AirNav Systems Forum
AirNav RadarBox and RadarBox24.com => AirNav RadarBox and RadarBox24.com Discussion => Topic started by: DaveReid on November 24, 2008, 03:19:42 PM
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I notice on the screenshots in the Forum that the Flights list has a column headed "Hdg".
Is this the aircraft heading decoded from the Mode S Heading and Speed Report, or is it the track derived from the ADS-B Airborne Velocity transmission ?
MTIA
Dave
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Development will know these details but I "think" it uses the track from the ADS-B details and the Mode-S details of heading if the aircraft does not have ADS-B.
Not a question we get often so that will need to be confirmed.
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Development will know these details but I "think" it uses the track from the ADS-B details and the Mode-S details of heading if the aircraft does not have ADS-B.
Not a question we get often so that will need to be confirmed.
Thanks - if that is confirmed by Development then it would represent an improvement over the "other" Mode S receiver, which only displays track for ADS-B aircraft and neither track nor heading for non-ADS-B.
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Unfourtenly its the same as the other Mode S receiver, however as some customers will see sometimes aircraft which don't have a globe icon in the list have heading information, this is usually due to the aircraft either just about to timeout or getting the first ADS-B packets.
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Unfourtenly its the same as the other Mode S receiver
But they call it track and you call it heading - which is it ?
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Dave, why all the "third degree" questions of late?
I had assumed that you were a RadarBox User and just wanted to get definitive answers, but I can't see why you are so determined to get AirNav to say something then take them to task for their answer?
Maybe just me being too sensitive?
Are you planning to get a RadarBox, or am I mistaken and you've already got one :-)
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It is the track, as its from the ADS-B data, we just call it heading as our normal customers will find that more helpful.
Checking our support logs we have one other person mention that and he wanted to use the data for professional reasons.
I am sure Dave is asking these questions under technical curiousty.
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Fair enough.
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Dave, why all the "third degree" questions of late?
I, for one, am delighted Mr Reid is asking these questions - it can only help in clarifying these areas of doubt, improve our technical understanding and hopefully help RadarBox in becoming an even better product. His wealth of experience with the SBS should be mined for all it's worth.
Sid
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It is the track, as its from the ADS-B data, we just call it heading as our normal customers will find that more helpful.
Thanks. I'm not sure I agree with the need to oversimplify things, but I guess that's your prerogative.
It's a shame, though, that neither Mode S receiver can decode the Mode S Heading and Speed Report - IAS would be very useful as that's what we hear ATC using.
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We do have IAS in the MyFlights table, however it seems only some AA appear to have IAS details. Don't have a pic of this at the moment, maybe someone can dig one out.
There may be others, rare but some appear with those details.
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We do have IAS in the MyFlights table, however it seems only some AA appear to have IAS details. Don't have a pic of this at the moment, maybe someone can dig one out.
There may be others, rare but some appear with those details.
Thanks. I assume you're referring to aircraft that transmit the Airborne Velocity Squitter Subtype 3 (Airspeed and Heading) instead of the much more common Subtype 1 (Velocity Over Ground).
I too would be interested if anyone can dig out a screenshot - looking through my logs it would appear that some (but not all) AFR and UAL B772s fall into this category, as do UAL B763s (although strictly speaking it's TAS rather than IAS that they all transmit).
Interestingly, those B772s also report magnetic heading in the same transmission, in the absence of track. SBS ignores this completely and presumably RadarBox does too if it's actually track being shown in your Hdg column.
If anyone is able to post a screenshot which features the above types/operators to help improve my understanding of what aircraft transmit what data, that would be much appreciated.
MTIA
Dave
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Dave, you really should get yourself a Radarbox, if only for research purposes!!!
I'll keep a lookout for anything showing an IAS. A couple of UAL B772's on the network at the moment. Interestingly, they don't show IAS, but neither do they show GS or Heading.
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I'll keep a lookout for anything showing an IAS. A couple of UAL B772's on the network at the moment. Interestingly, they don't show IAS, but neither do they show GS or Heading.
I've been running a packet capture for the last couple of hours and it's logged 20 aircraft transmitting airspeed, mostly B772s of UAL/COA/AFR/MSR, plus a solitary E-3, a B763 and a DLH A321. All the 777s transmit magnetic heading too but not, rather unsportingly, the AWACS :-)
RadarBox's ability, as per Support's post, to display this data would be a good justification for buying one, but a screenshot would be a nice confirmation.
Any offers?
MTIA
Dave
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Someone in the US should get plenty of them, I have feeling the IAS values are not sent across the network which leads them to showing blank on the network (something we hope to rectify in later versions)
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Someone in the US should get plenty of them
Or indeed any RB user in the southern UK - I've had 17 different UAL B772 flights so far today on SBS.
I take your point that it needs to be a user who gets them locally and not via the network - anyone using RB near Heathrow ?
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Approx 1614z two aircraft LX-N90443 and S2-ADK showing IAS
(http://www.polarorbiter.co.uk/Graphics/IAS.jpg)
Cheers,
Peter
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Thanks Peter, What have you picked up which is at 84,600ft?
