ADS-B question

[First_Principal]

As with a lot of these things it seems somewhat more difficult to get the information than it should be ... however, from CS-ACNS (issue 4):

The ADS-B Out system provides the following minimum set of data parameters:
(1) Aircraft Identification;
(2) Mode A Code;
(3) ICAO 24-bit aircraft address;
(4a) Airborne Horizontal Position — Latitude and Longitude;
(4b) Airborne Navigation Integrity Category: NIC;
(4c) Airborne/Surface Navigation Accuracy Category for Position: NACp;
(4d) Airborne/Surface Source Integrity Level: SIL;
(4e) Airborne/Surface System Design Assurance: SDA;
(5) Pressure Altitude (incl. NICbaro);
(6) Special Position Identification (SPI);
(7a) Emergency Status;
(7b) Emergency Indication;
(8) 1090 ES Version Number;
(9a) Airborne velocity over Ground — (East/West and North/South);
(9b) Airborne/Surface Navigation Accuracy Category for Velocity: NACv;
(10) Emitter Category;
(11) Vertical Rate;
(12a) Surface Horizontal Position — Latitude and Longitude;
(12b) Surface Navigation Integrity Category: NIC;
(13) Surface Ground Track;
(14) Movement (surface ground speed);
(15) Length/width of Aircraft;
(16) GPS Antenna Longitudinal Offset;
(17a) Geometric Altitude; and
(17b) Geometric Altitude Quality: GVA.

Where available in a suitable format, the ADS-B Out system provides the following data
parameters:
(1) Selected Altitude;
(2) Barometric Pressure Setting; an

Thus, I think 9(a) strictly answers your question? However along with some of the other transmitted information (+ historical data where needed) this should allow a receiver to derive (and display if required) the aircraft actual vector+velocity fairly simply.

That's the way I see it from the information I've read to date, but I say that from first principles - someone with experience in the field may be able to provide a more useful real-world answer.

FP.