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VDL2 Handoff procedure

Dick
 

Hello Patrick,

 


For those users that like to see the Handoff procedure that is used when an aircraft changes to another Ground Station it would be useful to change MultiPSK so that these type of messages are recognizable.
At this moment MultiPSK shows “XID (Exchange Identification)” for all of them.
Below are three Handoff messages the way dumpvdl2 shows them and the way MultiPSK shows them.


Just a suggestion :-) 

 

 

XID: Handoff Response

 

[2019-02-25 07:50:30 GMT] [136.975] [-40.2/-51.6 dBFS] [11.4 dB] [-0.9 ppm]

29D1D7 (Ground station, On ground) -> 47340E (Aircraft): Response

   82 80 00 14 01 09 38 38 38 35 3a 31 39 39 33 02 02 00 01 03 03 20 a4 88 f0 00 25 00 01 56 01 01 01 03 01 02 04 01 20 c1 04 45 47 53 53 c8 03 20 70 02 c4 06 53 49 54 00 00 01 c5 04 94 00 00 00

AVLC: type: U (XID) P/F: 1

XID: Handoff Response

Public params:

Parameter set ID: 8885:1993

Procedure classes: 00 01

HDLC options: 20 a4 88

VDL params:

Parameter set ID: V

Connection management: 01

XID sequencing: 02

AVLC specific options: 20

Airport coverage: EGSS

Ground station location: 51.9N 0.2E

ATN router NETs: 53 49 54 00 00 01          "SIT..."

System mask: 94 00 00 00

 

 

25/02/19 07:50:33 UTC

Destination address (hexa): 47340E (Aircraft)

Source address (hexa): 29D1D7 (Ground Station, delegated address , On the ground , response frame)

XID (Exchange Identification) frame F=1

Data (hexa): 828000140109383838353A3139393302020001030320A488F00025000156010101030102040120C10445475353C803207002C406534954000001C50494000000

Public parameters:HDLC public parameter: 8885:1993

Classes of procedures (hexa): 0001

HDLC functions (hexa): 20A488

Private parameter set identifier: V

Connection management parameter (hexa): 01

XID sequencing parameter (hexa): 02

AVLC specific options parameter (hexa): 20

Airports covered by the ground station: EGSS STANSTED AIRPORT (UNITED KINGDOM)

Ground station (+/- 3'): 51°54'N 000°12'E

ATN router nets:

  * ADM identifier (hexa): 534954   User field (hexa): 000001

Station operator mask (address) (hexa): 200000

 

 

XID: Handoff Request / Broadcast Handoff

 

[2019-02-25 07:50:38 GMT] [136.975] [-39.9/-50.8 dBFS] [10.9 dB] [-1.0 ppm]

29D1D7 (Ground station, On ground) -> 4BAA84 (Aircraft): Command

   82 80 00 14 01 09 38 38 38 35 3a 31 39 39 33 02 02 00 01 03 03 20 a4 88 f0 00 21 00 01 56 01 01 01 03 01 01 40 02 2e 5d 41 04 96 a0 6a a2 c4 06 53 49 54 00 00 01 c5 04 94 00 00 00

AVLC: type: U (XID) P/F: 0

XID: Handoff Request / Broadcast Handoff

Public params:

Parameter set ID: 8885:1993

Procedure classes: 00 01

HDLC options: 20 a4 88

VDL params:

Parameter set ID: V

Connection management: 01

XID sequencing: 01

Autotune frequency: 136.775 MHz (VDL-M2, D8PSK, 31500 bps)

Replacement ground stations: 216B45

 ATN router NETs: 53 49 54 00 00 01          "SIT..."

System mask: 94 00 00 00

 

25/02/19 07:50:42 UTC

Destination address (hexa): 4BAA84 (Aircraft)

Source address (hexa): 29D1D7 (Ground Station, delegated address , On the ground , command frame)

XID (Exchange Identification) frame F=0

Data (hexa): 828000140109383838353A3139393302020001030320A488F0002100015601010103010140022E5D410496A06AA2C406534954000001C50494000000

Public parameters:HDLC public parameter: 8885:1993

Classes of procedures (hexa): 0001

HDLC functions (hexa): 20A488

Private parameter set identifier: V

Connection management parameter (hexa): 01

XID sequencing parameter (hexa): 01

Aircraft frequency and modulation: 136.770 MHz in D8PSK Mode 2, 31500 bits/s

Replacement ground stations DLS address (hexa): 216B45

ATN router nets:

  * ADM identifier (hexa): 534954   User field (hexa): 000001

Station operator mask (address) (hexa): 200000

 

 

XID: Handoff Initiation

 

[2019-02-25 07:50:42 GMT] [136.975] [-37.0/-51.8 dBFS] [14.9 dB] [-1.7 ppm]

