Just a thought..Hi Rob,
In PAW you already input your 24-bit ICAO code. So when PAW receives ADS-B, it will see its own ICAO code. Perhaps adding one or two lines to the web interface showing "This station: <flag A><flag B><flag C>", whichever flags need to be set correctly, and then making a screenshot to send to the LAA will allow you to self-certify?
Hi Steve,
I'm at a loss to know how to make the required setting for SIL and SDA. There is no mention in the installation and operation manual for the Becker BXP6401-2 transponder which we have in our EV97A.
I emailed Harry Mendlessohn technical dept. where we purchased it and they haven't been able to elicit any info from Becker. HM weren't aware any settings needed to be changed on these units.
Some different makes seem to apply these settings automatically, perhaps the same for Becker. Do you have any information on how to achieve these settings, or do you know of anyone who can help?
Sorry for misusing PAW forum in this way but didn't know how to contact you otherwise. Any reply you give might in any case, assist other PAW users.
B. The equipment is capable to operate with following certified GPS receivers:
- FreeFlight System GPS/WAAS 1201 Sensor, part number 84100-02-XXXX
- NexNav miniGNSS/ GPS-SBAS Sensor/ Receiver.
The equipment is capable to operate with following non-certified GPS receivers:
- Garmin GNS 430
- Garmin GNS 530
The equipment is also capable to operate with GPS receivers which provide
EIA-232C or EIA-422 interface with serial asynchronous transmission parameters:
4800, n, 8, 1 and transmit data with NMEA-0183 protocol GGA and VTG
sentences.
I'm Currently setting up with NATS for the ADS-B Trials..... I can only speak as a Trig User. The SIL=0 and SDA=0 Levels are, I think, the levels that the NATS flight recording sees the aircraft. Level 6 been the highest ( Certified Traffic & GPS)Hi Richard,
For Trigg you need the latest version update. Then set the transponder to "Uncertified GPS Source" There is no setting within the GPS Source to set the SIL=0 and SDA=0 levels this is within the Transponder. The GPS just supplies the relevant GPS info.
This Is how I understand it but if I'm incorrect I apologize and wait to be corrected.
Re: SIL/SDA/etc and ADS-B message specs, this is a useful reference (so long as you ignore the U.S. only info, e.g. regarding UAT):Reading this document, it appears that SDA is a hard-coded firmware value that the transponder manufacturer has to set. SIL is something that should be set at installation. A fully certified solution can have a SIL>0. Neither seem to be a function of the GPS data source.
http://www.faa.gov/documentLibrary/media/Advisory_Circular/AC%2020-165.pdf (http://www.faa.gov/documentLibrary/media/Advisory_Circular/AC%2020-165.pdf)
SIL = Source Integrity Level (basically SIL=0 means "Unknown")
SDA=System Design Assurance (again, 0 means "Unknown")
Thanks & Regards,
Steve
Neither seem to be a function of the GPS data source.Setting SIL is not a function 'performed' by the GPS device but it is a function 'of', as in 'should be dependent on' the GPS device.
SIL is based solely on the position source’s probability of exceeding the reported integrity value and should be set based on design data from the position source equipment manufacturer.It wouldn't generally be applicable to the type of a/c we are talking about, but AC 20-165 describes far more sophisticated scenarios such as dynamically selecting GPS data feeds from one of many installed GPS devices where the SIL setting might need to be dynamically changed based on the GPS data source selected at any given time.
I assume the LAA test wants to verify that simple installations with non-certified GPS sources do not confuse any transponders into transmitting bogus information. It would be kinda bad if a flawed ADS-B transmission inadvertantly projects you in the path of an airliner. Having SIL and SDA at zero will flag your information as unreliable or even 'to be ignored' for daily operations.Yes, correct, plus the installer ensuring the right settings are configured in the transponder's setup menu.
For PAW this probably means that sending $GPRMC strings over a serial port is the only thing that's required for this to work. It's up to the transponder firmware to handle things properly after that.
