gps-ads-b-out (http://fasvig.org/trig-transponder-support-for-uncertified-gps-ads-b-out)
-
Hi Steve and PA forum posters
Thanks for all the info in this thread.
I found today my Trig TT31 saw "GPS Input Activity" but no Position (Lat/Long) yep I'm running on old software V 2.1 (2009) and now sending unit to Trig for "free: upgrade to V3.4 or higher. Very helpful and efficient in the support dept..
Keep up all the good work and keep posting guys, as it really is a font of knowledge on here.
;)
Regards
Pete
-
Has anyone tried PilotAware with (or know the NMEA/RS232/SIL/SDA specs for) a Bendix King KT74 transponder ?
-
The KT74 is essentially a Trig TT31 in drag but questions remain regarding firmware levels, etc. I am seriously considering the KT74 for my steed and the question regarding SIL/SDA settings is with Harry Mendelssohn's right now. I'll post any response that I get here.
-
Cool - thanks. A friend has one so am interested on his behalf.
I like the number buttons for entering the codes rather than the knob and button approach.
-
I too far prefer the number buttons for squawk code entry, having been spoilt for it by my GTX328.
You could always get your friend to hook up a GPS and then use the latest version of PAW to see what the KT74 makes of it. If Mendelssohn's don't get an answer to the question soon (getting information out of BK is difficult) then I was going to suggest to their techy guy Dan that I take a trip up to Edinburgh with my PAW.
-
I've just received advice from Mendelssohn that the KT74 has TT31 version 3.4 firmware and that it therefore is compliant with the SIL=SDA=0 requirement. It's not clear whether this applies to all KT74s or just the current stock. I would still recommend a trial with PAW in attendance.
-
Thanks. Any idea if PAW sends the right NMEA messages for it ? I guess that might be one for Lee.
-
Thanks. Any idea if PAW sends the right NMEA messages for it ? I guess that might be one for Lee.
Output from the GPS/GLONOS USB Dongle;
$GPRMC,113156.00,A,5126.31393,N,00103.39777,W,0.182,,201115,,,A*6A
$GPVTG,,T,,M,0.182,N,0.337,K,A*2F
$GPGGA,113156.00,5126.31393,N,00103.39777,W,1,08,1.01,59.2,M,46.7,M,,*78
$GPGSA,A,3,01,03,28,23,08,14,17,19,,,,,1.64,1.01,1.30*09
$GPGSV,3,1,09,01,87,355,27,03,57,228,25,08,24,164,28,14,26,048,22*7E
$GPGSV,3,2,09,17,28,311,13,19,66,264,26,22,03,060,31,23,06,182,23*7A
$GPGSV,3,3,09,28,25,271,21*4A
$GPGLL,5126.31393,N,00103.39777,W,113156.00,A,A*7E
Not sure what Lee is passing on as I haven't sniffed that output yet.
-
The TT31 installation manual says:
The TT31 GPS input can recognise the following protocols:
- Industry standard “Aviation” protocol
- NMEA 0183 protocol ($GPRMC message)
- FreeFlight and NexNav GPS proprietary protocols
- Garmin proprietary ADS-B protocols
- Trig ADS-B protocol
I think the NMEA 0183 protocol should do it.
-
John, have a look at this thread:
http://forums.flyer.co.uk/viewtopic.php?f=1&t=97653 (http://forums.flyer.co.uk/viewtopic.php?f=1&t=97653)
Rob P has tried wiring up a KT74 and appears to have got nothing out. I don't know what firmware he has.
-
You might have a look at the Garrecht VT-2000 transponder, maybe a bit more expensive, but it is easy to use and mine accepted NMEA serial data from a Garmin GPS90. It fits in a KT76 rack and only needs a small solder bridge to connect the external GPS.
Simon
-
John, have a look at this thread
Thanks Paul. I'm there now. This trial with its unusual parameter requirements has certainly forced some issues to the surface!
-
This trial with its unusual parameter requirements has certainly forced some issues to the surface!
It certainly has. It would appear that the NEMA message set output from the GPS devices does include an indication of accuracy.
The NEMA GGA message in particular defines if the position fix is:
0 Fix not available or invalid
1 GPS SPS Mode, fix valid
2 Differential GPS, SPS Mode, fix valid
3 GPS PPS Mode, fix valid
I've analysed the outputs from a Garmin 196 and the GPS/GLONOS UBS device used on the PilotAware.