47947C (Aircraft, Airborne) -> 261EF7 (Ground station): Command

   82 80 00 14 01 09 38 38 38 35 3a 31 39 39 33 02 02 00 01 03 03 20 a4 88 f0 00 12 00 01 56 01 01 05 03 01 13 04 01 25 83 04 45 47 4b 4b

AVLC: type: U (XID) P/F: 1

XID: Handoff Initiation

Public params:

Parameter set ID: 8885:1993

Procedure classes: 00 01

HDLC options: 20 a4 88

VDL params:

Parameter set ID: V

Connection management: 05

XID sequencing: 13

AVLC specific options: 25

Destination airport: EGKK

 

 

25/02/19 07:50:46 UTC

Destination address (hexa): 261EF7 (Ground Station, delegated address)

Source address (hexa): 47947C (Aircraft , Aircraft airborne , command frame)

XID (Exchange Identification) frame F=1

Data (hexa): 828000140109383838353A3139393302020001030320A488F00012000156010105030113040125830445474B4B

Public parameters:HDLC public parameter: 8885:1993

Classes of procedures (hexa): 0001

HDLC functions (hexa): 20A488

Private parameter set identifier: V

Connection management parameter (hexa): 05

XID sequencing parameter (hexa): 13

AVLC specific options parameter (hexa): 25

Destination Airport identifier: EGKK LONDON/GATWICK A (UNITED KINGDOM)

 

 

Cheers,

Dick

 

Tomasz Lemiech
 



On Tue, Feb 26, 2019 at 7:07 PM Sergio Sarabia <sarabia.sergio@...> wrote:

XID sequencing parameter (hexa): 02 <-- Handoff Response


XID sequencing parameter (hexa): 01 <-- Handoff Request / Broadcast Handoff


XID sequencing parameter (hexa): 13 <-- Handoff Initiation


Nope. This is XID sequence number. It has nothing to do with the XID type.

--
Tomasz Lemiech

Patrick Lindecker
 

Hello,

 

The problem with the XID sequence number is that there is no indication on VDL2 specifications about the meaning to give to this number. It’s surely true this relation to handoff procedures, but I have not read it on any documents, so…

 

73
Patrick

 

De : multipsk@groups.io [mailto:multipsk@groups.io] De la part de Tomasz Lemiech
Envoyé : mardi 26 février 2019 21:11
À : multipsk@groups.io
Objet : Re: [multipsk] VDL2 Handoff procedure

 

 

 

On Tue, Feb 26, 2019 at 7:07 PM Sergio Sarabia <sarabia.sergio@...> wrote:

 

XID sequencing parameter (hexa): 02 <-- Handoff Response

 

XID sequencing parameter (hexa): 01 <-- Handoff Request / Broadcast Handoff

 

XID sequencing parameter (hexa): 13 <-- Handoff Initiation

 

Nope. This is XID sequence number. It has nothing to do with the XID type.

 

--

Tomasz Lemiech




Avast logo

L'absence de virus dans ce courrier électronique a été vérifiée par le logiciel antivirus Avast.
www.avast.com


Dick
 

On Tue, Feb 26, 2019 at 10:20 PM, Patrick Lindecker wrote:


I have not read it on any documents
Maybe Tomasz (author of dumpvdl2) can give you a hint or you can look in his code to see how he does determines the XID type..
But only if you feel it is an improvement for MultiPSK..

Cheers,
Dick

Sergio Sarabia
 

Hex XID with the same examples. SIT is SITA and XAA is ARINC, but in some GS they leave it blank:

Sergio Sarabia
 

Example beacon:

Patrick Lindecker
 

Hello Dick and Sergio,

Giving more meaning to the decoded information can be (and is) done by other programs using the decoding information.

Congratulations to Tomasz (author of dumpvdl2), as the VDL2 is not simple at all, especially the Reed Solomon part.

73
Patrick

-----Message d'origine-----
De : multipsk@groups.io [mailto:multipsk@groups.io] De la part de Dick
Envoyé : jeudi 28 février 2019 15:17
À : multipsk@groups.io
Objet : Re: [multipsk] VDL2 Handoff procedure

On Tue, Feb 26, 2019 at 10:20 PM, Patrick Lindecker wrote:


I have not read it on any documents
Maybe Tomasz (author of dumpvdl2) can give you a hint or you can look in his code to see how he does determines the XID type..
But only if you feel it is an improvement for MultiPSK..

Cheers,
Dick




---
L'absence de virus dans ce courrier électronique a été vérifiée par le logiciel antivirus Avast.
https://www.avast.com/antivirus

Dick
 

Hello Patrick,

It was just a suggestion, as it seems many VDL2 loggers are using MultiPSK (which is a great program, congratulations to Patrick ;-)
To use dumpvdl2 you need a (cheap) unix box like Raspberry Pi, which might be a too big change for windows users.

Thank you for considering it..

73, Dick