I'm Currently setting up with NATS for the ADS-B Trials..... I can only speak as a Trig User. The SIL=0 and SDA=0 Levels are, I think, the levels that the NATS flight recording sees the aircraft. Level 6 been the highest ( Certified Traffic & GPS)Hi Richard,
For Trigg you need the latest version update. Then set the transponder to "Uncertified GPS Source" There is no setting within the GPS Source to set the SIL=0 and SDA=0 levels this is within the Transponder. The GPS just supplies the relevant GPS info.
This Is how I understand it but if I'm incorrect I apologize and wait to be corrected.
I'm guessing you were the Richard who was bcc'd on the email I received from NATS last week related to Trig firmware. I'm just getting Trig to confirm the minimum software version required to support ADS-B Out with uncert GPS to avoid bad advice that would cause people to send in their transponders for unnecessary upgrade. It's taking Trig a little while to make the checks to make absolutely sure. And yes, with the correct firmware the Trig TT21/TT22/TT31 transponders will set the SIL/SDA/etc values correctly for uncertified GPS if fed with NMEA 0183 format GPS data.
Re: SIL/SDA/etc and ADS-B message specs, this is a useful reference (so long as you ignore the U.S. only info, e.g. regarding UAT):
http://www.faa.gov/documentLibrary/media/Advisory_Circular/AC%2020-165.pdf (http://www.faa.gov/documentLibrary/media/Advisory_Circular/AC%2020-165.pdf)
SIL = Source Integrity Level (basically SIL=0 means "Unknown")
SDA=System Design Assurance (again, 0 means "Unknown")
Thanks & Regards,
Steve
This ADSB lark, and the way the manufacturers have implemented it all seems to be a bit of a pig's breakfast, considering they happily sell their transponder's to the GA user.
I wonder which NMEA parameter the transponders are supposed to look at for determining the right values in a certified installation. PAW should then easily be able to send the right string.Rob,
I had a definitive reply from Becker Avionics today ( also relayed by HM dealership).
"Our ADSB solution in BXP6401;
The Surveillance Integrity Level is set to 0,
The System Design Assurance is set to 2 (it corresponds to Software and Hardware Design Assurance Level C).
Sorry, but those parameters are hard-coded and there is no possibility and not allowed to change them."
2.2.3.2.7.2.4.6 “System Design Assurance” OM Code Subfield in Aircraft Operational Status MessagesSo......
The System Design Assurance (SDA) subfield is a 2-bit (―ME‖ bits 31 – 32, Message bits 63 – 64) field that shall define the failure condition that the ADS-B system is designed to support as defined in Table 2.2.3.2.7.2.4.6.
The supported failure condition will indicate the probability of an ADS-B system fault causing false or misleading information to be transmitted. The definitions and probabilities associated with the supported failure effect are defined in AC 25.1309-1A, AC 23-1309-1C, and AC 29-2C. All relevant systems attributes should be considered including software and complex hardware in accordance with RTCA DO-178B (EUROCAE ED-12B) or RTCA DO-254 (EUROCAE ED-80).
The ADS-B system includes the ADS-B transmission equipment, ADS-B processing equipment, position source, and any other equipment that processes the position data transmitted by the ADS-B system.
Table 2.2.3.2.7.2.4.6: “System Design Assurance” OM Subfield in Aircraft Operational Status Messages
SDA Value Supported Failure
ConditionProbability of Undetected
Fault causing transmission
of False or Misleading
InformationSoftware & Hardware
Design Assurance Leveldecimal binary 0 00 Unknown/ No
safety effect> 1X10-3 per flight hour
or UnknownN/A 1 01 Minor ≤ 1X10-3 per flight hour D 2 10 Major ≤ 1X10-5 per flight hour C 3 11 Hazardous ≤ 1X10-7 per flight hour B
I'm trying to get to the bottom of all this as well, as I am looking into replacing my non ES transponder with a TT31/KT74 (same innards, different panel). Confusingly the TT31 manual talks about certification levels A to D, which is at variance with the nomenclature in your reference. So I am still not certain that I can set an SDA of zero in the Trig kit.For Trig devices, the latest firmware does allow the setting of 'good' values for pairing with uncertified GPS devices. Buying new would get you the latest firmware at time of purchase so ought to be fine.