GPS/GLONASS USB Dongle
$GPGGA,113156.00,5126.31393,N,00103.39777,W,1,08,1.01,59.2,M,46.7,M,,*78
Garmin 196 WAAS not available
$GPGGA,120720,5126.3133,N,00103.4034,W,1,06,2.4,55.9,M,48.2,M,,*62
Garmin 196 WAAS available
$GPGGA,133754,5126.3067,N,00103.4207,W,2,07,1.1,51.6,M,48.2,M,,*6E
The humble Garmin 196 updates the output of the appropriate NEMA message to indicate increased accuracy when WAAS is available and used. The GPS/GLONASS USB Stick does not a the device description say is supports, note not uses, DGPS (WAAS).
In my opinion therefore the combination of Transponder and GPS Data source needs to be carefully thought through. For example;
On the Flyer Thread a SkyMap IIIC is DGPS Capable but in the manual indicates it requires a separate receiver as it is not built into the device. it was connected to a KT74 but was not providing the GPS data to allow ADS-B out.
If, and I don't know the inner workings of the device, the KT74 requires the appropriate flag in the NEMA GGA message to indicate DGPS then these two combinations are not going to function. That might change if the firmware in the KT754 is upgraded but again I have no knowledge of the inner workings of the KT74.
It would appear that the Garmin 196, and the AVMap V, have these built in so provide the GGA message to indicate increased accuracy from a DGPS (inbuilt WAAS) source.
From an earlier thread I believe that FASVIG posted something from Trig that indicated that the TT21 devices used the NEMA RMC message. This message only has a flag data valid or not valid but no indication of DGPS therefore more flexible in the GPS source.
As an aside I have just completed a standalone GPS project using off-the-shelf components which provides the NEMA message set on an RS232 out cable. It does require some soldering knowledge. Powered by 12volts it can drive up to two devices but is not DGPS (WAAS) enabled.
Hope this helps someone.
-
That's very interesting. Lee could always set the parameter on the output of the PAW rather than sending through what the GPS sends, but that would be cheating! :)
-
Indeed, very interesting analysis, Alan. Especially noteworthy is the distinction between being "WAAS capable" or "WAAS enabled" and actually setting the $GPGGA sentence correctly. That's a whole new Pandora's box of potential issues! This is a level of detail that we probably can't expect suppliers, even those as good as Mendelssohn to be able to fully resolve.
Is anyone dealing with Trig, Garmin et al to find out more about this? I am happy to have a go if no-one else is on the case.
-
There was a question regarding which sentences are sent from PilotAware to the Transponder
in fact if you want to 'sniff' the sentences , as somebody said, simply tick the 'trp' checkbox
on the config page of the web browser, and you will see everything that goes to the transponder
so I am sending (if available)
$GPRMC
$GPGGA
$GPVTG
There may need to be some configuration of these at some point, either by transponder type,
or a set of checkboxes to say which sentences you want passed to the transponder
Thx
Lee
-
I've just checked the PAW->transponder serial output and can confirm that PAW is outputting the three sentences exactly as Less says. The position fix field in the $GPGGA sentence is 1 for my UBlox7 GPS suggesting that it's not seeing EGNOS WAAS (or at least is not setting the field correctly). The GPS antenna is indoors at the moment so it might just be not seeing the necessary satellites. I'll extend the USB outdoors tomorrow to see if things change.
BTW, Lee, I don't see a "trp" check box in the config on my 20151114 PAW. I did it the hard way via a serial port into PuTTYtel!
-
BTW, Lee, I don't see a "trp" check box in the config on my 20151114 PAW. I did it the hard way via a serial port into PuTTYtel!
Doh ?!?
You are right, sorry, this is not in the released software yet, it will be in the next release.
Putty is another great way, I use it all the time.
Regarding position fix, you will get a better fix when you have a decent satellite view.
Also remember you can get the fix info from the web page, rather than decoding the sentences
http://192.168.1.1
Thx
Lee
-
EGNOS satellites are geostationary, so you need a clear view of the sky to the south, like with your Sky dish. Unless you're in the southern hemisphere of course.
-
Is anyone dealing with Trig, Garmin et al to find out more about this?
As you know, FASVIG is keen to encourage voluntary adoption of ADS-B, and we see support for uncertified GPS ADS-B Out as the most likely means of maximising adoption in GA.
