IAS, VRate, Tail No. and Route in RB?

[Aeroscan]

Dear all,

1. Please, advise me why did AirNav team add IAS (Indicated Airspeed) column in the RB SW if RB is not able to decode this parameter for current moment and this column is always empty?

2. Smbdy can explain me how VRate comes out?

Do RB really decodes it from the ADS-B massage or this parameter is just calculated by RB software by the use of altitude changing (altitude that is received and decoded by RB) for period of time?
I have noticed that VRate is only shown for ADS-B equipped aircrafts and isn’t for non-ADS-B equipped aircrafts.
I also have noticed that the resolution for VRate parameter is 1 ft/minute in the RB SW.
But why the most ADS-B aircrafts very often have 000 VRate.
You clearly know and understand that in practice VRate that is calculated by the board Airdata computer cannot be always 0 ft/m even in the leveled flight.
It always jumps so if the resolution is 1 ft/minute why we do not see this minimum changes?

Thank you in advance

Vladimir
Aeroscan
 

[AirNav Support]

Hi Vladimir,

1.) Is being looked at for Version 2.10. Some aircraft were sending IAS and it was being displayed in RB (though rare occasions) However some customers suggested the IAS was being wrongly decoded.

2.) The VRate comes from the Extended squitter and is not derived. The resolution is 1ft per minute but I think the Vrate won't change and send us the data unless the change is more than 10ft per minute.

[DaveReid]

The VRate comes from the Extended squitter and is not derived. The resolution is 1ft per minute but I think the Vrate won't change and send us the data unless the change is more than 10ft per minute.

Hi Vladimir

VRate resolution is not 1 ft/min.  The airborne velocity Extended Squitter, which includes Vertical Rate, has a resolution of 32 ft/min (Subtype 0) or 64 ft/min (Subtypes 1 & 3).

EHS VRate (both baro and inertial) which RadarBox doesn't decode but third-party software can as we previously discussed, has a resolution of 32 fpm.

[Aeroscan]

Dear AirNav Support team,

So I guess when the v. 2.10 is released we’ll gona watch IAS again?
I hope so, because for our purposes IAS is much needed.
I didn’t notice that VRate is always odd numbers and they all are really divided by 64.
So Dave is right and I had time to make sure that he is an expert in such technical issues.

We are finishing a ground bench at our laboratory which will include aircraft Air Data Computer, ADS-B/EHS Transponder Garmin GTX 330, Garmin GPS 400W, Radar Box and Transponder/TCAS test bench where we will try to check all ES Transponder and RB features and nuances and to find the answers for all questions we have now before we get the dealership with AirNav and start the selling process in the Ukraine.
Potential customers will ask me not you how this product properly works ;-)
So we want to be ready to answer for all their questions.

[Aeroscan]

Dave,

F of All I’d to thank you.

I have some questions to you and AirNav Team:

1. As I correctly understand RB doesn’t have the resolution at all, it depends on the resolution that airborne transponder has, RB just decodes this parameter (ES velocity) and displays it, am I right?
So I should check my ADS-B/EHS Transponder Garmin GTX 330 what kind of resolution 32 ft/min (Subtype 0) or 64 ft/min (Subtypes 1 & 3) it has.

2. As I suppose aircraft Registration Number (TAIL NO.) in RB is got from the Database but not from the decoded Mode S discrete address (obtained from Mode S All Call DF11).

3. The same question I have about Flight Plan (ROUTE) that is shown for some flights, is it really got from one of ES BDS registers or not?
If yes, from which one BDS?

Tank you in advance

[AirNav Support]

1.) Correct
2.) The Mode-S is decoded from the and then the Registration is looked up from the database. The database has entries from Mode S codes to Registration.
3.) It is not in any registers. This is gained from the Flight ID and looking up in our database of routes.

[Aeroscan]

Roger that.
Thank you

[DaveReid]

The same question I have about Flight Plan (ROUTE) that is shown for some flights, is it really got from one of ES BDS registers or not?
If yes, from which one BDS?

Transponder register BDS2,0 contains the 8-byte Aircraft Identification field, formatted as per ICAO Annex 10, Volume IV, 3.1.2.9.  This should contain either the same value as in the corresponding flight plan or, if no flight plan exists, then the aircraft registration.

Where the flight plan ID is a flight number preceded by the operator's ICAO designator, then there is a chance that the route will be available from the database or, failing that, from one of the specialist lookup sites such as http://www.flightroutelookup.com/FlightRoute/

Obviously if the ID is the registration or a non-ICAO military callsign then there is no point in trying to do a lookup.

Aircraft Identification is sent in the 1090ES and the ELS Aircraft ID parameter.

HTH
Dave