Your contention made be true, though in your previous quote from the Becker Manual, they do define two certified GPS units that are designed to work with their transponder, so presumably the reliability of these units could have been taken into account in determining their SDA setting.Yes, it could be that Becker have taken the deliberate decision to hardcode their transponder firmware such that it only outputs the correct SDA value when it is paired with a position source appropriate to an SDA of 2. Not helpful for the currently required settings for use with an uncertified GPS.
Does an SDA of 2 imply that a TCAS system would take note and act on such transmissions?A very good question and one I decided yesterday I needed to chase up.
Hi Lee,
I have installed latest software 20151114 and see the "traffic" screen. Can you explain how the validation test should be done? I see CAT on the traffic screen but without the data analysis (SIL, SDA etc), as included in your screen-shot
Thanks Lee,
I think Brian's TRT-800 screen shot may have been the result of a test via the NATS verification process, judging from the text.
Regards,
Chris
I understand that CAT TCAS will ignore traffic broadcasting SIL=0/SDA=0. I don't know whether CAT TCAS will respond differently to SIL=0/SDA=2 traffic broadcasts.
BTW, for those wondering, Lee advised rows with DIST-KM of 999.000 are Mode C/S (non-ADS-B) broadcasts.Thanks for that! was looking at that today and wondering how I was capturing a/c at 999km!
Thanks Brian.
SIL/SDA looking good. 8)
BTW, for those wondering, like I did, Lee advised me the rows with DIST-KM of 999.000 are Mode C/S (non-ADS-B) broadcasts detected by PAW.
Steve
Just got this screen shot with the latest software.
Somhow did same attachment twice, cant work out how to remove!
Don't remove it! 'no fix, Mode C/S' maybe, with an option to email them an offer of a PilotAware :oDIST-KM of 999.000 are Mode C/S (non-ADS-B) broadcasts detected by PAWApologies, I will fix that, can be confusing
I do not have a handle on the precise reasoning for both SIL=0 and SDA=0 being requirements for uncert GPS ADS-B Out. I am trying to find out. I understand that CAT TCAS will ignore traffic broadcasting SIL=0/SDA=0. I don't know whether CAT TCAS will respond differently to SIL=0/SDA=2 traffic broadcasts.
This means the permissible SIL and SDA values for non-certified GPS sources prevent that data from being used on approved Cockpit Display of Traffic Information (CDTI) devices. I would not be surprised if you found this situation bizarre, particularly because EASA have approved the installation of PowerFLARM in AC23 type aircraft and PowerFLARM does not have a certified GPS source.
Wow... I wonder how many people who joined the NATS trial realised that the settings meant the transmission would not be used by anyone except Flight Radar 24... I'm out, and staying with a plain vanilla non ADSB transponder.
I have learned today from an authoritative source that ADS-B messages tagged as:
- Version 0 do not support/include SIL or SDA data.
- Version 1 do not support/include SDA data but do support/include SIL
- Version 2 does support/include SIL and SDA data, AND the definition of SIL was changed between Version 1 and Version 2.
Interesting - I don't see any SDA/SIL entries for our TRT800 transponder so I guess it's running "version 0". Does that equate to SIL=0 SDA=0 ?!!Ian,
BTW, for those wondering, Lee advised rows with DIST-KM of 999.000 are Mode C/S (non-ADS-B) broadcasts.Thanks for that! was looking at that today and wondering how I was capturing a/c at 999km!
Do we know whether they need full +/- 12v RS232 or whether it copes with +/- 5v TTL RS232.John,
John
Ours appears to be too old to upgrade - funny as it basically seems to work !!
Hi Ian,
After I received the document I phoned the chap up in Germany and quizzed him on the minimum version as it conflicted with advice others had been given that had been shared with me.Ours appears to be too old to upgrade - funny as it basically seems to work !!
If, by "basically seems to work", you mean it outputs SIL=0 and SDA=0 then that may well be true.
However..... I was advised by NATS that a couple of transponders in their uncertified GPS ADS-B trial output faulty GPS position coordinates (flipped minus sign on LAT or LONG). And the Funke chap on Friday said that there were bugs in the pre-v5.3 code to do with intermittent faulty GPS position. I put 2 and 2 together!!!