So, I am hoping to do the following:
1) Encourage the CAA to more heavily support uncert GPS ADS-B and press others to do so to.
2) Make available info on which transponder makes/models/firmware version support uncert GPS ADS-B.
3) Persuade LAA and other associations to simplify MOD approval using new PAW Traffic Display feature.
4) Make available better info on exactly how (including precise data input reqs) to get uncert GPS ADS-B working.
5) Use the above to 'encourage' those manufacturers that do not support uncert GPS ADS-B to reconsider.
I am already doing 1) via the CAA Conspicuity Working Group.
On 2) I have info from Trig (already on www.fasvig.org (http://www.fasvig.org)) and a reply from Air Avionics (Garrecht) saying they will help. I am awaiting responses from Becker, Bendix King, Dittel and Funke. I did not email Garmin as I already know they are not interested in supporting uncert GPS ADS-B Out with their transponders. They declined invitations to assist in the NATS uncertified GPS trial so there seemed no point. If there are any other manufacturers you think I should contact please let me know.
On 3) I was at LAA Turweston yesterday and had further discussion with the CEO but unfortunately LAA Engineering staff were not available. They have my proposal. If I succeed with the LAA I will turn my attention to other associations.
I already knew there was a need for 4) but the KT74 discussion here and elsewhere reinforce this.
On 5) the more manufacturer support for uncertified GPS ADS-B that can be achieved, the greater the commercial pressure on non-supporting manufacturers to review their position. Activity on 1) helps too.
Any other suggestions on approach gratefully received.
Steve
-
The NEMA GGA message in particular defines if the position fix is:
0 Fix not available or invalid
1 GPS SPS Mode, fix valid
2 Differential GPS, SPS Mode, fix valid
3 GPS PPS Mode, fix valid
I've analysed the outputs from a Garmin 196 and the GPS/GLONOS UBS device used on the PilotAware.
GPS/GLONASS USB Dongle
$GPGGA,113156.00,5126.31393,N,00103.39777,W,1,08,1.01,59.2,M,46.7,M,,*78
I did some tests today with the GPS/GLONASS USB Dongle outside with a clear view of the southern sky and found that it does see EGNOS and it sets the DGPS flag accordingly:
$GPGGA,122133.00,5434.29993,N,00237.87591,W,2,09,1.10,210.7,M,49.1,M,,0000*46
The NMEA sentence above is a copy and paste of PAW's output to the transponder, so PAW is correctly sending the DGPS flag to the transponder.
It must be said though that I had to get the GPS well out into the clear before it picked up the EGNOS satellite. I'm not sure one could rely on it with the GPS/GLONASS USB Dongle on the coaming - unless you only fly ever south that is ;D
-
Any other suggestions on approach gratefully received.
It sounds like you're covering all the bases there Steve. I'm the Senior Air Traffic Engineer at Carlisle Airport and as such have various useful contacts in CAA SARG. Generally when I engage with them on GA issues they are very happy to put me in contact with the relevant key personnel. For example I've been doing quite a lot of work on the 8.33kHz saga. If you think this might provide you with another route in to CAA or if I can help with your workload then I am happy to assist.
-
It must be said though that I had to get the GPS well out into the clear before it picked up the EGNOS satellite. I'm not sure one could rely on it with the GPS/GLONASS USB Dongle on the coaming - unless you only fly ever south that is ;D
Given mine a better view of the sky and likewise now showing the same.
Location, Location, Location ;)
-
Thanks John,
Appreciate that. I want to think you did, but just in case.....
Did you do this: http://fasvig.org/volunteer (http://fasvig.org/volunteer)
Maybe you did already. If so, apologies.
We have 97 Champions now and I cannot remember all their names!
See here: http://fasvig.org/fasvip/poc/vee/vee-5 (http://fasvig.org/fasvip/poc/vee/vee-5)
This is the basis underpinning what I am doing. It is just me at the moment as the Champion project teams have not yet started up, but will be very soon. I could include you on this project team.
Regards,
Steve
-
P.s., AlanB, don't worry. I know you have volunteered to be a FASVIG Champion and you are already on my list for the ADS-B Project Team.
Steve
-
P.s., AlanB, don't worry. I know you have volunteered to be a FASVIG Champion and you are already on my list for the ADS-B Project Team.
Steve
:)
-
Steve: you have PM.