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Must be that guy with the white beard and red coat, they were building his grotto in the shopping centre today.
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Thanks, guys - that's impressive, and also something that the SBS can't do.
I'm worried about that Bangladeshi, though - the A310's Vmo is 360kt, so the wings must have been in danger of falling off at 456kt IAS !!
Dave
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Thanks, guys - that's impressive, and also something that the SBS can't do.
I'm worried about that Bangladeshi, though - the A310's Vmo is 360kt, so the wings must have been in danger of falling off at 456kt IAS !!
Dave
I thought that the A310 series had a max cruise speed of around 0.85 mach, 485 kt at 35,000 ft!
Tom
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I thought that the A310 series had a max cruise speed of around 0.85 mach, 485 kt at 35,000 ft!
At 35,000ft 485kt TAS equates to approximately 285kt IAS.
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At 35,000ft 485kt TAS equates to approximately 285kt IAS.
You are of course correct. Senior moment on my part. :(
Tom
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You are of course correct. Senior moment on my part.
I know the feeling :-)
My original comment about the wings falling off was simply meant to illustrate that the column in the display labelled "IAS" isn't IAS at all, it's TAS which, as we know, is something completely different.
AirNav ?
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The Enhanced Mode S IAS is where we are getting the data from for that column but as the 86,000ft and various other anomalies we see in some of the Mode-S Enhanced or ADS-B data it all depends on the actual aircraft and whether its correctly setup.
However we have seen some American aircraft display values in the 250-280 but can't remember whether these were descending rather than at cruise level.
Unfortunately the aircraft giving this extra information are rare at the moment.
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The Enhanced Mode S IAS is where we are getting the data from for that column but as the 86,000ft and various other anomalies we see in some of the Mode-S Enhanced or ADS-B data it all depends on the actual aircraft and whether its correctly setup.
Are you correctly decoding Bit 25 in the Airspeed/Heading Squitter ?
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As far as I am as aware yes :)
I will pass on the query to the Development and Hardware just in case though.
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As far as I am as aware yes :)
I will pass on the query to the Development and Hardware just in case though.
Any resolution on this ?
Over the past few days I've captured nearly 140,000 Airspeed/Heading Squitters from 97 different aircraft and not one contained IAS, all were TAS, which begs the question of where you are finding aircraft that transmit IAS in the squitter?
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Hello Dave: can you tell us which Mode-s/ADS-B frame number contains that information?
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Hello Dave: can you tell us which Mode-s/ADS-B frame number contains that information?
DF17 (Extended Squitter) Format Type Code 19 (Airspeed and Heading) Subtype 3 (airspeed/subsonic aircraft). Bit 25 has values 0 (IAS) or 1 (TAS).
But surely you must know that already if you are currently displaying airspeed in RadarBox ?
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Hi Dave. Tks for the detailed info. We will investigate it now.
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Copied this one. We have identified the problem now and will be corrected for V2.10.
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Copied this one. We have identified the problem now and will be corrected for V2.10.
That's good to hear.
It would be a big plus for RadarBox if you could display the four values that can be transmitted by an ADS-B aircraft: groundspeed, track, TAS and heading. Most aircraft transmit only two out of the four, but all are equally useful and when present they are all be found in the DF17.
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All copied Dave. Tks a lot for the important info and we will add it for next version.
Do you have an idea of the % of aircraft transmitting those messages? I mean x % sending GS, % sending TAS, etc?
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As a matter of interest when is version V2.10 due for release?
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We are still collecting suggestions/problem reports and we plan to release it in later January.
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Thanks for the update
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Do you have an idea of the % of aircraft transmitting those messages? I mean x % sending GS, % sending TAS, etc?
Aircraft sending airspeed and heading are in the minority, but over the past few days I've picked up the following (from SE UK):
A30B DHL x 2
A30B MSR x 1
A310 BBC x 1
A319 BMA x 2
A319 DLH x 3
A319 PLK x 1
A320 AMC x 1
A320 BMA x 6
A320 EIN x 3
A321 AFR x 1
A321 BMA x 1
A321 DLH x 1
A321 EIN x 2
A321 MON x 1
A321 TCX x 1
B741 CKS x 1
B742 CKS x 6
B744 AFR x 1
B752 ETH x 1
B763 UAL x 8
B763 UPS x 1
B772 AAL x 10
B772 AFR x 13
B772 AIC x 2
B772 COA x 12
B772 MSR x 3
B772 UAE x 1
B772 UAL x 26
B77W AFR x 2
CRJ9 ANE x 1
DC10 OAE x 4
E3TF NATO x 1
F100 PGA x 1
RJ85 CFE x 1
RJ85 CLH x 2
Some of these were sending groundspeed and track as well as airspeed/heading, some airspeed/heading only and a few (e.g. the AWACS) airspeed only.
HTH
Dave
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We are still collecting suggestions/problem reports and we plan to release it in later January.
Airnav Development, is v2.10 still on schedule for release this month?
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Just answered on another topic.