As I now understand it, Funke started providing support for ADS-B from v4.8 onwards but 100% correct support for uncertified GPS ADS-B is only from v5.3 or later.
Steve
Interesting. By "basically seemed to work" I mean no SIL/SDA but GPS coords look reasonable.That sounds very much like ADS-B Version 0 to me, Ian
Interesting. By "basically seemed to work" I mean no SIL/SDA but GPS coords look reasonable.That sounds very much like ADS-B Version 0 to me, Ian
Does it show Vers 0 in the PAW Traffic Display?
Cheers,
Steve
If anyone has a Becker BXP6401 transponder (I recall Welsh Flyer does), I complained to the company about them setting SDA=2 after they indicated they would NOT update the firmware, and the SDA setting also seemed at odds with the fact that SIL was set to zero. I let them know that they appeared to be out of step with other manufacturers in these matters.
I received a reply from their General Manager that they will update their ADS-B offerings to support this but we will have to wait until second quarter of 2016.
I'm trying to get to the bottom of all this as well, as I am looking into replacing my non ES transponder with a TT31/KT74 (same innards, different panel).
The way it is looking the solution may be to the unit as a Mode S and see what comes out if a non-certified GPS is connected (obviously with the collaboration of CAA/FASVIG etc), may be as an adjunct to the trial.
This whole thing is a farce. I wonder:
a) How many uncertified GPS + Mode S ES transponder combinations are out there which actually pass the requirements of the trial/LAA-mod and have successfully joined the trial/LAA mod, compared to combinations that do not.
b) How many a/c are flying around with combinations connected that do not pass the requirements because it 'appears to work'.
Perhaps the manufacturers will get their act together in the future, but it does feel like those of us that bought an early Mode S transponder because it had ES/ADS-B "capability" have been somewhat taken for a ride.
Just got this screen shot with the latest software.I'm just getting to use my PilotAware; could someone please tell me how to get a screenshot like that in the reference link?
Somhow did same attachment twice, cant work out how to remove!
(Admin, removed for you, btw, lots of traffic here!)
I'm just getting to use my PilotAware; could someone please tell me how to get a screenshot like that in the reference link?
Thanks Lee, but what "Traffic button"? I can only see Configure and Logging. Am I perhaps on a software that doesn't have this feature?
Should be fairly easy to cut the DB9 connector off and re-terminate it with a Molex connector.
Do you have access to a laptop with a true RS-232 interface? You could see if the laptop sees ADS-B out data out of PAW
Just be careful which RS232/USB you buy, and what your transponder requires.
RS232 or RS232-TTL
RS232 is +/- 12v (inverted logic)
RS232 is 0v/5v
They are totally incompatible
Thx
Lee
Software drivers cannot be loaded in into the PAw. What is needed is a standalone hardware solution, i.e usb to 232 protocol + level shifting.
John
Sorted now - see the other thread.
I was connected to port 3 instead of port 1. No wonder there was no data.
If anyone has a Becker BXP6401 transponder (I recall Welsh Flyer does), I complained to the company about them setting SDA=2 after they indicated they would NOT update the firmware, and the SDA setting also seemed at odds with the fact that SIL was set to zero. I let them know that they appeared to be out of step with other manufacturers in these matters.
I received a reply from their General Manager that they will update their ADS-B offerings to support this but we will have to wait until second quarter of 2016.
Hi does anyone know if Becker has updated the SDA code and if so how to resolve this for a BXP6401 already installed? Thanks
If anyone has a Becker BXP6401 transponder (I recall Welsh Flyer does), I complained to the company about them setting SDA=2 after they indicated they would NOT update the firmware, and the SDA setting also seemed at odds with the fact that SIL was set to zero. I let them know that they appeared to be out of step with other manufacturers in these matters.
I received a reply from their General Manager that they will update their ADS-B offerings to support this but we will have to wait until second quarter of 2016.
Hi does anyone know if Becker has updated the SDA code and if so how to resolve this for a BXP6401 already installed? Thanks